2021
Record 1 of 318 | |||||||||||||||||||||
Title: Scientific objectives and payloads of the lunar sample return mission-Chang'E-5 | |||||||||||||||||||||
Author(s): Zhou, CY (Zhou, Changyi); Jia, YZ (Jia, Yingzhuo); Liu, JZ (Liu, Jianzhong); Li, HJ (Li, Huijun); Fan, Y (Fan, Yu); Zhang, ZL (Zhang, Zhanlan); Liu, Y (Liu, Yang); Jiang, YY (Jiang, Yuanyuan); Zhou, B (Zhou, Bin); He, ZP (He, Zhiping); Yang, JF (Yang, Jianfeng); Hu, YF (Hu, Yongfu); Liu, ZH (Liu, Zhenghao); Qin, L (Qin, Lang); Lv, BH (Lv, Bohan); Fu, ZL (Fu, Zhongliang); Yan, J (Yan, Jun); Wang, C (Wang, Chi); Zou, YL (Zou, Yongliao) | |||||||||||||||||||||
Source: ADVANCES IN SPACE RESEARCH Volume: 69 Issue: 1 Pages: 823-836 DOI: 10.1016/j.asr.2021.09.001 Early Access Date: DEC 2021 Published: JAN 1 2022 | |||||||||||||||||||||
Abstract: In the early morning on December 17, 2020 Beijing time, China's chang'E-5 probe successfully returned to the Earth with 1731 g of lunar samples after completing drilling, shoveling, packaging of lunar soil and scientific exploration on lunar surface. It is the successful completion of the third phase of China's lunar exploration project, namely "circling, landing and returning to the moon". The scientific objectives of CE-5 mission are to carry out in situ investigation and analysis of the lunar landing region, laboratory research and analysis of lunar return samples. This paper analyzes scientific exploration tasks of CE-5 mission conducted on the lunar surface, and carries out the scientific payload system architecture design and individual scientific payload design with the scientific exploration task requirements as the target, and proposes the working mode and main technical index requirements of the scientific payloads. Based on the preliminary geological background study of the Mons Ruemker region which is the landing region of CE-5, the lunar scientific exploration and the laboratory physicochemical characterization of the return samples are of great scientific significance for our in-depth understanding of the formation and evolution of the Earth-Moon system and the chemical evolution history of the lunar surface. | |||||||||||||||||||||
Accession Number: WOS:000734907800009 | |||||||||||||||||||||
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ISSN: 0273-1177 | |||||||||||||||||||||
eISSN: 1879-1948 |
Record 2 of 318 |
Title: Direct Observation of Axial Dynamics of Particle Manipulation With Weber Self-Accelerating Beams |
Author(s): An, S (An, Sha); Peng, T (Peng, Tong); Yan, SH (Yan, Shaohui); Yao, BL (Yao, Baoli); Zhang, P (Zhang, Peng) |
Source: FRONTIERS IN PHYSICS Volume: 9 Article Number: 816844 DOI: 10.3389/fphy.2021.816844 Published: DEC 16 2021 |
Abstract: Optical manipulation of micro-particles with nondiffracting and self-accelerating beams has been successfully applied in many research fields such as chemicophysics, material sciences and biomedicine. Such operation mainly focuses on the particle transport and control in the beam propagation direction. However, the conventional optical microscopy is specifically designed for obtaining the sample information located in the lateral plane, which is perpendicular to the optical axis of the detecting objective lens, making the real-time observation of particle dynamics in axial plane a challenge. In this work, we propose and demonstrate a technique which integrates a special beam optical tweezer with a direct axial plane imaging system. Here, particles are transported in aqueous solution along a parabolic trajectory by a designed nonparaxial Weber self-accelerating beam, and the particle motion dynamics both in lateral and axial plane are monitored in real-time by the axial plane imaging technique. |
Accession Number: WOS:000738327900001 |
ISSN: 2296-424X |
Record 3 of 318 | |||||||||||||||||||||||||||
Title: Highly Versatile Broadband RF Photonic Fractional Hilbert Transformer Based on a Kerr Soliton Crystal Microcomb | |||||||||||||||||||||||||||
Author(s): Tan, MX (Tan, Mengxi); Xu, XY (Xu, Xingyuan); Boes, A (Boes, Andreas); Corcoran, B (Corcoran, Bill); Wu, JY (Wu, Jiayang); Nguyen, TG (Nguyen, Thach G.); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Lowery, AJ (Lowery, Arthur J.); Morandotti, R (Morandotti, Roberto); Mitchell, A (Mitchell, Arnan); Moss, DJ (Moss, David J.) | |||||||||||||||||||||||||||
Source: JOURNAL OF LIGHTWAVE TECHNOLOGY Volume: 39 Issue: 24 Pages: 7581-7587 DOI: 10.1109/JLT.2021.3101816 Published: DEC 15 2021 | |||||||||||||||||||||||||||
Abstract: We demonstrate an RF photonic fractional Hilbert transformer based on an integrated Kerr micro-comb source featuring a record low free spectral range of 48.9 GHz, yielding 75 microcomb lines across the C-band. By programming and shaping the comb lines according to calculated tap weights, we demonstrate that the Hilbert transformer can achieve tunable bandwidths ranging from 1.2 to 15.3 GHz, switchable centre frequencies from baseband to 9.5 GHz, and arbitrary fractional orders. We experimentally characterize the RF amplitude and phase response of the tunable bandpass and lowpass Hilbert transformers with 90 and 45-degree phase shift. The experimental results show good agreement with theory, confirming the effectiveness of our approach as a powerful way to implement the standard as well as fractional Hilbert transformers with broad and switchable processing bandwidths and centre frequencies, together with high reconfigurability and greatly reduced size and complexity. | |||||||||||||||||||||||||||
Accession Number: WOS:000728929200010 | |||||||||||||||||||||||||||
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ISSN: 0733-8724 | |||||||||||||||||||||||||||
eISSN: 1558-2213 |
Record 4 of 318 | ||||||||||||
Title: Enhanced Photoluminescence of Monolayer MoSe<sub>2</sub> in a Double Resonant Plasmonic Nanocavity with Fano Resonance and Mode Matching | ||||||||||||
Author(s): Li, CY (Li, Chenyang); Wang, QF (Wang, Qifa); Diao, H (Diao, Hang); Hao, Z (Hao, Zhen); Yu, WX (Yu, Weixing); Liu, KH (Liu, Kaihui); Gan, XT (Gan, Xuetao); Xiao, FJ (Xiao, Fajun); Zhao, JL (Zhao, Jianlin) | ||||||||||||
Source: LASER & PHOTONICS REVIEWS Volume: 16 Issue: 2 Article Number: 2100199 DOI: 10.1002/lpor.202100199 Early Access Date: DEC 2021 Published: FEB 2022 | ||||||||||||
Abstract: Two-dimensional transition metal dichalcogenides exhibit remarkable optical properties. However, their applications in electronics and photonics are severely limited by the intrinsically low absorption and emission rates. Here, the photoluminescence (PL) enhancement by integrating the monolayer MoSe2 into an Ag nanowire-on-mirror (NWoM) nanocavity is reported. From the dark-field scattering spectrum, a Fano resonance resulting from the coupling between discrete exciton state of MoSe2 and broad plasmon mode of nanocavity is observed. This Fano resonance, as a characteristic of intermediate plasmon-exciton coupling, shows remarkable ability to accelerate emission rate of MoSe2. Furthermore, the nanocavity with multiple resonances provides an excellent spatial mode overlap at excitation and emission wavelengths that affords the intriguing opportunity to resonantly enhance the absorption and PL quantum yield at the same location. The combination of Fano resonance and mode matching allows the attainment of over 1800-fold PL enhancement. These results provide a facile way to enhance the PL intensity of monolayer MoSe2 that may facilitate highly efficient optoelectronic devices. | ||||||||||||
Accession Number: WOS:000729431600001 | ||||||||||||
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ISSN: 1863-8880 | ||||||||||||
eISSN: 1863-8899 |
Record 5 of 318 | |||||||||
Title: Enhancement of UV laser-induced damage resistance of the fluoride-containing phosphate glasses by regulating the intrinsic defects | |||||||||
Author(s): Li, SW (Li, Shengwu); Wan, R (Wan, Rui); Ma, Y (Ma, Yuan); Wang, PF (Wang, Pengfei) | |||||||||
Source: JOURNAL OF THE AMERICAN CERAMIC SOCIETY Volume: 105 Issue: 4 Pages: 2546-2555 DOI: 10.1111/jace.18255 Early Access Date: DEC 2021 Published: APR 2022 | |||||||||
Abstract: Low fluorine content containing fluorophosphate glasses have promising potential as ultraviolet (UV) optics to be used in high-energy laser systems. Systematic studies on the iron-doped and iron-free fluoride-containing phosphate glasses that were prepared at high and low melting temperatures explore the underlying interrelationship among the glass preparation conditions, intrinsic defects in produced glasses, and the anti-laser-damage properties. For the iron-doped fundamental frequency (1 omega) absorptive glass, melting at high-temperature (1200 degrees C) can reduce the extrinsic "impurity" concentration of Fe3+ ions, resulting in tiny increase of optical bandgap (by 1.6%) but significant reduce of the absorption coefficient by 34% at 355 nm. However, only tiny increase of the laser-induced damage threshold (LIDT) was achieved. For the iron-free third harmonic frequency (3 omega) transparent glass, low-temperature (1000 degrees C) melting process significantly reduced the absorptive intrinsic defects content of PO3-EC, PO4-EC, and phosphorous oxygen-bonded hole center defects, which made the UV absorption edge blue-shifted by 50 nm and the optical bandgap increased by similar to 18%. The UV (355 nm) LIDT was significantly enhanced by similar to 27%. Much lower absorption coefficient and larger bandgap of the iron-free glass relative to the iron-doped one endow it with larger a LIDT. In short, optimizing the glass melting temperature is a feasible method to enhance the UV laser-induced damage resistance of the fluoride-containing phosphate glasses through controlling the content of the extrinsic or intrinsic defects in produced glasses. The general routine is to achieve both the lower UV absorptive defect concentration (i.e., lower UV absorption at 355 nm) and the lower non-bridged oxygen ratio (i.e., denser glass network), as well as a larger optical bandgap (i.e., reduced probability of avalanche ionization breakdown), which together contribute to the enhancement of the anti-laser-damage performance of the investigated fluoride-containing phosphate glasses. | |||||||||
Accession Number: WOS:000729273000001 | |||||||||
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ISSN: 0002-7820 | |||||||||
eISSN: 1551-2916 |
Record 6 of 318 | ||||||
Title: Spatial X-ray detection system based on simultaneous communication and radar | ||||||
Author(s): Ma, WH (Ma Weihong); Li, Y (Li Yao); Sheng, LZ (Sheng Lizhi); Su, T (Su Tong); Zhang, YJ (Zhang Yingjun); Liu, JN (Liu Jiani); Xia, FY (Xia Fangyuan); Tan, ZK (Tan Zhenkun); Zhang, FR (Zhang Furui); Chen, R (Chen Rui) | ||||||
Source: INTERNATIONAL JOURNAL OF MODERN PHYSICS B Volume: 35 Issue: 30 Article Number: 2150307 DOI: 10.1142/S0217979221503070 Published: DEC 10 2021 | ||||||
Abstract: An integrated scheme of X-ray communication and detection is proposed in this paper, which is used for the detection of the unknown target inside the coating while communication. In contrast to the X-ray communication methods reported previously, simultaneous communication and radar detection have two distinct features. One is that both communication and detection signals share the same X-ray source and channel, so the spatial resources can be effectively utilized. The other is that X-ray can penetrate the metal shielding structure and detect the internal materials effectively. In order to achieve the above goals, the propagation feasibility of an X-ray signal in space and space sparse plasma environment are first analyzed. Simulation and experiment results indicate that the X-ray carrier can realize transmission without attenuation in space environment. Then, an X-ray radar and communication demonstration system is built to verify the detection ability of coated materials. Experimental results show that when the characteristic spectrum value of the unknown target is much higher than that of the rest shell, the spatial X-ray radar system can achieve more accurate discrimination. Finally, a conclusion is reached, and some feasible detection suggestions are provided for this simultaneous detection and communication system. | ||||||
Accession Number: WOS:000724332900006 | ||||||
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ISSN: 0217-9792 | ||||||
eISSN: 1793-6578 |
Record 7 of 318 | ||||||
Title: Laser beam jitter control of the link in free space optical communication systems | ||||||
Author(s): Wang, X (Wang, Xuan); Su, XQ (Su, Xiuqin); Liu, GZ (Liu, Guizhong); Han, JF (Han, Junfeng); Wang, R (Wang, Rui); Wang, KD (Wang, Kaidi) | ||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 25 Pages: 41582-41599 DOI: 10.1364/OE.443411 Published: DEC 6 2021 | ||||||
Abstract: The pointing and tracking performance of laser beams in free space optical communication (FSOC) systems and other precision laser systems is severely limited by beam jitter. This research proposes an adaptive control method to suppress beam jitter by adjusting the deflection angle of the beam by controlling the fast steering mirror (FSM) driven by piezoelectric ceramics. In order to verify the effectiveness of the control method, we have established an experimental platform. First, the internal controller of the FSM is adjusted to an approximately linear system, aiming to turn the input and output control signals into a linear relationship. Based on the adaptive filter, a filtered-x variable step-size normalized least mean square (FxVSNLMS) algorithm is proposed. To further improve the robustness of the controller, a Proportion Integral Differential (PID) controller and an adaptive controller which work in parallel are then added to the control loop. Finally, experimental results are provided and compare with the traditional controller and other adaptive control methods. Experimental results show that for more complex narrow-band and broad-band mixed beam disturbances, the control scheme developed in this research is significantly improved. This conclusion has also been verified on the ground experimental platform of FSOC. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||
Accession Number: WOS:000726115900070 | ||||||
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ISSN: 1094-4087 |
Record 8 of 318 |
Title: Optimal superpixel selection for hyperspectral image classification of limited training samples |
Author(s): Wang, WN (Wang, Wenning); Liu, XB (Liu, Xuebin); Mou, XQ (Mou, Xuanqin) |
Source: INTERNATIONAL JOURNAL OF REMOTE SENSING Volume: 42 Issue: 23 Pages: 9059-9075 DOI: 10.1080/01431161.2021.1988184 Published: DEC 2 2021 |
Abstract: The hyperspectral image (HSI) classification method based on superpixel segmentation can solve the HSI classification problem of limited training samples. The proposed method improves the classification accuracy of each test sample by selecting the optimal superpixel for it and then extracting classification features. First, an HSI is segmented into superpixels with different scales. Subsequently, we propose an optimal superpixel evaluation method that selects the optimal superpixel for each sample in the HSI to extract classification feature. Lastly, the optimal superpixel is selected for each training sample to augment the training samples and improve the accuracy of the classifier. Experiments on two datasets indicate that the proposed method can effectively improve the classification accuracy of HSIs with limited training samples. |
Accession Number: WOS:000711679400001 |
ISSN: 0143-1161 |
eISSN: 1366-5901 |
Record 9 of 318 | |||||||||||||||
Title: Dual-wavelength in-line digital holography with untrained deep neural networks | |||||||||||||||
Author(s): Bai, C (Bai, Chen); Peng, T (Peng, Tong); Min, JW (Min, Junwei); Li, RZ (Li, Runze); Zhou, Y (Zhou, Yuan); Yao, BL (Yao, Baoli) | |||||||||||||||
Source: PHOTONICS RESEARCH Volume: 9 Issue: 12 Pages: 2501-2510 DOI: 10.1364/PRJ.441054 Published: DEC 1 2021 | |||||||||||||||
Abstract: Dual-wavelength in-line digital holography (DIDH) is one of the popular methods for quantitative phase imaging of objects with non-contact and high-accuracy features. Two technical challenges in the reconstruction of these objects include suppressing the amplified noise and the twin-image that respectively originate from the phase difference and the phase-conjugated wavefronts. In contrast to the conventional methods, the deep learning network has become a powerful tool for estimating phase information in DIDH with the assistance of noise suppressing or twin-image removing ability. However, most of the current deep learning-based methods rely on supervised learning and training instances, thereby resulting in weakness when it comes to applying this training to practical imaging settings. In this paper, a new DIDH network (DIDH-Net) is proposed, which encapsulates the prior image information and the physical imaging process in an untrained deep neural network. The DIDH-Net can effectively suppress the amplified noise and the twin-image of the DIDH simultaneously by automatically adjusting the weights of the network. The obtained results demonstrate that the proposed method with robust phase reconstruction is well suited to improve the imaging performance of DIDH. (C) 2021 Chinese Laser Press | |||||||||||||||
Accession Number: WOS:000724596800021 | |||||||||||||||
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ISSN: 2327-9125 |
Record 10 of 318 | |||||||||
Title: Improving physical parameters estimation in the single-beam multiple-intensity reconstruction | |||||||||
Author(s): Chen, XY (Chen, Xiaoyi); Duan, YX (Duan, Yaxuan); Da, ZS (Da, Zhengshang) | |||||||||
Source: JOURNAL OF OPTICS Volume: 23 Issue: 12 Article Number: 125601 DOI: 10.1088/2040-8986/ac2ea9 Published: DEC 2021 | |||||||||
Abstract: The iterative phase retrieval based on phase diversity technologies can solve the stagnation problem of Gerchberg-Saxton algorithm which performs Fourier transform to iterate back and forth between the object and spectral planes with known constraints. However, the application of phase diversity technologies in iterative phase retrieval methods will bring in multiple physical parameters such as distances or wavelengths. The measured accuracy of these physical parameters will ultimately affect the accuracy of the iterative phase retrieval methods. In this paper, a physical parameters estimation method which has the advantages of high global convergence and local convergence is proposed to improve the accuracy of iterative phase retrieval methods. Meanwhile, this method is introduced in the single-beam multiple-intensity reconstruction (SBMIR), termed PE-SBMIR, and its performance is verified by simulations and experiments. By simulating multiple sets of distance parameters with errors, the retrieved accuracy using PE-SBMIR can be improved by 2-4 orders of magnitude compared with SBMIR. Experimental results show that whether it is an amplitude-type object or phase-type object, the accuracy using PE-SBMIR is significantly higher than using SBMIR. The physical parameters estimation method proposed in this paper may be adopted in other iterative phase retrieval methods using phase diversity technologies. | |||||||||
Accession Number: WOS:000714212100001 | |||||||||
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ISSN: 2040-8978 | |||||||||
eISSN: 2040-8986 |
Record 11 of 318 | |||||||||
Title: Deep Category-Level and Regularized Hashing With Global Semantic Similarity Learning | |||||||||
Author(s): Chen, YX (Chen, Yaxiong); Lu, XQ (Lu, Xiaoqiang) | |||||||||
Source: IEEE TRANSACTIONS ON CYBERNETICS Volume: 51 Issue: 12 Pages: 6240-6252 DOI: 10.1109/TCYB.2020.2964993 Published: DEC 2021 | |||||||||
Abstract: The hashing technique has been extensively used in large-scale image retrieval applications due to its low storage and fast computing speed. Most existing deep hashing approaches cannot fully consider the global semantic similarity and category-level semantic information, which result in the insufficient utilization of the global semantic similarity for hash codes learning and the semantic information loss of hash codes. To tackle these issues, we propose a novel deep hashing approach with triplet labels, namely, deep category-level and regularized hashing (DCRH), to leverage the global semantic similarity of deep feature and category-level semantic information to enhance the semantic similarity of hash codes. There are four contributions in this article. First, we design a novel global semantic similarity constraint about the deep feature to make the anchor deep feature more similar to the positive deep feature than to the negative deep feature. Second, we leverage label information to enhance category-level semantics of hash codes for hash codes learning. Third, we develop a new triplet construction module to select good image triplets for effective hash functions learning. Finally, we propose a new triplet regularized loss (Reg-L) term, which can force binary-like codes to approximate binary codes and eventually minimize the information loss between binary-like codes and binary codes. Extensive experimental results in three image retrieval benchmark datasets show that the proposed DCRH approach achieves superior performance over other state-of-the-art hashing approaches. | |||||||||
Accession Number: WOS:000733232400054 | |||||||||
PubMed ID: 32112686 | |||||||||
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ISSN: 2168-2267 | |||||||||
eISSN: 2168-2275 |
Record 12 of 318 | ||||||||||||
Title: Multisource Remote Sensing Data Classification With Graph Fusion Network | ||||||||||||
Author(s): Du, XQ (Du, Xingqian); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang); Doudkin, AA (Doudkin, Alexander A.) | ||||||||||||
Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Volume: 59 Issue: 12 Pages: 10062-10072 DOI: 10.1109/TGRS.2020.3047130 Published: DEC 2021 | ||||||||||||
Abstract: The land cover classification has been an important task in remote sensing. With the development of various sensors technologies, carrying out classification work with multisource remote sensing (MSRS) data has shown an advantage over using a single type of data. Hyperspectral images (HSIs) are able to represent the spectral properties of land cover, which is quite common for land cover understanding. Light detection and ranging (LiDAR) images contain altitude information of the ground, which is greatly helpful with urban scene analysis. Current HSI and LiDAR fusion methods perform feature extraction and feature fusion separately, which cannot well exploit the correlation of data sources. In order to make full use of the correlation of multisource data, an unsupervised feature extraction-fusion network for HSI and LiDAR, which utilizes feature fusion to guide the feature extraction procedure, is proposed in this article. More specifically, the network takes multisource data as input and directly output the unified fused feature. A multimodal graph is constructed for feature fusion, and graph-based loss functions including Laplacian loss and t-distributed stochastic neighbor embedding (t-SNE) loss are utilized to constrain the feature extraction network. Experimental results on several data sets demonstrate the proposed network can achieve more excellent classification performance than some state-of-the-art methods. | ||||||||||||
Accession Number: WOS:000722170500024 | ||||||||||||
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ISSN: 0196-2892 | ||||||||||||
eISSN: 1558-0644 |
Record 13 of 318 | ||||||||||||
Title: Selective Etching of Sr-Modified and Directionally Solidified Industrial Al-Si Eutectic Alloys for Fabricating Fibrous Eutectic Si | ||||||||||||
Author(s): Gao, JJ (Gao, Jianjun); Gu, W (Gu, Wei); Zhang, FF (Zhang, Fenfei); Geng, HB (Geng, Haibin); Zhong, JH (Zhong, Jianhua); Yao, LG (Yao, Ligang); Zhao, ZL (Zhao, Zhilong); Wang, JN (Wang, Junning) | ||||||||||||
Source: METALS Volume: 11 Issue: 12 Article Number: 1974 DOI: 10.3390/met11121974 Published: DEC 2021 | ||||||||||||
Abstract: In order to fabricate fibrous eutectic Si, the selective etching of industrial Al-Si eutectic alloys directionally solidified at different growth rates and modified by different amounts of Sr was studied. Flake eutectic and fibrous Si were obtained by selective etching of non-modified, Sr-modified or directionally solidified Al-Si eutectic alloys. The optimal amount of Sr for fabricating branching eutectic Si was 0.04-0.07%. Through directional solidification with a high enough growth rate (more than 200 mu m/s), lamellar eutectic Si transforms to fibrous eutectic Si for use in non-modified Al-Si eutectic alloys. The potentiodynamic polarization and cyclic voltammetry methods were used to test the corrosion behavior of non-modified and Sr-modified Al-Si eutectic alloys. With a constant potential of 0.5 V in HCl solution, non-modified Al-Si eutectic alloys displayed initial pitting corrosion and subsequent spalling corrosion, and 0.04% Sr-modified samples displayed uniform pitting corrosion. Compared with non-modified Al-Si eutectic alloys, Sr-modified samples displayed better corrosion resistance with lower current density and shallower pit depth during the same etching conditions. | ||||||||||||
Accession Number: WOS:000736320400001 | ||||||||||||
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eISSN: 2075-4701 |
Record 14 of 318 | ||||||
Title: High-throughput fast full-color digital pathology based on Fourier ptychographic microscopy via color transfer (vol 64, 114211, 2021) | ||||||
Author(s): Gao, YT (Gao, Yuting); Chen, JR (Chen, Jiurun); Wang, AY (Wang, Aiye); Pan, A (Pan, An); Ma, CW (Ma, Caiwen); Yao, BL (Yao, Baoli) | ||||||
Source: SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY Volume: 64 Issue: 12 Article Number: 124251 DOI: 10.1007/s11433-021-1762-8 Published: DEC 2021 | ||||||
Accession Number: WOS:000714035800001 | ||||||
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ISSN: 1674-7348 | ||||||
eISSN: 1869-1927 |
Record 15 of 318 |
Title: Cross-Domain Scene Classification by Integrating Multiple Incomplete Sources |
Author(s): Gong, TF (Gong, Tengfei); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang) |
Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Volume: 59 Issue: 12 Pages: 10035-10046 DOI: 10.1109/TGRS.2020.3034344 Published: DEC 2021 |
Abstract: Cross-domain scene classification identifies scene categories by learning knowledge from a labeled data set (source domain) to an unlabeled data set (target domain), where the source data and the target data are sampled from different distributions. A lot of domain adaptation methods are used to reduce the distribution shift across domains, and most existing methods assume that the source domain shares the same categories with the target domain. It is usually hard to find a source domain that covers all categories in the target domain. Some works exploit multiple incomplete source domains to cover the target domain. However, in such setting, the categories of each source domain are a subset of the target-domain categories, and the target domain contains "unknown" categories for each source domain. The existence of unknown categories results in the conventional domain adaptation unsuitable. Known and unknown categories should be treated separately. Therefore, a separation mechanism is proposed to separate the known and unknown categories in this article. First, multiple-source classifiers trained on the multiple source domains are used to coarsely separate the known/unknown categories in the target domain. The target images with high similarities to source images are selected as known categories, and the target images with low similarities are selected as unknown categories. Then, a binary classifier trained using the selected images is used to finely separate all target-domain images. Finally, only the known categories are implemented in the cross-domain alignment and classification. The target images get labels by integrating the hypotheses of multiple-source classifiers on the known categories. Experiments are conducted on three cross-domain data sets to demonstrate the effectiveness of the proposed method. |
Accession Number: WOS:000722170500022 |
ISSN: 0196-2892 |
eISSN: 1558-0644 |
Record 16 of 318 | ||||||
Title: Numerical Simulation Study on Gain Nonlinearity of Microchannel Plate in Photomultiplier Tube | ||||||
Author(s): Guo, LH (Guo, Lehui); Chen, P (Chen, Ping); Li, LL (Li, Lili); Gou, YS (Gou, Yongsheng); Liu, HL (Liu, Hulin); Liu, ZY (Liu, Ziyu); Xin, LW (Xin, Liwei); Tian, JS (Tian, Jinshou) | ||||||
Source: IEEE TRANSACTIONS ON NUCLEAR SCIENCE Volume: 68 Issue: 12 Pages: 2711-2716 DOI: 10.1109/TNS.2021.3121583 Published: DEC 2021 | ||||||
Abstract: Microchannel plate-photomultiplier tubes (MCP-PMTs) with high dynamic ranges and strong outputs are still challenges for the future inertial confinement fusion (ICF) studies, aiming at detecting the large-scale intensities of the radiation pulses. In this article, to investigate the influence factors of the gain nonlinearity causing high-linearity limits of the MCP-PMTs, 3-D microchannel plate (MCP) channel models were built in computer simulation technology (CST) Particle Studio. The Monte Carlo and particle-in-cell methods were carried out to simulate the electron cascade processes in the channels of the MCPs. The dependences of MCP gain nonlinearity on the number of incident electrons, operating voltage, and secondary electron emission (SEE) yield properties were studied. The gains obtained by the simulations for the conventional one-stage and two-stage MCPs are in good agreement with the available experimental data, which verifies the reliabilities of the 3-D MCP models. The simulation results show that the gain of the MCP single channel decreases as the number of incident electrons increases due to the space charge effects. The higher the operating voltage and SEE yield of the MCP, the faster the gain deteriorates. To mitigate the gain saturation effect of MCP single channels, a novel structural design of MCP-PMTs has been proposed by adjusting the design of the MCP chevron pair. A significant improvement in the output pulse peak can be obtained. | ||||||
Accession Number: WOS:000731147000007 | ||||||
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ISSN: 0018-9499 | ||||||
eISSN: 1558-1578 |
Record 17 of 318 | ||||||||||||
Title: Nonlinear Full-Spectrum Quantitative Analysis Algorithm of Complex Water Based on IERT | ||||||||||||
Author(s): Liu, JC (Liu Jia-cheng); Hu, BL (Hu Bing-liang); Yu, T (Yu Tao); Wang, XJ (Wang Xue-ji); Du, J (Du Jian); Liu, H (Liu Hong); Liu, X (Liu Xiao); Huang, QX (Huang Qi-xing) | ||||||||||||
Source: SPECTROSCOPY AND SPECTRAL ANALYSIS Volume: 41 Issue: 12 Pages: 3922-3930 DOI: 10.3964/j.issn.1000-0593(2021)12-3922-09 Published: DEC 2021 | ||||||||||||
Abstract: Water is a finite resource, essential for agriculture, industry and even human existence. A good water environment is an important guarantee for sustainable development. The scientific monitoring of water quality information is the basis for optimal allocation and efficient use of water resources. The United Nations Environment Program (UNEP) and the World Health Organization (WHO) pointed out that national water quality monitoring networks in developing countries should be strengthened, including improving analytical capabilities and data quality assurance. As an emerging water quality analysis method, spectral method has the characteristics of "fast response, synchronization of multiple parameters, environmental protection and pollution-free" compared with traditional chemical water quality monitoring methods. The traditional single-band, multi-band linear model, relies on the absorption characteristics of water at specific bands, and it cannot be used for multi-component mixed solutions and has poor universality. Therefore, this paper proposes a non-linear full-spectrum quantitative analysis algorithm based on IERT. The concentration prediction model suitable for multi-component mixed solution is established to use full spectrum information to predict concentration information. We use the COD, BOD5, TOC multi-component mixed solution and NO3-N, turbidity, chroma multi-component mixed solution configured in the laboratory as the experimental sample, use the spectrometer to collect the spectral curve of the sample, and conduct the concentration prediction experiment through the full spectrum data. The experimental results show that for COD, BOD5, TOC multi-component mixed solutions, the determination coefficients (R-2) of this algorithm for the three components are 0. 999 3, 0. 991 4 and 0. 999 3. The root means square error (RMSE) is 0. 024 4, 0. 057 7 and 0. 000 4. For the multi-component mixed solution of NO3-N, turbidity, and colority, the coefficient of determination (R-2) is 0.983 4, 0.868 4 and 0.981 0. The root means square error (RMSE) is 0. 100 5, 0.326 4 and 0. 120 2. By comparing the experimental results of this algorithm with partial least squares (PLS), support vector regression (SVR), decision tree (DT), and extreme random tree (ERT) for the same set of data, the results show that in the experiment of mixed solution, this algorithm is the best alternative to the coefficient of determination (R-2) of each component. The root means square error (RMSE) has been greatly reduced compared with other comparison algorithms. This algorithm can use spectral information to analyze the multi-component mixed solution quantitatively. It can effectively improve the concentration prediction accuracy and reduce the root-mean-square error of the quantitative analysis in the case of equivalent calculation time. Moreover, this algorithm can provide a theoretical basis for spectral methods on water quality monitoring. | ||||||||||||
Accession Number: WOS:000747245000044 | ||||||||||||
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ISSN: 1000-0593 |
Record 18 of 318 | |||||||||||||||||||||
Title: Frequency Comb Distillation for Optical Superchannel Transmission | |||||||||||||||||||||
Author(s): Prayoonyong, C (Prayoonyong, Chawaphon); Boes, A (Boes, Andreas); Xu, XY (Xu, Xingyuan); Tan, MX (Tan, Mengxi); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Morandotti, R (Morandotti, Roberto); Mitchell, A (Mitchell, Arnan); Moss, DJ (Moss, David J.); Corcoran, B (Corcoran, Bill) | |||||||||||||||||||||
Source: JOURNAL OF LIGHTWAVE TECHNOLOGY Volume: 39 Issue: 23 Pages: 7383-7392 DOI: 10.1109/JLT.2021.3116614 Published: DEC 1 2021 | |||||||||||||||||||||
Abstract: Optical frequency combs can potentially provide an efficient light source for multi-terabit-per-second optical superchannels. However, as the bandwidth of these multi-wavelength light sources is increased, it can result in low per-line power. Optical amplifiers can be used to overcome power limitations, but the accompanying spontaneous optical noise can degrade performance in optical systems. To overcome this, we demonstrate wideband noise reduction for comb lines using a high-Q microring resonator whose resonances align with the comb lines, providing tight optical filtering of multiple combs lines at the same time. By distilling an optical frequency comb in this way, we are able to reduce the required comb line OSNR when these lines are used in a coherent optical communications system. Through performance tests on a 19.45-GHz-spaced comb generating 71 lines, using 18 Gbaud, 64-QAM sub-channels at a spectral efficiency of 10.6 b/s/Hz, we find that noise-corrupted comb lines can reduce the optical signal-to-noise ratio required for the comb by similar to 9 dB when used as optical carriers at the transmitter side, and by similar to 12 dB when used as a local oscillator at the receiver side. This demonstration provides a method to enable low power optical frequency combs to be able to support high bandwidth and high-capacity communications. | |||||||||||||||||||||
Accession Number: WOS:000722717700004 | |||||||||||||||||||||
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ISSN: 0733-8724 | |||||||||||||||||||||
eISSN: 1558-2213 |
Record 19 of 318 | ||||||
Title: Polarization-Independent Large Third-Order-Nonlinearity of Orthogonal Nanoantennas Coupled to an Epsilon-Near-Zero Material | ||||||
Author(s): Shi, WJ (Shi, Wenjuan); Liu, HJ (Liu, Hongjun); Wang, ZL (Wang, Zhaolu) | ||||||
Source: NANOMATERIALS Volume: 11 Issue: 12 Article Number: 3424 DOI: 10.3390/nano11123424 Published: DEC 2021 | ||||||
Abstract: The nonlinear optical response of common materials is limited by bandwidth and energy consumption, which impedes practical application in all-optical signal processing, light detection, harmonic generation, etc. Additionally, the nonlinear performance is typically sensitive to polarization. To circumvent this constraint, we propose that orthogonal nanoantennas coupled to Al-doped zinc oxide (AZO) epsilon-near-zero (ENZ) material show a broadband (~1000 nm bandwidth) large optical nonlinearity simultaneously for two orthogonal polarization states. The absolute maximum value of the nonlinear refractive index n(2) is 7.65 cm(2)center dot GW(-)(1), which is 4 orders of magnitude larger than that of the bare AZO film and 7 orders of magnitude larger than that of silica. The coupled structure not only realizes polarization independence and strong nonlinearity, but also allows the sign of the nonlinear response to be flexibly tailored. It provides a promising platform for the realization of ultracompact, low-power, and highly nonlinear all-optical devices on the nanoscale. | ||||||
Accession Number: WOS:000736289600001 | ||||||
PubMed ID: 34947773 | ||||||
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eISSN: 2079-4991 |
Record 20 of 318 | |||||||||||||||||||||||||||
Title: Integral order photonic RF signal processors based on a soliton crystal micro-comb source | |||||||||||||||||||||||||||
Author(s): Tan, MX (Tan, Mengxi); Xu, XY (Xu, Xingyuan); Wu, JY (Wu, Jiayang); Corcoran, B (Corcoran, Bill); Boes, A (Boes, Andreas); Nguyen, TG (Nguyen, Thach G.); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Morandotti, R (Morandotti, Roberto); Mitchell, A (Mitchell, Arnan); Moss, DJ (Moss, David J.) | |||||||||||||||||||||||||||
Source: JOURNAL OF OPTICS Volume: 23 Issue: 12 Article Number: 125701 DOI: 10.1088/2040-8986/ac2eab Published: DEC 2021 | |||||||||||||||||||||||||||
Abstract: Soliton crystal micro-combs are powerful tools as sources of multiple wavelength channels for radio frequency (RF) signal processing. They offer a compact device footprint, a large number of wavelengths, very high versatility, and wide Nyquist bandwidths. Here, we demonstrate integral order RF signal processing functions based on a soliton crystal micro-comb, including a Hilbert transformer and first, second and third-order differentiators. We compare and contrast the results and the trade-offs involved with varying the comb spacing, and tap design and shaping methods. | |||||||||||||||||||||||||||
Accession Number: WOS:000714247200001 | |||||||||||||||||||||||||||
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ISSN: 2040-8978 | |||||||||||||||||||||||||||
eISSN: 2040-8986 |
Record 21 of 318 | |||||||||
Title: A New Design of Large-format Streak Tube with Single-lens Focusing System | |||||||||
Author(s): Tian, LP (Tian, Liping); Shen, LB (Shen, Lingbin); Chen, L (Chen, Lin); Li, LL (Li, Lili); Tian, JS (Tian, Jinshou); Chen, P (Chen, Ping); Zhao, W (Zhao, Wei) | |||||||||
Source: MEASUREMENT SCIENCE REVIEW Volume: 21 Issue: 6 Pages: 191-196 DOI: 10.2478/msr-2021-0026 Published: DEC 2021 | |||||||||
Abstract: Streak tubes with large-format and high spatial resolution are central to mm-spatial-resolved STIL detection system and hyperspectral resolved ICF experiment. In this paper, we established a large-format streak tube with a three-coaxial-cylindrical single-lens focusing system, a spherically curved photocathode and phosphor screen model in CST Particle Studio. The temporal and spatial resolution were calculated and mimicked based on the Monte-Carlo sampling method in static and dynamic mode. The simulated results show that the static spatial resolution reaches 50 lp/mm over the whole 50 mm effective photocathode length, and the physical temporal resolution is better than 45 ps. Furthermore, in dynamic working mode, the streak tube can achieve spatial resolution of 10 lp/mm and temporal resolution of 60 ps. The simulation results will be used to guide the design and production for large-format with high spatial resolution streak tube development. | |||||||||
Accession Number: WOS:000712538800005 | |||||||||
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ISSN: 1335-8871 |
Record 22 of 318 | ||||||
Title: Sliding Mode Robust Active Disturbance Rejection Control for Single-Link Flexible Arm with Large Payload Variations | ||||||
Author(s): Wang, F (Wang, Fan); Liu, P (Liu, Peng); Jing, F (Jing, Feng); Liu, B (Liu, Bo); Peng, W (Peng, Wei); Guo, M (Guo, Min); Xie, ML (Xie, Meilin) | ||||||
Source: ELECTRONICS Volume: 10 Issue: 23 Article Number: 2995 DOI: 10.3390/electronics10232995 Published: DEC 2021 | ||||||
Abstract: This paper proposes a novel robust control scheme for tip trajectory tracking of a lightweight flexible single-link arm. The developed control scheme deals with the influence of tip payload changes and disturbances during the working process of the flexible arm, thus realizing the accurate tracking for the tip reference trajectory. The robust control scheme is composed of an inner loop and an outer loop. The inner loop adopts the traditional PD control, and an active disturbance rejection control (ADRC) with a sliding mode (SM) compensation is designed in the outer loop. Moreover, the sliding mode compensation is mainly used to cope with the disturbance estimation error from the extended state observer (ESO), by which the insensitivity to tip payload variations and strong disturbance resistance is achieved. Finally, some numerical simulations are performed to support the theoretical analysis. The results show that the system is more robust to the tip mass variations of the arm and more resistant to the external torque after adding the sliding mode robustness term to the ADRC. | ||||||
Accession Number: WOS:000735162900001 | ||||||
Author Identifiers: | ||||||
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eISSN: 2079-9292 |
Record 23 of 318 | ||||||
Title: Numerical study and improvement of the dynamic performance of dilation x-ray imager | ||||||
Author(s): Wang, QQ (Wang, Qiangqiang); Cao, ZR (Cao, Zhurong); Chen, T (Chen, Tao); Deng, B (Deng, Bo); Deng, KL (Deng, Keli); Tian, JS (Tian, Jinshou) | ||||||
Source: REVIEW OF SCIENTIFIC INSTRUMENTS Volume: 92 Issue: 12 Article Number: 123305 DOI: 10.1063/5.0061685 Published: DEC 1 2021 | ||||||
Abstract: We present in this Note a numerical study on the dynamic performance of a Dilation X-ray Imager (DIXI). The DIXI including a photoelectron tube (PT) and a magnetic solenoid is modeled in 3D space. The initial parameters of the photoelectrons are sampled with a Monte Carlo code. The trajectories of the photoelectrons are calculated by using the particle-in-cell method, and the transit time spread (TTS) and temporal magnification are analyzed in detail. We have designed a PT with a double-microstrip structure and compared the performance of the double-microstrip PT with the traditional single-microstrip PT. The results show that the sensitivity of the TTS and the temporal magnification to the emission time of the photoelectrons can be significantly reduced by using the double-microstrip PT, resulting in an improvement of the time window. Therefore, the dynamic performance of the DIXI is improved. | ||||||
Accession Number: WOS:000733061600002 | ||||||
PubMed ID: 34972428 | ||||||
Author Identifiers: | ||||||
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ISSN: 0034-6748 | ||||||
eISSN: 1089-7623 |
Record 24 of 318 | ||||||||||||||||||
Title: Rapid Repetition Rate Fluctuation Measurement of Soliton Crystals in a Microresonator | ||||||||||||||||||
Author(s): Xie, P (Xie, Peng); Wang, XY (Wang, Xinyu); Wang, WQ (Wang, Weiqiang); Zhang, WF (Zhang, Wenfu); Lu, ZZ (Lu, Zhizhou); Wang, Y (Wang, Yang); Zhao, W (Zhao, Wei) | ||||||||||||||||||
Source: JOVE-JOURNAL OF VISUALIZED EXPERIMENTS Issue: 178 Article Number: e60689 DOI: 10.3791/60689 Published: DEC 2021 | ||||||||||||||||||
Abstract: Temporal solitons have attracted great interest in the past decades for their behavior in a steady state, where the dispersion is balanced by the nonlinearity in a propagation Kerr medium. The development of dissipative Kerr solitons (DKSs) in high-Q microcavities drives a novel, compact, chip-scale soliton source. When DKSs serve as femtosecond pulses, the repetition rate fluctuation can be applied to ultrahigh precision metrology, high-speed optical sampling, and optical clocks, etc. In this paper, the rapid repetition rate fluctuation of soliton crystals (SCs), a special state of DKSs where particle-like solitons are tightly packed and fully occupy a resonator, is measured based on the well-known delayed self-heterodyne method. The SCs are generated using a thermal-controlled method. The pump is a frequency fixed laser with a linewidth of 100 Hz. The integral time in frequency fluctuation measurements is controlled by the length of the delay fiber. For a SC with a single vacancy, the repetition rate fluctuations are similar to 53.24 Hz within 10 mu s and similar to 509.32 Hz within 125 mu s, respectively. | ||||||||||||||||||
Accession Number: WOS:000802600300004 | ||||||||||||||||||
PubMed ID: 34978297 | ||||||||||||||||||
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ISSN: 1940-087X |
Record 25 of 318 | |||||||||
Title: Light-controlled pulsed x-ray tube with photocathode* | |||||||||
Author(s): Xuan, H (Xuan, Hao); Liu, YA (Liu, Yong-An); Qiang, PF (Qiang, Peng-Fei); Su, T (Su, Tong); Yang, XH (Yang, Xiang-Hui); Sheng, LZ (Sheng, Li-Zhi); Zhao, BS (Zhao, Bao-Sheng) | |||||||||
Source: CHINESE PHYSICS B Volume: 30 Issue: 11 Article Number: 118502 DOI: 10.1088/1674-1056/abff1e Published: DEC 2021 | |||||||||
Abstract: Unstable mechanical structure, low energy efficiency, and cooling requirements limit the application of conventional x-ray tubes based on filament as cathode in several academic areas. In this paper, we demonstrate a light-controlled pulsed x-ray tube using multialkali cathode as electron generator. The photocathode active area of the light controlled x-ray tube is 13.2 cm(2) (41 mm in diameter), which provides high photoelectron-emitting efficiency up to 0.288 mA/lm in 460-nm LED and 2.37-mA maximum tube current. Furthermore, the modulation ability from 1 kHz to 100 kHz of the x-ray tube is tested. The results suggest that the light-controlled pulsed x-ray tube has easy modulation and short x-ray pulse properties and is promising to be the next generation x-ray tube with wide applications in medical radiationtherapy as well as the calibration for detectors and scintillators. | |||||||||
Accession Number: WOS:000727700500001 | |||||||||
Author Identifiers: | |||||||||
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ISSN: 1674-1056 | |||||||||
eISSN: 2058-3834 |
Record 26 of 318 | |||||||||
Title: Abnormal event detection by a weakly supervised temporal attention network | |||||||||
Author(s): Zheng, XT (Zheng, Xiangtao); Zhang, YC (Zhang, Yichao); Zheng, YP (Zheng, Yunpeng); Luo, FL (Luo, Fulin); Lu, XQ (Lu, Xiaoqiang) | |||||||||
Source: CAAI TRANSACTIONS ON INTELLIGENCE TECHNOLOGY Volume: 7 Issue: 3 Pages: 419-431 DOI: 10.1049/cit2.12068 Early Access Date: DEC 2021 Published: SEP 2022 | |||||||||
Abstract: Abnormal event detection aims to automatically identify unusual events that do not comply with expectation. Recently, many methods have been proposed to obtain the temporal locations of abnormal events under various determined thresholds. However, the specific categories of abnormal events are mostly neglect, which are important to help in monitoring agents to make decisions. In this study, a Temporal Attention Network (TANet) is proposed to capture both the specific categories and temporal locations of abnormal events in a weakly supervised manner. The TANet learns the anomaly score and specific category for each video segment with only video-level abnormal event labels. An event recognition module is exploited to predict the event scores for each video segment while a temporal attention module is proposed to learn a temporal attention value. Finally, to learn anomaly scores and specific categories, three constraints are considered: event category constraint, event separation constraint and temporal smoothness constraint. Experiments on the University of Central Florida Crime dataset demonstrate the effectiveness of the proposed method. | |||||||||
Accession Number: WOS:000724293300001 | |||||||||
Author Identifiers: | |||||||||
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ISSN: 2468-6557 | |||||||||
eISSN: 2468-2322 |
Record 27 of 318 | ||||||
Title: RETRACTED: Energy Efficiency Analysis in Modified GoF Spectrum Sensing-Based AF Relay Cooperative Cognitive Sensor Network with Energy Harvesting (Retracted Article) | ||||||
Author(s): Mi, Y (Mi, Yin); Lu, GY (Lu, Guangyue); Gao, WB (Gao, Wenbin) | ||||||
Source: SECURITY AND COMMUNICATION NETWORKS Volume: 2021 DOI: 10.1155/2021/3340525 Published: NOV 30 2021 | ||||||
Abstract: In this paper, we propose a joint sensing duration and transmission power allocation scheme to maximize the energy efficiency (EE) of the secondary user (SU) in a cooperative cognitive sensor network (CSN). At the initial time slot of the frame, the secondary transmitter (ST) performs energy harvesting (EH) and spectrum sensing simultaneously using power splitting (PS) protocol. The modified goodness of fit (GoF) spectrum sensing algorithm is employed to detect the licensed spectrum, which is not sensitive to an inaccurate noise power estimate. Based on the imperfect sensing results, the ST will act as an amplify-and-forward (AF) relay and assist in transmission of the primary user (PU) or transmit its own data. The SU's EE maximization problem is constructed under the constraints of meeting energy causality, sensing reliability, and PU's quality of service (QoS) requirement. Since the SU's EE function is a nonconvex problem and difficult to solve, we transform the original problem into a tractable convex one with the aid of Dinkelbach's method and convex optimization technique by applying a nonlinear fractional programming. The closed-form expression of the ST's transmission power is also derived through Karush-Kuhn-Tucker (KKT) and gradient method. Simulation results show that our scheme is superior to the existing schemes. | ||||||
Accession Number: WOS:000771302700006 | ||||||
Author Identifiers: | ||||||
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ISSN: 1939-0114 | ||||||
eISSN: 1939-0122 |
Record 28 of 318 | |||||||||||||||||||||||||||
Title: Impact remnants rich in carbonaceous chondrites detected on the Moon by the Chang'e-4 rover | |||||||||||||||||||||||||||
Author(s): Yang, YZ (Yang, Yazhou); Li, S (Li, Shuai); Zhu, MH (Zhu, Meng-Hua); Liu, Y (Liu, Yang); Wu, B (Wu, Bo); Du, J (Du, Jun); Fa, WZ (Fa, Wenzhe); Xu, R (Xu, Rui); He, ZP (He, Zhiping); Wang, C (Wang, Chi); Xue, B (Xue, Bin); Yang, JF (Yang, Jianfeng); Zou, YL (Zou, Yongliao) | |||||||||||||||||||||||||||
Source: NATURE ASTRONOMY Volume: 6 Issue: 2 Pages: 207-+ DOI: 10.1038/s41550-021-01530-w Early Access Date: NOV 2021 Published: FEB 2022 | |||||||||||||||||||||||||||
Abstract: The Moon has experienced an intense bombardment history since its formation(1). Fragments of the impactor can remain on the lunar surface(2-4) and can provide evidence of the evolution of the impactor composition and impact population in the Earth-Moon system(3-5). However, the retained impactor fragments previously identified in the Apollo samples have been well mixed into bulk lunar regolith due to the subsequent impact gardening, and their properties cannot be easily isolated(3,6,7). Here we report observations of a two-metre-sized crater that formed less than one million years ago obtained by the Yutu-2 rover of Chang'e-4. Hyperspectral images in the visible and near-infrared range (0.45-0.945 mu m) with a spatial resolution less than 1 mm per pixel highlight the presence of glassy material with high concentration (47%) of carbonaceous chondrites. We identify this material as remnants of the original impactor that was not entirely vaporized by the impact. Although carbonaceous chondrite fragments have been found in Apollo samples(8,9,) no carbonaceous chondrite remnant had been directly observed on the lunar surface by remote sensing exploration. We suggest that carbonaceous chondrite-like bodies may still provide one of the sources of water to the present Moon. | |||||||||||||||||||||||||||
Accession Number: WOS:000722538400001 | |||||||||||||||||||||||||||
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ISSN: 2397-3366 |
Record 29 of 318 |
Title: Dwarfism computer-aided diagnosis algorithm based on multimodal pyradiomics |
Author(s): Qiu, S (Qiu, Shi); Jin, Y (Jin, Yi); Feng, SH (Feng, Songhe); Zhou, T (Zhou, Tao); Li, YD (Li, Yidong) |
Source: INFORMATION FUSION Volume: 80 Pages: 137-145 DOI: 10.1016/j.inffus.2021.11.012 Early Access Date: NOV 2021 Published: APR 2022 |
Abstract: Dwarfism refers to the phenomenon that children with same gender and age are lower than two standard deviations of normal height in the same living environment. It is of great significance for early diagnosis and early treatment of dwarfism. Dwarfism can be divided into growth hormone deficiency (GHD) and idiopathic short stature (ISS). GHD can be distinguished by growth hormone, while ISS is difficult to distinguish because its hormone features are not obvious. Thus, a computer-aided diagnosis model based on brain image data and clinical features is established for the first time and a dwarfism prediction algorithm is proposed based on multimodal pyradiomics. Firstly, we establish the extraction of pituitary gland based on tensor and binary wavelet model, as the pituitary gland is an important organ that affects the growth hormone. Then, the multidimensional fusion model is established to distinguish dwarfism. In the process of distinguishment, the pyradiomics features and clinical features are extracted to distinguish together. Finally, dwarfism computer-aided diagnosis algorithm based on multimodal pyradiomics is realized. |
Accession Number: WOS:000724320000008 |
ISSN: 1566-2535 |
eISSN: 1872-6305 |
Record 30 of 318 | |||||||||
Title: Monolithic RGB Micro-Light-Emitting Diodes Fabricated with Quantum Dots Embedded inside Nanoporous GaN | |||||||||
Author(s): Song, J (Song, Jie); Kang, JH (Kang, Jin-ho); Han, J (Han, Jung) | |||||||||
Source: ACS APPLIED ELECTRONIC MATERIALS Volume: 3 Issue: 11 Pages: 4877-4881 DOI: 10.1021/acsaelm.1c00700 Published: NOV 23 2021 | |||||||||
Abstract: We report the use of colloidal quantum dots (QDs) embedded in nanoporous (NP) gallium nitride (GaN) as a color converter to achieve different emission colors and fabricate micro-light-emitting diodes (micro-LEDs). The optical property of NP-GaN has been studied by analyzing the light transmittance propagating in NP-GaN. A strong light scattering effect can be induced by NP-GaN, resulting in a dramatically increased optical transmission path for blue light and high light absorption by QDs loaded inside NP-GaN. A 4 in. color converter has been achieved with a wavelength deviation of 1 nm across the entire wafer. Monolithic red, green, and blue micro-LEDs have been fabricated with a pixel size of around 35 x 35 mu m(2). | |||||||||
Accession Number: WOS:000756989100023 | |||||||||
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eISSN: 2637-6113 |
Record 31 of 318 | |||||||||
Title: Visual inspection system for battery screen print using joint method with multi-level block matching and K nearest neighbor algorithm | |||||||||
Author(s): Zhao, Z (Zhao, Zhuo); Li, B (Li, Bing); Liu, TK (Liu, Tongkun); Zhang, SJ (Zhang, Shaojie); Lu, JS (Lu, Jiasheng); Geng, LQ (Geng, Leqi); Cao, J (Cao, Jie) | |||||||||
Source: OPTIK Volume: 250 Article Number: 168332 DOI: 10.1016/j.ijleo.2021.168332 Early Access Date: NOV 2021 Part: 1 Published: JAN 2022 | |||||||||
Abstract: To overcome the drawbacks of manual quality inspection in battery industry, an online vision system is designed for battery screen print. Defect detection technique is based on the joint method of multi-level block matching and K nearest neighbor (KNN) algorithm. Firstly, execute preprocessing to origin images in segmentation, tilt correction and region cutting; Then create block templates on print area and train the corresponding models for active shape model (ASM) and KNN methods; Finally, coarse and accurate block matchings are applied to extract print defects in subsequent stages. In this period, KNN uses shape features of region components to recheck each target block. In addition, we adopt dynamic model updating mechanism to enhance system adaptability of condition changing. The joint method has two advantages: fault detection caused by print distortion is obviously reduced; accurate defect localization is also assured. Meanwhile, system hardware and software are also developed and calibrated to support detection method. Performance comparison, recognition rate and time efficiency are validated in experiment stage. It can be concluded that the proposed method has superior performances in both simulations and industrial application. | |||||||||
Accession Number: WOS:000737258200005 | |||||||||
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ISSN: 0030-4026 | |||||||||
eISSN: 1618-1336 |
Record 32 of 318 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Title: Direct generation of ultrafast vortex beam from a Tm:CaYAlO<sub>4</sub> oscillator featuring pattern matching of a folded-cavity resonator | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Cao, X (Cao, Xue); Liu, YY (Liu, Yangyu); Xian, AH (Xian, Anhua); Li, YF (Li, Yifei); Wu, K (Wu, Kun); Xu, XD (Xu, Xiaodong); Zhou, W (Zhou, Wei); Wang, HT (Wang, Haotian); Huang, HT (Huang, Haitao); Jia, BH (Jia, Baohua); Wang, YS (Wang, Yishan); Tang, DY (Tang, Dingyuan); Shen, DY (Shen, Deyuan) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 24 Pages: 39312-39322 DOI: 10.1364/OE.437584 Published: NOV 22 2021 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: Optical vortices, beams with spiral wavefronts and screw phase dislocations have been explored in applications in optical manipulation, quantum optics, and the next generation of optical communications. In traditional methods, optical vortices are generated using space light modulators or spiral phase plates, which would sharply decrease the integration of optical systems. Different from previous transverse mode conversion outside the cavity, here we experimentally demonstrate a direct generation of ultrafast vortex beam from a Tm:CaYAlO4 oscillator by pattern matching of a six-mirror-folded-cavity resonator. By accurately adjusted the angle of the end mirror and the distance L between the M4 and the SESAMs to control the beam diameter of laser incidence on the gain medium in the sagittal and tangential planes, a stable 2 mu m ultrafast vortex laser emission of annular Laguerre-Gaussian (LG) mode was obtained with a maximum output power of 327 mW and pulse duration of 2.1 ps. A simple YAG crystal plate was used as handedness selector and a homemade Mach-Zehnder (MZ) interferometer has verified the vortical property of the LG(01) mode. By furtherly controlling the cavity mode pattern matching, other stable transverse-mode operations for TEM00, high-order Hermite-Gaussian (HG) transverse mode and doughnut-shaped beams were successfully realized. This work provides a flexible and reliable way to generate mid-infrared ultrafast vortex beams and is of special significance for applications in the areas of molecular spectroscopy and organic material processing amongst others. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000722251200032 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
PubMed ID: 34809298 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 1094-4087 |
Record 33 of 318 | ||||||
Title: Partially Coherent Illumination Based Point-Diffraction Digital Holographic Microscopy Study Dynamics of Live Cells | ||||||
Author(s): Zhuo, KQ (Zhuo, Kequn); Wang, Y (Wang, Yu); Wang, Y (Wang, Yang); Wen, K (Wen, Kai); Liu, M (Liu, Min); Ma, Y (Ma, Ying); Zheng, JJ (Zheng, Juanjuan); Gao, P (Gao, Peng) | ||||||
Source: FRONTIERS IN PHYSICS Volume: 9 Article Number: 796935 DOI: 10.3389/fphy.2021.796935 Published: NOV 22 2021 | ||||||
Abstract: This paper presents a partially coherent point-diffraction digital holographic microscopy (PC-pDHM) prototype and demonstrates its application in label-free imaging of the dynamic processes of live cells. In PC-pDHM, the light scattered by a rotating diffuser is coupled into a multi-mode fiber, and the output light is used as the partially coherent illumination (PCI), which reduces the speckle noise significantly in PC-pDHM. A polarization-grating is used to remold the object and the reference waves, and the fringe contrast of the generated hologram can be adjusted by changing the polarization of the illumination wave. Using the PC-pDHM prototype, transparent samples and notably the dynamic processes of live cells were imaged with high contrast and in a label-free manner, discovering the pathological mechanisms of biology in the cellular and sub-cellular levels. | ||||||
Accession Number: WOS:000727186100001 | ||||||
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ISSN: 2296-424X |
Record 34 of 318 | ||||||
Title: Study on the Application of Super-Resolution Ultrasound for Cerebral Vessel Imaging in Rhesus Monkeys | ||||||
Author(s): Yan, L (Yan, Li); Bai, C (Bai, Chen); Zheng, Y (Zheng, Yu); Zhou, XD (Zhou, Xiaodong); Wan, MX (Wan, Mingxi); Zong, YJ (Zong, Yujin); Chen, SS (Chen, Shanshan); Zhou, Y (Zhou, Yin) | ||||||
Source: FRONTIERS IN NEUROLOGY Volume: 12 Article Number: 720320 DOI: 10.3389/fneur.2021.720320 Published: NOV 17 2021 | ||||||
Abstract: Background: Ultrasound is ideal for displaying intracranial great vessels but not intracranial microvessels and terminal vessels. Even with contrast agents, the imaging effect is still unsatisfactory. In recent years, significant theoretical advances have been achieved in super-resolution imaging. The latest commonly used ultrafast plane-wave ultrasound Doppler imaging of the brain and microbubble-based super-resolution ultrasound imaging have been applied to the imaging of cerebral microvessels and blood flow in small animals such as mice but have not been applied to in vivo imaging of the cerebral microvessels in monkeys and larger animals. In China, preliminary research results have been obtained using super-resolution imaging in certain fields but rarely in fundamental and clinical experiments on large animals. In recent years, we have conducted a joint study with the Xi'an Jiaotong University to explore the application and performance of this new technique in the diagnosis of cerebrovascular diseases in large animals.Objective: To explore the characteristics and advantages of microbubble-based super-resolution ultrasound imaging of intracranial vessels in rhesus monkeys compared with conventional transcranial ultrasound.Methods: First, the effectiveness and feasibility of the super-resolution imaging technique were verified by modular simulation experiments. Then, the imaging parameters were adjusted based on in vitro experiments. Finally, two rhesus monkeys were used for in vivo experiments of intracranial microvessel imaging.Results: Compared with conventional plane-wave imaging, super-resolution imaging could measure the inner diameters of cerebral microvessels at a resolution of 1 mm or even 0.7 mm and extract blood flow information. In addition, it has a better signal-to-noise ratio (5.625 dB higher) and higher resolution (~30-fold higher). The results of the experiments with rhesus monkeys showed that microbubble-based super-resolution ultrasound imaging can achieve an optimal resolution at the micron level and an imaging depth >35 mm.Conclusion: Super-resolution imaging can realize the monitoring imaging of high-resolution and fast calculation of microbubbles in the process of tissue damage, providing an important experimental basis for the clinical application of non-invasive transcranial ultrasound. | ||||||
Accession Number: WOS:000725749000001 | ||||||
PubMed ID: 34867712 | ||||||
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ISSN: 1664-2295 |
Record 35 of 318 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Title: A large dispersion-managed monolithic all-fiber chirped pulse amplification system for high-energy femtosecond laser generation | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Li, F (Li, Feng); Zhao, W (Zhao, Wei); Wang, YS (Wang, Yishan); Wang, N (Wang, Na); Li, QL (Li, Qianglong); Yang, Y (Yang, Yang); Wen, WL (Wen, Wenlong) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Source: OPTICS AND LASER TECHNOLOGY Volume: 147 Article Number: 107684 DOI: 10.1016/j.optlastec.2021.107684 Early Access Date: NOV 2021 Published: MAR 2022 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: A high energy monolithic all fiber chirped pulse amplification (CPA) system composed of fiber-silicate glass fiber is demonstrated in this work. In this compact system, the optical stretcher consists of two large dispersion chirped fiber Bragg gratings that offer a high stretch ratio to lower the nonlinearity that accumulates in the fiber amplifier. By employing high gain silicate glass fiber with a length of 20 cm as the main amplifier, an optimal balance of pulse energy and the B-integral is achieved. An amplified power of 42.6 W, corresponding to a pulse energy of 213 mu J, is obtained with an injection power of 100 mW. After compression, the laser pulses are compressed by a novel polarization-controlled double-pass configuration of a chirped volume Bragg grating (CVBG) to match the dispersion of the fiber stretcher. A total compression efficiency of 79.8% is obtained. The dispersion between the stretcher and the compressor is matched with the self-made temperature tuning device of the fiber grating. An optimized pulse width of 781 fs and a pulse energy of 170 mu J are obtained with the single mode beam profile. To the best of our knowledge, this is the highest energy ever obtained with a single-mode beam profile for a spliced monolithic all-fiber CPA system. This compact high-energy fiber system will be useful in scientific research and industrial applications. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000724478500004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 0030-3992 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
eISSN: 1879-2545 |
Record 36 of 318 | |||||||||||||||
Title: Spectral Characteristics of Fiber-Based S-Shape Taper Refractometer With High Sensitivity | |||||||||||||||
Author(s): Ma, JW (Ma, Jianwen); Cheng, HH (Cheng, Haihao); Yang, XM (Yang, Xuemei); Zhang, SY (Zhang, Songyang); Li, YQ (Li, Yongqi); Wang, S (Wang, Shun); Wu, S (Wu, Shun) | |||||||||||||||
Source: IEEE PHOTONICS TECHNOLOGY LETTERS Volume: 33 Issue: 22 Pages: 1266-1269 DOI: 10.1109/LPT.2021.3115955 Published: NOV 15 2021 | |||||||||||||||
Abstract: In this work, we have experimentally demonstrated the refractive index (RI) sensing characteristics of a S-shape taper refractometer (STR) based on modal interference theory. Our preliminary theoretical analysis reveals that there exists a critical cladding mode, which is essential for understanding the sensing characteristics. When the dominant cladding mode involved in a core-cladding interference is close to the critical cladding mode, the resulting RI sensitivity tends to reach a maximum value. Moreover, both the critical and the dominant cladding mode are dependent on ambient RI. Our sensor achieves a high RI sensitivity of 2109.7 nm/RIU for a transmission dip at around 1505 nm with a measurement range of 1.36 to 1.39. | |||||||||||||||
Accession Number: WOS:000704821300001 | |||||||||||||||
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ISSN: 1041-1135 | |||||||||||||||
eISSN: 1941-0174 |
Record 37 of 318 | |||||||||
Title: Method to Improve the Detection Accuracy of Quadrant Detector Based on Neural Network | |||||||||
Author(s): Wang, X (Wang, Xuan); Su, XQ (Su, Xiuqin); Liu, GZ (Liu, Guizhong); Han, JF (Han, Junfeng); Zhu, WH (Zhu, Wenhua); Liu, ZX (Liu, Zengxin) | |||||||||
Source: IEEE PHOTONICS TECHNOLOGY LETTERS Volume: 33 Issue: 22 Pages: 1254-1257 DOI: 10.1109/LPT.2021.3116240 Published: NOV 15 2021 | |||||||||
Abstract: The quadrant detector (QD), has developed into a core detector in the free space optical communication system. The light power received by the detector surface will be very weak after long distance transmission of laser, it brings great challenges to the high precision spot position detection of the detector. Therefore, this letter proposes a method to improve the spot position detection accuracy of the QD through artificial neural network. The neural network can solve the impact of multiple different factors on the detection accuracy of the detector at one time, which can save a lot of time and cost. Moreover, the test results of the detection accuracy of the network show that the neural network has significantly improved the detection accuracy of the spot position of the QD. | |||||||||
Accession Number: WOS:000704108500005 | |||||||||
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ISSN: 1041-1135 | |||||||||
eISSN: 1941-0174 |
Record 38 of 318 | ||||||||||||||||||||||||||||||||||||||||||
Title: Analogous Optical Activity in Free Space Using a Single Pancharatnam-Berry Phase Element | ||||||||||||||||||||||||||||||||||||||||||
Author(s): Liu, S (Liu, Sheng); Qi, SX (Qi, Shuxia); Li, P (Li, Peng); Wei, BY (Wei, Bingyan); Chen, P (Chen, Peng); Hu, W (Hu, Wei); Zhang, Y (Zhang, Yi); Gan, XT (Gan, Xuetao); Zhang, P (Zhang, Peng); Lu, YQ (Lu, Yanqing); Chen, ZG (Chen, Zhigang); Zhao, JL (Zhao, Jianlin) | ||||||||||||||||||||||||||||||||||||||||||
Source: LASER & PHOTONICS REVIEWS Volume: 16 Issue: 1 Article Number: 2100291 DOI: 10.1002/lpor.202100291 Early Access Date: NOV 2021 Published: JAN 2022 | ||||||||||||||||||||||||||||||||||||||||||
Abstract: It is commonly believed that optical activity (OA) is manifested mainly in chiral media, but rare in non-chiral structures. Here, an analog of OA in free space is experimentally demonstrated by using a single liquid-crystal Pancharatnam-Berry phase element (PBPE), for which the mechanism is highly consistent with that of the traditional OA. The specifically designed PBPE supports the direction-dependent polarization rotation of a Bessel beam with controllable "rotatory power." Such a polarization rotation can be revoked by another PBPE with the same structure. Unlike in a chiral medium, this scheme shows simultaneous realization of equivalent leverotation and dextorotation merely by switching the optical element orientation, promising for applications non-magnetic optical devices such as optical isolators. | ||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000718008000001 | ||||||||||||||||||||||||||||||||||||||||||
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ISSN: 1863-8880 | ||||||||||||||||||||||||||||||||||||||||||
eISSN: 1863-8899 |
Record 39 of 318 | |||||||||||||||
Title: Axial resolution enhancement for planar Airy beam light-sheet microscopy via the complementary beam subtraction method | |||||||||||||||
Author(s): Liu, C (Liu, Chao); Yu, XH (Yu, Xianghua); Bai, C (Bai, Chen); Li, X (Li, Xing); Zhou, Y (Zhou, Yuan); Yan, SH (Yan, Shaohui); Min, JW (Min, Junwei); Dan, D (Dan, Dan); Li, RZ (Li, Runze); Gu, SY (Gu, Shuangyu); Yao, BL (Yao, Baoli) | |||||||||||||||
Source: APPLIED OPTICS Volume: 60 Issue: 32 Pages: 10239-10245 DOI: 10.1364/AO.441070 Published: NOV 10 2021 | |||||||||||||||
Abstract: Airy beam light-sheet illumination can extend the field of view (FOV) of light-sheet fluorescence microscopy due to the unique propagation properties of non-diffraction and self-acceleration. However, the side lobes create undesirable out-of-focus background, leading to poor axial resolution and low image contrast. Here, we propose an Airy complementary beam subtraction (ACBS) method to improve the axial resolution while keeping the extended FOV. By scanning the optimized designed complementary beam that has two main lobes (TML), the generated complementary light-sheet has almost identical intensity distribution to that of the planar Airy light-sheet except for the central lobe. Subtraction of the two images acquired by double exposure respectively using the planar Airy light-sheet and the planar TML light-sheet can effectively suppress the influence of the out-of-focus background. The axial resolution improves from similar to 4 mu m to 1.2 mu m. The imaging performance was demonstrated by imaging specimens of aspergillus conidiophores and GFP labeled mouse brain section. The results show that the ACBS method enables the Airy beam light-sheet fluorescence microscopy to obtain better imaging quality. (C) 2021 Optical Society of America | |||||||||||||||
Accession Number: WOS:000717521700030 | |||||||||||||||
PubMed ID: 34807133 | |||||||||||||||
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ISSN: 1559-128X | |||||||||||||||
eISSN: 2155-3165 |
Record 40 of 318 | |||||||||
Title: A synchroscan streak tube with high deflection sensitivity | |||||||||
Author(s): Liu, XL (Liu Xue-Ling); Tian, JS (Tian Jin-Shou); Tian, LP (Tian Li-Ping); Chen, P (Chen Ping); Zhang, MR (Zhang Min-Rui); Xue, YH (Xue Yan-Hua); Li, YH (Li Ya-Hui); Fang, YM (Fang Yu-Man); Xu, XY (Xu Xiang-Yan); Liu, BY (Liu Bai-Yu); Gou, YS (Gou Yong-Sheng) | |||||||||
Source: ACTA PHYSICA SINICA Volume: 70 Issue: 21 Article Number: 218502 DOI: 10.7498/aps.70.20210814 Published: NOV 5 2021 | |||||||||
Abstract: A synchroscan streak tube with high spatiotemporal resolution and high deflection sensitivity is proposed, which contains several innovation designs. Some measures are taken to improve the imaging performances of the streak tube. Firstly, in order to obtain a high deflection sensitivity, the difference in voltage between the photocathode and anode and the length of the equipotential region of the streak tube are reduced as much as possible. Secondly, by introducing a hyperfine grid behind the cathode, reasonably designing the voltages applied to the six-electrode electrostatic focusing system, and moving the electron beam crossing point to the entrance of the deflection plates, the temporal dispersion and the temporal distortion of the streak tube are reduced, and the spatiotemporal resolution of the streak tube is improved. Besides, the streak tube is technically analyzed by tracking the temporal and spatial distribution of electrons under an operating voltage of 7000 V with the aid of computer simulation technology (CST) software. The results show that the deflection sensitivity is 125 mm/kV, the physical temporal resolution is better than 1.83 ps @MTF = 10%, and the static spatial resolution on the photocathode is better than 38 lp/mm @MTF = 10% over the effective photocathode area with a size of 10 mm x 4 mm. By applying a synchronous scanning voltage with a repetition frequency of 250 MHz to the deflection electrode, the results show that the dynamic spatial resolution of the streak tube is better than 16 lp/mm, the limit of the dynamic temporal resolution is 1.39 ps, and two rectangular electron pulses with a size of 10 mm x 20 mu m and an interval of 2.3 ps emitted from the photocathode can be well resolved by the streak tube. In addition, the experimental measurements are conducted with a streak tube developed in our laboratory. The results demonstrate that the photocathode of the streak tube can work in the entire visible light region, and the response in the short wavelength region is significantly better than that in the long wavelength region. The static spatial resolution of this streak tube is 40 lp/mm in the center of the photocathode. The temporal resolution of this streak tube is 5.55 ps measured under a synchronous scanning voltage with a repetition frequency of 75 MHz. | |||||||||
Accession Number: WOS:000716870500008 | |||||||||
Author Identifiers: | |||||||||
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ISSN: 1000-3290 |
Record 41 of 318 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Title: Analysis of a higher-energy structure in nanotip enhanced fields | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Gao, XZ (Gao, Xu-Zhen); Landsman, AS (Landsman, Alexandra S.); Wang, HS (Wang, Hushan); Huang, P (Huang, Pei); Zhang, YP (Zhang, Yanpeng); Wang, B (Wang, Bo); Wang, YS (Wang, Yishan); Cao, HB (Cao, Huabao); Fu, YX (Fu, Yuxi); Pi, LW (Pi, Liang-Wen) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Source: NEW JOURNAL OF PHYSICS Volume: 23 Issue: 11 Article Number: 113017 DOI: 10.1088/1367-2630/ac320c Published: NOV 2021 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: We investigate strong field ionization of an atomic gas in a plasmonically enhanced field resulting from the illumination of a nanometer-sized structure with ultrafast laser pulse. We use perturbation theory to derive an approximate solution for electron's motion following ionization. These analytical estimates are corroborated by the time-dependent Schrodinger equation and classical trajectory Monte Carlo simulations. Notably, our approach can be used to obtain electron energy spectra without having to rely on numerical simulations. This allows for a deeper study of the dependence of electron energy spectrum on the properties of the near-field, suggesting electric field sensor applications. We derive an analytical expression for the location of the peak of the higher-energy structure (HES) as a function of laser parameters and near-field decay length. We find a particularly strong dependence of the energy peak on laser frequency, with lower frequencies causing a significant upward shift in the final electron energies. Combined with control of the width of the HES, which can be done by changing the size of the nanostructure, this points to the possibility of using nanotips as sources of ultrashort electron beams of tunable energy. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000716132600001 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 1367-2630 |
Record 42 of 318 | ||||||
Title: High-throughput fast full-color digital pathology based on Fourier ptychographic microscopy via color transfer | ||||||
Author(s): Gao, YT (Gao, Yuting); Chen, JR (Chen, Jiurun); Wang, AY (Wang, Aiye); Pan, A (Pan, An); Ma, CW (Ma, Caiwen); Yao, BL (Yao, Baoli) | ||||||
Source: SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY Volume: 64 Issue: 11 Article Number: 114211 DOI: 10.1007/s11433-021-1730-x Published: NOV 2021 | ||||||
Abstract: The usage of full-color imaging in digital pathology produces significant results. Compared with a grayscale image or a pseudocolor image containing contrast information, a full-color image can identify and detect the target object better with color texture information. Fourier ptychographic microscopy (FPM) is a high-throughput computational imaging technique that breaks the tradeoff between high resolution (HR) and a large field of view. It also eliminates the artifacts of scanning and stitching in digital pathology and improves its imaging efficiency. However, the conventional full-color digital pathology based on FPM is still time-consuming because of the repeated experiments with tri-wavelengths. A color transfer FPM approach termed "CFPM" was reported. The color texture information of a low-resolution full-color pathologic image is directly transferred to the HR grayscale FPM image captured by only a single wavelength. Both of the color space of FPM based on the standard CIE-XYZ color model and the display based on the standard RGB color space were established. Different FPM colorization schemes were analyzed and compared with 30 biological samples. Three types of evaluation approaches were provided, including the root-mean-square error (RMSE), the difference maps, and the image histogram cosine similarity. The average RMSE values of the conventional method and CFPM compared with the ground truth were 5.3% and 5.7%, respectively. Therefore, the reconstruction time is significantly reduced by 2/3 with the sacrifice of precision of only 0.4%. The CFPM method is also compatible with advanced fast FPM approaches to further reduce computation time. | ||||||
Accession Number: WOS:000682673300001 | ||||||
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ISSN: 1674-7348 | ||||||
eISSN: 1869-1927 |
Record 43 of 318 | ||||||||||||
Title: Ultra-Broadband Polarization Conversion Metasurface with High Transmission for Efficient Multi-Functional Wavefront Manipulation in the Terahertz Range | ||||||||||||
Author(s): Jiang, XQ (Jiang, Xiaoqiang); Fan, WH (Fan, Wenhui); Qin, C (Qin, Chong); Chen, X (Chen, Xu) | ||||||||||||
Source: NANOMATERIALS Volume: 11 Issue: 11 Article Number: 2895 DOI: 10.3390/nano11112895 Published: NOV 2021 | ||||||||||||
Abstract: Recently, terahertz (THz) wireless communication has been widely investigated as the future prospect of wireless network architecture. However, most of the natural existing materials are inapplicable for THz devices, which hinder their further development. To promote the integration and channel capacity of the THz wireless communication systems, an ultrabroadband polarization conversion metasurface for efficient multi-functional wavefront manipulation is proposed. The designed metasurface is composed of an arrow-type structure sandwiched by a pair of orthogonal gratings, which can induce the Fabry-Perot-like cavity for improving the transmission. Simulated results indicate that the transmission coefficient of the cross-polarization metasurface is higher than 90% from 0.73 THz to 2.24 THz, and the corresponding polarization conversion ratio is greater than 99.5%. Moreover, the phase coverage of 0-2 pi at operation frequency can be easily obtained by altering the geometric parameter of the metasurface. To demonstrate the concept of wavefront manipulation, anomalous refraction, focusing metalens, and vortex beam generation are investigated in detail. All of these applications exhibit a remarkable performance of the proposed metasurface that has great potential in prompting the efficient, broadband and compact systems for THz wireless communication. | ||||||||||||
Accession Number: WOS:000727288400001 | ||||||||||||
PubMed ID: 34835660 | ||||||||||||
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eISSN: 2079-4991 |
Record 44 of 318 | |||||||||
Title: Off-axis optical levitation and transverse spinning of metallic microparticles | |||||||||
Author(s): Liang, YS (Liang, Yansheng); Yan, SH (Yan, Shaohui); Wang, ZJ (Wang, Zhaojun); Yao, BL (Yao, Baoli); Lei, M (Lei, Ming) | |||||||||
Source: PHOTONICS RESEARCH Volume: 9 Issue: 11 Pages: 2144-2151 DOI: 10.1364/PRJ.431413 Published: NOV 1 2021 | |||||||||
Abstract: Optical manipulation of metallic microparticles remains a significant challenge because of the strong scattering forces arising from the high extinction coefficient of the particles. This paper reports a new mechanism for stable confinement of metallic microparticles using a tightly focused linearly polarized Gaussian beam. Theoretical and experimental results demonstrate that metallic microparticles can be captured off the optical axis in such a beam. Meanwhile, the three-dimensionally confined particles are observed spinning transversely as a response to the asymmetric force field. The off-axis levitation and transverse spinning of metallic micropartides may provide a new way for effective manipulation of metallic micropartides. (C) 2021 Chinese Laser Press | |||||||||
Accession Number: WOS:000713930800002 | |||||||||
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ISSN: 2327-9125 |
Record 45 of 318 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Title: Ultrafast photonics applications of zirconium carbide as a novel mode-locker for fiber lasers | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Liu, SC (Liu, Sicong); Lv, RD (Lv, Ruidong); Wang, J (Wang, Jiang); Wang, YS (Wang, Yishan); Wang, HS (Wang, Hushan); Zhang, H (Zhang, Han); Wang, YG (Wang, Yonggang) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Source: JOURNAL OF MATERIALS CHEMISTRY C Volume: 9 Issue: 47 Pages: 16985-16990 DOI: 10.1039/d1tc04073a Early Access Date: NOV 2021 Published: DEC 9 2021 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: Zirconium carbide (ZrC), as a novel member of the MXene family, has outstanding physical and chemical properties; however, the applications of ZrC in ultrafast photonics are still rare. Herein, a ZrC film was deposited by magnetron sputtering deposition (MSD) technology onto a D-shaped fiber and the nonlinear optical properties of the ZrC film were demonstrated. MSD technology is an advanced preparation method applicable to various materials. The saturation intensity and the modulation depth of the ZrC film were measured to be 197.6 MW cm(-2) and 11.9%, respectively. After inserting the ZrC SA into an erbium-doped fiber laser (EDFL) cavity, a passive mode-locked EDFL pulse was formed. In mode-locked operation, conventional solitons with an ultrashort pulse duration of 395 fs and an output power of 49.86 mW were achieved in the communication band. The corresponding central wavelength of the output spectrum was 1562.19 nm with a 7.73 nm spectral width. This work pioneers the application of a ZrC-based device as a mode-locker to achieve ultrashort pulses for the first time and expands the application of the ZrC material. The experimental results open new opportunities for the use of ZrC in mode-locked lasers and photonics applications. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000719960600001 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 2050-7526 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
eISSN: 2050-7534 |
Record 46 of 318 | ||||||
Title: Numerical Simulation of Cavitation and Damping Force Characteristics for a High-Speed Supercavitation Vehicle | ||||||
Author(s): Lu, R (Lu, Rui); Pan, G (Pan, Guang); Tan, K (Tan, Kun); Yin, SP (Yin, Shaoping) | ||||||
Source: JOURNAL OF MARINE SCIENCE AND ENGINEERING Volume: 9 Issue: 11 Article Number: 1171 DOI: 10.3390/jmse9111171 Published: NOV 2021 | ||||||
Abstract: In this study, an attempt has been made to investigate the supercavitation and hydrodynamic characteristics of high-speed vehicles. A homogeneous equilibrium flow model and a Schnerr-Sauer model based on the Reynolds-averaged Navier-Stokes method are used. Grid-independent inspection and comparison with experimental data in the literature have been carried out to verify the accuracy of numerical methods. The effect of the navigation speed and angle of attack on the cavitation morphology and dynamic characteristics has been investigated. It has been demonstrated that the angle of attack has a remarkable influence on the wet surface and hydrodynamic force, whereas navigation speed has little effect on the position force of the vehicle under the circumstance of no wet surface. The hydrodynamic force changes periodically with the swing of the vehicle, but its maximum is greater than that for the direct navigation state at the same attack angle. Moreover, the damping effect obviously affects the hydrodynamic force amplitude and movement trend. | ||||||
Accession Number: WOS:000723377300001 | ||||||
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eISSN: 2077-1312 |
Record 47 of 318 |
Title: The phase uncertainty from the fringe contrast of interferogram in Doppler asymmetric spatial heterodyne spectroscopy |
Author(s): Sun, C (Sun, Chen); Feng, YT (Feng, Yutao); Fu, D (Fu, Di); Wang, PC (Wang, Pengchong); Sun, J (Sun, Jian); Bai, QL (Bai, Qinglan) |
Source: JOURNAL OF OPTICS Volume: 23 Issue: 11 Article Number: 115703 DOI: 10.1088/2040-8986/ac2462 Published: NOV 2021 |
Abstract: The Doppler asymmetric spatial heterodyne spectroscopy is one of the primary techniques for measuring the upper atmospheric wind profile. In this work, the detailed derivation of the analytical expression of phase uncertainty was presented, including two significant parameters, fringe contrast and signal-to-noise ratio. The effectiveness of the re-parameterized analytical expression was proved using the numerical simulations and laboratory experiments, and both results are in good agreement with them from the analytical expression. Therefore, the re-parameterized analytical expression could be used to optimize the interferometer design and evaluating the instrument performance. |
Accession Number: WOS:000714210300001 |
ISSN: 2040-8978 |
eISSN: 2040-8986 |
Record 48 of 318 |
Title: Efficient two-step focal length calibration of space zoom camera without targets |
Author(s): Wang, H (Wang, Hao); Peng, JW (Peng, Jianwei); Zeng, H (Zeng, Hong); Zhang, GP (Zhang, Gaopeng); Wang, F (Wang, Feng); Liao, JW (Liao, Jiawen) |
Source: OPTICAL ENGINEERING Volume: 60 Issue: 11 Article Number: 114104 DOI: 10.1117/1.OE.60.11.114104 Published: NOV 2021 |
Abstract: Computer vision plays a key role in measuring the relative posture and position between spacecrafts, especially in various close-range space tasks. As one of the essential steps for computer vision, camera calibration is important for obtaining precise three-dimensional contours of a space target. The focal length of on-orbit zoom cameras constantly changes. Thus, it is practical to calibrate the focal length rather than other intrinsic camera parameters. However, traditional calibration targets, such as checkerboards, cannot be used to calibrate a space camera in orbit. To address this problem, we propose a two-step process for focal length calibration. In the first step, the initial estimate of the camera focal length was generated with vanishing points obtained from the solar panels of satellites. In the second step, the initial solution was optimized by the particle swarm optimization algorithm. The results of the simulations and laboratory experiments confirmed the accuracy, flexibility, and good antinoise interference performance of the proposed method. Thus, the proposed method has practical significance for space tasks, such as space rendezvous-docking and on-orbit maintenance. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE) |
Accession Number: WOS:000724546600005 |
ISSN: 0091-3286 |
eISSN: 1560-2303 |
Record 49 of 318 | ||||||
Title: New Results on Small and Dim Infrared Target Detection | ||||||
Author(s): Wang, H (Wang, Hao); Zhao, ZH (Zhao, Zehao); Kwan, C (Kwan, Chiman); Zhou, GQ (Zhou, Geqiang); Chen, YH (Chen, Yaohong) | ||||||
Source: SENSORS Volume: 21 Issue: 22 Article Number: 7746 DOI: 10.3390/s21227746 Published: NOV 2021 | ||||||
Abstract: Real-time small infrared (IR) target detection is critical to the performance of the situational awareness system in high-altitude aircraft. However, current IR target detection systems are generally hardware-unfriendly and have difficulty in achieving a robust performance in datasets with clouds occupying a large proportion of the image background. In this paper, we present new results by using an efficient method that extracts the candidate targets in the pre-processing stage and fuses the local scale, blob-based contrast map and gradient map in the detection stage. We also developed mid-wave infrared (MWIR) and long-wave infrared (LWIR) cameras for data collection experiments and algorithm evaluations. Experimental results using both publicly available datasets and image sequences acquired by our cameras clearly demonstrated that the proposed method achieves high detection accuracy with the mean AUC being at least 22.3% higher than comparable methods, and the computational cost beating the other methods by a large margin. | ||||||
Accession Number: WOS:000723415700001 | ||||||
PubMed ID: 34833822 | ||||||
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eISSN: 1424-8220 |
Record 50 of 318 |
Title: Summary of the R&D of 20-inch MCP-PMTs for neutrino detection |
Author(s): Wu, Q (Wu, Q.); Qian, S (Qian, S.); Cao, Y (Cao, Y.); Huang, G (Huang, G.); Jin, M (Jin, M.); Jin, Z (Jin, Z.); Li, D (Li, D.); Liu, H (Liu, H.); Li, K (Li, K.); Liu, S (Liu, S.); Ma, L (Ma, L.); Ren, L (Ren, L.); Si, S (Si, S.); Sun, J (Sun, J.); Tian, J (Tian, J.); Wang, X (Wang, X.); Zhan, H (Zhan, H.); Zhu, Y (Zhu, Y.) |
Group Author(s): MCP-PMT Workgrp |
Source: JOURNAL OF INSTRUMENTATION Volume: 16 Issue: 11 Article Number: C11003 DOI: 10.1088/1748-0221/16/11/C11003 Published: NOV 2021 |
Abstract: The Jiangmen Underground Neutrino Observatory (JUNO) in China aiming to determine the neutrino mass hierarchy is under construction. A new kind of large area microchannel-plate photomultiplier tube (MCP-PMT) was put forward for the JUNO by the researchers in Institute of High Energy Physics (IHEP) in China. After breaking through several core technotical barriers, the 20-inch MCP-PMT prototype with great performance was successfully produced by the MCP-PMT group in China and got 75% PMT orders (15,000 pics) from JUNO. The mass production line and batch test system was completed in North Night Vision Technology Co., Ltd. (NNVT). The performance of the MCP-PMT including the gain, the quantum efficiency, the P/V ratio, the dark count rate and the transit time spread can be batch tested. During the mass production process, the technical progress in the cathode deposition method improved the quantum efficiency of the photocathode from 30% to 35%. The aging behaviour, temperature effect, the after-pulse distribution and the flash signal of the 20-inch MCP-PMT are all detailly studied. By August of 2020, the 15,000 MCP-PMTs, which will be installed as the central liquid scintillator detector of JUNO, have been completed and delivered to Jiangmen. The average QE at 400nm for the 15,000 pieces of MCP-PMTs is 32%. |
Accession Number: WOS:000755333200003 |
ISSN: 1748-0221 |
Record 51 of 318 |
Title: Optical design of an integrated imaging system of optical camera and synthetic aperture radar |
Author(s): Li, RC (Li, Ruichang); Feng, LJ (Feng, Liangjie); Xu, KJ (Xu, Kaijiang); Wang, N (Wang, Nan); Fan, XW (Fan, Xuewu) |
Source: OPTICS EXPRESS Volume: 29 Issue: 22 Pages: 36796-36812 DOI: 10.1364/OE.438979 Published: OCT 25 2021 |
Abstract: This paper presents an integrated imaging system of optical camera and synthetic aperture radar (SAR). The system can realize 400 nm-900 nm visible and near infrared band and 35 GHz microwave Ka band dual-band imaging. Compared with the single band imaging system, the observation ability and environmental adaptability of the integrated imaging system have been significantly improved. The optical camera shares a common front system with the synthetic aperture radar. After simulation, the average modulation transfer function (MTF) of 50 line pairs per millimeter (lp/mm) of the optical subsystem is 0.47. In addition, a principle prototype with a pupil diameter of 210 mm was developed to verify the performance of synthetic aperture radar antennas. After the experimental test, the SAR radiation pattern simulation results are in good conformity with the measured results, which are in line with the expected results. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement |
Accession Number: WOS:000710928500145 |
PubMed ID: 34809082 |
ISSN: 1094-4087 |
Record 52 of 318 |
Title: Painting and calligraphy identification method based on hyperspectral imaging and convolution neural network |
Author(s): Tang, XJ (Tang, Xingjia); Zhang, PC (Zhang, Penchang); Du, J (Du, Jian); Xu, ZB (Xu, Zongben) |
Source: SPECTROSCOPY LETTERS Volume: 54 Issue: 9 Pages: 645-664 DOI: 10.1080/00387010.2021.1982988 Early Access Date: OCT 2021 Published: OCT 21 2021 |
Abstract: It is of great social value and cultural and technological innovation demonstration value to carry out the research on the scientific identification method of painting and calligraphy works of art, and it is of great effect to the trade, collection, and protection of painting and calligraphy works of art. Spectral imaging, as an information acquisition method of attribute and visual synchronous perception, can be used for painting and calligraphy identification. In particular, through hyperspectral imaging and data analyses, we can identify the pigment ink used in painting, judge the printing characteristics, and find the painting information invisible to human eyes, to comprehensively judge the authenticity and abnormality of painting. However, due to its lack of matching painting and calligraphy identification model and algorithm, as well as special painting and calligraphy atlas database support, it is difficult to be competent for rapid and accurate identification in practice. Because of the above problems, in this paper, it is simulated the expert identification process for artificial intelligence analysis and modeling, adopts the idea of combining hyperspectral imaging and Atlas intelligent learning, proposes a method of atlas feature extraction for calligraphy and painting identification, and designs and studies convolution neural network(CNN) based on atlas feature, traditional image feature, and the mixed feature of atlas and image, to judge the authenticity of calligraphy and painting, the author and so on. The actual test results show that the convolution neural network based on the atlas features is the best, the author classification accuracy and authenticity identification rate in the test sample set are more than 96.5%, and it can also be seen that in the pseudo color image data, adding multivariate spectral features can greatly improve the accuracy significantly. |
Accession Number: WOS:000711271000001 |
ISSN: 0038-7010 |
eISSN: 1532-2289 |
Record 53 of 318 | |||||||||||||||
Title: Parallel Multistage Wide Neural Network | |||||||||||||||
Author(s): Xi, JB (Xi, Jiangbo); Ersoy, OK (Ersoy, Okan K.); Fang, JW (Fang, Jianwu); Wu, TJ (Wu, Tianjun); Wei, X (Wei, Xin); Zhao, CY (Zhao, Chaoying) | |||||||||||||||
Source: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS Volume: 34 Issue: 8 Pages: 4019-4032 DOI: 10.1109/TNNLS.2021.3120331 Early Access Date: OCT 2021 Published: AUG 2023 | |||||||||||||||
Abstract: Deep learning networks have achieved great success in many areas, such as in large-scale image processing. They usually need large computing resources and time and process easy and hard samples inefficiently in the same way. Another undesirable problem is that the network generally needs to be retrained to learn new incoming data. Efforts have been made to reduce the computing resources and realize incremental learning by adjusting architectures, such as scalable effort classifiers, multi-grained cascade forest (gcForest), conditional deep learning (CDL), tree CNN, decision tree structure with knowledge transfer (ERDK), forest of decision trees with radial basis function (RBF) networks, and knowledge transfer (FDRK). In this article, a parallel multistage wide neural network (PMWNN) is presented. It is composed of multiple stages to classify different parts of data. First, a wide radial basis function (WRBF) network is designed to learn features efficiently in the wide direction. It can work on both vector and image instances and can be trained in one epoch using subsampling and least squares (LS). Second, successive stages of WRBF networks are combined to make up the PMWNN. Each stage focuses on the misclassified samples of the previous stage. It can stop growing at an early stage, and a stage can be added incrementally when new training data are acquired. Finally, the stages of the PMWNN can be tested in parallel, thus speeding up the testing process. To sum up, the proposed PMWNN network has the advantages of: 1) optimized computing resources; 2) incremental learning; and 3) parallel testing with stages. The experimental results with the MNIST data, a number of large hyperspectral remote sensing data, and different types of data in different application areas, including many image and nonimage datasets, show that the WRBF and PMWNN can work well on both image and nonimage data and have very competitive accuracy compared to learning models, such as stacked autoencoders, deep belief nets, support vector machine (SVM), multilayer perceptron (MLP), LeNet-5, RBF network, recently proposed CDL, broad learning, gcForest, ERDK, and FDRK. | |||||||||||||||
Accession Number: WOS:000732406900001 | |||||||||||||||
PubMed ID: 34699372 | |||||||||||||||
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ISSN: 2162-237X | |||||||||||||||
eISSN: 2162-2388 |
Record 54 of 318 | ||||||
Title: Development of point diffraction interferometer by a dimension-reduction-based phase-shifting algorithm | ||||||
Author(s): Feng, LJ (Feng, Leijie); Du, HB (Du, Hubing); Liu, C (Liu, Chang); Han, JL (Han, Jinlu); Zhang, GP (Zhang, Gaopeng); Wang, F (Wang, Feng); Zhao, ZX (Zhao, Zixin); Gao, F (Gao, Fen) | ||||||
Source: APPLIED OPTICS Volume: 60 Issue: 30 Pages: 9440-9446 DOI: 10.1364/AO.439512 Published: OCT 20 2021 | ||||||
Abstract: To avoid exhaustive calibration of the shifter device in point diffraction interferometers, we present a dimensionreduction-based method to reconstruct the phase map from more phase-shifting fringe patterns with three or more frames. The proposed method assumes that the intensity space can be described adequately by the sine and cosine of multiple phase shifts introduced, which are the basis of the intensity space. Then, low-dimensional approximations of high-dimensional intensity spaces are determined by the newly developed reduced basis decomposition technique. Finally, the phase is reconstructed using the low-dimensional surrogates of the intensity spaces without the knowledge of accurate phase steps. Numerical and experimental studies demonstrated that the proposed method outperforms the existing popular phase reconstruction techniques in terms of accuracy and efficiency. Moreover, the performance of the proposed method is not limited by variations in the background and modulation, unlike the existing phase-shifting-algorithm-based approaches. (C) 2021 Optical Society of America | ||||||
Accession Number: WOS:000709548800025 | ||||||
PubMed ID: 34807084 | ||||||
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ISSN: 1559-128X | ||||||
eISSN: 2155-3165 |
Record 55 of 318 | ||||||||||||||||||
Title: Autonomous on-chip interferometry for reconfigurable optical waveform generation | ||||||||||||||||||
Author(s): Fischer, B (Fischer, Bennet); Chemnitz, M (Chemnitz, Mario); MacLellan, B (MacLellan, Benjamin); Roztocki, P (Roztocki, Piotr); Helsten, R (Helsten, Robin); Wetzel, B (Wetzel, Benjamin); Little, BE (Little, Brent E.); Chu, S (Chu, Sai T.); Moss, DJ (Moss, David J.); Azaña, J (Azana, Jose); Morandotti, R (Morandotti, Roberto) | ||||||||||||||||||
Source: OPTICA Volume: 8 Issue: 10 Pages: 1268-1276 DOI: 10.1364/OPTICA.435435 Published: OCT 20 2021 | ||||||||||||||||||
Abstract: The generation of user-defined optical temporal waveforms with picosecond resolution is an essential task for many applications, ranging from telecommunications to laser engineering. Realizing this functionality in an on-chip reconfigurable platformremains a significant challenge. Towards this goal, autonomous optimization methods are fundamental to counter fabrication imperfections and environmental variations, as well as to enable a wider range of accessible waveform shapes and durations. In this work, we introduce and demonstrate a self-adjusting on-chip optical pulse-shaper based on the concept of temporal coherence synthesis. The scheme enables on-the-fly reconfigurability of output optical waveforms by using an all-optical sampling technique in combination with an evolutionary optimization algorithm. We further show that particle-swarm optimization can outperform more commonly used algorithms in terms of convergence time. Hence, our system combines all key ingredients for realizing fully on-chip smart optical waveform generators for next-generation applications in telecommunications, laser engineering, and nonlinear optics. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||||||||
Accession Number: WOS:000709553000005 | ||||||||||||||||||
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ISSN: 2334-2536 |
Record 56 of 318 |
Title: A novel microstructured polymer tube for THz vortex beams guidance |
Author(s): Yuan, Y (Yuan, Yuan); Kong, DP (Kong, Depeng); Guan, L (Guan, Lei); Wang, LL (Wang, Lili) |
Source: OPTICS COMMUNICATIONS Volume: 505 Article Number: 127502 DOI: 10.1016/j.optcom.2021.127502 Early Access Date: OCT 2021 Published: FEB 15 2022 |
Abstract: A novel microstructured polymer tube (MPT) incorporating a central hollow, ring core, porous outer cladding is proposed for terahertz (THz) orbital angular momentum (OAM) guidance, focusing on the enhancement of the quantity of modes and bandwidth. The proposed MPT can support 70 modes (66 THz OAM ones) with large mode effective refractive index separation (>2.197x10(-3)) over 0.6 similar to 1.25 THz while maintaining single-mode condition radially, and the number of guiding modes can be further increased by properly equiproportional enhancing the size of the tube. Besides, the designed MPT has strong confinement property, high purity (>97.06%), and flat dispersion over the whole operating bandwidth. The result of this work reveals that this kind of MPT is promising to accelerate the development of the compact, light-weight THz communication system, and can be applied in OAM-based mode-division multiplexing combined with wavelength-division multiplexing technique without multiple-input multiple-output digital signal processing. |
Accession Number: WOS:000711570200018 |
ISSN: 0030-4018 |
eISSN: 1873-0310 |
Record 57 of 318 | ||||||||||||
Title: Structured illumination microscopy with partially coherent illumination for phase and fluorescent imaging | ||||||||||||
Author(s): Wen, K (Wen, Kai); Gao, ZL (Gao, ZhaoLin); Fang, X (Fang, Xiang); Liu, M (Liu, Min); Zheng, JJ (Zheng, JuanJuan); Ma, Y (Ma, Ying); Zalevsky, Z (Zalevsky, Zeev); Gao, P (Gao, Peng) | ||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 21 Pages: 33679-33693 DOI: 10.1364/OE.435783 Published: OCT 11 2021 | ||||||||||||
Abstract: This study presents a partially coherent illumination based (PCI-based) SIM apparatus for dual-modality (phase and fluorescent) microscopic imaging. The partially coherent illumination (PCI) is generated by placing a rotating diffuser on a monochromatic laser beam, which suppresses speckle noise in the dual-modality images and endows the apparatus with sound sectioning capability. With this system, label-free quantitative phase and super-resolved/sectioned fluorescent images can be obtained for the same sample. We have demonstrated the superiority of the system in phase imaging of transparent cells with high endogenous contrast and in a quantitative manner. In the meantime, we have also demonstrated fluorescent imaging of fluorescent beads, rat tail crosscut, wheat anther, and hibiscus pollen with super-resolution and optical sectioning. We envisage that the proposed method can be applied to many fields, including but not limited to biomedical, industrial, chemistry fields. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||
Accession Number: WOS:000708940500078 | ||||||||||||
PubMed ID: 34809175 | ||||||||||||
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ISSN: 1094-4087 |
Record 58 of 318 | ||||||
Title: Biomimetic multispectral curved compound eye camera for real-time multispectral imaging in an ultra-large field of view | ||||||
Author(s): Zhang, YJ (Zhang, Yuanjie); Xu, HR (Xu, Huangrong); Guo, Q (Guo, Quan); Wu, DS (Wu, Dengshan); Yu, WX (Yu, Weixing) | ||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 21 Pages: 33346-33356 DOI: 10.1364/OE.438710 Published: OCT 11 2021 | ||||||
Abstract: In this work, we demonstrate a prototype of a biomimetic multispectral curved compound eye camera (BMCCEC). In comparison with traditional multispectral imaging systems, the BMCCEC developed in this work has the distinct features of multi-spectral imaging on multiple targets in real time in an ultra-large field of view (FOV), which can be attributed to its biomimetic curved compound eye structure as well as the multispectral cluster network. Specifically, the BMCCEC has a total of 104 multispectral ommatidia and a FOV of 98 degrees x98 degrees, which is able to realize 7-band multispectral imaging with center wavelengths of 500 nm, 560 nm, 600 nm, 650nm, 700nm, 750nm and 800nm and a spectral resolution of 10 nm. A prototype of BMCCEC was then manufactured and multispectral imaging experiments were performed based on it. As a result, the red edge feature of the spectrum of green plants has been successfully obtained and retrieved with a good accuracy. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||
Accession Number: WOS:000708940500051 | ||||||
PubMed ID: 34809148 | ||||||
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ISSN: 1094-4087 |
Record 59 of 318 | ||||||||||||
Title: Generalized Scene Classification From Small-Scale Datasets With Multitask Learning | ||||||||||||
Author(s): Zheng, XT (Zheng, Xiangtao); Gong, TF (Gong, Tengfei); Li, XB (Li, Xiaobin); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||
Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Volume: 60 DOI: 10.1109/TGRS.2021.3116147 Early Access Date: OCT 2021 Published: 2022 | ||||||||||||
Abstract: Remote sensing images contain a wealth of spatial information. Efficient scene classification is a necessary precedent step for further application. Despite the great practical value, the mainstream methods using deep convolutional neural networks (CNNs) are generally pretrained on other large datasets (such as ImageNet) and thus fail to capture the specific visual characteristics of remote sensing images. For another, it lacks the generalization ability to new tasks when training a new CNN from scratch with an existing remote sensing dataset. This article addresses the dilemma and uses multiple small-scale datasets to learn a generalized model for efficient scene classification. Since the existing datasets are heterogeneous and cannot be directly combined to train a network, a multitask learning network (MTLN) is developed. The MTLN treats each small-scale dataset as an individual task and uses complementary information contained in multiple tasks to improve generalization. Concretely, the MTLN consists of a shared branch for all tasks and multiple task-specific branches with each for one task. The shared branch extracts shared features for all tasks to achieve information sharing among tasks. The task-specific branch distills the shared features into task-specific features toward the optimal estimation of each specific task. By jointly learning shared features and task-specific features, the MTLN maintains both generalization and discrimination abilities. Two types of MTL scenarios are explored to validate the effectiveness of the proposed method: one is to complete multiple scene classification tasks and the other is to jointly perform scene classification and semantic segmentation. | ||||||||||||
Accession Number: WOS:000732806700001 | ||||||||||||
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ISSN: 0196-2892 | ||||||||||||
eISSN: 1558-0644 |
Record 60 of 318 | ||||||
Title: Cross-scale feature fusion connection for a YOLO detector | ||||||
Author(s): Ruan, ZL (Ruan, Zhongling); Wang, H (Wang, Hao); Cao, JZ (Cao, Jianzhong); Zhang, HB (Zhang, Hongbo) | ||||||
Source: IET COMPUTER VISION Volume: 16 Issue: 2 Pages: 99-110 DOI: 10.1049/cvi2.12069 Early Access Date: OCT 2021 Published: MAR 2022 | ||||||
Abstract: Multi-scale feature fusion is often used to address the issue of scale variations in object detection. However, most of the proposed network architectures only combine the features of two adjacent levels sequentially, so the first fusion nodes in both top-down and bottom-up pathways must be blank nodes that only have one input with no feature fusion. In this work, cross-scale feature fusion connection (CFFC) is proposed which aims to enhance the entire feature hierarchy by propagating the features of each level more efficiently. The proposed method reuses and aggregates all the features of other scales to the blank nodes in both top-down and bottom-up pathways. Furthermore, the authors remove the 1 x 1 convolutional layer and replace the shortcut with concatenation before fusing multiple features. These concatenated feature maps are then supervised by the channel attention block at the fusion nodes. This modification allows the network to learn the important degree of each level in concatenated feature maps along the channel dimension. It is also observed that the proposed method alleviates the inconsistency in feature pyramids with fewer parameters. The performance of a YOLO object detector equipped with the proposed method on the COCO test-dev 2017 is evaluated. The results show that the proposed method outperforms other architectures presented in the literature. | ||||||
Accession Number: WOS:000706173300001 | ||||||
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ISSN: 1751-9632 | ||||||
eISSN: 1751-9640 |
Record 61 of 318 | ||||||||||||
Title: Synchronous detection of heavy metal ions in aqueous solution by gold nanoparticle surface-enhanced laser-induced breakdown spectroscopy | ||||||||||||
Author(s): Yao, YQ (Yao, Yaqian); He, F (He, Fan); Lin, QY (Lin, Qingyu); Tian, YH (Tian, Yonghui); Zhang, TL (Zhang, Tianlong); Xu, BP (Xu, Boping); Qi, XY (Qi, Xinyuan); Duan, YX (Duan, Yixiang) | ||||||||||||
Source: JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY Volume: 36 Issue: 12 Pages: 2639-2648 DOI: 10.1039/d1ja00310k Early Access Date: OCT 2021 Published: DEC 1 2021 | ||||||||||||
Abstract: Heavy metal ion-induced water pollution has become a severe environmental problem in the world. Although providing a powerful technique for multi-element detection, laser-induced breakdown spectroscopy (LIBS) suffers from insufficient sensitivity for detecting heavy metal ions in aqueous solution due to water splashing and surface ripples. In this work, a simple and sensitive method called gold nanoparticle (AuNP) surface-enhanced laser-induced breakdown spectroscopy (SELIBS) was proposed to detect trace or ultra-trace heavy metal ions in aqueous solutions using a portable instrument. Firstly, the coulombic force allows the adhesion of negatively charged AuNPs and cationic amphiphilic solutions to capture heavy ions, thereby directly improving signal intensity. Interestingly, AuNP size-dependent signal enhancement was found in heavy metal ions through LIBS. To be specific, the signal intensity of Cu, Pb, and Cr increased by 9, 23, and 26 times, respectively, under the optimal AuNP size with a diameter of 13 nm compared to that of the pure target solution. Although the sizes of AuNPs did not affect the plasma temperature and electron density, the local electric field and coulombic force effectively enhanced the LIBS signal. Under optimized experimental conditions, the proposed method achieves sensitive detection of heavy metal ions of Cu, Pb, and Cr with low detection limits (LODs) of 5 ng mL(-1), 22 ng mL(-1), and 9 ng mL(-1), respectively. Moreover, the recoveries of all analytical elements in environmental water samples were analyzed by the standard addition method. The recoveries were in the range of 92.70-100.19%, which further proves the feasibility and potential of surface-enhanced laser-induced breakdown spectroscopy of AuNPs in analyzing actual liquid samples. | ||||||||||||
Accession Number: WOS:000709366700001 | ||||||||||||
Author Identifiers: | ||||||||||||
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ISSN: 0267-9477 | ||||||||||||
eISSN: 1364-5544 |
Record 62 of 318 | ||||||||||||
Title: Ultrahigh-<i>Q</i> terahertz sensor based on simple all-dielectric metasurface with toroidal dipole resonance | ||||||||||||
Author(s): Jiang, XQ (Jiang, Xiao-Qiang); Fan, WH (Fan, Wen-Hui); Chen, X (Chen, Xu); Yan, H (Yan, Hui) | ||||||||||||
Source: APPLIED PHYSICS EXPRESS Volume: 14 Issue: 10 Article Number: 102008 DOI: 10.35848/1882-0786/ac27b7 Published: OCT 1 2021 | ||||||||||||
Abstract: A simple all-dielectric metasurface with symmetric structure, exhibiting strong toroidal dipole (TD) resonance and ultrahigh quality factor (Q-factor), is proposed. The physical mechanisms of the TD resonance are investigated by calculating the electromagnetic field and the scattering power of multipoles. Simulated results demonstrate that the Q-factor is up to 3.71 x 10(4) and the corresponding figure of merit is 636.7. Moreover, the TD resonance can be excited under both x- and y-polarized incident terahertz waves due to the symmetric structure. The remarkable performances make the proposed metasurface has feasible capability for biological and chemical sensing in terahertz range. | ||||||||||||
Accession Number: WOS:000700765000001 | ||||||||||||
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ISSN: 1882-0778 | ||||||||||||
eISSN: 1882-0786 |
Record 63 of 318 | ||||||||||||
Title: 808 nm broad-area laser diodes designed for high efficiency at high-temperature operation | ||||||||||||
Author(s): Lan, Y (Lan, Yu); Yang, GW (Yang, Guowen); Liu, YX (Liu, Yuxian); Zhao, YL (Zhao, Yuliang); Wang, ZF (Wang, Zhenfu); Li, T (Li, Te); Demir, A (Demir, Abdullah) | ||||||||||||
Source: SEMICONDUCTOR SCIENCE AND TECHNOLOGY Volume: 36 Issue: 10 Article Number: 105012 DOI: 10.1088/1361-6641/ac2160 Published: OCT 2021 | ||||||||||||
Abstract: Semiconductor lasers with high power conversion efficiency (PCE) and output power are heavily investigated driven by more energy-efficient commercial applications. In this paper, an asymmetric broad area laser (A-BAL) design is studied and compared with a conventional symmetric broad area laser (S-BAL) design for 808 nm single emitter laser diodes. We present a comparative theoretical and experimental investigation by studying the thermal effects on the laser parameters. The output characteristics and efficiency loss paths for the designs were analyzed. The leakage of carriers was identified as the primary source of the PCE reduction with temperature. Suppressing this leakage by optimization of the A-BAL design, a record continuous-wave PCE of 68% at 25 degrees C and 60.4% at 75 degrees C were achieved for a single emitter laser with 10 W output power. These devices deliver high efficiency at high temperatures with reliable operation achieving 2000 h of an accelerated aging lifetime without failures. | ||||||||||||
Accession Number: WOS:000697833600001 | ||||||||||||
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ISSN: 0268-1242 | ||||||||||||
eISSN: 1361-6641 |
Record 64 of 318 |
Title: Design of a Dual-Band Compact Integrated Remote Sensing System for Visible Light and Long-Wave Infrared |
Author(s): Li, RC (Li, Ruichang); Zou, GY (Zou, Gangyi); Feng, LJ (Feng, Liangjie); Fan, XW (Fan, Xuewu) |
Source: APPLIED SCIENCES-BASEL Volume: 11 Issue: 20 Article Number: 9370 DOI: 10.3390/app11209370 Published: OCT 2021 |
Abstract: This paper presents a design of a dual-band integrated space telescope system for visible light and long-wave infrared. The system can simultaneously image the visible light band of 450-900 nm and the long-wave infrared band of 7700-10,500 nm. The dual-band integrated imaging system can freely switch the observation band to adapt to different scenes and environmental changes. The camera can also further expand its capabilities in the fields of multi-spectral observation and low-light observation by collocation with different detectors. This design is based on a coaxial reflection system, the two bands share the camera's primary and secondary mirrors, and the separation of the two bands is achieved through a separate field of view design. After simulation, the average Modulation Transfer Function (MTF) value of the visible light band of the system at 50 lp/mm (line pairs per millimeter) reaches 0.45, and the average MTF value of the long-wave infrared band at 50 lp/mm reaches 0.36. In addition, tolerance analysis, ambient temperature analysis and transmittance analysis of the integrated system are carried out in this paper to further improve the integrated system scheme, and the feasibility of the system is further verified. |
Accession Number: WOS:000715233300001 |
eISSN: 2076-3417 |
Record 65 of 318 | |||||||||
Title: Spectral Discrimination of Rabbit Liver VX2 Tumor and Normal Tissue Based on Genetic Algorithm-Support Vector Machine | |||||||||
Author(s): Liu, CY (Liu Chen-yang); Xu, HR (Xu Huang-rong); Duan, F (Duan Feng); Wang, TS (Wang Tai-sheng); Lu, ZW (Lu Zhen-wu); Yu, WX (Yu Wei-xing) | |||||||||
Source: SPECTROSCOPY AND SPECTRAL ANALYSIS Volume: 41 Issue: 10 Pages: 3123-3128 DOI: 10.3964/j.issn.1000-0593(2021)10-3123-06 Published: OCT 2021 | |||||||||
Abstract: Rabbit liver VX2 tumor is a tumor model that can grow rapidly in various organs, such as liver, lung, rectum, etc. , and is often used in tumor research. In this paper, using high-near-infrared spectrum technology to four rabbits VX2 liver tumor and normal tissue in vivo and in vitro reflection spectrum detection, then respectively the Two categories based on support vector machine (normal liver tissue and liver VX2 tumor tissue) and Four categories (not bleeding living normal liver tissue, not living liver VX2 tumor tissue bleeding, bleeding in vitro normal liver tissue and hemorrhage in vitro liver VX2 tumor tissue). According to its spectral reflection curve characteristics, the data in the range of 400 similar to 1800 nm are selected as characteristic variables. In order to further improve the classification accuracy, the kernel parameter g and penalty factor c of the support vector machine was optimized by using a 50 fold cross-validation and genetic algorithm, respectively. The optimization parameters and classification results of the 50-fold cross-validation are as follows : penalty parameter c of the dichotomy optimization is 4, kernel parameter g is 0. 125 0, and the accuracy of the correction set and prediction set reaches 100%. The optimized parameters c and g are 8 and 0. 121 1, and the accuracy of the correction set and the prediction set are 99. 242 4% and 93. 33 3% , respectively. The optimized parameters and results of the genetic algorithm are as follows: the optimized parameters c and g in dichotomy are 0. 845 6 and 0. 062 5 , respectively, and the accuracy of Two categories, the correction set and the prediction set, is agreed to reach 100%. The optimized parameter C in the Four categories was 5. 530 7 and g was 0. 068 5, and the accuracy of the correction set and the prediction set reached 99. 242 4% and 100% , respectively. The results show that the two optimization methods have achieved good results, and the genetic algorithm is more accurate in the classification of the Four categories. In order to further improve the speed of the algorithm, the method of variable selection at intervals was adopted to reduce the characteristic variables continuously. Finally, a variable was selected for every 100 nm spectral segment, and a total of 14 spectral segments were selected as the characteristic variables. Parameters of support vector machine were optimized by using genetic algorithm for the classification was studied, the results show that the Two categories and Four categories of both results of the calibration set and prediction set were 99. 242 4% , and the running time of 11. 4 s and 20. 0 s respectively, and choosing all band running time: 340. 3 s and 491. 0 s compared to how spectroscopy can be in the identification of hepatic VX2 tumor tissue and normal liver tissue. The classification accuracy rate can reach more than 99% , and the running time shorten a lot. Therefore, it also lays a foundation for realising rapid real-time online detection and classification of tumor tissues in the future clinical tumor diagnosis with multi-spectrum technology, showing great application potential. | |||||||||
Accession Number: WOS:000715857400021 | |||||||||
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ISSN: 1000-0593 |
Record 66 of 318 | ||||||||||||
Title: UAV-Borne Hyperspectral Imaging Remote Sensing System Based on Acousto-Optic Tunable Filter for Water Quality Monitoring | ||||||||||||
Author(s): Liu, H (Liu, Hong); Yu, T (Yu, Tao); Hu, BL (Hu, Bingliang); Hou, XS (Hou, Xingsong); Zhang, ZF (Zhang, Zhoufeng); Liu, X (Liu, Xiao); Liu, JC (Liu, Jiacheng); Wang, XJ (Wang, Xueji); Zhong, JJ (Zhong, Jingjing); Tan, ZX (Tan, Zhengxuan); Xia, SX (Xia, Shaoxia); Qian, B (Qian, Bao) | ||||||||||||
Source: REMOTE SENSING Volume: 13 Issue: 20 Article Number: 4069 DOI: 10.3390/rs13204069 Published: OCT 2021 | ||||||||||||
Abstract: Unmanned aerial vehicle (UAV) hyperspectral remote sensing technologies have unique advantages in high-precision quantitative analysis of non-contact water surface source concentration. Improving the accuracy of non-point source detection is a difficult engineering problem. To facilitate water surface remote sensing, imaging, and spectral analysis activities, a UAV-based hyperspectral imaging remote sensing system was designed. Its prototype was built, and laboratory calibration and a joint air-ground water quality monitoring activity were performed. The hyperspectral imaging remote sensing system of UAV comprised a light and small UAV platform, spectral scanning hyperspectral imager, and data acquisition and control unit. The spectral principle of the hyperspectral imager is based on the new high-performance acousto-optic tunable (AOTF) technology. During laboratory calibration, the spectral calibration of the imaging spectrometer and image preprocessing in data acquisition were completed. In the UAV air-ground joint experiment, combined with the typical water bodies of the Yangtze River mainstream, the Three Gorges demonstration area, and the Poyang Lake demonstration area, the hyperspectral data cubes of the corresponding water areas were obtained, and geometric registration was completed. Thus, a large field-of-view mosaic and water radiation calibration were realized. A chlorophyl-a (Chl-a) sensor was used to test the actual water control points, and 11 traditional Chl-a sensitive spectrum selection algorithms were analyzed and compared. A random forest algorithm was used to establish a prediction model of water surface spectral reflectance and water quality parameter concentration. Compared with the back propagation neural network, partial least squares, and PSO-LSSVM algorithms, the accuracy of the RF algorithm in predicting Chl-a was significantly improved. The determination coefficient of the training samples was 0.84; root mean square error, 3.19 mu g/L; and mean absolute percentage error, 5.46%. The established Chl-a inversion model was applied to UAV hyperspectral remote sensing images. The predicted Chl-a distribution agreed with the field observation results, indicating that the UAV-borne hyperspectral remote sensing water quality monitoring system based on AOTF is a promising remote sensing imaging spectral analysis tool for water. | ||||||||||||
Accession Number: WOS:000715609800001 | ||||||||||||
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eISSN: 2072-4292 |
Record 67 of 318 |
Title: Timing Fluctuation Correction of A Femtosecond Regenerative Amplifier |
Author(s): Liu, KY (Liu, Keyang); Li, HY (Li, Hongyang); Wang, XL (Wang, Xinliang); Liu, YQ (Liu, Yanqi); Song, LW (Song, Liwei); Leng, YX (Leng, Yuxin) |
Source: CRYSTALS Volume: 11 Issue: 10 Article Number: 1242 DOI: 10.3390/cryst11101242 Published: OCT 2021 |
Abstract: We report on the long-term correction of a timing fluctuation between the femtosecond regenerative amplifier and the reference oscillator for the seed 100 PW laser system in the Station of Extreme Light (SEL). The timing fluctuation was characterized by a noncollinear balanced optical cross-correlator that maps the time difference to the sum frequency intensity of the amplifier and oscillator laser pulses. A feedback loop was employed to correct the timing jitter by adjusting the time delay line in the amplifier beam path. The timing fluctuation was reduced to 1.26 fs root-mean-square from hundreds of fs over 10 hours. Benefitting from excellent performance and long-term stability, this timing jitter correction scheme, as a component of optical synchronization in the 100 PW laser facility, will be integrated into SEL. |
Accession Number: WOS:000713978600001 |
eISSN: 2073-4352 |
Record 68 of 318 | ||||||||||||||||||
Title: Direct femtosecond laser inscription of an IR fluorotellurite fiber Bragg grating | ||||||||||||||||||
Author(s): Liu, LT (Liu, Lutao); Chen, FY (Chen, Fengyi); Xiao, XS (Xiao, Xusheng); Li, XY (Li, Xingyong); Wang, RH (Wang, Ruohui); Liu, CZ (Liu, Chengzhen); Guo, HT (Guo, Haitao) | ||||||||||||||||||
Source: OPTICS LETTERS Volume: 46 Issue: 19 Pages: 4832-4835 DOI: 10.1364/OL.439290 Published: OCT 1 2021 | ||||||||||||||||||
Abstract: This study proposes a novel, to the best of our knowledge, development of fluorotellurite glass fiber Bragg gratings (FBGs). Shell-like morphology was achieved using a single femtosecond laser pulse illuminated through the fiber's polymer coating. Different FBG fabrication methods and parameters were systematically studied to optimize performance. The fluorotellurite FBG exhibited a high sensitivity to writing laser power and reflectivity saturation effect in repetitive writing. A low-insertion-loss fluorotellurite FBG with a reflectivity of over 99% and bandwidth of less than 1 nm was successfully inscribed. The flexible inscription methods can write an FBG at any wavelength in the fluorotellurite glass transparent window, and are applicable to infrared fiber lasers or sensors. (C) 2021 Optical Society of America | ||||||||||||||||||
Accession Number: WOS:000702746400032 | ||||||||||||||||||
PubMed ID: 34598211 | ||||||||||||||||||
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ISSN: 0146-9592 | ||||||||||||||||||
eISSN: 1539-4794 |
Record 69 of 318 | |||||||||||||||||||||
Title: Demonstration of an external cavity semiconductor mode-locked laser | |||||||||||||||||||||
Author(s): Yuan, MY (Yuan, Meiyan); Wang, WQ (Wang, Weiqiang); Wang, XY (Wang, Xinyu); Wang, Y (Wang, Yang); Yang, QH (Yang, Qinghua); Cheng, D (Cheng, Dong); Liu, Y (Liu, Yang); Huang, L (Huang, Long); Zhang, MR (Zhang, Mingran); Liang, B (Liang, Bo); Zhao, W (Zhao, Wei); Zhang, WF (Zhang, Wenfu) | |||||||||||||||||||||
Source: OPTICS LETTERS Volume: 46 Issue: 19 Pages: 4855-4858 DOI: 10.1364/OL.428794 Published: OCT 1 2021 | |||||||||||||||||||||
Abstract: Electrically pumped semiconductor mode-locked lasers (SMLs) are promising in a wide range of applications due to compact size, high energy efficiency, and low cost. However, the long gain interaction length increases the spontaneous emission noise. In this Letter, an external cavity structure is adopted to improve the SML noise performance, as well as the flexibility to adjust the repetition rate. Two external cavity SMLs with repetition rates of 255 MHz and 10 GHz are demonstrated. For the 10 GHz SML, the signal-noise-ratio and radio frequency linewidth of the fundamental frequency reach 81.1 dB and 40 Hz, respectively. The high performance makes the laser a promising light source for microwave and communication applications. (C) 2021 Optical Society of America | |||||||||||||||||||||
Accession Number: WOS:000702746400038 | |||||||||||||||||||||
PubMed ID: 34598217 | |||||||||||||||||||||
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ISSN: 0146-9592 | |||||||||||||||||||||
eISSN: 1539-4794 |
Record 70 of 318 | ||||||||||||
Title: PbS Quantum Dots Saturable Absorber for Dual-Wavelength Solitons Generation | ||||||||||||
Author(s): Yun, L (Yun, Ling); Zhao, W (Zhao, Wei) | ||||||||||||
Source: NANOMATERIALS Volume: 11 Issue: 10 Article Number: 2561 DOI: 10.3390/nano11102561 Published: OCT 2021 | ||||||||||||
Abstract: PbS quantum dots (QDs), a representative zero-dimensional material, have attracted great interest due to their unique optical, electronic, and chemical characteristics. Compared to one- and two-dimensional materials, PbS QDs possess strong absorption and an adjustable bandgap, which are particularly fascinating in near-infrared applications. Here, fiber-based PbS QDs as a saturable absorber (SA) are studied for dual-wavelength ultrafast pulses generation for the first time to our knowledge. By introducing PbS QDs SA into an erbium-doped fiber laser, the laser can simultaneously generate dual-wavelength conventional solitons with central wavelengths of 1532 and 1559 nm and 3 dB bandwidths of 2.8 and 2.5 nm, respectively. The results show that PbS QDs as broadband SAs have potential application prospects for the generation of ultrafast lasers. | ||||||||||||
Accession Number: WOS:000712678000001 | ||||||||||||
PubMed ID: 34685000 | ||||||||||||
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eISSN: 2079-4991 |
Record 71 of 318 | ||||||
Title: Monitoring Cyanobacteria Bloom in Dianchi Lake Based on Ground-Based Multispectral Remote-Sensing Imaging: Preliminary Results | ||||||
Author(s): Zhao, H (Zhao, Huan); Li, JS (Li, Junsheng); Yan, X (Yan, Xiang); Fang, SZ (Fang, Shengzhong); Du, YC (Du, Yichen); Xue, B (Xue, Bin); Yu, K (Yu, Kai); Wang, C (Wang, Chen) | ||||||
Source: REMOTE SENSING Volume: 13 Issue: 19 Article Number: 3970 DOI: 10.3390/rs13193970 Published: OCT 2021 | ||||||
Abstract: Some lakes in China have undergone serious eutrophication, with cyanobacterial blooms occurring frequently. Dynamic monitoring of cyanobacterial blooms is important. At present, the traditional lake-survey-based cyanobacterial bloom monitoring is spatiotemporally limited and requires considerable human and material resources. Although satellite remote sensing can rapidly monitor large-scale cyanobacterial blooms, clouds and other factors often mean that effective images cannot be obtained. It is also difficult to use this method to dynamically monitor and manage aquatic environments and provide early warnings of cyanobacterial blooms in lakes and reservoirs. In contrast, ground-based remote sensing can operate under cloud cover and thus act as a new technical method to dynamically monitor cyanobacterial blooms. In this study, ground-based remote-sensing technology was applied to multitemporal, multidirectional, and multiscene monitoring of cyanobacterial blooms in Dianchi Lake via an area array multispectral camera mounted on a rotatable cloud platform at a fixed station. Results indicate that ground-based imaging remote sensing can accurately reflect the spatiotemporal distribution characteristics of cyanobacterial blooms and provide timely and accurate data for salvage treatment and early warnings. Thus, ground-based multispectral remote-sensing data can operationalize the dynamic monitoring of cyanobacterial blooms. The methods and results from this study can provide references for monitoring such blooms in other lakes. | ||||||
Accession Number: WOS:000756792600001 | ||||||
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eISSN: 2072-4292 |
Record 72 of 318 |
Title: Broadband hybrid plasmonic graphene modulator operating at mid-Infrared wavelength |
Author(s): Ban, XQ (Ban, Xiaoqiang); Zhong, M (Zhong, Ming); Little, BE (Little, Brent E.) |
Source: OPTIK Volume: 247 Article Number: 168036 DOI: 10.1016/j.ijleo.2021.168036 Early Access Date: SEP 2021 Published: DEC 2021 |
Abstract: A broadband modulator with hybrid plasmonic graphene waveguide is proposed. The waveguide is very convenient to transfer graphene and improve fabrication tolerance. We use tip enhancement effect of graphene-based hybrid wedge SPPs mode to enhance light absorption modulation. The interaction between the hybrid plasmonic graphene structure and the optical field is numerically investigated. We get the geometrical optimization value by sweeping the parameter with FDTD method. The result demonstrates that modulation depth of our proposed modulator exceeds 3 dB when wavelength changes from 3.3 to 3.7 mu m. Moreover, compared with previous papers, our proposed modulator can obtain broader modulation bandwidth (156.49 GHz) and need lower power consumption (477 fJ/bit), which has a better performance in potential applications such as optoelectronic countermeasure systems and optical signal processing. |
Accession Number: WOS:000728530400006 |
ISSN: 0030-4026 |
eISSN: 1618-1336 |
Record 73 of 318 | |||||||||||||||
Title: Optical separation and discrimination of chiral particles by vector beams with orbital angular momentum | |||||||||||||||
Author(s): Li, MM (Li, Manman); Yan, SH (Yan, Shaohui); Zhang, YN (Zhang, Yanan); Chen, X (Chen, Xu); Yao, BL (Yao, Baoli) | |||||||||||||||
Source: NANOSCALE ADVANCES Volume: 3 Issue: 24 Pages: 6897-6902 DOI: 10.1039/d1na00530h Early Access Date: SEP 2021 Published: DEC 7 2021 | |||||||||||||||
Abstract: Chirality describes a reduced symmetry and abounds in nature. The handedness-dependent response usually occurs only when a chiral object interacts with another chiral entity. Light carrying orbital angular momentum (OAM) is inherently chiral due to the helical wave front. Here, we put forward a scheme that enables optical separation and simultaneous discrimination of single chiral particles using focused vector beams with OAM. Such focused vector vortex beams carrying radial-splitting optical chirality can selectively trap one enantiomer inside or outside the intensity maxima depending on the sign of the OAM. The particles with different chirality parameters can be trapped on different orbits and experience enhanced orbital motion. Moreover, the magnitude of OAM as well as the size of particle plays an important role in the chiral separation and discrimination. In addition to particle manipulation, the discussion of OAM in chiral light-matter interactions has potential application in, for example, optical enantioseparation or chiral detection. | |||||||||||||||
Accession Number: WOS:000706169300001 | |||||||||||||||
PubMed ID: 36132368 | |||||||||||||||
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ISSN: 2516-0230 |
Record 74 of 318 | ||||||
Title: Near-infrared image recovery based on modulation instability in CdZnTe:V | ||||||
Author(s): Liao, Y (Liao, Yuan); Wang, ZL (Wang, Zhaolu); Huang, N (Huang, Nan); Liu, HJ (Liu, Hongjun) | ||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 20 Pages: 31145-31155 DOI: 10.1364/OE.438061 Published: SEP 27 2021 | ||||||
Abstract: We propose a near-infrared image recovery method based on modulation instability in the photorefractive semiconductor CdZnTe: V. The formation mechanism of modulation instability in CdZnTe:V is discussed, and the theoretical gain model is derived. Theoretical results of optical image recovery at 1 mu m and 1.5 mu m wavelengths demonstrate that the maximum cross-correlation gain is 2.6 with a signal to noise intensity ratio of 0.1. These results suggest that our method could be one of potential aids for near-infrared imaging. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||
Accession Number: WOS:000702060000015 | ||||||
PubMed ID: 34615214 | ||||||
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ISSN: 1094-4087 |
Record 75 of 318 | |||||||||||||||
Title: Snapshot spectroscopic Mueller matrix polarimetry based on spectral modulation with increased channel bandwidth | |||||||||||||||
Author(s): Quan, NC (Quan, Naicheng); Zhang, CM (Zhang, Chunmin); Mu, TK (Mu, Tingkui); Li, SY (Li, Siyuan); You, CY (You, Caiyin) | |||||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 20 Pages: 31607-31614 DOI: 10.1364/OE.440026 Published: SEP 27 2021 | |||||||||||||||
Abstract: This paper presents a snapshot spectroscopic Mueller matrix polarimetry based on spectral modulation. The polarization state generator consists of a linear polarizer in front of two high-order retarders, and the polarization state analyzer is formed by two non-polarization beam splitters incorporated with three high-order retarder/linear analyzer pairs. It can simultaneously generate three modulated spectra used for reconstructing the 16 spectroscopic Mueller elements of the sample. Since each of the modulated spectra produces seven separate channels equally spaced in the Fourier domain, the channel bandwidth can be enhanced efficiently compared with the conventional spectrally modulated spectroscopic Mueller matrix polarimetry. The feasibility of the proposed spectroscopic Mueller matrix polarimetry is demonstrated by the experimental measurement of an achromatic quarter-wave plate. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | |||||||||||||||
Accession Number: WOS:000702060000052 | |||||||||||||||
PubMed ID: 34615251 | |||||||||||||||
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ISSN: 1094-4087 |
Record 76 of 318 | |||||||||||||||||||||
Title: Soliton Burst and Bi-Directional Switching in the Platform with Positive Thermal-Refractive Coefficient Using an Auxiliary Laser | |||||||||||||||||||||
Author(s): Zhao, YJ (Zhao, Yanjing); Chen, L (Chen, Liao); Zhang, C (Zhang, Chi); Wang, WQ (Wang, Weiqiang); Hu, H (Hu, Hao); Wang, RL (Wang, Ruolan); Wang, XY (Wang, Xinyu); Chu, ST (Chu, Sai T.); Little, B (Little, Brent); Zhang, WF (Zhang, Wenfu); Zhang, XL (Zhang, Xinliang) | |||||||||||||||||||||
Source: LASER & PHOTONICS REVIEWS Volume: 15 Issue: 11 Article Number: 2100264 DOI: 10.1002/lpor.202100264 Early Access Date: SEP 2021 Published: NOV 2021 | |||||||||||||||||||||
Abstract: Dissipative Kerr solitons in optical microresonators enable the generation of stable ultrashort pulses and phase-locked frequency combs, leading to their widespread applications. For traditional platforms with positive thermal-refractive coefficient, strong thermal effect increases the difficulties of soliton triggering and prohibits the deterministic control of soliton number. Here, using an auxiliary laser to tune thermal effect, soliton burst and bi-directional switching are demonstrated in high-index doped silica glass platform. First, by varying the parameters of the auxiliary laser, the thermal effect tuning of the microresonator is studied with different thermal compensation states achieved, leading to distinct soliton switching features. Especially, the solitons burst and bi-directional switch in over-compensated state. The corresponding process is recorded in real time based on a temporal magnification system, uncovering transient dynamics from continuum background noise to soliton formation. Finally, the deterministic generation of solitons is enabled with controllable soliton number spanning from 1 to 21. The present work provides insight into soliton dynamics and enables soliton generation on demand with a large range of soliton numbers inside a single device. | |||||||||||||||||||||
Accession Number: WOS:000698361800001 | |||||||||||||||||||||
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ISSN: 1863-8880 | |||||||||||||||||||||
eISSN: 1863-8899 |
Record 77 of 318 | ||||||
Title: Phase retrieval based on difference map and deep neural networks | ||||||
Author(s): Li, BP (Li, Baopeng); Ersoy, OK (Ersoy, Okan K.); Ma, CW (Ma, Caiwen); Pan, ZB (Pan, Zhibin); Wen, WS (Wen, Wansha); Song, ZX (Song, Zongxi); Gao, W (Gao, Wei) | ||||||
Source: JOURNAL OF MODERN OPTICS Volume: 68 Issue: 20 Pages: 1108-1120 DOI: 10.1080/09500340.2021.1977860 Early Access Date: SEP 2021 Published: NOV 28 2021 | ||||||
Abstract: Phase retrieval occurs in many research areas. There are some classical phase retrieval methods such as hybrid input-output (HIO) and difference map (DM). However, phase retrieval results are sensitive to noise, and the reconstructed images always include artefacts. In this paper, we use the DM algorithm together with DNN to get better phase retrieval results. We train one deep neural network using amplitude images and phase images, respectively. First, using DM, we get initial reconstructed amplitude and phase results. Then, using DNN improves both amplitude and phase results. Finally, using the DM algorithm again improves the DNN results further. The numerical experimental results show that using DM gives better results than HIO, and using DNN improves phase information better than just using DNN to train for amplitude information alone. Compared with only using DNN improves amplitude methods, our method using DM plus DNN plus DM yields a better reconstruction performance for both amplitude and phase. | ||||||
Accession Number: WOS:000697200100001 | ||||||
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ISSN: 0950-0340 | ||||||
eISSN: 1362-3044 |
Record 78 of 318 | |||||||||||||||||||||
Title: Optical vortex array with deformable hybrid Ferris structures | |||||||||||||||||||||
Author(s): Long, ZX (Long, Zixu); Zhang, H (Zhang, Hao); Tai, YP (Tai, Yuping); Tang, MM (Tang, Miaomiao); Li, HH (Li, Hehe); Li, XZ (Li, Xinzhong) | |||||||||||||||||||||
Source: OPTICS AND LASER TECHNOLOGY Volume: 145 Article Number: 107524 DOI: 10.1016/j.optlastec.2021.107524 Early Access Date: SEP 2021 Published: JAN 2022 | |||||||||||||||||||||
Abstract: We proposed an optical vortex array (OVA) with deformable hybrid Ferris structures (DH-OVA). The DH-OVA was generated via the coaxial coherent superposition of two grafted elliptic perfect optical vortices (OVs) with different topological charges (TCs). The proposed DH-OVA exhibited the capacity of a free transformation from a circle to an ellipse except for the modulation of the number and sign of the unit OVs on the array. The OV distribution obeys the rule of uniform distribution of the area on the upper or lower half. By adjusting the initial phase difference, the orientation factor, and the direction of the grafted axis, a more complex OV motion and the entire hybrid rotation of the DH-OVA can be easily conducted according to the desired application. For instance, for the unidirectional and bidirectional motions of the OVs, regardless of whether they possessed the same or opposite signs, the entire rotation contained the unit OV's motion. During the OV's motion, the number of dark cores was not conserved, whereas the total TCs of the OVs were conserved on the DH-OVA. Results contrasted with the conventional wisdom on OVAs. Furthermore, the bidirectional motion of yeast particles via the DH-OVA was executed experimentally. This work provided a flexible DH-OVA, which will result in new potential applications in particle transfer, polarity particle sorting, and micro-particle manipulation. | |||||||||||||||||||||
Accession Number: WOS:000697058900001 | |||||||||||||||||||||
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ISSN: 0030-3992 | |||||||||||||||||||||
eISSN: 1879-2545 |
Record 79 of 318 | ||||||||||||||||||||||||
Title: Free carrier induced dark pulse generation in microresonators | ||||||||||||||||||||||||
Author(s): Liu, ML (Liu, Mulong); Shi, WM (Shi, Wenmi); Sun, QY (Sun, Qiyuan); Huang, HM (Huang, Huimin); Lu, ZZ (Lu, Zhizhou); Wang, YY (Wang, Yuanyuan); Cai, YA (Cai, Yanan); Wang, C (Wang, Chang); Li, Y (Li, Yao); Zhao, W (Zhao, Wei) | ||||||||||||||||||||||||
Source: OPTICS LETTERS Volume: 46 Issue: 18 Pages: 4462-4465 DOI: 10.1364/OL.435668 Published: SEP 15 2021 | ||||||||||||||||||||||||
Abstract: We theoretically demonstrate a novel, to the best of our knowledge, mechanism for dark pulse excitation in normal dispersion microresonators exploiting free carrier dispersion and free carrier absorption effects due to multi-photon absorption. Dark pulses can be generated in the three- and four-photon absorption regimes in the presence or absence of external reverse bias to control the lifetime of free carriers, respectively. Direct generation of dark pulses is proven to be feasible in both regimes with a frequency fixed laser. The dynamics of their temporal and spectral evolution have also been investigated. Our findings establish a reliable path for dark pulse and Kerr microcomb generation in related platforms with simplified controlling and tuning techniques. (C) 2021 Optical Society of America | ||||||||||||||||||||||||
Accession Number: WOS:000696222700008 | ||||||||||||||||||||||||
PubMed ID: 34525022 | ||||||||||||||||||||||||
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ISSN: 0146-9592 | ||||||||||||||||||||||||
eISSN: 1539-4794 |
Record 80 of 318 | |||||||||||||||
Title: Non-Invasive Measurement for Cardiac Variations Using a Fiber Optic Sensor | |||||||||||||||
Author(s): Lyu, WM (Lyu, Weimin); Xu, W (Xu, Wei); Yang, FA (Yang, Fangang); Chen, SY (Chen, Shuyang); Tan, FZ (Tan, Fengze); Yu, CY (Yu, Changyuan) | |||||||||||||||
Source: IEEE PHOTONICS TECHNOLOGY LETTERS Volume: 33 Issue: 18 Pages: 990-993 DOI: 10.1109/LPT.2021.3078757 Published: SEP 15 2021 | |||||||||||||||
Abstract: Cardiovascular diseases (CVDs) are very common in modern society, such as atherosclerosis, hypertension, etc., which have a great impact on heart function. Therefore, hospitalization monitoring alone is far from enough. Long-term monitoring of the heart is needed in daily life. The technology of non-invasive monitoring of the cardiovascular system can meet the needs of long-term monitoring of the heart condition, helping to promote the improvement of lifestyle and daily care, reducing the overall risk of developing CVDs. The purpose of this study is to investigate the cardiac response after different exercises using a 3 x 3 demodulation scheme-based ballisto-cardiography (BCG) monitoring system. A fiber optic sensor (FOS)-based smart cushion is used to replace the traditional inconvenient electrocardiogram (ECG) for heart rate variability (HRV). The correlation between BCG inter-beat interval (IBI) and ECG IBI is 0.9862, and the RMSE is 0.0139. The BCG signal can assess cardiac contractility by analyzing RJ interval with ECG, which is a practical alternative to the pre-ejection period (PEP). | |||||||||||||||
Accession Number: WOS:000692735600005 | |||||||||||||||
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ISSN: 1041-1135 | |||||||||||||||
eISSN: 1941-0174 |
Record 81 of 318 | |||||||||
Title: Experimental Demonstration of Nonlinear Scattering Processes in a Microbottle Resonator Based on a Robust Packaged Platform | |||||||||
Author(s): Wang, MY (Wang, Mengyu); Yang, Y (Yang, Yu); Lu, ZZ (Lu, Zhizhou); Wang, WQ (Wang, Weiqiang); Zhang, WF (Zhang, Wenfu); Xie, CF (Xie, Chengfeng); Zhong, HK (Zhong, Huikai); Wu, LF (Wu, Lingfeng); Wu, T (Wu, Tao); Tan, QG (Tan, Qinggui); Fu, YN (Fu, Yanjun); Wang, KY (Wang, Keyi) | |||||||||
Source: JOURNAL OF LIGHTWAVE TECHNOLOGY Volume: 39 Issue: 18 Pages: 5917-5924 DOI: 10.1109/JLT.2021.3092636 Published: SEP 15 2021 | |||||||||
Abstract: Microbottle resonators (MBR) have attracted research interest for studying nonlinear optical interactions in last two decades, due to the ultra-tight optical confinement in spaces of three dimensions. In this paper, silica MBRs exhibiting rich resonant modes with ultra-high quality factor up to 3.73 x 10(8) are demonstrated, based on which a portable and robust packaged platform with a tapered fiber coupling is established. Such a packaged platform effectively avoids external perturbations such as air flow and tiny mechanical vibrations, which supports our experimental demonstration of nonlinear scattering effects including four-wave mixing (FWM), simulated Raman scattering, and simulated Brillouin scattering. As a result, Raman-assisted FWM and Brillouin-assisted FWM are observed due to the strong field enhancement in the MBR. In a further investigation, a Kerr frequency comb with broad bandwidth of similar to 200 nm and a Raman-assisted comb with a bandwidth up to similar to 50 nm is achieved, correspondingly. Our works show the versatility of MBR for fundamental research and may open a new route to the development of practical applications in frequency conversion, spectroscopy and communications. | |||||||||
Accession Number: WOS:000703026100027 | |||||||||
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ISSN: 0733-8724 | |||||||||
eISSN: 1558-2213 |
Record 82 of 318 | ||||||
Title: Ultra-broadband Bragg concave diffraction grating designs on 220-nm SOI for wavelength demultiplexing | ||||||
Author(s): Li, K (Li, Ke); Zhu, JP (Zhu, Jingping); Duan, QH (Duan, Qihang); Sun, YZ (Sun, Yuzhou); Hou, X (Hou, Xun) | ||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 19 Pages: 30259-30271 DOI: 10.1364/OE.431133 Published: SEP 13 2021 | ||||||
Abstract: The appropriate broadband design of a de/multiplexer can significantly increase the channel number and consequently the transmission capacity of a wavelength division multiplexing system. Herein, we present the first ultra-broadband Bragg concave diffraction grating (CDG) on a 220-nm silicon-on-insulator, covering most of the E, S, C, L, and U telecommunication wavebands spanning from 1.425 to 1.675 mu m. A wide-band-gap Bragg mirror is employed to facilitate broadband reflection, with a low diffraction order of grating for a sufficient free spectral range. Numerical simulations show that the proposed approaching blazed concave diffraction grating (AB-CDG) for the two-material case exhibits a high integration, simple fabrication process, and promising spectral performance. We fabricate the grating for design verification with a low transmission loss of -0.6 dB and a crosstalk below -33.7 dB for the eight measured wavelength channels covering the spectral range from 1.5 to 1.61 mu m that is limited by the bandwidth of the grating coupler. This design can be used for broadband wavelength demultiplexing, frontier astronomical observation, and spectroscopic imaging. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||
Accession Number: WOS:000695619200053 | ||||||
PubMed ID: 34614752 | ||||||
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ISSN: 1094-4087 |
Record 83 of 318 | ||||||||||||
Title: Hyperspectral anomaly detection via super-resolution reconstruction with an attention mechanism | ||||||||||||
Author(s): Chong, D (Chong, Dan); Hu, BL (Hu, Bingliang); Gao, H (Gao, Hao); Gao, XH (Gao, Xiaohui) | ||||||||||||
Source: APPLIED OPTICS Volume: 60 Issue: 26 Pages: 8109-8119 DOI: 10.1364/AO.432704 Published: SEP 10 2021 | ||||||||||||
Abstract: Hyperspectral anomaly detection aims to classify the anomalous objects in the scene. However, the spatial resolution of the hyperspectral images is relatively low, leading to inaccurate detection of abnormal pixels. Existing methods either ignore the low-resolution problem or leverage super-resolution models to reconstruct the global image to detect abnormal pixels. We claim that reconstructing super-resolution of the global image is unnecessary, while the area where the abnormal target is located should be paid more attention to be reconstructed. In this paper, we propose a super-resolution reconstruction with an attention mechanism for hyperspectral anomaly detection. Our method can automatically extract additional high-frequency information from low-spatial-resolution images and detect abnormal pixels simultaneously. Furthermore, the spatial-channel attention mechanism is adopted to select significant features for reconstructing super-resolution images by assigning different weights to different channels and different spatial-spectral locations. Finally, a regularized join loss function is proposed that balances different tasks by adjusting the relative weight. The experimental results on the public hyperspectral real datasets demonstrate that the proposed method outperforms the state-of-the-art methods. (C) 2021 Optical Society of America | ||||||||||||
Accession Number: WOS:000695067100032 | ||||||||||||
PubMed ID: 34613074 | ||||||||||||
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ISSN: 1559-128X | ||||||||||||
eISSN: 2155-3165 |
Record 84 of 318 | ||||||||||||
Title: Terahertz photoconductive antenna based on antireflection dielectric metasurfaces with embedded plasmonic nanodisks | ||||||||||||
Author(s): Jiang, XQ (Jiang, Xiao-Qiang); Fan, WH (Fan, Wen-Hui); Song, C (Song, Chao); Chen, X (Chen, Xu); Wu, Q (Wu, Qi) | ||||||||||||
Source: APPLIED OPTICS Volume: 60 Issue: 26 Pages: 7921-7928 DOI: 10.1364/AO.431678 Published: SEP 10 2021 | ||||||||||||
Abstract: By taking advantage of dielectric metasurfaces and plasmonic nanostructures, a terahertz photoconductive antenna (THz-PCA) is proposed and investigated in detail. The designed dielectric metasurfaces can reduce the optical reflection down to 1.4% and accelerate the switching process (electric conductive to resistive) that broadens the THz spectrum emitted from THz-PCA. Simultaneously, the embedded plasmonic nanostructures can realize 11.2 times enhancement in local electric field without affecting the switching process and the damage threshold of the THz-PCA. Simulated results indicate that the proposed THz-PCA is 70.56 times stronger in THz radiation power than that of the traditional THz-PCA. The significant enhancement ensures the proposed THz-PCA has great prospects in promoting THz technology based on the THz-PCA. (C) 2021 Optical Society of America | ||||||||||||
Accession Number: WOS:000695067100009 | ||||||||||||
PubMed ID: 34613051 | ||||||||||||
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ISSN: 1559-128X | ||||||||||||
eISSN: 2155-3165 |
Record 85 of 318 | ||||||
Title: Enhanced optical absorption surface of titanium fabricated by a femtosecond laser assisted with airflow pressure | ||||||
Author(s): Li, X (Li, Xun); Li, M (Li, Ming); Liu, HJ (Liu, Hongjun) | ||||||
Source: CHINESE OPTICS LETTERS Volume: 19 Issue: 9 Article Number: 091404 DOI: 10.3788/COL202119.091404 Published: SEP 10 2021 | ||||||
Abstract: We propose an effective way to achieve an enhanced optical absorption surface of titanium alloy 7 (Ti7) fabricated by a femtosecond (fs) laser assisted with airflow pressure. The effect of laser scanning speed and laser power on the surfaces' morphology and average reflectivity was studied. In order to further reduce the surface's reflectivity, different airflow pressure was introduced during the fabrication of Ti7 by a fs laser. Furthermore, the average reflectivity of samples fab-ricated under different laser parameters assisted with airflow was presented. In addition, the high and low temperature tests of all samples were performed to test the stability performance of the hybrid micro/nanostructures in extreme envi-ronments. It is demonstrated that the airflow pressure has an important influence on the micro/nanostructures for light trapping, the average reflectivity of which could be as low as 2.31% over a broad band of 250-2300 nm before high and low temperature tests, and the reflection for specific wavelengths can go below 1.5%. | ||||||
Accession Number: WOS:000712400800019 | ||||||
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ISSN: 1671-7694 |
Record 86 of 318 | |||||||||||||||
Title: Collective multipartite Einstein-Podolsky-Rosen steering via cascaded four-wave mixing of rubidium atoms | |||||||||||||||
Author(s): Liu, Y (Liu, Yang); Cai, Y (Cai, Yin); Luo, BS (Luo, Binshuo); Yan, J (Yan, Jin); Niu, MQ (Niu, Mengqi); Li, F (Li, Feng); Zhang, YP (Zhang, Yanpeng) | |||||||||||||||
Source: PHYSICAL REVIEW A Volume: 104 Issue: 3 Article Number: 033704 DOI: 10.1103/PhysRevA.104.033704 Published: SEP 7 2021 | |||||||||||||||
Abstract: Collective multipartite Einstein-Podolsky-Rosen (EPR) steering is a type of quantum correlation shared among n parties, where the EPR paradox of one party can be realized only by performing local measurements on all the remaining n - 1 parties. Here, we propose an efficient method to produce collective multipartite EPR steering via symmetrically and asymmetrically cascading parametric amplification processes, i.e., four-wave mixing (FWM) of rubidium atoms. The simplified collective-steering criterion is introduced using the Coffman-Kundu-Wootters monogamy relation. Moreover, by actively adjusting the parametric gains, the collective EPR steerability is optimized in our schemes. We find that the scale of collective steering can be extended by cascading more FWMs; in particular, introducing optical loss is useful for generating collective steering with more parties only in the asymmetry structure. Our results pave the way for the construction of quantum networks and provide a promising candidate for one-sided device-independent quantum cryptography among multiple users. | |||||||||||||||
Accession Number: WOS:000693413800020 | |||||||||||||||
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ISSN: 2469-9926 | |||||||||||||||
eISSN: 2469-9934 |
Record 87 of 318 | ||||||||||||||||||
Title: Memory Deficit in Patients With Temporal Lobe Epilepsy: Evidence From Eye Tracking Technology | ||||||||||||||||||
Author(s): Zhu, GP (Zhu, Guangpu); Wang, J (Wang, Jing); Xiao, L (Xiao, Ling); Yang, K (Yang, Ke); Huang, KL (Huang, Kailing); Li, BB (Li, Beibin); Huang, S (Huang, Sha); Hu, BL (Hu, Bingliang); Xiao, B (Xiao, Bo); Liu, D (Liu, Ding); Feng, L (Feng, Li); Wang, Q (Wang, Quan) | ||||||||||||||||||
Source: FRONTIERS IN NEUROSCIENCE Volume: 15 Article Number: 716476 DOI: 10.3389/fnins.2021.716476 Published: SEP 7 2021 | ||||||||||||||||||
Abstract: Objective: To explore quantitative measurements of the visual attention and neuroelectrophysiological relevance of memory deficits in temporal lobe epilepsy (TLE) by eye tracking and electroencephalography (EEG).</p> | ||||||||||||||||||
Accession Number: WOS:000697387900001 | ||||||||||||||||||
PubMed ID: 34557066 | ||||||||||||||||||
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eISSN: 1662-453X |
Record 88 of 318 |
Title: A time-correlated single photon counting signal denoising method based on elastic variational mode extraction |
Author(s): Wang, SC (Wang Shu-Chao); Su, XQ (Su Xiu-Qin); Zhu, WH (Zhu Wen-Hua); Chen, SM (Chen Song-Mao); Zhang, ZY (Zhang Zhen-Yang); Xu, WH (Xu Wei-Hao); Wang, DJ (Wang Ding-Jie) |
Source: ACTA PHYSICA SINICA Volume: 70 Issue: 17 Article Number: 174304 DOI: 10.7498/aps.70.20210149 Published: SEP 5 2021 |
Abstract: The performance of the method of measuring the time-correlated single photon counting signal is the key to improving the ranging accuracy of single photon light detection and ranging (LiDAR) technique, where noise elimination is a critically essential step to obtain the characteristics of signal. In this paper, a new method called elastic variational mode extraction (EVME) is proposed to extract the feature of the reflected photons from noisy environment. The method takes into account the characteristic of photon counting signal, and improves variational mode decomposition (VMD) method by adopting a new assumption that the extractive mode signal should be compact around desired center frequency. The proposed method also uses the elastic net regularization to solve ill-posed problem instead of Tikhonov regularization mentioned in VMD. Elastic net regularization takes into account both L2-norm regularization and L1-norm regularization, which can add an extra analysis dimension compared with the Tikhonov regularization. The method is validated with real data which are acquired on condition that average transmitting power is 25 nW while the average background noise power is 19.51 mu W. The root mean square error of the reconstruction accuracy reaches 1.414 ns. Furthermore, compared with VMD, Haar wavelet, Hibert envelope, empirical mode decomposition (EMD) and complete ensemble empirical mode decomposition method based on adaptive noise (CEEMDAN) under different conditions, the proposed method show fast and stable performance under an extreme case. |
Accession Number: WOS:000695077200018 |
ISSN: 1000-3290 |
Record 89 of 318 | |||||||||
Title: Wideband low-profile dual-polarized dielectric patch antenna with metallic pins | |||||||||
Author(s): Cao, ZX (Cao, Zhi-Xun); Zhang, L (Zhang, Li); Wang, H (Wang, Hao); Lu, H (Lu, Hao); Liu, JF (Liu, Jianfeng); Qiu, YH (Qiu, Yonghui) | |||||||||
Source: MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Volume: 63 Issue: 12 Pages: 3079-3085 DOI: 10.1002/mop.33036 Early Access Date: SEP 2021 Published: DEC 2021 | |||||||||
Abstract: In this article, a lowprofile dual-polarized dielectric patch antenna (DPA) using TM101 and TM121 modes is proposed for achieving the impedance bandwidth (BW) enhancement. By introducing four metallic pins in a dielectric patch resonator (DPR), the TM121 mode is shifted to low frequencies while TM101 mode is shifted to high frequencies. Therefore, the two modes can be close to each other for obtaining wide working bandwidth. Moreover, two orthogonal aperture-coupled feeders are employed to excite the proposed DPR to realize the dual polarization. Finally, the proposed antenna is fabricated and measured. The simulated and measured results show that the 10 dB impedance matching bandwidth is 15.2% (5.05-5.87 GHz), while maintaining the low-profile characteristics with the height of 0.07 lambda(0) (lambda(0) is free space wavelength at the center frequency f(0)). In addition, the antenna achieved a peak gain of 8.55 dBi in the operating frequency. | |||||||||
Accession Number: WOS:000692641200001 | |||||||||
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ISSN: 0895-2477 | |||||||||
eISSN: 1098-2760 |
Record 90 of 318 | |||||||||||||||
Title: Size effects in a hybrid plasmonic waveguide based power monitor with a bolometric method | |||||||||||||||
Author(s): Li, Y (Li, Yan); Chen, AN (Chen, Anqi); Dai, TG (Dai, Tingge); Chen, WW (Chen, Weiwei); Liu, HJ (Liu, Hongjun); Wang, PJ (Wang, Pengjun) | |||||||||||||||
Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS Volume: 54 Issue: 35 Article Number: 355107 DOI: 10.1088/1361-6463/ac0927 Published: SEP 2 2021 | |||||||||||||||
Abstract: A silicon based hybrid plasmonic waveguide (HPW) configuration has been widely utilized to monitor the power flowing in the plasmonic circuit. Due to the approximately linear relationship between resistance and temperature change (the temperature coefficient of resistance, TCR), the voltage-signal variation directly leads to the change of resistance and the corresponding change of coupled-in power. However, the size effect is rarely explored and demonstrated, which plays a substantial role while the metal-strip thickness approaches to its electron mean free path. It exhibits different electric properties, such as reduced TCR and thermal conductivity, resulting in deviations of resistivity. On the contrary, due to the increase of boundary scattering and narrow-strip absorption, an improvement of the responsivity and excepted sensitivity is found. Therefore, considering a trade-off associated with size effects, 50 nm silver-strip and gold-strip were utilized as the conductor layer in the HPW configuration with different geometries, respectively. Meanwhile, a 50 nm x 300 nm gold-strip HPW provides an improvement performance, up to 13.7 mV mW V-1, 0.05 mu W sensitivity at bias 0.1 V. Its responsivity is about 1.4 times larger than that of silver, which contradicts to the macroscopic model. | |||||||||||||||
Accession Number: WOS:000664292800001 | |||||||||||||||
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ISSN: 0022-3727 | |||||||||||||||
eISSN: 1361-6463 |
Record 91 of 318 | |||||||||
Title: Performance of a visible light photon counting imaging detector for weak light intensities | |||||||||
Author(s): Liu, Y' (Liu, Yong'an); Sheng, LZ (Sheng, Lizhi); Zhao, H (Zhao, Hui); Tian, JS (Tian, Jinshou); Zhao, BS (Zhao, Baosheng) | |||||||||
Source: JOURNAL OF MODERN OPTICS Volume: 68 Issue: 19 Pages: 1019-1025 DOI: 10.1080/09500340.2021.1968053 Early Access Date: SEP 2021 Published: NOV 11 2021 | |||||||||
Abstract: In this study, a visible light photon-counting imaging detector was developed for weak light intensities, such as biofluorescence and photon-counting 3D imaging radars. The proposed visible light photon-counting imaging detector was based on a semitransparent S25 photocathode able of responding to visible light or even near-infrared wavelengths. The detector adopted image charge readout mode through high-resistance Ge layer receiver of electron cloud from the microchannel plate. The performance of the as-obtained visible light photon-counting imaging detector was tested in existing readout electronics and newly designed position-sensitive anodes. The quantum efficiency of the as-prepared detector reached 13.4% (@532 nm) with spatial resolution better than 100 mu m. Preliminary imaging results of real objects with commercial lens and detector were also obtained and applied to ultra-weak light detection. In sum, these results look promising for future applications in photon-counting radars and biofluorescence imaging. | |||||||||
Accession Number: WOS:000693268500001 | |||||||||
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ISSN: 0950-0340 | |||||||||
eISSN: 1362-3044 |
Record 92 of 318 |
Title: Design analysis and test verification of a rigid-flexible, dual-mode coupling support structure for space-based rectangular curved prisms |
Author(s): Jia, XY (Jia, Xin-Yin); Wang, FC (Wang, Fei-Cheng); Li, LB (Li, Li-Bo); Zhang, ZH (Zhang, Zhao-Hui); Liu, J (Liu, Jia); Hu, BL (Hu, Bing-Liang) |
Source: APPLIED OPTICS Volume: 60 Issue: 25 Pages: 7563-7573 DOI: 10.1364/AO.431394 Published: SEP 1 2021 |
Abstract: In view of the functional requirements of high reliability and stability support of optical components of space remote sensors, a rigid-flexible, dual-mode coupling support structure for space-based rectangular curved prisms (SRCPs) was designed. In-depth studies of the support principle and engineering realization of the SRCPs and optimization of the flexible adhesive structure were performed. Static and dynamic simulations were conducted on the mirror subassembly by means of finite element analysis, and test verification was also performed. The tests revealed that the surface shape error of the mirror subassembly after mechanical testing was 0.021 lambda, the displacement of the mirror body was 0.008 mm, the inclination angle was similar to 0.8 '', the mass of the mirror subassembly was 4.79 kg, the fundamental frequency was 283 Hz, and the maximum amplification of the total rms acceleration was 4.37. All indexes were superior to those of the design requirements. On this basis, bonding tests and mechanical tests of a rectangular curved prism reflector, a rectangular curved prism, and a rectangular plane reflector employing this proposed support structure were continued. The test results verified the reliability, stability, and universal applicability of the proposed rigid-flexible, dual-mode peripheral bonding support structure. (C) 2021 Optical Society of America |
Accession Number: WOS:000692206400035 |
PubMed ID: 34613222 |
ISSN: 1559-128X |
eISSN: 2155-3165 |
Record 93 of 318 | ||||||||||||
Title: Characteristics of nonlinear terahertz-wave radiation generated by mid-infrared femtosecond pulse laser excitation | ||||||||||||
Author(s): Shibuya, K (Shibuya, Kyuki); Nawata, K (Nawata, Kouji); Nakajima, Y (Nakajima, Yoshiaki); Fu, YX (Fu, Yuxi); Takahashi, EJ (Takahashi, Eiji J.); Midorikawa, K (Midorikawa, Katsumi); Yasui, T (Yasui, Takeshi); Minamide, H (Minamide, Hiroaki) | ||||||||||||
Source: APPLIED PHYSICS EXPRESS Volume: 14 Issue: 9 Article Number: 092004 DOI: 10.35848/1882-0786/ac1a48 Published: SEP 1 2021 | ||||||||||||
Abstract: We report on efficient terahertz-wave generation in organic and inorganic crystals by nonlinear wavelength conversion approach using a 3.3 mu m femtosecond pulse laser. Experimental results reveal the relation between pump power and terahertz-wave output power, which is proportional to the square of the pump power at the range of mega- to tera-watt cm(-2) class even if the pump wavelength is different. Damage threshold of organic and inorganic crystals are recorded 0.6 and 18 tera-watt cm(-2) by reducing several undesirable nonlinear optical effects using mid-infrared source. (C) 2021 The Japan Society of Applied Physics | ||||||||||||
Accession Number: WOS:000686471100001 | ||||||||||||
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ISSN: 1882-0778 | ||||||||||||
eISSN: 1882-0786 |
Record 94 of 318 | ||||||||||||
Title: Difference Curvature Multidimensional Network for Hyperspectral Image Super-Resolution | ||||||||||||
Author(s): Zhang, C (Zhang, Chi); Zhang, MJ (Zhang, Mingjin); Li, YS (Li, Yunsong); Gao, XB (Gao, Xinbo); Qiu, S (Qiu, Shi) | ||||||||||||
Source: REMOTE SENSING Volume: 13 Issue: 17 Article Number: 3455 DOI: 10.3390/rs13173455 Published: SEP 2021 | ||||||||||||
Abstract: In recent years, convolutional-neural-network-based methods have been introduced to the field of hyperspectral image super-resolution following their great success in the field of RGB image super-resolution. However, hyperspectral images appear different from RGB images in that they have high dimensionality, implying a redundancy in the high-dimensional space. Existing approaches struggle in learning the spectral correlation and spatial priors, leading to inferior performance. In this paper, we present a difference curvature multidimensional network for hyperspectral image super-resolution that exploits the spectral correlation to help improve the spatial resolution. Specifically, we introduce a multidimensional enhanced convolution (MEC) unit into the network to learn the spectral correlation through a self-attention mechanism. Meanwhile, it reduces the redundancy in the spectral dimension via a bottleneck projection to condense useful spectral features and reduce computations. To remove the unrelated information in high-dimensional space and extract the delicate texture features of a hyperspectral image, we design an additional difference curvature branch (DCB), which works as an edge indicator to fully preserve the texture information and eliminate the unwanted noise. Experiments on three publicly available datasets demonstrate that the proposed method can recover sharper images with minimal spectral distortion compared to state-of-the-art methods. PSNR/SAM is 0.3-0.5 dB/0.2-0.4 better than the second best methods. | ||||||||||||
Accession Number: WOS:000694615600001 | ||||||||||||
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eISSN: 2072-4292 |
Record 95 of 318 | |||||||||||||||
Title: Lensless multimode fiber imaging based on wavefront shaping | |||||||||||||||
Author(s): Zhang, ZK (Zhang, Zaikun); Kong, DP (Kong, Depeng); Geng, Y (Geng, Yi); Chen, H (Chen, Hui); Wang, RD (Wang, Ruiduo); Da, Z (Da, Zhengshang); He, ZQ (He, Zhengquan) | |||||||||||||||
Source: APPLIED PHYSICS EXPRESS Volume: 14 Issue: 9 Article Number: 092002 DOI: 10.35848/1882-0786/ac19d4 Published: SEP 1 2021 | |||||||||||||||
Abstract: In this letter, we proposed a compact multimode fiber (MMF)-based laser scanning endoscope (LSE) using wavefront shaping with a liquid crystal spatial light modulator. Experimentally, we demonstrated the lensless imaging capability of the LSE using a negative USAF-1951 test target placed near the distal MMF facet, obtaining similar to 7000-pixel images with micro-level spatial resolution and high contrast across a 105 mu m field of view. This study proves the feasibility of a single MMF imaging without mechanical scanning, and also paves the way for ultra-thin micro-endoscopic imaging. | |||||||||||||||
Accession Number: WOS:000684701400001 | |||||||||||||||
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ISSN: 1882-0778 | |||||||||||||||
eISSN: 1882-0786 |
Record 96 of 318 | ||||||
Title: A Novel NMF Guided for Hyperspectral Unmixing From Incomplete and Noisy Data | ||||||
Author(s): Dong, L (Dong, Le); Lu, XQ (Lu, Xiaoqiang); Liu, GC (Liu, Ganchao); Yuan, Y (Yuan, Yuan) | ||||||
Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Volume: 60 DOI: 10.1109/TGRS.2021.3101504 Early Access Date: AUG 2021 Published: 2022 | ||||||
Abstract: The nonnegative matrix factorization (NMF)-combined spatial-spectral information has been widely applied in the unmixing of hyperspectral images (HSIs). However, how to select the appropriate similarity pixels and explore the spatial information and how to adapt the unmixing algorithm to complex data are both great challenges. In this article, we propose a novel unmixing method named spatial-spectral neighborhood preserving NMF (SSNPNMF) for incomplete and noisy HSI data. First, a spatial-spectral kernel regularizer is introduced to preprocess the HSI, which can reduce noise and complete missing elements. Second, a distance metric SSD based on spatial-spectral information is designed to select similar pixels in the image. Subsequently, the spatial-spectral relationship of the selected first k similar pixels is used to reconstruct the image and obtain the reconstruction matrix. Finally, the reconstruction matrix is used to constrain the abundances and improve the unmixing performance. Experimental results on synthetic data and Cuprite data indicate that SSNPNMF has a more effective unmixing performance compared with the state-of-the-art methods. | ||||||
Accession Number: WOS:000732810700001 | ||||||
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ISSN: 0196-2892 | ||||||
eISSN: 1558-0644 |
Record 97 of 318 | |||||||||||||||
Title: Optical coherence tomography-surveilled laser ablation using multifunctional catheter and 355-nm optical pulses | |||||||||||||||
Author(s): Kang, JQ (Kang, Jiqiang); Zhu, R (Zhu, Rui); Li, JN (Li, Jianan); Liu, HP (Liu, Haiping); Ma, XQ (Ma, Xiuquan); Tao, L (Tao, Ling); Sun, YX (Sun, Yunxu) | |||||||||||||||
Source: OPTICS COMMUNICATIONS Volume: 501 Article Number: 127364 DOI: 10.1016/j.optcom.2021.127364 Early Access Date: AUG 2021 Published: DEC 15 2021 | |||||||||||||||
Abstract: An optical coherence tomography (OCT)-monitored laser ablation system is presented in this study. The laser ablation subsystem is constructed using the third harmonic output of a Nd:YAG laser source operating at a 355-nm optical wavelength with a single pulse energy greater than 160 mJ and a 1-10 Hz tunable repetition rate. The imaging subsystem is a typical M-mode swept-source OCT system. Moreover, a type of all-fiber multifunctional integrated catheter is demonstrated. The ablation catheter consists of a fiber bundle including 41 multi-mode fibers with an outer diameter of 0.9 mm. A forward-viewing OCT imaging probe is inserted into the ablation catheter for M-mode imaging. The performance of the system is demonstrated by OCT surveillance of the laser ablation process using expanded polystyrene foam as the sample. The OCT system can be used to record the ablation process and simultaneously count the laser ablation duration. This study proposes an effective potential technique to surveil material laser ablation processes, especially in situations where bulky optics are prohibited and all-fiber devices are required. | |||||||||||||||
Accession Number: WOS:000696943300004 | |||||||||||||||
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ISSN: 0030-4018 | |||||||||||||||
eISSN: 1873-0310 |
Record 98 of 318 | ||||||||||||
Title: Algorithm of Pulmonary Vascular Segment and Centerline Extraction | ||||||||||||
Author(s): Qiu, S (Qiu, Shi); Lian, J (Lian, Jie); Ding, Y (Ding, Yan); Zhou, T (Zhou, Tao); Liang, T (Liang, Ting) | ||||||||||||
Source: COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE Volume: 2021 Article Number: 3859386 DOI: 10.1155/2021/3859386 Published: AUG 26 2021 | ||||||||||||
Abstract: Because pulmonary vascular lesions are harmful to the human body and difficult to detect, computer-assisted diagnosis of pulmonary blood vessels has become the focus and difficulty of the current research. An algorithm of pulmonary vascular segment and centerline extraction which is consistent with the physician's diagnosis process is proposed for the first time. We construct the projection of maximum density, restore the vascular space information, and correct random walk algorithm to satisfy automatic and accurate segmentation of blood vessels. Construct a local 3D model to restrain Hessian matrix when extracting centerline. In order to assist the physician to make a correct diagnosis and verify the effectiveness of the algorithm, we proposed a visual expansion model. According to the 420 high-resolution CT data of lung blood vessels labeled by physicians, the accuracy of segmentation algorithm AOM reached 93%, and the processing speed was 0.05 s/frame, which achieved the clinical application standards. | ||||||||||||
Accession Number: WOS:000693117500001 | ||||||||||||
PubMed ID: 34484415 | ||||||||||||
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ISSN: 1748-670X | ||||||||||||
eISSN: 1748-6718 |
Record 99 of 318 | ||||||||||||
Title: Compact 2D serpentine optical phased array | ||||||||||||
Author(s): Ren, YM (Ren, Yangming); Zhang, LX (Zhang, Lingxuan); Zhao, W (Zhao, Wei); Wang, GX (Wang, Guoxi); Feng, NN (Feng, NingNing); Wu, W (Wu, Wei); Sun, XC (Sun, Xiaochen); Zhang, WF (Zhang, Wenfu) | ||||||||||||
Source: APPLIED OPTICS Volume: 60 Issue: 24 Pages: 7158-7163 DOI: 10.1364/AO.431942 Published: AUG 20 2021 | ||||||||||||
Abstract: We present a two-dimensional (2D) Si photonics optical phased array (OPA) using a serpentine design which eliminates the long directional couplers used in many 2D OPA designs. It significantly reduces the distance between the antenna benefitting far-field sidelobe reduction while maintaining high optical power use efficiency. (C) 2021 Optical Society of America | ||||||||||||
Accession Number: WOS:000687563200015 | ||||||||||||
PubMed ID: 34613002 | ||||||||||||
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ISSN: 1559-128X | ||||||||||||
eISSN: 2155-3165 |
Record 100 of 318 | ||||||
Title: Multi-brightness layers with a genetic optimization algorithm for stereo matching under dramatic illumination changes | ||||||
Author(s): Yang, T (Yang, Tao); Yang, R (Yang, Rui); Qiu, YH (Qiu, Yuehong) | ||||||
Source: APPLIED OPTICS Volume: 60 Issue: 24 Pages: 7371-7380 DOI: 10.1364/AO.432015 Published: AUG 20 2021 | ||||||
Abstract: Stereo matching under dramatic illumination changes is a big challenge in imbalanced binocular vision, self-driving cars, and the remote sensing image field. A novel, to the best of our knowledge, multi-brightness layer mechanism with a genetic optimization algorithm is proposed in this paper. The mechanism of multi-brightness layers transforms the two images with dramatic illumination changes into a series of matched pairs with similar brightness by the stretching function and histogram matching principle. Therefore, the large illumination variations are reduced greatly. Moreover, the initial disparities as first generation of genetic optimization approach are generated from matched pairs using fast segmentation local stereo matching to increase the efficiency and accuracy. For further improving the accuracy of disparity, an enhanced genetic optimization algorithm for stereo matching is designed to have more inliers and continuity. The experimental results comparing with state-of-the-art stereo matching methods demonstrate that the proposed method has better performance in accuracy and stability. (C) 2021 Optical Society of America | ||||||
Accession Number: WOS:000687563200039 | ||||||
PubMed ID: 34613026 | ||||||
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ISSN: 1559-128X | ||||||
eISSN: 2155-3165 |
Record 101 of 318 | ||||||||||||||||||
Title: Spectral Super-Resolution of Multispectral Images Using Spatial-Spectral Residual Attention Network | ||||||||||||||||||
Author(s): Zheng, XT (Zheng, Xiangtao); Chen, WJ (Chen, Wenjing); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||||||||
Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Volume: 60 DOI: 10.1109/TGRS.2021.3104476 Early Access Date: AUG 2021 Published: 2022 | ||||||||||||||||||
Abstract: The spectral super-resolution of multispectral image (MSI) refers to improving the spectral resolution of the MSI to obtain the hyperspectral image (HSI). Most recent works are based on the sparse representation to unfold the MSI into the 2-D matrix in advance for subsequent operations, which results in that the spatial information of MSI cannot be fully explored. In this article, a spatial-spectral residual attention network (SSRAN) is proposed to simultaneously explore the spatial and spectral information of MSI for reconstructing the HSI. The proposed SSRAN is composed of the feature extraction part, the nonlinear mapping part, and the reconstruction part. Firstly, the multispectral features of the input MSI are extracted in the feature extraction part. Second, in the nonlinear mapping part, the spatial-spectral residual blocks are proposed to explore spatial and spectral information of MSI for mapping the multispectral features to the hyperspectral features. Finally, in the reconstruction part, a 2-D convolution is used to reconstruct the HSI from the hyperspectral features. Also, a neighboring spectral attention module is specially designed to explicitly constrain the reconstructed HSI to maintain the correlation among neighboring spectral bands. The proposed SSRAN outperforms the state-of-the-art methods on both simulated and real databases. | ||||||||||||||||||
Accession Number: WOS:000732810400001 | ||||||||||||||||||
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ISSN: 0196-2892 | ||||||||||||||||||
eISSN: 1558-0644 |
Record 102 of 318 | ||||||||||||||||||||||||
Title: Hyperspectral Unmixing Using Nonlocal Similarity-Regularized Low-Rank Tensor Factorization | ||||||||||||||||||||||||
Author(s): Yuan, Y (Yuan, Yuan); Dong, L (Dong, Le); Li, XL (Li, Xuelong) | ||||||||||||||||||||||||
Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Volume: 60 DOI: 10.1109/TGRS.2021.3095488 Early Access Date: AUG 2021 Published: 2022 | ||||||||||||||||||||||||
Abstract: Recently, methods based on nonnegative tensor factorization (NTF), which benefits from the tensor representation of hyperspectral imagery (HSI) without any information loss, have attracted increasing attention. However, most existing methods fail to explore the internal spatial structure of data, resulting in low unmixing performance. Moreover, when the algorithm is optimized, the solution is unstable. In this article, a regularizer based on nonlocal tensor similarity is proposed, which can not only fully preserve the global information of HSI but also mine the internal information of data in the spatial domain. HSI is regarded as a 3-D tensor and is directly subjected to endmember extraction and abundance estimation. To fully explore the structural characteristics of data, we simultaneously use the local smoothing and low tensor rank prior of the data to constrain the unmixing model. First, several 4-D tensor groups can be obtained after the nonlocal similarity structure of HSI is learned. Subsequently, a low tensor rank prior is applied to each 4-D tensor, which can fully simulate the nonlocal similarity in the image. In addition, total variation (TV) is also used to explore the local spatial relationship of data, which can generate a smooth abundance map through edge preservation. The optimization is solved by the ADMM algorithm. Experiments on synthetic and real data illustrate the superiority of the proposed method. | ||||||||||||||||||||||||
Accession Number: WOS:000732753000001 | ||||||||||||||||||||||||
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ISSN: 0196-2892 | ||||||||||||||||||||||||
eISSN: 1558-0644 |
Record 103 of 318 | ||||||
Title: Infrared and visible image fusion based on variational auto-encoder and infrared feature compensation | ||||||
Author(s): Ren, L (Ren, Long); Pan, ZB (Pan, Zhibin); Cao, JZ (Cao, Jianzhong); Liao, JW (Liao, Jiawen) | ||||||
Source: INFRARED PHYSICS & TECHNOLOGY Volume: 117 Article Number: 103839 DOI: 10.1016/j.infrared.2021.103839 Early Access Date: AUG 2021 Published: SEP 2021 | ||||||
Abstract: With high sensitivity to capture rich details, visible imaging equipment can take images containing more textures and contours which are important to visual perception. Unlike visible cameras, infrared imaging devices can detect targets invisible in visible images, because the imaging principle of infrared sensors derives from differences of thermal radiation. Thus, the purpose of image fusion is to merge as much meaningful feature information from the infrared and visible images into the fused image as possible, such as contours as well as textures of the visible image and thermal targets of the infrared image. In this paper, we propose an image fusion network based on variational auto-encoder (VAE), which performs the image fusion process in deep hidden layers. We divide the proposed network into image fusion network and infrared feature compensation network. Firstly, in the image fusion network, the encoder of the image fusion network is created to generate the latent vectors in hidden layers from the input visible image and infrared image. Secondly, two different latent vectors merge into one based on the product of Gaussian probability density; accordingly, the decoder begins to reconstruct the fused image with the descent of the loss function value. Meanwhile, Residual block and symmetric skip connection methods are added to the network to enhance the efficiency of network training. Finally, due to the defect of the loss function setting in the fusion network, an infrared feature compensation network is designed to compensate critical radiation features of the infrared image. Experimental results on public available datasets demonstrate that the proposed method is superior to other traditional and deep learning methods in both objective metrics and subjective visual perception. | ||||||
Accession Number: WOS:000691626400004 | ||||||
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ISSN: 1350-4495 | ||||||
eISSN: 1879-0275 |
Record 104 of 318 | ||||||||||||||||||
Title: Spin-decoupled metasurface for broadband and pixel-saving polarization rotation and wavefront control | ||||||||||||||||||
Author(s): Ji, RN (Ji, Ruonan); Song, K (Song, Kun); Guo, XY (Guo, Xuyue); Xie, X (Xie, Xin); Zhao, Y (Zhao, Yang); Jin, CA (Jin, Chuan); Wang, SW (Wang, Shaowei); Jiang, CM (Jiang, Chengming); Yin, JB (Yin, Jianbo); Liu, YH (Liu, Yahong); Zhai, SL (Zhai, Shilong); Zhao, XP (Zhao, Xiaopeng); Lu, W (Lu, Wei) | ||||||||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 16 Pages: 25720-25730 DOI: 10.1364/OE.431740 Published: AUG 2 2021 | ||||||||||||||||||
Abstract: In this paper, a strategy to achieve a simultaneous wavefront shaping and polarization rotation, without compromising the number of pixels and energy efficiency as well as having broadband operation range, is proposed. This strategy is based on the application of a spin-decoupled phase metasurface composed by only one set of metal-insulator-metal (MIM) umbrella-shaped chiral unit cells. Quasi-non-dispersive and spin-decoupled phase shift can be achieved simply by changing single structural parameter of the structure. By further merging the Pancharatnam-Berry (PB) geometric phase, conversion of an incident LP light beam into right-and left-handed circularly polarized reflected beams with similar amplitudes, desired phase profiles and controlled phase retardation on a nanoscale is enabled with high efficiency. Based on the proposed strategy, a polarization-insensitive hologram generator with control optical activity, and a multiple ring vortex beam generator are realized. The results obtained in this work provide a simple and pixel-saving approach to the design of integratable and multitasking devices combining polarization manipulation and wavefront shaping functions, such as vectorial holographic generators, multifocal metalenses, and multichannel vector beam generators. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||||||||
Accession Number: WOS:000678755000083 | ||||||||||||||||||
PubMed ID: 34614895 | ||||||||||||||||||
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ISSN: 1094-4087 |
Record 105 of 318 | |||||||||||||||||||||||||||||||||
Title: Design and verification of the HXI collimator on the ASO-S mission | |||||||||||||||||||||||||||||||||
Author(s): Chen, DY (Chen, Deng-Yi); Hu, YM (Hu, Yi-Ming); Ma, T (Ma, Tao); Su, Y (Su, Yang); Yang, JF (Yang, Jian-Feng); Wang, JP (Wang, Jian-Ping); Xu, GZ (Xu, Guang-Zhou); Jiang, XK (Jiang, Xian-Kai); Guo, JH (Guo, Jian-Hua); Zhang, YQ (Zhang, Yong-Qiang); Zhang, Y (Zhang, Yan); Chen, W (Chen, Wei); Chang, J (Chang, Jin); Zhang, Z (Zhang, Zhe) | |||||||||||||||||||||||||||||||||
Source: RESEARCH IN ASTRONOMY AND ASTROPHYSICS Volume: 21 Issue: 6 Article Number: 136 DOI: 10.1088/1674-4527/21/6/136 Published: AUG 2021 | |||||||||||||||||||||||||||||||||
Abstract: A space-borne hard X-ray collimator, comprising 91 pairs of grids, has been developed for the Hard X-ray Imager (HXI). The HXI is one of the three scientific instruments onboard the first Chinese solar mission: the Advanced Space-based Solar Observatory (ASO-S). The HXI collimator (HXI-C) is a spatial modulation X-ray telescope designed to observe hard X-rays emitted by energetic electrons in solar flares. This paper presents the detailed design of the HXI-C for the qualification model that will be inherited by the flight model. Series tests on the HXI-C qualification model are reported to verify the ability of the HXI-C to survive the launch and to operate normally in on-orbit environments. Furthermore, results of the X-ray beam test for the HXI-C are presented to indirectly identify the working performance of the HXI-C. | |||||||||||||||||||||||||||||||||
Accession Number: WOS:000684224300001 | |||||||||||||||||||||||||||||||||
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ISSN: 1674-4527 | |||||||||||||||||||||||||||||||||
eISSN: 2397-6209 |
Record 106 of 318 | |||||||||
Title: Distortion mapping correction in the AIMS primary mirror testing by a computer-generated hologram | |||||||||
Author(s): Ke-Wei, E (Ke-Wei, E.); Zhao, JK (Zhao, Jian-Ke); Wang, B (Wang, Bo); Wang, DG (Wang, Dong-Guang); Shen, YL (Shen, Yu-Liang); Fu, X (Fu, Xin); Xu, SB (Xu, Song-Bo); Li, J (Li, Jing); Xue, X (Xue, Xun); Chang, M (Chang, Ming); Zhou, Y (Zhou, Yan) | |||||||||
Source: RESEARCH IN ASTRONOMY AND ASTROPHYSICS Volume: 21 Issue: 7 Article Number: 165 DOI: 10.1088/1674-4527/21/7/165 Published: AUG 2021 | |||||||||
Abstract: The National Solar Observatory is currently developing the Accurate Infrared Magnetic Field Measurements of the Sun (AIMS). The primary mirror of the AIMS solar telescope is an off-axis parabolic with a diameter of 1 m and with a large off-axis amount of 1 m. Due to the surface figure of the primary mirror under the used state is directly related to image quality of the whole system, a computer-generated hologram (CGH) is carried out to test the primary mirror, and the test results are used to polish the mirror to a higher surface accuracy. However, the fact that the distortion exists in the testing results leads to the failure of a further guide to deterministic optical processing. In this paper, a distortion correction method is proposed, which uses an orthogonal set of vector polynomials to mapping the coordinates of the mirror and the pixels of fringes, and then an interpolation method is adopted to obtain the corrected results. The testing accuracy by using CGH is also verified by an auto-collimate test experiment. According to the distorted corrected results, the root-mean-square of the surface figure is about 1/50 lambda (lambda = 632.8 nm) after polishing. | |||||||||
Accession Number: WOS:000691273200001 | |||||||||
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ISSN: 1674-4527 | |||||||||
eISSN: 2397-6209 |
Record 107 of 318 |
Title: High-accuracy twist measurement based on he spherical wave Talbot effect for a bi-grid modulation collimator |
Author(s): Liu, SR (Liu, Shengrun); Xue, B (Xue, Bin); Cheng, Y (Cheng, Ying); Yang, JF (Yang, Jianfeng) |
Source: APPLIED OPTICS Volume: 60 Issue: 22 Pages: 6547-6553 DOI: 10.1364/AO.429980 Published: AUG 1 2021 |
Abstract: The bi-grid modulation collimator is a significant way for imaging solar flares in hard x rays. It implements many subcollimators that consist of separated grid pairs (so-called front grid and rear grid) whose line orientations are parallel. However, when the twist of the front grid with respect to the other will be induced during testing of the bi-grid modulation collimator in the ground verification phase, the line orientation of the grid pairs are no longer parallel. Knowledge of the relative twist between the rear grid and the front grid is very helpful in improving the imaging quality of the bi-grid collimator. However, because of the wide spacing between grid pairs and the requirement of high measurement accuracy, it is a challenge to measure the relative twist. To meet this demand, a method based on the spherical wave Talbot effect is proposed. The Talbot images of the front grid and the rear grid are imaged on the same plane, respectively, through two proper spherical waves. The relative twist can be figured out through the angle between the stripes in the Talbot images of the front grid and the rear grid. In experiments, the measurement accuracy of the relative twist angle can reach 9 arcsec in the range of 370 arcsec. It demonstrates that this method can effectively measure the relative twist between the grid pairs with very high accuracy. (C) 2021 Optical Society of America |
Accession Number: WOS:000680164700039 |
PubMed ID: 34612896 |
ISSN: 1559-128X |
eISSN: 2155-3165 |
Record 108 of 318 | ||||||||||||||||||
Title: Perfect Soliton Crystals in the High-Q Microrod Resonator | ||||||||||||||||||
Author(s): Niu, R (Niu, Rui); Wan, S (Wan, Shuai); Wang, ZY (Wang, Zheng-Yu); Li, J (Li, Jin); Wang, WQ (Wang, Wei-Qiang); Zhang, WF (Zhang, Wen-Fu); Guo, GC (Guo, Guang-Can); Zou, CL (Zou, Chang-Ling); Dong, CH (Dong, Chun-Hua) | ||||||||||||||||||
Source: IEEE PHOTONICS TECHNOLOGY LETTERS Volume: 33 Issue: 15 Pages: 788-791 DOI: 10.1109/LPT.2021.3096645 Published: AUG 1 2021 | ||||||||||||||||||
Abstract: The coherent temporal soliton in optical microresonators has attracted great attention recently. Here, we have fabricated the microrod resonator with Q factor as high as 2x10(8) and demonstrated the dissipative Kerr soliton generation in such a microresonator, by utilizing an auxiliary-laser-assisted thermal response control. In addition, we have changed the pump laser and observed the perfect soliton crystals. With the simulation, we found that the perfect soliton crystals are generated based on the avoided mode crossing, which is affected by the pump resonance and pump power. | ||||||||||||||||||
Accession Number: WOS:000678334200003 | ||||||||||||||||||
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ISSN: 1041-1135 | ||||||||||||||||||
eISSN: 1941-0174 |
Record 109 of 318 | |||||||||
Title: The adaptive neural network sliding mode control for angle/force tracking of the dexterous hand | |||||||||
Author(s): Qin, X (Qin, Xing); Shi, H (Shi, Heng); Gao, X (Gao, Xin); Li, XY (Li, Xiyu) | |||||||||
Source: ADVANCES IN MECHANICAL ENGINEERING Volume: 13 Issue: 8 Article Number: 16878140211038096 DOI: 10.1177/16878140211038096 Published: AUG 2021 | |||||||||
Abstract: In order to achieve high precision control of the dexterous hand, an adaptive neural network sliding mode control algorithm based on the U-K (Udwadia-Kalaba) equation is proposed. Firstly, based on the U-K equation and considering the ideal and non-ideal constrained force at each link of the dexterous hand, the detailed dynamic equation is derived. Secondly, considering the uncertainty of the non-ideal constrained force (mainly the friction force on each link of the dexterous hand) and the chattering phenomenon when using sliding mode control alone, the adaptive neural network and the sliding mode control algorithm are combined to realize the high-precision tracking and estimation of each link angle trajectory and the non-ideal constrained force. Finally, in order to verify the correctness and rationality of the proposed algorithm, the 3-DOF spatial dexterous hand is taken as the simulated object. The simulation results show that the tracking and estimation errors of each link angle and the non-ideal constrained force are 10(-2) order of magnitude. | |||||||||
Accession Number: WOS:000698296300001 | |||||||||
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ISSN: 1687-8132 | |||||||||
eISSN: 1687-8140 |
Record 110 of 318 | ||||||
Title: Research on the Response Characteristics of Vanadium Pentoxide Film to the Irradiation of Ultrafast Pulsed Laser | ||||||
Author(s): Shi, QQ (Shi, Qianqian); Zhang, GD (Zhang, Guodong); Wang, YH (Wang, Yuheng); Lan, Y (Lan, Yu); Wang, J (Wang, Jiang); Cheng, GH (Cheng, Guanghua) | ||||||
Source: NANOMATERIALS Volume: 11 Issue: 8 Article Number: 2078 DOI: 10.3390/nano11082078 Published: AUG 2021 | ||||||
Abstract: Vanadium pentoxide (V2O5) is the most stable phase among many transition metal vanadium oxides, and has already been widely used in many fields. In this study, the morphological, structural, and optical responses of V2O5 film to ultrafast laser irradiation was investigated. The third-order nonlinear optical properties of V2O5 film were measured by common Z-scan technique, and the results showed that V2O5 film has self-defocusing and saturable absorption characteristics. The third-order nonlinear absorption coefficient and nonlinear refractive index were calculated to be -338 cm/GW and -3.62 x 10(-12) cm(2)/W, respectively. The tunable saturated absorption with modulation depth ranging from 13.8% to 29.3% was realized through controlling the thickness of vanadium pentoxide film. V2O5 film was irradiated by ultrafast laser with variable pulse energy, and the morphological and structural responses of the V2O5 to the laser with different energy densities were investigated. The irreversible morphological and structural responses of V2O5 films to ultrafast laser irradiation was analyzed using the phase-contrast microscope and Raman spectrum. The chemical structure change from V2O5 to V6O13 was considered the main reason for refractive index modification. | ||||||
Accession Number: WOS:000690139800001 | ||||||
PubMed ID: 34443908 | ||||||
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eISSN: 2079-4991 |
Record 111 of 318 | ||||||||||||
Title: <i>In situ</i> SERS detection of quinolone antibiotic residues in a water environment based on optofluidic in-fiber integrated Ag nanoparticles | ||||||||||||
Author(s): Teng, PP (Teng, Pingping); Gao, DH (Gao, Danheng); Yang, XH (Yang, Xinghua); Luo, M (Luo, Meng); Kong, DP (Kong, Depeng); Gao, S (Gao, Shuai); Liu, ZH (Liu, Zhihai); Li, ZA (Li, Zhanao); Wen, XY (Wen, Xingyue); Yuan, LB (Yuan, Libo); Li, K (Li, Kang); Bowkett, M (Bowkett, Mark); Copner, N (Copner, Nigel) | ||||||||||||
Source: APPLIED OPTICS Volume: 60 Issue: 22 Pages: 6659-6664 DOI: 10.1364/AO.426611 Published: AUG 1 2021 | ||||||||||||
Abstract: In this paper, we present a microstructured optofluidic in-fiber Raman sensor for the detection of quinolone antibiotic residue in a water environment based on Ag surface-enhanced Raman scattering (SERS) substrate grown on the surface of the suspended core of micro-hollow optical fiber (MHF). Here, MHF has a special structure with a suspended core and a microchannel inside, which can become a natural in-fiber optofluidic device. Meanwhile, the self-assembled Ag SERS substrate can be grown on the suspended core's surface through chemical bonds, forming a microstructured optofluidic device with a Raman enhancement effect. Therefore, it can effectively detect the Raman signal of unlabeled trace quinolone antibiotic residue (ciprofloxacin and norfloxacin) inside the optical fiber. The results show that the ciprofloxacin and norfloxacin detection limits (LOD) are 10(-10) M and 10(-11) M, respectively. Compared with the maximum residue limit (3.01 x 10(-7) mol/L) stipulated by the European Union, the results are much lower, and an ideal quantitative relationship can be obtained within the detection range. Significantly, this study provides an in-fiber microstructured optofluidic Raman sensor for the label-free detection of quinolone antibiotic residue, which will have good development prospects in the field of antibiotic water pollution environmental detection. (C) 2021 Optical Society of America | ||||||||||||
Accession Number: WOS:000680164700054 | ||||||||||||
PubMed ID: 34612910 | ||||||||||||
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ISSN: 1559-128X | ||||||||||||
eISSN: 2155-3165 |
Record 112 of 318 | |||||||||||||||||||||
Title: Sub-Pixel Scanning High-Resolution Panoramic 3D Imaging Based on a SPAD Array | |||||||||||||||||||||
Author(s): Xue, RK (Xue, Ruikai); Kang, Y (Kang, Yan); Zhang, TY (Zhang, Tongyi); Li, LF (Li, Lifei); Zhao, W (Zhao, Wei) | |||||||||||||||||||||
Source: IEEE PHOTONICS JOURNAL Volume: 13 Issue: 4 Article Number: 3900106 DOI: 10.1109/JPHOT.2021.3103817 Published: AUG 2021 | |||||||||||||||||||||
Abstract: 3D imaging based on single-photon avalanche diode (SPAD) arrays is of interest in many applications. Limited by the small array size and low fill-factor of the available SPAD array, it is difficult for SPAD array-based lidars to achieve high-resolution and high-quality 3D images currently. Here, we propose a sub-pixel continuously scanning panoramic 3D imaging method. This method uses sub-pixel scanning to increase spatial resolution and employs accumulating photon counts at the different pixel of the array for the same target point to improve 3D image quality. We have established an experimental system based on a 32x32 SPADarray and a diffraction optical element (DOE) with 32 x 32 beamlet. By sub-pixel scanning for a target 3 m away and accumulating photon counts, we demonstrated that the spatial resolution has been improved from 3 mm to 0.33 mm and the 3D image quality has been improved evidently. | |||||||||||||||||||||
Accession Number: WOS:000698687400003 | |||||||||||||||||||||
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ISSN: 1943-0655 | |||||||||||||||||||||
eISSN: 1943-0647 |
Record 113 of 318 | ||||||
Title: Investigation of the size of nanoparticles formed during femto- and nanosecond laser ablation of zircon | ||||||
Author(s): Yang, Y (Yang, Yong); Lou, R (Lou, Rui); Yuan, HL (Yuan, Honglin); Shu, YQ (Shu, Yiqing); Fan, WH (Fan, Wenhui); Cheng, GH (Cheng, Guanghua); Si, JH (Si, Jinhai) | ||||||
Source: OPTICAL ENGINEERING Volume: 60 Issue: 8 Article Number: 086108 DOI: 10.1117/1.OE.60.8.086108 Published: AUG 2021 | ||||||
Abstract: Laser ablation of zircon can be used to analyze its composition for geological history. However, the effect of laser properties on nanoparticle size has not been studied extensively. The effect of laser fluence and pulse duration on the diameter of zircon nanoparticles was analyzed using field-emission scanning electron microscopy and energy dispersive spectroscopy. The results showed that the diameters of the zircon nanoparticles induced by a femtosecond laser increased with increasing laser fluence, and that these particles were smaller than those induced by a nanosecond laser with the same laser fluence. Furthermore, the mechanism of zircon nanoparticle formation induced by laser ablation has been discussed. The explosion mechanism is the primary mechanism of nanoparticle generation. In particular, the zircon nanoparticles induced by the femtosecond laser were the result of Coulomb explosion, while phase explosion contributed to the zircon nanoparticles induced by the nanosecond laser. Therefore, the nature of zircon nanoparticles induced by laser ablation is mainly determined by the pulse duration. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE) | ||||||
Accession Number: WOS:000704977500030 | ||||||
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ISSN: 0091-3286 | ||||||
eISSN: 1560-2303 |
Record 114 of 318 | |||||||||||||||
Title: High-Precision Time-Frequency Signal Simultaneous Transfer System via a WDM-Based Fiber Link | |||||||||||||||
Author(s): Zang, Q (Zang, Qi); Quan, HL (Quan, Honglei); Zhao, K (Zhao, Kan); Zhang, X (Zhang, Xiang); Deng, X (Deng, Xue); Xue, WX (Xue, Wenxiang); Chen, FX (Chen, Faxi); Liu, T (Liu, Tao); Dong, RF (Dong, Ruifang); Zhang, SG (Zhang, Shougang) | |||||||||||||||
Source: PHOTONICS Volume: 8 Issue: 8 Article Number: 325 DOI: 10.3390/photonics8080325 Published: AUG 2021 | |||||||||||||||
Abstract: In this paper, we demonstrate a wavelength division multiplexing (WDM)-based system for simultaneously delivering ultra-stable optical frequency reference, 10 GHz microwave frequency reference, and a one pulse per second (1 PPS) time signal via a 50 km fiber network. For each signal, a unique noise cancellation technique is used to maintain their precision. After being compensated, the transfer frequency instability in terms of the overlapping Allan deviation (OADEV) for the optical frequency achieves 2 x 10(-17)/s and scales down to 2 x 10(-20)/10,000 s, which for the 10 GHz microwave reference, approaches 4 x 10(-15)/s and decreases to 1.4 x 10(-17)/10,000 s, and the time uncertainty of the 1 PPS time signal along the system is 2.08 ps. In this scheme, specific channels of WDM are, respectively, occupied for different signals to avoid the possible crosstalk interference effect between the transmitted reference signals. To estimate the performance of the above scheme, which is also demonstrated in this 50 km link independent of these signals, the results are similar to that in the case of simultaneous delivery. This work shows that the WDM-based system is a promising method for building a nationwide time and frequency fiber transfer system with a communication optical network. | |||||||||||||||
Accession Number: WOS:000689809700001 | |||||||||||||||
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eISSN: 2304-6732 |
Record 115 of 318 |
Title: Residual Self-Calibration and Self-Attention Aggregation Network for Crop Disease Recognition |
Author(s): Zhang, Q (Zhang, Qiang); Sun, BY (Sun, Banyong); Cheng, YX (Cheng, Yaxiong); Li, XJ (Li, Xijie) |
Source: INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH Volume: 18 Issue: 16 Article Number: 8404 DOI: 10.3390/ijerph18168404 Published: AUG 2021 |
Abstract: The correct diagnosis and recognition of crop diseases play an important role in ensuring crop yields and preventing food safety. The existing methods for crop disease recognition mainly focus on accuracy while ignoring the algorithm's robustness. In practice, the acquired images are often accompanied by various noises. These noises lead to a huge challenge for improving the robustness and accuracy of the recognition algorithm. In order to solve this problem, this paper proposes a residual self-calibration and self-attention aggregation network (RCAA-Net) for crop disease recognition in actual scenarios. The proposed RCAA-Net is composed of three main modules: (1) multi-scale residual module, (2) feedback self-calibration module, and (3) self-attention aggregation module. Specifically, the multi-scale residual module is designed to learn multi-scale features and provide both global and local information for the appearance of the disease to improve the performance of the model. The feedback self-calibration is proposed to improve the robustness of the model by suppressing the background noise in the original deep features. The self-attention aggregation module is introduced to further improve the robustness and accuracy of the model by capturing multi-scale information in different semantic spaces. The experimental results on the challenging 2018ai_challenger crop disease recognition dataset show that the proposed RCAA-Net achieves state-of-the-art performance on robustness and accuracy for crop disease recognition in actual scenarios. |
Accession Number: WOS:000689162000001 |
PubMed ID: 34444152 |
eISSN: 1660-4601 |
Record 116 of 318 | |||||||||
Title: Mechanism of All-Optical Spatial Light Modulation in Graphene Dispersion | |||||||||
Author(s): Liu, S (Liu, Shan); Han, J (Han, Jing); Cheng, XM (Cheng, Xuemei); Wang, X (Wang, Xing); Zhang, Q (Zhang, Qian); He, B (He, Bo); Jiao, TF (Jiao, Tengfei); Ren, ZY (Ren, Zhaoyu) | |||||||||
Source: JOURNAL OF PHYSICAL CHEMISTRY C Volume: 125 Issue: 30 Pages: 16598-16604 DOI: 10.1021/acs.jpcc.1c04423 Early Access Date: JUL 2021 Published: AUG 5 2021 | |||||||||
Abstract: Graphene is a superb material with significant potential in broadband all-optical modulation. However, the mechanism of the all-optical modulation in graphene dispersion is still under debate. Here, we report on a pump power-dependent spatial light modulation by using the 780 nm CW laser as the pump and signal beams via graphene dispersion. The results indicate that graphene is able to convert the Gaussian signal beam into a hollow beam with a ring pattern. Examining the temporal evolution of the ring pattern, we found that spatial cross-phase modulation (SXPM) plays the dominant role at low pump power, while nonlinear scattering (NLS) becomes dominant when the pump power is high. Furthermore, the dependence of the size and intensity of the signal ring pattern on the pump power is investigated. The results can be well explained by SXPM, NLS, and saturation absorption (SA) effects. Finally, an all-optical switch is developed based on the dependence of the signal intensity on the pump power. It is demonstrated that both in-phase and out-phase modulation can be realized in one system. This work not only provides useful information in understanding the mechanism of graphene in interacting with the light, but also suggests a new way to produce hollow beam with tunable size and achieve an all-optical switch with both inphase and out-phase modulation. | |||||||||
Accession Number: WOS:000683810700027 | |||||||||
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ISSN: 1932-7447 | |||||||||
eISSN: 1932-7455 |
Record 117 of 318 | |||||||||||||||
Title: Two-center interference and stereo Wigner time delay in photoionization of asymmetric molecules | |||||||||||||||
Author(s): Liao, YJ (Liao, Yijie); Zhou, YM (Zhou, Yueming); Pi, LW (Pi, Liang-Wen); Ke, QH (Ke, Qinghua); Liang, JT (Liang, Jintai); Zhao, Y (Zhao, Yong); Li, M (Li, Min); Lu, PX (Lu, Peixiang) | |||||||||||||||
Source: PHYSICAL REVIEW A Volume: 104 Issue: 1 Article Number: 013110 DOI: 10.1103/PhysRevA.104.013110 Published: JUL 20 2021 | |||||||||||||||
Abstract: We present numerical simulations of the time delay in photoemission of asymmetric diatomic molecules using the technique of reconstruction of attosecond beating by interference of two-photon transitions (RABITT) by solving the time-dependent Schrodinger equation. Our results show an obvious time delay between photoelectrons emitted to the left and right and this relative time delay oscillates as the photoelectron energy changes. More interestingly, the amplitude of this oscillation increases when the asymmetry degree of diatomic molecules decreases. With the method of the selected continuum wave functions, we calculate the Wigner time delay in photoionization. The obtained stereo Wigner time delay also oscillates with photoelectron energy. This oscillation is traced back to two-center interferences and it could explain the relative time delay in the RABITT measurement. Furthermore, our results indicate that the continuum-continuum time delay in photoemission of heteronuclear molecules is asymmetric. | |||||||||||||||
Accession Number: WOS:000675550300005 | |||||||||||||||
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ISSN: 2469-9926 | |||||||||||||||
eISSN: 2469-9934 |
Record 118 of 318 | ||||||||||||
Title: Flexible dynamic structural color based on an ultrathin asymmetric Fabry-Perot cavity with phase-change material for temperature perception | ||||||||||||
Author(s): Zhao, JC (Zhao, Jiancun); Zhou, Y (Zhou, Yi); Huo, YH (Huo, Yihui); Gao, B (Gao, Bo); Ma, YG (Ma, Yungui); Yu, YT (Yu, Yiting) | ||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 15 Pages: 23273-23281 DOI: 10.1364/OE.431906 Published: JUL 19 2021 | ||||||||||||
Abstract: Dynamic structural color has attracted considerable attentions due to its good tunable characteristics. Here, an ultrathin asymmetric Fabry-Perot (FP)-type structural color with phase-change material VO2 cavity is proposed. The color-switching performance can be realized by temperature regulation due to the reversible monoclinic-rutile phase transition of VO2. The various, vivid structural color can be generated by simply changing the thickness of VO2 and Ag layers. Moreover, the simple structural configuration enables a large-scale, low-cost preparation on both rigid and flexible substrates. Accordingly, a flexible dynamic structural color membrane is adhered on a cup with a curved surface to be used for temperature perception. The proposed dynamic structural color has potential applications in anti-counterfeiting, temperature perception, camouflage coatings among other flexible optoelectronic devices. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||
Accession Number: WOS:000674671200035 | ||||||||||||
PubMed ID: 34614594 | ||||||||||||
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ISSN: 1094-4087 |
Record 119 of 318 | |||||||||
Title: Two-stream network for infrared and visible images fusion | |||||||||
Author(s): Liu, LL (Liu, Luolin); Chen, ML (Chen, Mulin); Xu, ML (Xu, Mingliang); Li, XL (Li, Xuelong) | |||||||||
Source: NEUROCOMPUTING Volume: 460 Pages: 50-58 DOI: 10.1016/j.neucom.2021.05.034 Early Access Date: JUL 2021 Published: OCT 14 2021 | |||||||||
Abstract: Long-wave infrared(thermal) images distinguish the target and background according to different thermal radiation. They are insensitive to light conditions, and cannot present details obtained from reflected light. By contrast, the visible images have high spatial resolution and texture details, but they are easily affected by the occlusion and light conditions. Combining the advantages of the two sources may generate a new image with clear targets and high resolution, which satisfy requirements in all-weather and allday/night conditions. Most of the existing methods cannot fully capture the underlying characteristics in the infrared and visible images, and ignore complementary information between the sources. In this paper, we propose an end-to-end model (TSFNet) for infrared and visible image fusion, which is able to handle the sources simultaneously. In addition, it adopts an adaptive weight allocation strategy to capture the informative global features. Experiments on public datasets demonstrate the proposed fusion method achieves state-of-the-art performance, in both global visual quality and quantitative comparison. (c) 2021 Published by Elsevier B.V. | |||||||||
Accession Number: WOS:000696919200006 | |||||||||
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ISSN: 0925-2312 | |||||||||
eISSN: 1872-8286 |
Record 120 of 318 | ||||||||||||||||||||||||||||||||||||||||||||||||
Title: High sensitivity FBG humidity sensor coated with graphene and polyimide films | ||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Li, ZW (Li, Ziwan); Dong, B (Dong, Bo); Chen, EQ (Chen, Enqing); Li, Y (Li, Yang); Zhao, W (Zhao, Wei); Wang, YS (Wang, Yishan); Gao, CX (Gao, Cunxiao) | ||||||||||||||||||||||||||||||||||||||||||||||||
Source: OPTICAL FIBER TECHNOLOGY Volume: 66 Article Number: 102635 DOI: 10.1016/j.yofte.2021.102635 Early Access Date: JUL 2021 Published: OCT 2021 | ||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: A high sensitivity FBG humidity sensor coated with polyimide and graphene films is proposed. The sensing probe is based on a fiber Bragg grating coated with an inner polyimide film and an outer graphene film. The sensor shows the high humidity sensitivity and experimental results show that its sensitivity is 1.80 times that of the sensor coated with only polyimide film. Within the humidity range of 30%-70%RH, its sensitivity reaches 19.8 pm/%RH and is almost 25 times that of the other lower sensitivity FBG humidity sensor. | ||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000701808900001 | ||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 1068-5200 | ||||||||||||||||||||||||||||||||||||||||||||||||
eISSN: 1095-9912 |
Record 121 of 318 | |||||||||||||||
Title: Effect of melting atmospheres on the optical property of radiation-hard fluorophosphate glass | |||||||||||||||
Author(s): Ma, Y (Ma, Yuan); Su, HQ (Su, Haiqin); Zhang, ZJ (Zhang, Zhijun); Wan, R (Wan, Rui); Li, SW (Li, Shengwu); Peng, B (Peng, Bo); Wang, PF (Wang, Pengfei) | |||||||||||||||
Source: CERAMICS INTERNATIONAL Volume: 47 Issue: 16 Pages: 22468-22477 DOI: 10.1016/j.ceramint.2021.04.256 Early Access Date: JUL 2021 Published: AUG 15 2021 | |||||||||||||||
Abstract: High-energy radiation in space and nuclear irradiation environment induces colour centres in optical glass, causing solarisation, and a serious condition can render optical systems and optical loads unusable. To develop space radiation-resistant optical glass, CeO2-stabilised radiation-hard fluorophosphate glass was prepared under three different atmospheres (nitrogen, oxygen, and ambient air). The glass-melting atmospheres' effects on the glass's transmission, defect formation, and structural changes before and after exposure to gamma radiation were investigated by a comprehensive study on their transmittance, absorption, and electron paramagnetic resonance spectra. Introducing a small amount of CeO2 (similar to 0.34 wt%) into the fluorophosphate base glass converted NBO and BO into ABO in the glass network, red-shifted the UV absorption edge, and decreased the optical density increment by almost half after radiation. As the total dose of gamma radiation increased, the transmittance of the irradiated glass at a wavelength of 385 nm significantly increased due to absorption of POHC2 defects. After exposure to 250 k of rad gamma irradiation, the corresponding optical density increment per centimeter thickness at 385 nm of the radiation-hard fluorophosphate glass that melted in the nitrogen, oxygen, and air atmospheres decreased from 1.839 to 1.388 and 1.215. As it melted in air, the NBO ratio of the fluorophosphate glass reached the lowest level and the Ce4+ ratio in the glass was 92.49%, which helped suppress the generation of POHC, Fe3+, PO4-EC, and PO3-EC defects during the gamma irradiation process, improving the glass's radiation resistance. | |||||||||||||||
Accession Number: WOS:000675523800003 | |||||||||||||||
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ISSN: 0272-8842 | |||||||||||||||
eISSN: 1873-3956 |
Record 122 of 318 | |||||||||
Title: Multichannel left-subtract-right feature vector piston error detection method based on a convolutional neural network | |||||||||
Author(s): Wang, PF (Wang, Peng-Fei); Zhao, H (Zhao, Hui); Xie, XP (Xie, Xiao-Peng); Zhang, YT (Zhang, Ya-Ting); Li, C (Li, Chuang); Fan, XW (Fan, Xue-Wu) | |||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 14 Pages: 21320-21335 DOI: 10.1364/OE.428690 Published: JUL 5 2021 | |||||||||
Abstract: To realize the large-scale and high-precision co-phasing adjustment of synthetic-aperture telescopes, we propose a multichannel left-subtract-right feature vector piston error detection method based on a convolutional neural network, which inherits the high precision and strong noise resistance of the DFA-LSR method while achieving a detection range of (-139 lambda, 139 lambda) (lambda = 720 nm). In addition, a scheme to build large training datasets was proposed to solve the difficulty in collecting datasets using traditional neural network methods. Finally, simulations verified that this method can guarantee at least 94.96% accuracy with large samples, obtaining a root mean square error of 10.2 nm when the signal-to-noise ratio is 15. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | |||||||||
Accession Number: WOS:000670054200022 | |||||||||
PubMed ID: 34265922 | |||||||||
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ISSN: 1094-4087 |
Record 123 of 318 | ||||||
Title: Enhanced upconversion emission of NaGdF<sub>4</sub>: Yb<SUP>3+</SUP>/Tm<SUP>3+</SUP> crystals by introducing Li<SUP>+</SUP> ions for anti-counterfeiting recognition | ||||||
Author(s): Li, DD (Li, Dongdong); Mo, JY (Mo, Jianye); Wang, C (Wang, Chong); Wu, ZW (Wu, Zhiwei); Hao, AH (Hao, Aihua); She, JB (She, Jiangbo) | ||||||
Source: APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING Volume: 127 Issue: 7 Article Number: 522 DOI: 10.1007/s00339-021-04674-8 Published: JUL 2021 | ||||||
Abstract: The upconversion efficiency could be affected by Li+ ions with changing the local crystal field of nanoparticles. Therefore, a series of NaGdF4:Yb3+/Tm3+ micro-particles with different Li+ doping concentrations were synthesized and investigated, respectively. The structure and morphology of the synthesized materials were tested by X-ray diffraction and scanning electron microscope. The photoluminescence properties were studied with different concentrations Li+ ions doping under the irradiation of 980 nm laser. The emission peaks of Tm3+ ions are 449, 477, 645, 723, 800 nm which are attributed to high excited states to ground state H-3(6) transition through a multiple steps resonance energy transfer from excited Yb3+. The enormous increase in upconversion emission in upconversion micro-particles (UCMPs) by introducing Li+ ions was observed by the naked eye. The strongest photoluminescence intensity is the sample with 2.5% doped Li+ ions. Additionally, the practicality of the resultant UCMPs for photoluminescence visible imaging was systematically investigated. These results suggest that the Li+ doped NaGdF4: Yb3+/Tm3+ is very promising as a screen printing material for anti-counterfeiting recognition. | ||||||
Accession Number: WOS:000691551200002 | ||||||
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ISSN: 0947-8396 | ||||||
eISSN: 1432-0630 |
Record 124 of 318 | ||||||
Title: Fabrication of an Anti-Reflective Microstructure on ZnS by Femtosecond Laser Bessel Beams | ||||||
Author(s): Li, X (Li, Xun); Li, M (Li, Ming); Liu, HJ (Liu, Hongjun); Guo, Y (Guo, Yan) | ||||||
Source: MOLECULES Volume: 26 Issue: 14 Article Number: 4278 DOI: 10.3390/molecules26144278 Published: JUL 2021 | ||||||
Abstract: As an important mid-infrared to far-infrared optical window, ZnS is extremely important to improve spectral transmission performance, especially in the military field. However, on account of the Fresnel reflection at the interface between the air and the high-strength substrate, surface optical loss occurs in the ZnS optical window. In this study, the concave antireflective sub-wavelength structures (ASS) on ZnS have been experimentally investigated to obtain high transmittance in the far-infrared spectral range from 6 mu m to 10 mu m. We proposed a simple method to fabricate microhole array ASS by femtosecond Bessel beam, which further increased the depth of the microholes and suppressed the thermal effects effectively, including the crack and recast layer of the microhole. The influence of different Gaussian and Bessel beam parameters on the microhole morphology were explored, and three ASS structures with different periods were prepared by the optimized Bessel parameters. Ultimately, the average transmittance of the sample with the ASS microhole array period of 2.6 mu m increased by 4.1% in the 6 mu m to 10 mu m waveband, and the transmittance was increased by 5.7% at wavelength of 7.2 mu m. | ||||||
Accession Number: WOS:000676155800001 | ||||||
PubMed ID: 34299553 | ||||||
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eISSN: 1420-3049 |
Record 125 of 318 | ||||||||||||
Title: Histogram clustering for rapid time-domain fluorescence lifetime image analysis | ||||||||||||
Author(s): Li, YH (Li, Yahui); Sapermsap, N (Sapermsap, Natakorn); Yu, J (Yu, Jun); Tian, JS (Tian, Jinshou); Chen, Y (Chen, Yu); Li, DDU (Li, David Day-Uei) | ||||||||||||
Source: BIOMEDICAL OPTICS EXPRESS Volume: 12 Issue: 7 Pages: 4293-4307 DOI: 10.1364/BOE.427532 Published: JUL 1 2021 | ||||||||||||
Abstract: Fluorescence lifetime imaging (FLIM) [1] is a crucial technique for assessing microenvironments of fluorophores, such as pH, Ca2+, O2, viscosity, or temperature [2-5]. Combining with Forster Resonance Energy Transfer (FRET) techniques [6], FLIM can be a powerful "quantum ruler" to measure protein conformations and interactions [7]. In contrast to fluorescence intensity imaging, FLIM is independent of fluorescence intensities and fluorophore concentrations, making FLIM a robust quantitative imaging technique for life sciences applications [8,9], medical diagnosis [10], drug developments [11,12], and flow diagnosis [13-15]. A fluorescence decay is usually modeled as a sum of exponential decay functions: | ||||||||||||
Accession Number: WOS:000670305800004 | ||||||||||||
PubMed ID: 34457415 | ||||||||||||
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ISSN: 2156-7085 |
Record 126 of 318 | ||||||
Title: Heart-Rate Monitoring With an Ethyl Alpha-Cyanoacrylate Based Fiber Fabry-Perot Sensor | ||||||
Author(s): Li, Y (Li, Yang); Dong, B (Dong, Bo); Chen, EQ (Chen, Enqing); Wang, XL (Wang, Xiaoli); Zhao, YD (Zhao, Yudi) | ||||||
Source: IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS Volume: 27 Issue: 4 Article Number: 5600206 DOI: 10.1109/JSTQE.2020.3002084 Published: JUL-AUG 2021 | ||||||
Abstract: Heart-rate monitoring with an ethyl alpha-cyanoacrylate (EtCNA) based fiber Fabry-Perot (F-P) sensor is presented. The fiber F-P sensor is fixed in a capillary tube by using the EtCNA binder. Due to the lower Young's modulus of the EtCNA, the sensor can detect low frequency vibration with a high sensitivity. The fiber sensor is attached in a specially designed bracket to obtain the stable data. When the sensor with bracket is put on the human body, the heart-rate can be monitored accurately by monitoring the laser intensity variation induced by the heartbeat. Experimental results show that the sensor has the strain sensitivity of 2.57 pm/mu N with good responses to low frequency vibrations of 1 Hz, 2 Hz and 3 Hz. The maximum and the minimum mean square deviations of the volunteers' data are 4.434210 and 0.667499, respectively. Moreover, it has good adaptability to measure the heart-rate on different positions of human body, such as wrist, chest and neck. Due to the advantages of small size, low cost, good adaptability, pollution-free and no harm to body. Our proposed sensor is expected to be widely used in heart disease monitoring. | ||||||
Accession Number: WOS:000556333000001 | ||||||
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ISSN: 1077-260X | ||||||
eISSN: 1558-4542 |
Record 127 of 318 | |||||||||
Title: Nanoscale Vacuum Diode Based on Thermionic Emission for High Temperature Operation | |||||||||
Author(s): Shen, ZH (Shen, Zhihua); Li, QN (Li, Qiaoning); Wang, X (Wang, Xiao); Tian, JS (Tian, Jinshou); Wu, SL (Wu, Shengli) | |||||||||
Source: MICROMACHINES Volume: 12 Issue: 7 Article Number: 729 DOI: 10.3390/mi12070729 Published: JUL 2021 | |||||||||
Abstract: Vacuum diodes, based on field emission mechanisms, demonstrate a superior performance in high-temperature operations compared to solid-state devices. However, when considering low operating voltage and continuous miniaturization, the cathode is usually made into a tip structure and the gap between cathode and anode is reduced to a nanoscale. This greatly increases the difficulty of preparation and makes it difficult to ensure fabrication consistency. Here, a metal-insulator-semiconductor (MIS) structural nanoscale vacuum diode, based on thermionic emission, was numerically studied. The results indicate that this device can operate at a stable level in a wide range of temperatures, at around 600 degrees Kelvin above 260 K at 0.2 V voltage bias. Moreover, unlike the conventional vacuum diodes working in field emission regime where the emission current is extremely sensitive to the gap-width between the cathode and the anode, the emission current of the proposed diode shows a weak correlation to the gap-width. These features make this diode a promising alternative to vacuum electronics for large-scale production and harsh environmental applications. | |||||||||
Accession Number: WOS:000676701100001 | |||||||||
PubMed ID: 34206192 | |||||||||
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eISSN: 2072-666X |
Record 128 of 318 | |||||||||
Title: Design and characterization of a thermally stabilized fiber Fabry-Perot etalon as a wavelength calibrator for high-precision spectroscopy | |||||||||
Author(s): Tang, L (Tang, Liang); Ye, HQ (Ye, Huiqi); Hao, J (Hao, Jun); Wei, RY (Wei, Ruyi); Xiao, D (Xiao, Dong) | |||||||||
Source: APPLIED OPTICS Volume: 60 Issue: 19 Pages: D1-D8 DOI: 10.1364/AO.417586 Published: JUL 1 2021 | |||||||||
Abstract: Filtering light from a broadband source with a Fabry-Perot etalon generates comb-like peaks in the spectral domain that can serve as calibration reference for precise Doppler shift detection on astronomical spectrographs. Fiber Fabry-Perot etalons are small in size and easily aligned optically. In application, high thermal sensitivity of the fiber core material requires a highly stable temperature control system. Here, we report on the design, characterization, and thermal performance of a fiber Fabry-Perot etalon-based calibrator system insensitive to environmental temperature perturbation, aimed as a reference for m . s(-1) precision radial velocity measurements. A fast and simple method to estimate the etalon finesse and a dual-loop approach to achieve sub-millikelvin temperature fluctuation are proposed and demonstrated. (C) 2021 Optical Society of America | |||||||||
Accession Number: WOS:000668986500008 | |||||||||
PubMed ID: 34263823 | |||||||||
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ISSN: 1559-128X | |||||||||
eISSN: 2155-3165 |
Record 129 of 318 | |||||||||||||||
Title: Broad-band phase retrieval method for transient radial shearing interference using chirp Z transform technique | |||||||||||||||
Author(s): Xue, F (Xue, Fang); Duan, YX (Duan, Ya-Xuan); Chen, XY (Chen, Xiao-Yi); Li, M (Li, Ming); Yuan, SC (Yuan, Suo-Chao); Da, ZS (Da, Zheng-Shang) | |||||||||||||||
Source: CHINESE PHYSICS B Volume: 30 Issue: 8 Article Number: 084209 DOI: 10.1088/1674-1056/abff2f Published: JUL 2021 | |||||||||||||||
Abstract: The transient radial shearing interferometry technique based on fast Fourier transform (FFT) provides a means for the measurement of the wavefront phase of transient light field. However, which factors affect the spatial bandwidth of the wavefront phase measurement of this technology and how to achieve high-precision measurement of the broad-band transient wavefront phase are problems that need to be studied further. To this end, a theoretical model of phase-retrieved bandwidth of radial shearing interferometry is established in this paper. The influence of the spatial carrier frequency and the calculation window on phase-retrieved bandwidth is analyzed, and the optimal carrier frequency and calculation window are obtained. On this basis, a broad-band transient radial shearing interference phase-retrieval method based on chirp Z transform (CZT) is proposed, and the corresponding algorithm is given. Through theoretical simulation, a known phase is used to generate the interferogram and it is retrieved by the traditional method and the proposed method respectively. The residual wavefront RMS of the traditional method is 0.146 lambda, and it is 0.037 lambda for the proposed method, which manifests an improvement of accuracy by an order of magnitude. At the same time, different levels of signal-to-noise ratios (SNRs) from 50 dB to 10 dB of the interferogram are simulated, and the RMS of the residual wavefront is from 0.040 lambda to 0.066 lambda. In terms of experiments, an experimental verification device based on a phase-only spatial light modulator is built, and the known phase on the modulator is retrieved from the actual interferogram. The RMS of the residual wavefront retrieved through FFT is 0.112 lambda, and it decreases to 0.035 lambda through CZT. The experimental results verify the effectiveness of the method proposed in this paper. Furthermore, the method can be used in other types of spatial carrier frequency interference, such as lateral shearing interference, rotational shearing interference, flipping shearing interference, and four-wave shearing interference. | |||||||||||||||
Accession Number: WOS:000679076400001 | |||||||||||||||
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ISSN: 1674-1056 | |||||||||||||||
eISSN: 2058-3834 |
Record 130 of 318 | |||||||||||||||||||||
Title: Bio-Inspired Representation Learning for Visual Attention Prediction | |||||||||||||||||||||
Author(s): Yuan, Y (Yuan, Yuan); Ning, HL (Ning, Hailong); Lu, XQ (Lu, Xiaoqiang) | |||||||||||||||||||||
Source: IEEE TRANSACTIONS ON CYBERNETICS Volume: 51 Issue: 7 Pages: 3562-3575 DOI: 10.1109/TCYB.2019.2931735 Published: JUL 2021 | |||||||||||||||||||||
Abstract: Visual attention prediction (VAP) is a significant and imperative issue in the field of computer vision. Most of the existing VAP methods are based on deep learning. However, they do not fully take advantage of the low-level contrast features while generating the visual attention map. In this article, a novel VAP method is proposed to generate the visual attention map via bio-inspired representation learning. The bio-inspired representation learning combines both low-level contrast and high-level semantic features simultaneously, which are developed by the fact that the human eye is sensitive to the patches with high contrast and objects with high semantics. The proposed method is composed of three main steps: 1) feature extraction; 2) bio-inspired representation learning; and 3) visual attention map generation. First, the high-level semantic feature is extracted from the refined VGG16, while the low-level contrast feature is extracted by the proposed contrast feature extraction block in a deep network. Second, during bio-inspired representation learning, both the extracted low-level contrast and high-level semantic features are combined by the designed densely connected block, which is proposed to concatenate various features scale by scale. Finally, the weighted-fusion layer is exploited to generate the ultimate visual attention map based on the obtained representations after bio-inspired representation learning. Extensive experiments are performed to demonstrate the effectiveness of the proposed method. | |||||||||||||||||||||
Accession Number: WOS:000665001500014 | |||||||||||||||||||||
PubMed ID: 31484145 | |||||||||||||||||||||
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ISSN: 2168-2267 | |||||||||||||||||||||
eISSN: 2168-2275 |
Record 131 of 318 | |||||||||
Title: Design and Fabrication of an Integrated Dual-Channel Thin-Film Filter for the Mid-Infrared | |||||||||
Author(s): Zhou, S (Zhou, Shun); Zhang, LY (Zhang, Liyu); Guo, F (Guo, Feng); Wu, CF (Wu, Chunfang); Xu, JQ (Xu, Junqi); Zhang, KF (Zhang, Kaifeng); Li, K (Li, Kun); Liu, Z (Liu, Zheng); Xiao, XG (Xiao, Xiangguo); Song, SG (Song, Shigeng); Liu, WG (Liu, Weiguo) | |||||||||
Source: COATINGS Volume: 11 Issue: 7 Article Number: 803 DOI: 10.3390/coatings11070803 Published: JUL 2021 | |||||||||
Abstract: Micro-filters fabricated using integration methods is now the trend for multichannel filters in imaging spectrum systems. Traditional multichannel bandpass filters are mainly fabricated separately by multilayered thin films and then glued together. This approach involves the complexity of precision cutting, dicing, and adhesive bonding; therefore, the possibility of miniaturization is quite limited. In this work, a dual channel bandpass thin film filter for the mid-infrared was fabricated by using the lift-off process. The structure of a 4-cavity Fabray-Perot (F-P) type filter was designed and optimized. The bandpass filter over the range 3.55-3.75 mu m with full width at half maximum (FWHM) of 274 nm and the bandpass filter over the range 4.85-4.95 mu m with FWHM of 246 nm were obtained with a 4.5 mu m joint width. The average transmittance of the filters is more than 83.5% and optical density value of the cutoff is 3. The thickness of 3.55-3.75 mu m bandpass filter was measured and the thickness error was analyzed. The results show that the thickness error, especially the thickness error of spacer layers, induces the degradations of peak transmission and bandwidth. This kind of mid-infrared filter has important application in space remote sensing, military, and civil fields. | |||||||||
Accession Number: WOS:000676356500001 | |||||||||
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eISSN: 2079-6412 |
Record 132 of 318 | ||||||||||||||||||||||||
Title: Optical vortex lattice: an exploitation of orbital angular momentum | ||||||||||||||||||||||||
Author(s): Zhu, LH (Zhu, Liuhao); Tang, MM (Tang, Miaomiao); Li, HH (Li, Hehe); Tai, YP (Tai, Yuping); Li, XZ (Li, Xinzhong) | ||||||||||||||||||||||||
Source: NANOPHOTONICS Volume: 10 Issue: 9 Pages: 2487-2496 DOI: 10.1515/nanoph-2021-0139 Published: JUL 2021 | ||||||||||||||||||||||||
Abstract: Generally, an optical vortex lattice (OVL) is generated via the superposition of two specific vortex beams. Thus far, OVL has been successfully employed to trap atoms via the dark cores. The topological charge (TC) on each optical vortex (OV) in the lattice is only +/- 1. Consequently, the orbital angular momentum (OAM) on the lattice is ignored. To expand the potential applications, it is necessary to rediscover and exploit OAM. Here we propose a novel high-order OVL (HO-OVL) that combines the phase multiplication and the arbitrary mode-controllable techniques. TC on each OV in the lattice is up to 51, which generates sufficient OAM to manipulate microparticles. Thereafter, the entire lattice can be modulated to desirable arbitrary modes. Finally, yeast cells are trapped and rotated by the proposed HO-OVL. To the best of our knowledge, this is the first realization of the complex motion of microparticles via OVL. Thus, this work successfully exploits OAM on OVL, thereby revealing potential applications in particle manipulation and optical tweezers. | ||||||||||||||||||||||||
Accession Number: WOS:000672600300014 | ||||||||||||||||||||||||
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ISSN: 2192-8606 | ||||||||||||||||||||||||
eISSN: 2192-8614 |
Record 133 of 318 | |||||||||
Title: Digital micromirror device based ptychographic phase microscopy | |||||||||
Author(s): Zheng, JJ (Zheng, Juanjuan); Wen, K (Wen, Kai); Gao, ZL (Gao, Zhaolin); Zalevsky, Z (Zalevsky, Zeev); Gao, P (Gao, Peng) | |||||||||
Source: OPTICS COMMUNICATIONS Volume: 498 Article Number: 127218 DOI: 10.1016/j.optcom.2021.127218 Early Access Date: JUN 2021 Published: NOV 1 2021 | |||||||||
Abstract: In this paper, ptychographic phase microscopy (PPM) with digital illumination addressing via a digital micromirror device (DMD) was demonstrated. A moving circular pattern is sequentially lighted up by a DMD and projected on the sample for illumination stepping, and a CCD camera records the generated diffraction patterns. Then, the quantitative phase distribution of the sample can be reconstructed from the diffraction patterns by using an iterative algorithm. Compared with conventional PPM approaches, this method has a fundamentally enhanced imaging speed due to the usage of the digital scan to replace the conventional mechanical scan. Furthermore, parallelized illumination strategy, which loads multiple pupils to DMD simultaneously, is used to further improve the imaging speed to 0.8 s per phase image. We envisage that this method will contribute to high-contrast, quantitative phase imaging of transparent samples without labeling. | |||||||||
Accession Number: WOS:000677937800013 | |||||||||
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ISSN: 0030-4018 | |||||||||
eISSN: 1873-0310 |
Record 134 of 318 | ||||||
Title: Bonding strength enhancement by Ag-Zn-Cu intermetallic compounds and microscale tapers array fabricated by femtosecond laser | ||||||
Author(s): Wang, C (Wang, Cong); Li, CQ (Li, Chuanqiang); Luo, Z (Luo, Zhi); Li, M (Li, Ming); Lin, N (Lin, Nai); Ding, KW (Ding, Kaiwen); Man, S (Man, Shu); Duan, JA (Duan, Ji'an) | ||||||
Source: JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS Volume: 32 Issue: 14 Pages: 19543-19551 DOI: 10.1007/s10854-021-06473-6 Early Access Date: JUN 2021 Published: JUL 2021 | ||||||
Abstract: In this study, a highly reliable and effective method for copper bonding using femtosecond laser-fabricated microscale tapers array and Ag-Zn-Cu intermetallic compounds as assistants is proposed. By the growth of intermetallic compounds among the microscale tapers array, the copper interfaces were firmly sintered. The cross section after shearing test was marked for analysis of sintering quality. Also, the shearing strength of interconnected copper interfaces under different bonding temperature, and holding times was investigated. The results show that the shearing strength can reach up to 120.1 MPa under 300 degrees C bonding temperature and 30 min holding time. According to the interconnected cross section and shearing strength test, the mechanism of increased shearing strength is explained. The experimental results show that the shearing strength of interconnected interface is greatly enhanced by the increase of contact area caused by microscale tapers array and the mechanical locking caused by the growth of intermetallic compounds. More possibilities could be provided by this technology in the field of electronic packaging interconnection and three-dimensional integrated circuits. | ||||||
Accession Number: WOS:000668059400009 | ||||||
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ISSN: 0957-4522 | ||||||
eISSN: 1573-482X |
Record 135 of 318 | |||||||||||||||||||||||||||
Title: Collective energy-spectrum broadening of a proton beam in a gas-discharge plasma | |||||||||||||||||||||||||||
Author(s): Cheng, R (Cheng, Rui); Hu, ZH (Hu, Zhang-Hu); Hui, DX (Hui, De-Xuan); Zhao, YT (Zhao, Yong-Tao); Chen, YH (Chen, Yan-Hong); Gao, F (Gao, Fei); Lei, Y (Lei, Yu); Wang, YY (Wang, Yu-Yu); Zhu, BL (Zhu, Bing-Li); Yang, Y (Yang, Yang); Wang, Z (Wang, Zhao); Zhou, ZX (Zhou, Ze-Xian); Wang, YN (Wang, You-Nian); Yang, J (Yang, Jie) | |||||||||||||||||||||||||||
Source: PHYSICAL REVIEW E Volume: 103 Issue: 6 Article Number: 063216 DOI: 10.1103/PhysRevE.103.063216 Published: JUN 28 2021 | |||||||||||||||||||||||||||
Abstract: An accurate understanding of ion-beam transport in plasmas is crucial for applications in inertial fusion energy and high-energy-density physics. We present an experimental measurement on the energy spectrum of a proton beam at 270 keV propagating through a gas-discharge hydrogen plasma. We observe the energies of the beam protons changing as a function of the plasma density and spectrum broadening due to a collective beam-plasma interaction. Supported by linear theory and three-dimensional particle-in-cell simulations, we attribute this energy modulation to a two-stream instability excitation and further saturation by beam ion trapping in the wave. The widths of the energy spectrum from both experiment and simulation agree with the theory. | |||||||||||||||||||||||||||
Accession Number: WOS:000677991000003 | |||||||||||||||||||||||||||
PubMed ID: 34271707 | |||||||||||||||||||||||||||
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ISSN: 2470-0045 | |||||||||||||||||||||||||||
eISSN: 2470-0053 |
Record 136 of 318 | ||||||||||||||||||||||||
Title: Optical ranging system based on multiple pulse train interference using soliton microcomb | ||||||||||||||||||||||||
Author(s): Zheng, JH (Zheng, Jihui); Wang, Y (Wang, Yang); Wang, XY (Wang, Xinyu); Zhang, FM (Zhang, Fumin); Wang, WQ (Wang, Weiqiang); Ma, X (Ma, Xin); Wang, JD (Wang, Jindong); Chen, JW (Chen, Jiawei); Jia, LH (Jia, Linhua); Song, MY (Song, Mingyu); Yuan, MY (Yuan, Meiyan); Little, B (Little, Brent); Chu, ST (Chu, Sai Tek); Cheng, D (Cheng, Dong); Qu, XH (Qu, Xinghua); Zhao, W (Zhao, Wei); Zhang, WF (Zhang, Wenfu) | ||||||||||||||||||||||||
Source: APPLIED PHYSICS LETTERS Volume: 118 Issue: 26 Article Number: 261106 DOI: 10.1063/5.0054065 Published: JUN 28 2021 | ||||||||||||||||||||||||
Abstract: The multiple pulse train interference (MPTI) ranging system takes advantage of the high accuracy and absolute length measurement capability, but traditional scheme has a large measurement dead zone. In this Letter, we propose a MPTI ranging scheme based on chip-based soliton microcomb to achieve high-precision but no dead-zone measurement. The measurement optical path is improved to solve the problem of cross correlation interference fringe overlap, and a peak fitting algorithm is employed to further improve the measurement accuracy of the system. Using a commercial He-Ne interferometer, a 384nm precision is obtained in 1.5 m distance measurements. Advantages of the simple optical path, high precision, and no measurement dead zone are expected to realize on-chip integration and provide a solution for precision measurement. | ||||||||||||||||||||||||
Accession Number: WOS:000685541400001 | ||||||||||||||||||||||||
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ISSN: 0003-6951 | ||||||||||||||||||||||||
eISSN: 1077-3118 |
Record 137 of 318 | |||||||||
Title: Dark matter-wave gap solitons of Bose-Einstein condensates trapped in optical lattices with competing cubic-quintic nonlinearities | |||||||||
Author(s): Chen, JB (Chen, Junbo); Zeng, JH (Zeng, Jianhua) | |||||||||
Source: CHAOS SOLITONS & FRACTALS Volume: 150 Article Number: 111149 DOI: 10.1016/j.chaos.2021.111149 Early Access Date: JUN 2021 Published: SEP 2021 | |||||||||
Abstract: Solitons are nonlinear self-sustained wave excitations and probably among the most interesting and ex-citing emergent nonlinear phenomenon in the corresponding theoretical settings. Bright solitons with sharp peak and dark solitons with central notch have been well known and observed in various nonlin-ear systems. The interplay of periodic potentials, like photonic crystals and lattices in optics and optical lattices in ultracold atoms, with the dispersion has brought about gap solitons within the finite band gaps of the underlying linear Bloch-wave spectrum and, particularly, the bright gap solitons have been experimentally observed in these nonlinear periodic systems, while little is known about the underlying physics of dark gap solitons. Here, we theoretically and numerically investigate the existence, property and stability of one-dimensional matter-wave gap solitons and soliton clusters of Bose-Einstein conden-sates trapped in optical lattices with competing cubic-quintic nonlinearity, the higher-order of which is self-defocusing and the lower-order (cubic) one is chosen as self-defocusing or focusing nonlinearities. By means of the conventional linear-stability analysis and direct numerical calculations with initial pertur-bations, we identify the stability and instability areas of the corresponding dark gap solitons and clusters ones. (c) 2021 Elsevier Ltd. All rights reserved. | |||||||||
Accession Number: WOS:000687257500004 | |||||||||
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ISSN: 0960-0779 | |||||||||
eISSN: 1873-2887 |
Record 138 of 318 | ||||||
Title: A four-channel ICCD framing camera with nanosecond temporal resolution and high spatial resolution | ||||||
Author(s): Fang, YM (Fang, Yuman); Zhang, MR (Zhang, Minrui); Wang, JF (Wang, Junfeng); Guo, LH (Guo, Lehui); Liu, XL (Liu, Xueling); Lu, Y (Lu, Yu); Tian, JS (Tian, Jinshou) | ||||||
Source: JOURNAL OF MODERN OPTICS Volume: 68 Issue: 13 Pages: 661-669 DOI: 10.1080/09500340.2021.1937735 Early Access Date: JUN 2021 Published: JUL 29 2021 | ||||||
Abstract: In this paper, a high spatial resolution, high gating speed framing camera capable of four separate two-dimensional images is designed and tested. A mirror-based image splitter has been designed and developed to provide a separate image for each arm with equal path length and equal intensity splitting while having a spectral flat response. Fast gating of a single frame is accomplished by using a proximity-focused microchannle-plate image-intensifier (MCPII) gated by a MOSFET-based pulse module with adjustable gate width from 3 ns to D.C. operation. Multiple frames are obtained by using multiple gated tubes with time intervals between consecutive frames can be adjusted flexibly. Its spatial resolution reaches 36.5 lp/mm with each frame having a 4.6-ns gate width. Furthermore, a three-dimensional MCPII model is developed to investigate the transit time and spatial resolution of the proximity-focused MCPII based on the Finite Integral Technique (FIT) and Monte Carlo method (M-C method). | ||||||
Accession Number: WOS:000664904700001 | ||||||
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ISSN: 0950-0340 | ||||||
eISSN: 1362-3044 |
Record 139 of 318 | ||||||||||||
Title: Density saliency for clustered building detection and population capacity estimation | ||||||||||||
Author(s): Liu, K (Liu, Kang); Huang, J (Huang, Ju); Xu, ML (Xu, Mingliang); Perc, M (Perc, Matjaz); Li, XL (Li, Xuelong) | ||||||||||||
Source: NEUROCOMPUTING Volume: 458 Pages: 127-140 DOI: 10.1016/j.neucom.2021.06.002 Early Access Date: JUN 2021 Published: OCT 11 2021 | ||||||||||||
Abstract: Building detection is a critically important task in the field of remote sensing and it is conducive to urban construction planning, disaster survey, shantytown modification, and emergency landing, it etc. However, few studies have focused on the task of the clustered building detection which is inescapable and challenging for some relatively low space resolution images. The appearance structures of those buildings are not clear enough for the single-building detection. Whereas, it has been found that the distributions of clustered buildings are mostly dense and cellular, while the backgrounds are not. This clue will be beneficial to the clustered building detection. Motivated by the fact above and other similar density estimation applications, this work mainly focuses on the information mining mechanism of dense and cellular structure. Firstly, we propose a concept of Clustered Building Detection (CBD), which contributes to develop clustered building detection techniques of remote sensing images. Secondly, a saliency estimation algorithm is proposed to mine the prior information for the clustered buildings. Thirdly and most notably, combining with the CBD and the density saliency map, a Population Capacity Estimation (PCE) method is presented. The PCE can be easily used to estimate the population carrying capacity of certain areas and future applied for national land resource management. Moreover, a Clustered Building Detection Dataset (CBDD) from Gaofen-2 satellite is annotated and contributed for the public research. The experimental results by the representative detection algorithms manifest the effectiveness for the clustered building detection. (c) 2021 Elsevier B.V. All rights reserved. | ||||||||||||
Accession Number: WOS:000691559800011 | ||||||||||||
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ISSN: 0925-2312 | ||||||||||||
eISSN: 1872-8286 |
Record 140 of 318 | ||||||
Title: Comprehensive risk assessment of transmission lines affected by multi-meteorological disasters based on fuzzy analytic hierarchy process | ||||||
Author(s): Han, BN (Han, Binbin); Ming, ZF (Ming, Zhengfeng); Zhao, YH (Zhao, Yuhu); Wen, T (Wen, Tao); Xie, ML (Xie, Meilin) | ||||||
Source: INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS Volume: 133 Article Number: 107190 DOI: 10.1016/j.ijepes.2021.107190 Early Access Date: JUN 2021 Published: DEC 2021 | ||||||
Accession Number: WOS:000686735000002 | ||||||
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ISSN: 0142-0615 | ||||||
eISSN: 1879-3517 |
Record 141 of 318 | |||||||||
Title: Influence of Sm<SUP>3+</SUP> doping on the relaxation behaviors of KSr<sub>2</sub>Nb<sub>5</sub>O<sub>15</sub> ferroelectric ceramics and the luminescence modulation effect by polarization engineering | |||||||||
Author(s): Cao, SY (Cao, Shuyao); Chen, Q (Chen, Qian); Li, YP (Li, Yangping); Wu, CY (Wu, Changying); Feng, XY (Feng, Xiaoying); Xu, J (Xu, Jie); Cheng, GH (Cheng, Guanghua); Gao, F (Gao, Feng) | |||||||||
Source: CERAMICS INTERNATIONAL Volume: 47 Issue: 14 Pages: 20286-20297 DOI: 10.1016/j.ceramint.2021.04.037 Early Access Date: JUN 2021 Published: JUL 15 2021 | |||||||||
Abstract: The luminescence modulation behavior of lanthanide ion doped materials possesses great potential for applications in sensing, display and anti-counterfeiting devices. Unlike traditional tuning methods for chemical compositions, novel rare-earth doped ferroelectric oxides exhibit attractive luminescence modulation effects via electric polarization engineering, and enrich the development of multifunctional devices. In this work, Sm3+ doped KSr2Nb5O15 ceramics with abundant ferroelectric and luminescent properties were synthesized. The samples show different relaxation behaviors and ferroelectric features upon chemical and structural factors caused by Sm3+ doping, such as average ionic radii, local tolerance factors, and chemical bonds. After polarization at 20 kV/cm for 20 min, a considerable increase (similar to 40%) in the luminescent emission intensity was obtained in 4 mol. % Sm3+ doped KSr2Nb5O15 ceramics. The related luminescence modulation mechanism was attributed to controlling the environmental symmetry around Sm3+ by the electric polarization. | |||||||||
Accession Number: WOS:000663667600001 | |||||||||
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ISSN: 0272-8842 | |||||||||
eISSN: 1873-3956 |
Record 142 of 318 | |||||||||||||||||||||
Title: Two-dimensional optical gap solitons and vortices in a coherent atomic ensemble loaded on optical lattices | |||||||||||||||||||||
Author(s): Chen, ZM (Chen, Zhiming); Zeng, JH (Zeng, Jianhua) | |||||||||||||||||||||
Source: COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION Volume: 102 Article Number: 105911 DOI: 10.1016/j.cnsns.2021.105911 Early Access Date: JUN 2021 Published: NOV 2021 | |||||||||||||||||||||
Abstract: Coherent atomic systems, e.g., resonantly cold atomic gases within which electromagnetically induced transparency (EIT) operates, have recently received great attention, because of their remarkable scientific properties and pivotal implications. Light behavior in such systems governed by various potentials is a new and interesting research focus, but missing literally report on two-dimensional (2D) localized gap modes in coherent atomic systems loaded on optical lattices. We survey such issue in a coherent atomic gas inside where the EIT turns on, trapped by 2D optical lattices-constituted by counter-propagating far-detuned Stark laser fields, in the framework of nonlinear Schrodinger equation derived from Maxwell-Bloch equations. Using the linear stability analysis and direct perturbed evolution we address the formation, property, and stability of 2D localized gap modes of two types, gap solitons and gap vortices, in forbidden band gaps of the underlying linear Blochwave spectrum. The former mode is fundamental gap solitons, and the latter belongs to higher-order gap solitons with embedded topological charge. Our results are helpful not only for in-depth understanding of soliton dynamics in coherent atomic ensemble loaded on periodic potentials, but also for laying the groundwork for forthcoming applications in optical communications and quantum information processing. (C) 2021 Elsevier B.V. All rights reserved. | |||||||||||||||||||||
Accession Number: WOS:000685172800006 | |||||||||||||||||||||
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ISSN: 1007-5704 | |||||||||||||||||||||
eISSN: 1878-7274 |
Record 143 of 318 | |||||||||||||||||||||||||||||||||||||||||||||||||||
Title: Smart Optic Fiber Mattress for Animal Sleep Continuous Monitoring Based Multi-Modal Interferometer | |||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Li, Y (Li, Yang); Dong, B (Dong, Bo); Zhao, YD (Zhao, Yudi); Chen, EQ (Chen, Enqing); Wang, XL (Wang, Xiaoli); Zhao, W (Zhao, Wei); Wang, YS (Wang, Yishan) | |||||||||||||||||||||||||||||||||||||||||||||||||||
Source: JOURNAL OF LIGHTWAVE TECHNOLOGY Volume: 39 Issue: 12 Pages: 4131-4137 DOI: 10.1109/JLT.2020.3048958 Published: JUN 15 2021 | |||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: A smart optic fiber mattress for animal sleep continuous monitoring based on a multi-modal interferometer is presented. The sensor is fabricated by splicing two single mode fibers (SMFs) and a multimode fiber (MMF) with a grid structure. Due to the network structure of the sensor, it has wider contact surface for monitoring vital signs and reduces the detection difficulty caused by the change of measured object position. The sensing unit can be placed under the dog mattress. Experimental results show that it can continuously monitor the sleeping activities and respiration of the dog. The detected information includes activity rhythm, sleeping state and sleeping respiratory rates (SRR). This technique avoids some potential problems such as injuring caused by the sensor appendage and dispute caused by moral principles. It is qualified to be widely used in health care of pets and protection of wildlife. | |||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000658363000055 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 0733-8724 | |||||||||||||||||||||||||||||||||||||||||||||||||||
eISSN: 1558-2213 |
Record 144 of 318 | ||||||||||||
Title: Aerial Infrared Object Tracking via an improved Long-term Correlation Filter with optical flow estimation and SURF matching | ||||||||||||
Author(s): Wang, XT (Wang, Xiaotian); Zhang, K (Zhang, Kai); Zhang, XM (Zhang, Ximing); Li, SY (Li, Shaoyi); Yan, J (Yan, Jie) | ||||||||||||
Source: INFRARED PHYSICS & TECHNOLOGY Volume: 116 Article Number: 103790 DOI: 10.1016/j.infrared.2021.103790 Early Access Date: JUN 2021 Published: AUG 2021 | ||||||||||||
Abstract: At present, there are many excellent algorithms in the field of visual object tracking. The correlation filter algorithms are more suitable for infrared object tracking, for the tracking performance is the best. Especially, the long-term correlation tracking has received much attention, owing to its ability to handle the problems of universal tracking (e.g., slight deformation, small-displacement motion, partial occlusion and out of view). However, there are three imperfections such that it fails to solve the problem of rapid motion, it cannot cope with the problem of boundary effect perfectly, and it has poor tracking effect in the case of severe occlusion and severe deformation. Aiming at the problem of rapid motion, the FlowNet 2.0 is introduced to accomplish optical flow estimation, offering motion information and predicting trajectory change process. Aiming to address the concern of boundary effect perfectly, the adjustable Gaussian window is effective to separate the object and the background, improving classifier discrimination. Aiming at the issue of poor tracking effect in the case of severe occlusion and severe deformation, the SURF feature-based matching method is effective to accurately track object and improve the infrared object tracking performance. In addition, the ratio between average peak-tocorrelation energy (APCE) and its historical average, as a further complement of maximum response, is introduced to achieve the online updating mechanism, jointly determining whether the tracker needs to be updated, the SURF matching needs to be carried out or the tracker needs to be initialized by re-detector. Our algorithm is validated on synthetic infrared aerial object image sequences, real infrared thermal aerial object image sequences and a public database named AMCOM FLIR respectively. The extensive experimental testify that our improved approach achieves an optimal effect for aerial infrared object tracking in terms of precision plot, success plot and speed. | ||||||||||||
Accession Number: WOS:000674614300003 | ||||||||||||
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ISSN: 1350-4495 | ||||||||||||
eISSN: 1879-0275 |
Record 145 of 318 | |||||||||||||||
Title: Local and correlation attention learning for subtle facial expression recognition | |||||||||||||||
Author(s): Wang, SC (Wang, Shaocong); Yuan, Y (Yuan, Yuan); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang) | |||||||||||||||
Source: NEUROCOMPUTING Volume: 453 Pages: 742-753 DOI: 10.1016/j.neucom.2020.07.120 Early Access Date: JUN 2021 Published: SEP 17 2021 | |||||||||||||||
Abstract: Subtle facial expression recognition (SFER) aims to classify facial expressions with very low intensity into corresponding human emotions. Subtle facial expression can be regarded as a special kind of facial expression, whose facial muscle movements are more difficult to capture. In the last decade, various methods have been developed for common facial expression recognition (FER). However, most of them failed to automatically find the most discriminative parts of facial expression and the correlation of muscle movements when human makes facial expression, which makes them unsuitable for SFER. To better solve SFER problem, an attention mechanism based model focusing on salient local regions and their correlations is proposed in this paper. The proposed method: 1) utilizes multiple attention blocks to attend to distinct discriminative regions and extract corresponding local features automatically, 2) a correlation attention module is integrated in the model to extract global correlation feature over the salient regions, and finally 3) fuses the correlation feature and local features in an efficient way for the final facial expression classification. By this way, the useful but subtle local information can be utilized in more detail, and the correlation of different local regions is also extracted. Extensive experiment on the LSEMSW and CK+ datasets shows that the method proposed in this paper achieves superior results, which demonstrates its effectiveness. | |||||||||||||||
Accession Number: WOS:000663417700007 | |||||||||||||||
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ISSN: 0925-2312 | |||||||||||||||
eISSN: 1872-8286 |
Record 146 of 318 | |||||||||
Title: Accuracy-enhanced coherent Ising machine using the quantum adiabatic theorem | |||||||||
Author(s): Li, L (Li, Lin); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu) | |||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 12 Pages: 18530-18539 DOI: 10.1364/OE.426476 Published: JUN 7 2021 | |||||||||
Abstract: The coherent Ising machine (CIM) implemented by degenerate optical parametric oscillator (DOPO) networks is a novel optical platform to accelerate computation of hard combinatorial optimization problems. Nevertheless, with the increase of the problem size, the probability of the machine being trapped by local minima increases exponentially. According to the quantum adiabatic theorem, a physical system will remain in its instantaneous ground state if the time-dependent Hamiltonian varies slowly enough. Here, we propose a method to help the machine partially avoid getting stuck in local minima by introducing quantum adiabatic evolution to the ground-state-search process of the CIM, which we call A-CIM. Numerical simulation results demonstrate that A-CIM can obtain improved solution accuracy in solving MAXCUT problems of vertices ranging from 10 to 2000 than CIM. The proposed machine that is based on quantum adiabatic theorem is expected to solve optimization problems more correctly. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | |||||||||
Accession Number: WOS:000659223100062 | |||||||||
PubMed ID: 34154108 | |||||||||
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ISSN: 1094-4087 |
Record 147 of 318 | ||||||||||||||||||||||||
Title: Dynamics of dark breathers and Raman-Kerr frequency combs influenced by high-order dispersion | ||||||||||||||||||||||||
Author(s): Liu, ML (Liu, Mulong); Huang, HM (Huang, Huimin); Lu, ZZ (Lu, Zhizhou); Wang, YY (Wang, Yuanyuan); Cai, YA (Cai, Yanan); Zhao, W (Zhao, Wei) | ||||||||||||||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 12 Pages: 18095-18107 DOI: 10.1364/OE.427718 Published: JUN 7 2021 | ||||||||||||||||||||||||
Abstract: We investigate the dark breathers and Raman-Kerr microcombs generation influenced by stimulated Raman scattering (SRS) and high-order dispersion (HOD) effects in silicon microresonators with an integrated spatiotemporal formalism. The strong and narrow Raman gain constitute a threshold behavior with respect to free spectral range above which stable dark pulses can exist. The breathing dark pulses induced by HOD mainly depend on the amplitude and sign of third-order dispersion coefficient and their properties are also affected by the Raman assisted four wave mixing process. Such dissipative structures formed through perturbed switching waves, mainly exist in a larger red detuning region than that of stable dark pulses. Their breathing characteristics related to driving conditions have been analyzed in detail. Furthermore, the octave spanning mid-infrared (MIR) frequency combs via Cherenkov radiation are demonstrated, which circumvent chaotic and multi-soliton states compared with their anomalous dispersion-based counterpart. Our findings provide a viable way to investigate the physics inside dark pulses and broadband MIR microcombs generation. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||||||||||||||
Accession Number: WOS:000659223100031 | ||||||||||||||||||||||||
PubMed ID: 34154076 | ||||||||||||||||||||||||
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ISSN: 1094-4087 |
Record 148 of 318 | ||||||||||||
Title: Solving, analyzing, manufacturing, and experimental testing of thickness distribution for a cycloid-like variable curvature mirror | ||||||||||||
Author(s): Xie, XP (Xie, Xiaopeng); Xu, L (Xu, Liang); Wang, YJ (Wang, Yongjie); Shen, L (Shen, Le); Fan, XW (Fan, Xuewu); Fan, WH (Fan, Wenhui); Li, C (Li, Chuang); Zhao, H (Zhao, Hui) | ||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 12 Pages: 18010-18025 DOI: 10.1364/OE.426989 Published: JUN 7 2021 | ||||||||||||
Abstract: A cycloid-like variable curvature mirror (VCM) for zoom-imaging systems was investigated. An analytical-deformation solution to a thin-elastic plate with a cycloid-like thickness distribution and simply supported boundary condition under uniform pressure was found using a small parameter method. The finite-element analysis of the thin-elastic plate and designed VCM showed a good correlation with the analytical solution. The VCM was manufactured and polished to the initial shape with a root mean square (RMS) of 1/80 lambda. Finally, with air-pressure-based actuation testing under 0.07 MPa, the VCM deforms approximately 36.89 mu m and maintains the RMS surface performance of 1/10 lambda, 1/40 lambda with and without spherical aberrations, respectively. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||
Accession Number: WOS:000659223100025 | ||||||||||||
PubMed ID: 34154070 | ||||||||||||
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ISSN: 1094-4087 |
Record 149 of 318 | |||||||||||||||||||||||||||||||||||||||||||||||||||
Title: All-optical tunable fiber filter based on a few-mode optical fiber mode interferometer coated with graphene epoxy resin composite material | |||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Chen, EQ (Chen, Enqing); Dong, B (Dong, Bo); Li, Y (Li, Yang); Li, ZW (Li, Ziwan); Wang, XL (Wang, Xiaoli); Zhao, YD (Zhao, Yudi); Xu, W (Xu, Wei); Zhao, W (Zhao, Wei); Wang, YS (Wang, Yishan) | |||||||||||||||||||||||||||||||||||||||||||||||||||
Source: OPTICS COMMUNICATIONS Volume: 497 Article Number: 127140 DOI: 10.1016/j.optcom.2021.127140 Early Access Date: JUN 2021 Published: OCT 15 2021 | |||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: A compact all-optical tunable fiber filter based on a few-mode optical fiber modal interferometer coated with graphene epoxy resin composite material is proposed and experimentally demonstrated. The interferometer is constructed with a 2-cm FMF connected to two single mode fibers. After coating the graphene epoxy resin composite material on the outside of the interferometer, it shows the all-optical wavelength tunability, and experimental results show that the wavelength shift changes quasilinearly with the pump power changing. The wavelength tunable range reaches 5.062 nm with a step of 0.016 nm/mw. It is expected to have practical application in optical communication, fiber sensing, fiber laser and optical spectrum analysis. | |||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000670303800011 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 0030-4018 | |||||||||||||||||||||||||||||||||||||||||||||||||||
eISSN: 1873-0310 |
Record 150 of 318 | |||||||||
Title: Optimal optical path difference of an asymmetric common-path coherent-dispersion spectrometer | |||||||||
Author(s): Chen, SS (Chen, Shasha); Wei, RY (Wei, Ruyi); Xie, ZM (Xie, Zhengmao); Wu, YH (Wu, Yinhua); Di, LM (Di, Lamei); Wang, FC (Wang, Feicheng); Zhai, Y (Zhai, Yang) | |||||||||
Source: APPLIED OPTICS Volume: 60 Issue: 16 Pages: 4535-4543 DOI: 10.1364/AO.425491 Published: JUN 1 2021 | |||||||||
Abstract: Optical path difference (OPD) is a very significant parameter in the asymmetric common-path coherent-dispersion spectrometer (CODES), which directly determines the performance of the CODES. In order to improve the performance of the instrument as much as possible, a temperature-compensated optimal optical path difference (TOOPD) method is proposed. The method does not only consider the influence of temperature change on the OPD but also effectively solves the problem that the optimal OPD cannot be obtained simultaneously at different wavelengths. Taking the spectral line with a Gaussian-type power spectral density distribution as a representative, the relational expression between the OPD and the visibility of interference fringes formed by the CODES is derived for the stellar absorption/emission line. Further, the optimal OPD is deduced according to the efficiency function, and the relationship between the optimal OPD and wavelength is analyzed. Then, based on the materials' dispersion characteristics, different optical materials are combined and added to the interferometer's reflected and transmitted optical path to implement the optimal OPD at different wavelengths, thereby improving the detection precision. Meanwhile, the materials whose refractive index negatively changes with temperature are selected to reduce or even offset the temperature impact on OPD, and hence the system's stability is improved and further improves the detection precision. Under certain input conditions, the material combination that approximates the optimal OPD is performed within the range of 0.66-0.9 mu m. The simulation results show that the maximal difference between the optimal OPD obtained by the efficiency function and the OPD produced by the material combination is 0.733 mm for the absorption line and 1.122 mm for the emission line, which is reduced by 1 time compared with only one material. The influence of temperature on the OPD can be reduced by 2-3 orders of magnitude by material combination, which greatly ameliorates the stability of the whole spectrometer. Hence, the TOOPD method provides a new idea for further improving the high-precision radial velocity detection of the asymmetric common-path CODES. (C) 2021 Optical Society of America | |||||||||
Accession Number: WOS:000658194300005 | |||||||||
PubMed ID: 34143007 | |||||||||
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ISSN: 1559-128X | |||||||||
eISSN: 2155-3165 |
Record 151 of 318 | ||||||||||||
Title: Effect of Near-field Distribution on Transmission Characteristics of Fiber-fed Fabry-Perot Etalons | ||||||||||||
Author(s): Hao, J (Hao, Jun); Tang, L (Tang, Liang); Ye, HQ (Ye, Huiqi); Hao, ZB (Hao, Zhibo); Han, J (Han, Jian); Zhai, Y (Zhai, Yang); Zhang, K (Zhang, Kai); Wei, RY (Wei, Ruyi); Xiao, D (Xiao, Dong) | ||||||||||||
Source: ASTRONOMICAL JOURNAL Volume: 161 Issue: 6 Article Number: 258 DOI: 10.3847/1538-3881/abf045 Published: JUN 2021 | ||||||||||||
Abstract: Fiber-fed etalons are widely employed in advanced interferometric instruments such as gravitational-wave detectors, ultrastable lasers and calibration reference for high-precision spectrographs. We demonstrate that variation in near-field distribution of the feeding fiber would deteriorate the spectrum precision of the fiber-fed Fabry-Perot etalon, especially when precision at the order of 3 x 10(-10) or higher is required. The octagonal fiber reinforced with double scrambler could greatly improve the steadiness and uniformness of the near-field distribution. When building wavelength calibrators for sub-m s(-1) precision radial-velocity instruments, the double scrambler should be considered meticulously. | ||||||||||||
Accession Number: WOS:000648827400001 | ||||||||||||
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ISSN: 0004-6256 | ||||||||||||
eISSN: 1538-3881 |
Record 152 of 318 | |||||||||||||||||||||||||||
Title: China's Mars Exploration Mission and Science Investigation | |||||||||||||||||||||||||||
Author(s): Li, CL (Li, Chunlai); Zhang, RQ (Zhang, Rongqiao); Yu, DY (Yu, Dengyun); Dong, GL (Dong, Guangliang); Liu, JJ (Liu, Jianjun); Geng, Y (Geng, Yan); Sun, ZZ (Sun, Zezhou); Yan, W (Yan, Wei); Ren, X (Ren, Xin); Su, Y (Su, Yan); Zuo, W (Zuo, Wei); Zhang, TL (Zhang, Tielong); Cao, JB (Cao, Jinbin); Fang, GY (Fang, Guangyou); Yang, JF (Yang, Jianfeng); Shu, R (Shu, Rong); Lin, YT (Lin, Yangting); Zou, YL (Zou, Yongliao); Liu, DW (Liu, Dawei); Liu, B (Liu, Bin); Kong, DQ (Kong, Deqing); Zhu, XY (Zhu, Xinying); Ouyang, ZY (Ouyang, Ziyuan) | |||||||||||||||||||||||||||
Source: SPACE SCIENCE REVIEWS Volume: 217 Issue: 4 Article Number: 57 DOI: 10.1007/s11214-021-00832-9 Published: JUN 2021 | |||||||||||||||||||||||||||
Abstract: China's first Mars exploration mission (HuoXing-1) has been named as 'Tianwen-1' meaning Heaven Inquiry. Tianwen-1 was launched on July 23, 2020. In this paper, the scientific objectives of earlier and current Mars exploration missions worldwide are reviewed, and the scientific objectives, payloads and preliminary scientific investigation plan of China's first Mars exploration mission are introduced, and expected scientific achievements are analyzed. | |||||||||||||||||||||||||||
Accession Number: WOS:000654261300002 | |||||||||||||||||||||||||||
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ISSN: 0038-6308 | |||||||||||||||||||||||||||
eISSN: 1572-9672 |
Record 153 of 318 | |||||||||
Title: Apparatus for generation of nanojoule-class water-window high-order harmonics | |||||||||
Author(s): Nishimura, K (Nishimura, Kotaro); Fu, YX (Fu, Yuxi); Suda, A (Suda, Akira); Midorikawa, K (Midorikawa, Katsumi); Takahashi, EJ (Takahashi, Eiji J.) | |||||||||
Source: REVIEW OF SCIENTIFIC INSTRUMENTS Volume: 92 Issue: 6 Article Number: 063001 DOI: 10.1063/5.0045342 Published: JUN 1 2021 | |||||||||
Abstract: In our recent study [Fu et al., Commun. Phys. 3(1), 92 (2020)], we have developed an approach for energy-scaling of high-order harmonic generation in the water-window region under a neutral-medium condition. More specifically, we obtained a nanojoule-class water-window soft x-ray harmonic beam under a phase-matching condition. It has been achieved by combining a newly developed terawatt-class mid-infrared femtosecond laser and a loose-focusing geometry for high-order harmonic generation. The generated beam is more than 100 times intense compared to previously reported results. The experimental setup included two key parts: a terawatt mid-infrared femtosecond driving laser [Fu et al., Sci. Rep. 8(1), 7692 (2018)] and a specially designed gas cell. Despite the dramatic drop in the optimal gas pressure for phase-matching due to loose-focusing geometry, it still reached the 1 bar level for helium. Thus, we have designed a double-structured pulsed-gas cell with a differential pumping system, which enabled providing sufficiently high gas pressure. Moreover, it allowed reducing gas consumption significantly. A robust energy-scalable apparatus for high-order harmonic generation developed in this study will enable the generation of over ten-nanojoule water-window attosecond pulses in the near future. | |||||||||
Accession Number: WOS:000715954500005 | |||||||||
PubMed ID: 34243496 | |||||||||
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ISSN: 0034-6748 | |||||||||
eISSN: 1089-7623 |
Record 154 of 318 | ||||||
Title: Genetic-algorithm-based deep neural networks for highly efficient photonic device design | ||||||
Author(s): Ren, YM (Ren, Yangming); Zhang, LX (Zhang, Lingxuan); Wang, WQ (Wang, Weiqiang); Wang, XY (Wang, Xinyu); Lei, YF (Lei, Yufang); Xue, YL (Xue, Yulong); Sun, XC (Sun, Xiaochen); Zhang, WF (Zhang, Wenfu) | ||||||
Source: PHOTONICS RESEARCH Volume: 9 Issue: 6 Pages: B247-B252 DOI: 10.1364/PRJ.416294 Published: JUN 2021 | ||||||
Abstract: While deep learning has demonstrated tremendous potential for photonic device design, it often demands a large amount of labeled data to train these deep neural network models. Preparing these data requires high-resolution numerical simulations or experimental measurements and cost significant, if not prohibitive, time and resources. In this work, we present a highly efficient inverse design method that combines deep neural networks with a genetic algorithm to optimize the geometry of photonic devices in the polar coordinate system. The method requires significantly less training data compared with previous inverse design methods. We implement this method to design several ultra-compact silicon photonics devices with challenging properties including power splitters with uncommon splitting ratios, a TE mode converter, and a broadband power splitter. These devices are free of the features beyond the capability of photolithography and generally in compliance with silicon photonics fabrication design rules. (C) 2021 Chinese Laser Press | ||||||
Accession Number: WOS:000658338800001 | ||||||
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ISSN: 2327-9125 |
Record 155 of 318 | |||||||||
Title: Non-iterative complex wave-field reconstruction based on Kramers-Kronig relations | |||||||||
Author(s): Shen, C (Shen, Cheng); Liang, MS (Liang, Mingshu); Pan, A (Pan, An); Yang, CHE (Yang, Changhuei) | |||||||||
Source: PHOTONICS RESEARCH Volume: 9 Issue: 6 Pages: 1003-1012 DOI: 10.1364/PRJ.419886 Published: JUN 2021 | |||||||||
Abstract: A non-iterative and non-interferometric computational imaging method to reconstruct a complex wave field called synthetic aperture imaging based on Kramers-Kronig relations (KKSAI) is reported. By collecting images through a modified microscope system with pupil modulation capability, we show that the phase and amplitude profile of the sample at pupil limited resolution can be extracted from as few as two intensity images by using Kramers-Kronig (KK) relations. It is established that as long as each subaperture's edge crosses the pupil center, the collected raw images are mathematically analogous to off-axis holograms. This in turn allows us to adapt a recently reported KK-relations-based phase recovery framework in off-axis holography for use in KKSAI. KKSAI is non-iterative, free of parameter tuning, and applicable to a wider range of samples. Simulation and experiment results have proved that it has much lower computational burden and achieves the best reconstruction quality when compared with two existing phase imaging methods. (C) 2021 Chinese Laser Press | |||||||||
Accession Number: WOS:000658338800012 | |||||||||
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ISSN: 2327-9125 |
Record 156 of 318 |
Title: Remote Sensing Road Extraction by Road Segmentation Network |
Author(s): Tan, JH (Tan, Jiahai); Gao, M (Gao, Ming); Yang, K (Yang, Kai); Duan, T (Duan, Tao) |
Source: APPLIED SCIENCES-BASEL Volume: 11 Issue: 11 Article Number: 5050 DOI: 10.3390/app11115050 Published: JUN 2021 |
Abstract: Road extraction from remote sensing images has attracted much attention in geospatial applications. However, the existing methods do not accurately identify the connectivity of the road. The identification of the road pixels may be interfered with by the abundant ground such as buildings, trees, and shadows. The objective of this paper is to enhance context and strip features of the road by designing UNet-like architecture. The overall method first enhances the context characteristics in the segmentation step and then maintains the stripe characteristics in a refinement step. The segmentation step exploits an attention mechanism to enhance the context information between the adjacent layers. To obtain the strip features of the road, the refinement step introduces the strip pooling in a refinement network to restore the long distance dependent information of the road. Extensive comparative experiments demonstrate that the proposed method outperforms other methods, achieving an overall accuracy of 98.25% on the DeepGlobe dataset, and 97.68% on the Massachusetts dataset. |
Accession Number: WOS:000659578500001 |
eISSN: 2076-3417 |
Record 157 of 318 | |||||||||||||||||||||
Title: Small-size streak tube with high edge spatial resolution | |||||||||||||||||||||
Author(s): Tian, LP (Tian, Liping); Shen, LB (Shen, Lingbin); Li, LL (Li, Lili); Wang, X (Wang, Xing); Chen, P (Chen, Ping); Wang, JF (Wang, Junfeng); Chen, L (Chen, Lin); Zhao, W (Zhao, Wei); Tian, JS (Tian, Jinshou) | |||||||||||||||||||||
Source: OPTIK Volume: 242 Article Number: 166791 DOI: 10.1016/j.ijleo.2021.166791 Early Access Date: JUN 2021 Published: SEP 2021 | |||||||||||||||||||||
Abstract: A small-size streak tube with high spatial resolution over the entire working area is designed, manufactured and tested. The streak tube adopts curved photocathode and curved screen to improve the spatial resolution, especially at the edge area by decreasing the aberration. An accelerating slit electrode, instead of a mesh which limits the luminance gain of the tube, is employed next to the photocathode to improve the electrical resistance, reliability and the temporal resolution by increasing the electron acceleration field. The results in the numerical simulations show that the spatial resolution is 29 lp/mm @ MTF = 10 % over the whole effective photocathode area. The tested results show that the small-size streak tube can offer static spatial resolution as high as 20 lp/mm over the whole effective area. And, the maximum point of the static spatial resolution 25 lp/mm, is deviated away from the center of the photocathode. The experiment results indicate that the spatial resolution is higher than 23.4 lp/mm @ MTF = 10 %. The luminance gain can reach to 39.4 and the dimension of the streak tube is only phi 40 mm x 140 mm. Comparing with 5200 streak tube_XIOPM, we demonstrated that this small-size streak tube in our design not only possesses the compact size, but also obtain a much larger effective working area and much higher luminance gain. | |||||||||||||||||||||
Accession Number: WOS:000683386500001 | |||||||||||||||||||||
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ISSN: 0030-4026 | |||||||||||||||||||||
eISSN: 1618-1336 |
Record 158 of 318 | ||||||||||||
Title: Optical System for the Transit Spectral Observation of Exoplanet-Atmosphere Characteristics | ||||||||||||
Author(s): Wang, F (Wang, Fang); Fan, XW (Fan, Xuewu); Wang, H (Wang, Hu); Pan, Y (Pan, Yue); Shen, Y (Shen, Yang); Lu, XY (Lu, Xiaoyun); Du, XQ (Du, Xingqian); Lin, SM (Lin, Shangmin) | ||||||||||||
Source: APPLIED SCIENCES-BASEL Volume: 11 Issue: 12 Article Number: 5508 DOI: 10.3390/app11125508 Published: JUN 2021 | ||||||||||||
Abstract: Optical instrumentation with reliable performance is essential for the research of exoplanet atmosphere characteristics. However, due to long distances and weak signals, exoplanets are difficult to be imaged by traditional optical systems. To this end, a novel optical system based on transit spectroscopy is proposed in this paper. On the basis of the principle of the transit-spectroscopy method and the astronomical parameters of observed targets, the optional parameter ranges of a dedicated optical system are analyzed. The transit signal-to-noise ratio (SNR) is introduced for the determination of telescope aperture and throughput. Furthermore, an example of the optical system with a space telescope and spectrometer is proposed according to the above optical index, which is proven to meet the performance requirements. The optical system is required to cover the wavelength of 0.5-8 mu m and the field of view (FOV) of 27.9 '' within the diffraction limit. The collecting aperture should be greater than 2 m, and spectral resolutions of two spectrometer channels should approximately be 100 (2-4 mu m) and 30 (4-8 mu m). The point-spread function (PSF) of each channel at the minimal wavelength should cover 2 pixels. The telescope and dichroic system provide diffraction-limited input beams with the required aperture, FOV, and wavelength for the spectrometer slits. The simulation results of the optical system show that the spectral resolutions of the dual-channel spectrometer were 111-200 and 43-94. The image points of the spectrometer in each wavelength were smaller than the Airy spot within the slit FOV, and the full width at half-maximum (FWHM) of PSF at lambda(min) provided 2 pixels of 18 mu m sampling. The feasibility of the demonstrated optical parameters is proven by the design. | ||||||||||||
Accession Number: WOS:000666801500001 | ||||||||||||
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eISSN: 2076-3417 |
Record 159 of 318 | |||||||||
Title: Effects of CeO<sub>2</sub> and Sb<sub>2</sub>O<sub>3</sub> on the Nonlinear Photochemical Process in Ultrashort Laser Gaussian-Bessel Beams Irradiated Photo-Thermo-Refractive Glass | |||||||||
Author(s): Wang, X (Wang, Xu); Zhang, GD (Zhang, Guodong); Li, GY (Li, Guangying); Lou, R (Lou, Rui); Sun, Z (Sun, Zhe); Xie, XP (Xie, Xiaoping); Li, WN (Li, Weinan); Cheng, GH (Cheng, Guanghua) | |||||||||
Source: MICROMACHINES Volume: 12 Issue: 6 Article Number: 615 DOI: 10.3390/mi12060615 Published: JUN 2021 | |||||||||
Abstract: Microfluidic chips and optical elements can be fabricated based on the nonlinear photosensitivity in photo-thermo-refractive (PTR) glass by controlling the growth of nanocrystals in the femtosecond (fs) laser-irradiated region. Here, we focus on CeO2 and Sb2O3 that play important roles in UV irradiation, experimentally investigate the effects of the dopants on the nonlinear photochemical process in PTR glass triggered by fs Gaussian-Bessel beams. The results show that the generation of Ag-0 atoms and the Ag nanoparticles can be improved by CeO2 and Sb2O3 co-doping. Besides, each multivalent ion in PTR glass possibly participates in the electron transfer processes and contributes to the generation of Ag-0 atoms. Finally, X-ray diffraction analysis reveals the precipitation of NaF nanocrystals with an average size of 10 to 12 nm after laser irradiation and thermal treatment, which is unrelated to the dopants. | |||||||||
Accession Number: WOS:000667435400001 | |||||||||
PubMed ID: 34073636 | |||||||||
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eISSN: 2072-666X |
Record 160 of 318 | ||||||
Title: Nano-Crystal and Microstructure Formation in Fluoride Photo-Thermo-Refractive Glass Using Chirp-Controlled Ultrafast Laser Bessel Beams | ||||||
Author(s): Zhang, YJ (Zhang, Yunjie); Wang, X (Wang, Xu); Zhang, GD (Zhang, Guodong); Stoian, R (Stoian, Razvan); Cheng, GH (Cheng, Guanghua) | ||||||
Source: NANOMATERIALS Volume: 11 Issue: 6 Article Number: 1432 DOI: 10.3390/nano11061432 Published: JUN 2021 | ||||||
Abstract: Nano-crystals were formed in the exposed regions of photo-thermo-refractive glass undergoing irradiation with zeroth order chirp-controlled ultrafast laser Bessel beams and subsequent heat treatment. Effects of various writing powers, pulse durations and heat treatment time on the distribution and the size of the nano-crystals were investigated. The results show that nano-crystals' distribution depended on the laser power density spatial shape, while the size of the nano-crystals is quasi-independent. However, the average diameter of the nano-crystals was affected by the heat treatment time, decreasing from 175 to 105 nm with the time halved. In addition, using crystallographic characterization by X-ray diffraction, the nano-crystal composition in the laser-exposed regions was detected to be sodium fluoride. | ||||||
Accession Number: WOS:000667396300001 | ||||||
PubMed ID: 34071595 | ||||||
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eISSN: 2079-4991 |
Record 161 of 318 | ||||||||||||
Title: Multi-color structured illumination microscopy for live cell imaging based on the enhanced image recombination transform algorithm | ||||||||||||
Author(s): Zhao, TY (Zhao, Tianyu); Hao, HW (Hao, Huiwen); Wang, ZJ (Wang, Zhaojun); Liang, YS (Liang, Yansheng); Feng, K (Feng, Kun); He, MR (He, Minru); Yun, X (Yun, Xue); Bianco, PR (Bianco, Piero R.); Sun, YJ (Sun, Yujie); Yao, BL (Yao, Baoli); Lei, M (Lei, Ming) | ||||||||||||
Source: BIOMEDICAL OPTICS EXPRESS Volume: 12 Issue: 6 Pages: 3474-3484 DOI: 10.1364/BOE.423171 Published: JUN 1 2021 | ||||||||||||
Abstract: Structured illumination microscopy (SIM) has attracted considerable interest in super-resolution, live-cell imaging because of its low light dose and high imaging speed. Obtaining a high-quality reconstruction image in SIM depends on the precise determination of the parameters of the fringe illumination pattern. The image recombination transform (IRT) algorithm is superior to other algorithms in obtaining the precise initial phase without any approximation, which is promising to provide a considerable solution to address the difficulty of initial phase estimation at low-modulation-depth conditions. However, the IRT algorithm only considers a phase shift of pi/2, which limits its applications in general scenarios. In this letter, we present a general form of IRT algorithm suitable for arbitrary phase shifts, providing a powerful tool for parameter estimation in low signal-to-noise cases. To demonstrate the effectiveness of the enhanced IRT algorithm, we constructed a multicolor, structured illumination microscope and studied at super-resolution, the cargo traffic in HRPE cells, and monitored the movement of mitochondrial structures and microtubules in COS-7 cells. The custom SIM system using the enhanced IRT algorithm allows multicolor capability and a low excitation intensity fluorescence imaging less than 1 W/cm(2). High-quality super-resolution images are obtained, which demonstrates the utility of this approach in imaging in the life sciences. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||
Accession Number: WOS:000656912500002 | ||||||||||||
PubMed ID: 34221673 | ||||||||||||
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ISSN: 2156-7085 |
Record 162 of 318 | |||||||||||||||||||||
Title: High Efficiency 1.9 Kw Single Diode Laser Bar Epitaxially Stacked With a Tunnel Junction | |||||||||||||||||||||
Author(s): Zhao, YL (Zhao, Yuliang); Wang, ZF (Wang, Zhenfu); Demir, A (Demir, Abdullah); Yang, GW (Yang, Guowen); Ma, SF (Ma, Shufang); Xu, BS (Xu, Bingshe); Sun, C (Sun, Cheng); Li, B (Li, Bo); Qiu, BC (Qiu, Bocang) | |||||||||||||||||||||
Source: IEEE PHOTONICS JOURNAL Volume: 13 Issue: 3 Article Number: 1500708 DOI: 10.1109/JPHOT.2021.3073732 Published: JUN 2021 | |||||||||||||||||||||
Abstract: We report on the development of a 940-nm diode laser bar based on epitaxially stacked active regions by employing a tunnel junction structure. The tunnel junction and the device parameters were systematically optimized to achieve high output and power conversion efficiency. A record quasi-continuous wave (QCW) peak power of 1.91 kW at 25 degrees C was demonstrated from a 1-cm wide bar with a 2-mm cavity length at 1 kA drive current (200 mu s pulse width and 10 Hz repetition rate). Below the onset of the thermal rollover, the slope efficiency was as high as 2.23 W/A. The maximum power conversion efficiency of 61.1% at 25 degrees C was measured at 300 A. Reducing the heatsink temperature to 15 degrees C led to a marginal increase in the peak power to 1.95 kW. | |||||||||||||||||||||
Accession Number: WOS:000703752600002 | |||||||||||||||||||||
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ISSN: 1943-0655 | |||||||||||||||||||||
eISSN: 1943-0647 |
Record 163 of 318 | ||||||||||||
Title: Remote Sensing Image Generation From Audio | ||||||||||||
Author(s): Zheng, ZY (Zheng, Zhiyuan); Chen, J (Chen, Jun); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||
Source: IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Volume: 18 Issue: 6 Pages: 994-998 DOI: 10.1109/LGRS.2020.2992324 Published: JUN 2021 | ||||||||||||
Abstract: Generating image from other modal data has attracted much attention in cross-modal studies, since the generated image offers intuitive vision information. Unlike the previous works which generate an image from text, a novel task is introduced, generating an image from audio. However, semantic gap intrinsically exists in cross-modal data, which disturbs the generative results. In order to explore the relevance between the audio and image, a novel reranking audio-image translation method is proposed. The proposed method: 1) maps the audio and image into a uniform feature space; 2) designs an audio-audio matching network to match the related audio; and 3) adopts an audio-image matching network for every matched audio to generate a related image, and the most frequent image is voted as the final result. Extensive experiments on two remote sensing cross-modal data sets demonstrate that the proposed method can visualize the content of audio. | ||||||||||||
Accession Number: WOS:000652799700012 | ||||||||||||
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ISSN: 1545-598X | ||||||||||||
eISSN: 1558-0571 |
Record 164 of 318 | |||||||||||||||
Title: Evolvement Investigation of Secondary Electron Emission for Ultrathin MgO Coatings Prepared by Atomic Layer Deposition | |||||||||||||||
Author(s): Zhu, XP (Zhu, Xiangping); Guo, JJ (Guo, Junjiang); Li, XX (Li, Xiangxin); Zhou, RD (Zhou, Rundong); Wang, D (Wang, Dan); Zhao, W (Zhao, Wei) | |||||||||||||||
Source: APPLIED SCIENCES-BASEL Volume: 11 Issue: 11 Article Number: 4801 DOI: 10.3390/app11114801 Published: JUN 2021 | |||||||||||||||
Abstract: MgO is a kind of high secondary electron yield (SEY) material with important applications in electron multipliers. MgO coatings can be used as the electron emission layer for multiplier dynode to improve the electron gain significantly. However, the SEY investigation on ultrathin MgO coatings is not complete and needed to be supplemented urgently. In this work, a series of MgO coatings with increasing thickness were prepared by atomic layer deposition. SEY properties and energy spectra were characterized, and the effect of coating thickness on SEY was systematically analyzed. Experimental results show that SEY of MgO/Si samples rises as the coating thickness increases. Merely, SEY almost does not change with the coating thickness when the thickness exceeds 30 nm. Then, a SEY semi-empirical theory was employed to interpret the SEY regularities of MgO coatings by regarding the coating samples as ideal double-layer structures. Theoretical calculation quantitatively explained the SEY variation observed during the experiments, and further quantified the SEY contribution level of top coating and bottom substrate for the 1 nm and 20 nm MgO coatings. The work is of great significance for comprehending the SEY of ultrathin MgO coatings and expanding the applications of nanoscale coatings with high SEY. | |||||||||||||||
Accession Number: WOS:000659616000001 | |||||||||||||||
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eISSN: 2076-3417 |
Record 165 of 318 | |||||||||
Title: Advances in High-Speed Structured Illumination Microscopy | |||||||||
Author(s): Zhao, TY (Zhao, Tianyu); Wang, ZJ (Wang, Zhaojun); Chen, TS (Chen, Tongsheng); Lei, M (Lei, Ming); Yao, BL (Yao, Baoli); Bianco, PR (Bianco, Piero R.) | |||||||||
Source: FRONTIERS IN PHYSICS Volume: 9 Article Number: 672555 DOI: 10.3389/fphy.2021.672555 Published: MAY 28 2021 | |||||||||
Abstract: Super-resolution microscopy surpasses the diffraction limit to enable the observation of the fine details in sub-cellular structures and their dynamics in diverse biological processes within living cells. Structured illumination microscopy (SIM) uses a relatively low illumination light power compared with other super-resolution microscopies and has great potential to meet the demands of live-cell imaging. However, the imaging acquisition and reconstruction speeds limit its further applications. In this article, recent developments all targeted at improving the overall speed of SIM are reviewed. These comprise both hardware and software improvements, which include a reduction in the number of raw images, GPU acceleration, deep learning and the spatial domain reconstruction. We also discuss the application of these developments in live-cell imaging. | |||||||||
Accession Number: WOS:000660058400001 | |||||||||
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ISSN: 2296-424X |
Record 166 of 318 | ||||||||||||||||||
Title: Mutual Attention Inception Network for Remote Sensing Visual Question Answering | ||||||||||||||||||
Author(s): Zheng, XT (Zheng, Xiangtao); Wang, BQ (Wang, Binqiang); Du, XQ (Du, Xingqian); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||||||||
Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Volume: 60 DOI: 10.1109/TGRS.2021.3079918 Early Access Date: MAY 2021 Published: 2022 | ||||||||||||||||||
Abstract: Remote sensing images (RSIs) containing various ground objects have been applied in many fields. To make semantic understanding of RSIs objective and interactive, the task remote sensing visual question answering (VQA) has appeared. Given an RSI, the goal of remote sensing VQA is to make an intelligent agent answer a question about the remote sensing scene. Existing remote sensing VQA methods utilized a nonspatial fusion strategy to fuse the image features and question features, which ignores the spatial information of images and word-level information of questions. A novel method is proposed to complete the task considering these two aspects. First, convolutional features of the image are included to represent spatial information, and the word vectors of questions are adopted to present semantic word information. Second, attention mechanism and bilinear technique are introduced to enhance the feature considering the alignments between spatial positions and words. Finally, a fully connected layer with softmax is utilized to output an answer from the perspective of the multiclass classification task. To benchmark this task, a RSIVQA dataset is introduced in this article. For each of more than 37,000 RSIs, the proposed dataset contains at least one or more questions, plus corresponding answers. Experimental results demonstrate that the proposed method can capture the alignments between images and questions. The code and dataset are available at https://github.com/spectralpublic/RSIVQA. | ||||||||||||||||||
Accession Number: WOS:000733504200001 | ||||||||||||||||||
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ISSN: 0196-2892 | ||||||||||||||||||
eISSN: 1558-0644 |
Record 167 of 318 | ||||||||||||||||||
Title: Unsupervised Change Detection by Cross-Resolution Difference Learning | ||||||||||||||||||
Author(s): Zheng, XT (Zheng, Xiangtao); Chen, XM (Chen, Xiumei); Lu, XQ (Lu, Xiaoqiang); Sun, BY (Sun, Bangyong) | ||||||||||||||||||
Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Volume: 60 DOI: 10.1109/TGRS.2021.3079907 Early Access Date: MAY 2021 Published: 2022 | ||||||||||||||||||
Abstract: Change detection (CD) aims to identify the differences between multitemporal images acquired over the same geographical area at different times. With the advantages of requiring no cumbersome labeled change information, unsupervised CD has attracted extensive attention of researchers. Multitemporal images tend to have different resolutions as they are usually captured at different times with different sensor properties. It is difficult to directly obtain one pixelwise change map for two images with different resolutions, so current methods usually resize multitemporal images to a unified size. However, resizing operations change the original information of pixels, which limits the final CD performance. This article aims to detect changes from multitemporal images in the originally different resolutions without resizing operations. To achieve this, a cross-resolution difference learning method is proposed. Specifically, two cross-resolution pixelwise difference maps are generated for the two different resolution images and fused to produce the final change map. First, the two input images are segmented into individual homogeneous regions separately due to different resolutions. Second, each pixelwise difference map is produced according to two measure distances, the mutual information distance and the deep feature distance, between image regions in which the pixel lies. Third, the final binary change map is generated by fusing and binarizing the two cross-resolution difference maps. Extensive experiments on four datasets demonstrate the effectiveness of the proposed method for detecting changes from different resolution images. | ||||||||||||||||||
Accession Number: WOS:000732756300001 | ||||||||||||||||||
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ISSN: 0196-2892 | ||||||||||||||||||
eISSN: 1558-0644 |
Record 168 of 318 | ||||||||||||||||||||||||||||||
Title: Synthesized soliton crystals | ||||||||||||||||||||||||||||||
Author(s): Lu, ZZ (Lu, Zhizhou); Chen, HJ (Chen, Hao-Jing); Wang, WQ (Wang, Weiqiang); Yao, L (Yao, Lu); Wang, Y (Wang, Yang); Yu, Y (Yu, Yan); Little, BE (Little, B. E.); Chu, ST (Chu, S. T.); Gong, QH (Gong, Qihuang); Zhao, W (Zhao, Wei); Yi, X (Yi, Xu); Xiao, YF (Xiao, Yun-Feng); Zhang, WF (Zhang, Wenfu) | ||||||||||||||||||||||||||||||
Source: NATURE COMMUNICATIONS Volume: 12 Issue: 1 Article Number: 3179 DOI: 10.1038/s41467-021-23172-2 Published: MAY 26 2021 | ||||||||||||||||||||||||||||||
Abstract: Dissipative Kerr soliton (DKS) featuring broadband coherent frequency comb with compact size and low power consumption, provides an unparalleled tool for nonlinear physics investigation and precise measurement applications. However, the complex nonlinear dynamics generally leads to stochastic soliton formation process and makes it highly challenging to manipulate soliton number and temporal distribution in the microcavity. Here, synthesized and reconfigurable soliton crystals (SCs) are demonstrated by constructing a periodic intra-cavity potential field, which allows deterministic SCs synthesis with soliton numbers from 1 to 32 in a monolithic integrated microcavity. The ordered temporal distribution coherently enhanced the soliton crystal comb lines power up to 3 orders of magnitude in comparison to the single-soliton state. The interaction between the traveling potential field and the soliton crystals creates periodic forces on soliton and results in forced soliton oscillation. Our work paves the way to effectively manipulate cavity solitons. The demonstrated synthesized SCs offer reconfigurable temporal and spectral profiles, which provide compelling advantages for practical applications such as photonic radar, satellite communication and radio-frequency filter. Here the authors demonstrate an on-demand generation of perfect soliton crystal using synthesized potential field. The individual solitons can also be controlled, for example oscillate around their equilibrium position, by the external field. | ||||||||||||||||||||||||||||||
Accession Number: WOS:000658301200009 | ||||||||||||||||||||||||||||||
PubMed ID: 34039968 | ||||||||||||||||||||||||||||||
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ISSN: 2041-1723 |
Record 169 of 318 | ||||||||||||||||||
Title: Semisupervised Spectral Degradation Constrained Network for Spectral Super-Resolution | ||||||||||||||||||
Author(s): Chen, WJ (Chen, Wenjing); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||||||||
Source: IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Volume: 19 DOI: 10.1109/LGRS.2021.3079961 Early Access Date: MAY 2021 Published: 2022 | ||||||||||||||||||
Abstract: Recently, various deep learning-based methods have been designed to improve the spectral resolution of the multispectral image (MSI) to obtain the hyperspectral image (HSI). These methods usually rely on sufficient MSI/HSI pairs for supervised training. However, collecting plentiful HSIs is time-consuming. In this letter, a semisupervised spectral degradation constrained network (SSDCN) is proposed to improve the spectral resolution of MSI. SSDCN is an autoencoder-like network that is composed of an encoder subnetwork for estimating HSI from input MSI and a decoder subnetwork for reconstructing MSI from the estimated HSI. A semisupervised training method is proposed to explore both MSI/HSI pairs and MSIs without ground-truth HSIs to optimize SSDCN. Simulated and two real databases are employed to demonstrate the effectiveness of SSDCN. | ||||||||||||||||||
Accession Number: WOS:000732408100001 | ||||||||||||||||||
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ISSN: 1545-598X | ||||||||||||||||||
eISSN: 1558-0571 |
Record 170 of 318 |
Title: Magneto-optically reorientation-induced image reconstruction in bulk nematic liquid crystals |
Author(s): Zhang, YB (Zhang, Yongbin); Wang, ZL (Wang, Zhaolu); Huang, N (Huang, Nan); Liu, HJ (Liu, Hongjun) |
Source: OPTICS EXPRESS Volume: 29 Issue: 11 Pages: 17581-17590 DOI: 10.1364/OE.425642 Published: MAY 24 2021 |
Abstract: We theoretically propose the magneto-optically reorientation-induced image reconstruction in bulk nematic liquid crystals (NLCs). The underlying signals are reinforced and recovered at the expense of scattering noise under reorientation-induced self-focusing nonlinearity. The intensity perturbation gain is derived and the numerical results are presented to show the response of NLC molecules to the diffusive images. The nonlinear image recovery is influenced by the input light intensity, the magnetic field direction, and the correlation length. The results suggest an alternative approach to detect noisy images and promote the application of NLCs in image processing. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement |
Accession Number: WOS:000654369300135 |
PubMed ID: 34154298 |
ISSN: 1094-4087 |
Record 171 of 318 | |||||||||||||||||||||||||||
Title: Chirality-Assisted Aharonov-Anandan Geometric-Phase Metasurfaces for Spin-Decoupled Phase Modulation | |||||||||||||||||||||||||||
Author(s): Ji, RN (Ji, Ruonan); Xie, X (Xie, Xin); Guo, XY (Guo, Xuyue); Zhao, Y (Zhao, Yang); Jin, CA (Jin, Chuan); Song, K (Song, Kun); Wang, SW (Wang, Shaowei); Yin, JB (Yin, Jianbo); Liu, YH (Liu, Yahong); Jiang, CM (Jiang, Chengming); Yang, CS (Yang, Chaoshun); Zhao, XP (Zhao, Xiaopeng); Lu, W (Lu, Wei) | |||||||||||||||||||||||||||
Source: ACS PHOTONICS Volume: 8 Issue: 6 Pages: 1847-1855 DOI: 10.1021/acsphotonics.1c00505 Early Access Date: MAY 2021 Published: JUN 16 2021 | |||||||||||||||||||||||||||
Abstract: In this work, a quasi-nondispersive and spin-decoupled phase modulation strategy was proposed based on the chiral structure. Owing to the spin-dependent response of the chiral structure, the evolution of the Aharonov-Anandan (AA) geometric phase can be controlled by tuning different structural parameters independently. Additionally, the chiral structure was designed nonresonant or weak-resonant to minimize the influence of strong resonant absorption and large dispersive propagation phase shift, leading to an efficiently quasi-nondispersive phase modulation. To prove the validity of the strategy, a series of umbrella-shaped reflection-type metal-insulator-metal structures were designed as the unit cells and simulated with the finite element method. Moreover, the metasurfaces were designed based on such unit cells to generate broadband orbital angular momentums with different topological charges and spin-switchable holograms, respectively. Simulated and experimental results are in good agreement with the theoretical results. To the best of our knowledge, broadband spin-dependent phase modulation has been achieved without intentionally merging other types of phases for the first time in this work. We believe that this strategy provides a flexible approach for complex spin- or polarization-related applications in optical communication, integrated optics, optical sensing, and other related fields. | |||||||||||||||||||||||||||
Accession Number: WOS:000664306400040 | |||||||||||||||||||||||||||
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ISSN: 2330-4022 |
Record 172 of 318 | ||||||
Title: Simple reformulation of the coordinate transformation method for gratings with a vertical facet or overhanging profile | ||||||
Author(s): Ming, XS (Ming, Xianshun); Sun, LQ (Sun, Liqun) | ||||||
Source: APPLIED OPTICS Volume: 60 Issue: 15 Pages: 4305-4314 DOI: 10.1364/AO.423209 Published: MAY 20 2021 | ||||||
Abstract: We reformulate the coordinate transformation method (C method) for gratings with a vertical facet or overhanging profile (overhanging gratings), in which no tensor concept is involved, only the knowledge of elementary mathematics and Maxwell's equations in the rectangular coordinate system is used, and we provide a detailed recipe for programming. This formulation is easy to understand and implement. It adopts the strategy of a rotating coordinate system from Plumey et al. [J. Opt. Soc. Am. A 14, 610 (1997)] and expresses it with the method of changing variables from Li et al. [Appl. Opt. 38, 304 (1999)]. We investigate several typical overhanging gratings by the reformulated C method, and we validate and compare the results with the Fourier modal method, which shows that it is superior, especially for metal deep smooth gratings. This reformulation can facilitate the research in light couplers for optical engineers. (C) 2021 Optical Society of America | ||||||
Accession Number: WOS:000654242400023 | ||||||
PubMed ID: 34143117 | ||||||
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ISSN: 1559-128X | ||||||
eISSN: 2155-3165 |
Record 173 of 318 | |||||||||||||||
Title: Lidar-radar for underwater target detection using a modulated sub-nanosecond Q-switched laser | |||||||||||||||
Author(s): Li, GY (Li, Guangying); Zhou, Q (Zhou, Qiang); Xu, GQ (Xu, Guoquan); Wang, X (Wang, Xing); Han, WJ (Han, Wenjie); Wang, J (Wang, Jiang); Zhang, GD (Zhang, Guodong); Zhang, YF (Zhang, Yifan); Yuan, ZA (Yuan, Zhi'an); Song, SJ (Song, Sijia); Gu, ST (Gu, Shangtai); Chen, FB (Chen, Fubin); Xu, K (Xu, Ke); Tian, JS (Tian, Jinshou); Wan, JW (Wan, Jianwei); Xie, XP (Xie, Xiaoping); Cheng, GH (Cheng, Guanghua) | |||||||||||||||
Source: OPTICS AND LASER TECHNOLOGY Volume: 142 Article Number: 107234 DOI: 10.1016/j.optlastec.2021.107234 Early Access Date: MAY 2021 Published: OCT 2021 | |||||||||||||||
Abstract: Here we report on a modulated sub-nanosecond lidar-radar for underwater target detection. The modulated laser source is consisted of a 1064 nm master oscillator power amplifier (MOPA) and a frequency-doubling module, outputting pulse energy of 178.1 mJ at 1064 nm with 0.76 ns pulse duration and 87.6 mJ at 532 nm. By using a Fabry-Pe ' rot cavity containing a KTP crystal and two reflectors, the 532 nm laser pulse is modulated into the burst mode with a repetition rate of 500 MHz. A streak tube camera is used as the signal receiving apparatus. An underwater target detection experiment has been carried out. The results indicate that this lidar-radar could emit a stable and powerful modulated signal, which greatly increases the underwater detection range. The cooperation of the streak tube imaging and modulated laser source for underwater target detection experiments is the first attempt in this field. The clear 3-D and 4-D images of the target underwater across 20 m are obtained in the experiments and the spatial resolution of 9 mm can be achieved. | |||||||||||||||
Accession Number: WOS:000674584700003 | |||||||||||||||
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ISSN: 0030-3992 | |||||||||||||||
eISSN: 1879-2545 |
Record 174 of 318 | ||||||||||||||||||||||||||||||||||||
Title: Design of supercontinuum laser hyperspectral light detection and ranging (LiDAR) (SCLaHS LiDAR) | ||||||||||||||||||||||||||||||||||||
Author(s): Zhou, GQ (Zhou, Guoqing); Zhou, X (Zhou, Xiang); Song, YJ (Song, Youjian); Xie, DH (Xie, Donghui); Wang, L (Wang, Long); Yan, GJ (Yan, Guangjian); Hu, ML (Hu, Minglie); Liu, BW (Liu, Bowen); Shang, WD (Shang, Weidong); Gong, CH (Gong, Chenghu); Wang, C (Wang, Cheng); Huang, HG (Huang, Huaguo); Zhao, YQ (Zhao, Yiqiang); Liu, ZG (Liu, Zhigang); Zhang, GY (Zhang, Guangyun); Wang, X (Wang, Xing); Nie, S (Nie, Sheng); Ye, M (Ye, Mao); Liu, SL (Liu, Songlin); Tan, QF (Tan, Qiaofeng); Li, K (Li, Ke); Wei, FY (Wei, Fengyuan); Su, W (Su, Wei); Tian, JS (Tian, Jinshou); Ai, QK (Ai, Qingkang); Yang, LY (Yang, Lvyun); Song, B (Song, Bo); Xu, JS (Xu, Jiasheng); Zhang, LP (Zhang, Lieping); Li, W (Li, Wei); Wang, RR (Wang, Ruirui); Xue, H (Xue, Hao); Dong, H (Dong, Hao); Yu, Y (Yu, Ying); Wang, HT (Wang, Hongtao) | ||||||||||||||||||||||||||||||||||||
Source: INTERNATIONAL JOURNAL OF REMOTE SENSING Volume: 42 Issue: 10 Pages: 3731-3755 DOI: 10.1080/01431161.2021.1880662 Published: MAY 19 2021 | ||||||||||||||||||||||||||||||||||||
Abstract: Traditional Light Detection and Rangings (LiDARs) can quickly collect high-accuracy of three-dimensional (3D) point cloud data at a designated wavelength (i.e., cannot obtain hyperspectral data), while the passive hyperspectral imager can collect rich spectral data of ground objects, but are lack of 3D spatial data. This paper presents one innovative study on the design of airborne-oriented supercontinuum laser hyperspectral (SCLaHS) LiDAR with 50 bands covering 400 nm to 900 nm at a spectral resolution of 10 nm and ground sampling distance (GSD) of 0.5 m. The major innovations include (1) development of the high-power narrow-pulse supercontinuum laser source covering 400 nm to 900 nm with 50 bands using multi-core microstructure fibre, all-polarization maintaining fibre and ultra-long cavity structure, (2) a miniaturized aberration correction holographic concave grating spectroscopic and streak tube technique are developed for 50 bands laser echoes detection at high spectral-spatial-temporal resolution and dynamic airborne platform, and (3) the algorithm theoretic basis for SCLaHS LiDAR point cloud data 3D geodetic coordination calculation, including in-flight airborne calibration algorithm. The initial experimental results demonstrated that the designed SCLaHS LiDAR is doable, and a prototype of the (SCLaHS) LiDAR intends to be implemented. | ||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000617948700001 | ||||||||||||||||||||||||||||||||||||
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ISSN: 0143-1161 | ||||||||||||||||||||||||||||||||||||
eISSN: 1366-5901 |
Record 175 of 318 | ||||||
Title: Effective suppression of mode distortion induced by stimulated Raman scattering in high-power fiber amplifiers | ||||||
Author(s): Gao, W (Gao, Wei); Fan, WH (Fan, Wenhui); Ju, P (Ju, Pei); Li, G (Li, Gang); Zhang, YP (Zhang, Yanpeng); He, AF (He, Aifeng); Gao, Q (Gao, Qi); Li, Z (Li, Zhe) | ||||||
Source: HIGH POWER LASER SCIENCE AND ENGINEERING Volume: 9 Article Number: e20 DOI: 10.1017/hpl.2021.13 Published: MAY 14 2021 | ||||||
Abstract: Mode distortion induced by stimulated Raman scattering (SRS) has become a new obstacle for the further development of high-power fiber lasers with high beam quality. Here, an approach for effective suppression of the SRS-induced mode distortion in high-power fiber amplifiers has been demonstrated experimentally by adjusting the seed power (output power of seed source) and forward feedback coefficient of the rear port in the seed source. It is shown that the threshold power of the SRS-induced mode distortion can be increased significantly by reducing the seed power or the forward feedback coefficient. Moreover, it has also been found that the threshold power is extremely sensitive to the forward feedback power value from the rear port. The influence of the seed power on the threshold power can be attributed to the fact that the seed power plays an important role in the effective length of the gain fiber in the amplifier. The influence of the forward feedback coefficient on the threshold power can be attributed to the enhanced SRS configuration because the end surface of the rear port together with the fiber in the amplifier constitutes a half-opening cavity. This suppression approach will be very helpful to further develop the high-power fiber amplifiers with high beam quality. | ||||||
Accession Number: WOS:000652601300001 | ||||||
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ISSN: 2095-4719 | ||||||
eISSN: 2052-3289 |
Record 176 of 318 |
Title: Ligand-Free BaF<sub>2</sub>: Nd Nanoparticles With Low Cytotoxicity, High Stability and Enhanced Fluorescence Intensity as NIR-II Imaging Probes |
Author(s): Cui, XX (Cui, Xiaoxia); Xu, YT (Xu, Yantao); She, SF (She, Shengfei); Xiao, XS (Xiao, Xusheng); Hou, CQ (Hou, Chaoqi); Guo, HT (Guo, Haitao) |
Source: FRONTIERS IN PHYSICS Volume: 9 Article Number: 665956 DOI: 10.3389/fphy.2021.665956 Published: MAY 13 2021 |
Abstract: Ligand-free BaF2:Nd nanoparticles (NPs) with a size of 10 nm were fabricated by a novel synthetic route in the liquid phase. A transparent dispersion of the BaF2:Nd NPs mixed with propanetriol and DMSO-d6 was done. Highly stable and outstanding near-infrared (NIR) fluorescence centered at 1,058 nm was detected using an excitation wavelength of 808 nm laser. Moreover, the dispersion can be found to be stable for over 1 month, and the cytotoxicity of the BaF2:Nd NP dispersion has also been studied by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The superior performance of these NPs exhibits their great potential application in high-contrast and high-penetration in vivo imaging. |
Accession Number: WOS:000654965900001 |
ISSN: 2296-424X |
Record 177 of 318 | ||||||
Title: Effective strategy to achieve a metal surface with ultralow reflectivity by femtosecond laser fabrication | ||||||
Author(s): Li, X (Li, Xun); Li, M (Li, Ming); Liu, HJ (Liu, Hongjun) | ||||||
Source: CHINESE OPTICS LETTERS Volume: 19 Issue: 5 Article Number: 051401 DOI: 10.3788/COL202119.051401 Published: MAY 10 2021 | ||||||
Abstract: An effective and simple method is proposed for fabricating the micro/nano hybrid structures on metal surfaces by adjusting femtosecond laser fluence, scanning interval, and polarization. The evolution of surface morphology with the micro/nano structures is discussed in detail. Also, the mechanism of light absorption by the micro/nano hybrid structures is revealed. Compared with the typical periodic light-absorbing structures, this type of micro/nano hybrid structures has an ultralow average reflectivity of 2% in the 250-2300 nm spectral band and the minimum 1.5% reflectivity in UV band. By employing this method, large areas of the micro/nano hybrid structures with high consistency could be achieved. | ||||||
Accession Number: WOS:000649411000006 | ||||||
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ISSN: 1671-7694 |
Record 178 of 318 | |||||||||||||||
Title: A sealed X-ray microchannel plate imager with CsI photocathode to improve quantitative precision of framing camera | |||||||||||||||
Author(s): Yang, Y (Yang, Yang); Zhu, BL (Zhu, Bingli); Gou, YS (Gou, Yongsheng); Chen, Z (Chen, Zhen); Bai, XH (Bai, Xiaohong); Qin, JJ (Qin, Junjun); Bai, YL (Bai, Yonglin); Liu, BY (Liu, Baiyu); Cao, WW (Cao, Weiwei); Wang, B (Wang, Bo); Xu, P (Xu, Peng) | |||||||||||||||
Source: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Volume: 1005 Article Number: 165404 DOI: 10.1016/j.nima.2021.165404 Early Access Date: MAY 2021 Published: JUL 21 2021 | |||||||||||||||
Abstract: In this paper, we propose a hermetically sealed X-ray microchannel plate imager as a more effective and stable alternative to the traditional open-structured imager. With two microstrip photocathodes of 100 nm Au and 100 nm CsI, respectively, the proposed imager has a measured exposure time of 65 ps when applied with a 200 ps width gate pulse. The static response test shows that the image intensity of the CsI microstrip photocathode is 3.4 times that of the Au microstrip photocathode when illuminated by a non-monochromatic portable Xray source with high energy photons. The sealed imager not only enhances the sensitivity and stability of the framing camera, but also has the potential to reduce crosstalks and artifacts, thus further improves the precision of measurement in practice. | |||||||||||||||
Accession Number: WOS:000657668700005 | |||||||||||||||
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ISSN: 0168-9002 | |||||||||||||||
eISSN: 1872-9576 |
Record 179 of 318 | ||||||||||||
Title: Diode-pumped SESAM mode-locked low-repetition-rate Tm:CALGO picosecond laser at 1968 nm | ||||||||||||
Author(s): Guo, L (Guo, Lei); Yang, YL (Yang, Yaling); Zhao, SZ (Zhao, Shengzhi); Li, T (Li, Tao); Qiao, WC (Qiao, Wenchao); Wang, RH (Wang, Ruihua); Zhang, BT (Zhang, Baitao); Yang, KJ (Yang, Kejian); He, JL (He, Jingliang); Li, X (Li, Xun) | ||||||||||||
Source: OPTICS AND LASER TECHNOLOGY Volume: 142 Article Number: 107195 DOI: 10.1016/j.optlastec.2021.107195 Early Access Date: MAY 2021 Published: OCT 2021 | ||||||||||||
Abstract: A diode-pumped SESAM continuous-wave mode-locked (CWML) Tm:CALGO laser is demonstrated at a new center wavelength of 1968 nm based on a ultra-long Z-shaped folding cavity configuration. A total maximum dual-output power of 328 mW is achieved with a pulse duration of 33.2 ps at a repetition rate of 38.86 MHz, corresponding to a maximum single pulse energy of 4.2 nJ. | ||||||||||||
Accession Number: WOS:000674585400009 | ||||||||||||
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ISSN: 0030-3992 | ||||||||||||
eISSN: 1879-2545 |
Record 180 of 318 |
Title: Design of image-side telecentric off-axis three-mirror anastigmatic systems based on the coaxial parent mirrors |
Author(s): Li, XJ (Li, Xijie); Zou, CB (Zou, Chunbo); Yang, JT (Yang, Jiating) |
Source: OPTIK Volume: 241 Article Number: 166855 DOI: 10.1016/j.ijleo.2021.166855 Early Access Date: MAY 2021 Published: SEP 2021 |
Abstract: Image-side telecentric unobscured optical systems have significant application values in the field of space optics. However, off-axis astigmatism increases with an increase of field of view (FOV), relative aperture and image-side telecentricity, so it's very difficult to design image-side telecentric anastigmatic systems with an ultrawide FOV. To solve these issues, this paper proposes an effective method that is based on the coaxial parent mirrors. By calculating the off-axis aberration optical path of the primary mirror (PM), secondary mirror (SM) and tertiary mirror (TM), and introducing even aspheric surface and adding boundary constraints, a prospective system with a focal length of 400 mm, a relative aperture of 1/3, an FOV of 18 degrees x 6 degrees, and a telecentricity of greater than 0.5 degrees is designed. The design results show that the modulation transfer function (MTF) of the system is greater than 0.7 at the Nyquist frequency of 34 lp/mm, which is close to the diffraction limitation. It has a high imaging quality, thereby proving the image-side telecentric off-axis three-mirror anastigmatic (TMA) system to be effective. |
Accession Number: WOS:000672569800001 |
ISSN: 0030-4026 |
eISSN: 1618-1336 |
Record 181 of 318 |
Title: Modeling of high-speed laser photography system for field projectile testing |
Author(s): Sun, C (Sun, Ce); Jia, YY (Jia, Yangyu); Wang, DN (Wang, Danni) |
Source: OPTIK Volume: 241 Article Number: 166980 DOI: 10.1016/j.ijleo.2021.166980 Early Access Date: MAY 2021 Published: SEP 2021 |
Abstract: Field projectile testing plays a crucial role in national defense. Laser high-speed photography records transient processes with high temporal and spatial resolution and is an effective diagnostic method for range testing. In this study, a laser high-speed photography model is established from detailed aspects, including laser pulse energy for reflective imaging, accurate synchronization of pulse train and shutter signal, minimum exposure time and shooting frequency for targets with different velocities, and magnification correction used in the image measurement. Shooting experiments conducted in Nanshan Test center verify the correctness of the theoretical analysis and parameter selection. The models and methods described in this article can be a guidance for field testing. |
Accession Number: WOS:000672568600005 |
ISSN: 0030-4026 |
eISSN: 1618-1336 |
Record 182 of 318 |
Title: A driver-assistance algorithm based on multi-feature fusion |
Author(s): Zhou, DM (Zhou, Dongmei); Qiu, S (Qiu, Shi); Song, Y (Song, Yang) |
Source: INFRARED PHYSICS & TECHNOLOGY Volume: 116 Article Number: 103747 DOI: 10.1016/j.infrared.2021.103747 Early Access Date: MAY 2021 Published: AUG 2021 |
Abstract: The lane line is difficult to be distinguished in visible light for driver assistance, so a multi-feature fusion model is built from the perspective of infrared images to realize assistant driving. Firstly, the features of infrared imaging are analyzed, and the Enet network is improved to focus on the area of the lane line and locate the passable area. Then, the previous vehicle is located to guide the current vehicle based on the fuzzy set theory. Finally, a spatiotemporal association model is constructed. By constructing the relationship between the guiding vehicle and spatiotemporal traffic, the relationship between human-computer interaction is indirectly established to guide vehicle assisted driving. Our experimental results show that the proposed algorithm is in line with the manual driving process, and good results can be achieved under complex road conditions. |
Accession Number: WOS:000674610800012 |
ISSN: 1350-4495 |
eISSN: 1879-0275 |
Record 183 of 318 | ||||||
Title: Effects of secondary electron emission yield properties on gain and timing performance of ALD-coated MCP | ||||||
Author(s): Guo, LH (Guo, Lehui); Xin, LW (Xin, Liwei); Li, LL (Li, Lili); Gou, YS (Gou, Yongsheng); Sai, XF (Sai, Xiaofeng); Li, SH (Li, Shaohui); Liu, HL (Liu, Hulin); Xu, XY (Xu, Xiangyan); Liu, BY (Liu, Baiyu); Gao, GL (Gao, Guilong); He, K (He, Kai); Zhang, MR (Zhang, Mingrui); Qu, YS (Qu, Youshan); Xue, YH (Xue, Yanhua); Wang, X (Wang, Xing); Chen, P (Chen, Ping); Tian, JS (Tian, Jinshou) | ||||||
Source: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Volume: 1005 Article Number: 165369 DOI: 10.1016/j.nima.2021.165369 Early Access Date: MAY 2021 Published: JUL 21 2021 | ||||||
Abstract: The technology of atomic layer deposition has been used to improve the lifetime of the microchannel plate-photomultiplier tube (MCP-PMT) effectively and makes MCP possible to choose to coat different potential emissive materials on the internal surface of the MCP channels in the future. However, it is still an open question to what extent the secondary electron emission (SEE) yield properties of the emissive materials influence the behavior of the ALD-coated MCP. In this work, the dependences of the gain and timing performance on the SEE yield properties were assessed by using the Monte Carlo and particle-in-cell methods. We established the three-dimensional MCP single channel model in Computer Simulation Technology (CST) Particle Studio. Three important secondary electron emissions, the backscattered, rediffused and true SEEs, were discussed numerically based on the probabilistic model. The secondary electron cascade processes in the MCP single channel were simulated. The simulation results indicate that the opportunities for improving the gain of the ALD-coated MCP by improving the SEE yields corresponding to the incident energies of 0 eV-100 eV. The backscattered and rediffused electrons are found to have strong effects on the gain and timing performance of the MCP. Although the higher the SEE yield the higher the MCP gain, the drawback is the extremely high SEE yield will make the MCP saturated prematurely and degrade the time resolution. The simulation results will be used to guide the design and selection of emissive material for ALD-coated MCP development. | ||||||
Accession Number: WOS:000663780700017 | ||||||
Author Identifiers: | ||||||
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ISSN: 0168-9002 | ||||||
eISSN: 1872-9576 |
Record 184 of 318 | |||||||||||||||||||||
Title: Arbitrary Phase Access for Stable Fiber Interferometers | |||||||||||||||||||||
Author(s): Roztocki, P (Roztocki, Piotr); MacLellan, B (MacLellan, Benjamin); Islam, M (Islam, Mehedi); Reimer, C (Reimer, Christian); Fischer, B (Fischer, Bennet); Sciara, S (Sciara, Stefania); Helsten, R (Helsten, Robin); Jestin, Y (Jestin, Yoann); Cino, A (Cino, Alfonso); Chu, ST (Chu, Sai T.); Little, B (Little, Brent); Moss, DJ (Moss, David J.); Kues, M (Kues, Michael); Morandotti, R (Morandotti, Roberto) | |||||||||||||||||||||
Source: LASER & PHOTONICS REVIEWS Volume: 15 Issue: 7 Article Number: 2000524 DOI: 10.1002/lpor.202000524 Early Access Date: MAY 2021 Published: JUL 2021 | |||||||||||||||||||||
Abstract: Well-controlled yet practical systems that give access to interference effects are critical for established and new functionalities in ultrafast signal processing, quantum photonics, optical coherence characterization, etc. Optical fiber systems constitute a central platform for such technologies. However, harnessing optical interference in a versatile and stable manner remains technologically costly and challenging. Here, degrees of freedom native to optical fibers, i.e., polarization and frequency, are used to demonstrate an easily deployable technique for the retrieval and stabilization of the relative phase in fiber interferometric systems. The scheme gives access (without intricate device isolation) to <1.3 x 10(-3) pi rad error signal Allan deviation across 1 ms to 1.2 h integration times for all tested phases, ranging from 0 to 2 pi. More importantly, the phase-independence of this stability is shown across the full 2 pi range, granting access to arbitrary phase settings, central for, e.g., performing quantum projection measurements and coherent pulse recombination. Furthermore, the scheme is characterized with attenuated optical reference signals and single-photon detectors, and extended functionality is demonstrated through the use of pulsed reference signals (allowing time-multiplexing of both main and reference signals). Finally, the scheme is used to demonstrate radiofrequency-controlled interference of high-dimensional time-bin entangled states. | |||||||||||||||||||||
Accession Number: WOS:000646574500001 | |||||||||||||||||||||
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ISSN: 1863-8880 | |||||||||||||||||||||
eISSN: 1863-8899 |
Record 185 of 318 | ||||||
Title: Development of a predictive model of growth hormone deficiency and idiopathic short stature in children | ||||||
Author(s): Cong, MD (Cong, Mengdi); Qiu, S (Qiu, Shi); Li, RP (Li, Rongpin); Sun, HY (Sun, Haiyan); Cong, LN (Cong, Lining); Hou, ZZ (Hou, Zhenzhou) | ||||||
Source: EXPERIMENTAL AND THERAPEUTIC MEDICINE Volume: 21 Issue: 5 Article Number: 494 DOI: 10.3892/etm.2021.9925 Published: MAY 2021 | ||||||
Abstract: The aim of the present study was to develop predictive models using clinical features and MRI texture features for distinguishing between growth hormone deficiency (GHD) and idiopathic short stature (ISS) in children with short stature. This retrospective study included 362 children with short stature from Children's Hospital of Hebei Province. GHD and ISS were identified via the GH stimulation test using arginine. Overall, there were 190 children with GHD and 172 with ISS. A total of 57 MRI texture features were extracted from the pituitary gland region of interest using C++ language and Matlab software. In addition, the laboratory examination data were collected. Receiver operating characteristic (ROC) regression curves were generated for the predictive performance of clinical features and MRI texture features. Logistic regression models based on clinical and texture features were established for discriminating children with GHD and ISS. Two clinical features [IGF-1 (insulin growth factor-1) and IGFBP-3 (IGF binding protein-3) levels] were used to build the clinical predictive model, whereas the three best MRI textures were used to establish the MRI texture predictive model. The ROC analysis of the two models revealed predictive performance for distinguishing GHD from ISS. The accuracy of predicting ISS from GHD was 64.5% in ROC analysis [area under the curve (AUC), 0.607; sensitivity, 57.6%; specificity, 72.1%] of the clinical model. The accuracy of predicting ISS from GHD was 80.4% in ROC analysis (AUC, 0.852; sensitivity, 93.6%; specificity, 65.8%) of the MRI texture predictive model. In conclusion, these findings indicated that a texture predictive model using MRI texture features was superior for distinguishing children with GHD from those with ISS compared with the model developed using clinical features. | ||||||
Accession Number: WOS:000635131600001 | ||||||
PubMed ID: 33791003 | ||||||
Author Identifiers: | ||||||
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ISSN: 1792-0981 | ||||||
eISSN: 1792-1015 |
Record 186 of 318 | |||||||||
Title: Optical Remote Sensing Image Denoising and Super-Resolution Reconstructing Using Optimized Generative Network in Wavelet Transform Domain | |||||||||
Author(s): Feng, XB (Feng, Xubin); Zhang, WX (Zhang, Wuxia); Su, XQ (Su, Xiuqin); Xu, ZP (Xu, Zhengpu) | |||||||||
Source: REMOTE SENSING Volume: 13 Issue: 9 Article Number: 1858 DOI: 10.3390/rs13091858 Published: MAY 2021 | |||||||||
Abstract: High spatial quality (HQ) optical remote sensing images are very useful for target detection, target recognition and image classification. Due to the influence of imaging equipment accuracy and atmospheric environment, HQ images are difficult to acquire, while low spatial quality (LQ) remote sensing images are very easy to acquire. Hence, denoising and super-resolution (SR) reconstruction technology are the most important solutions to improve the quality of remote sensing images very effectively, which can lower the cost as much as possible. Most existing methods usually only employ denoising or SR technology to obtain HQ images. However, due to the complex structure and the large noise of remote sensing images, the quality of the remote sensing image obtained only by denoising method or SR method cannot meet the actual needs. To address these problems, a method of reconstructing HQ remote sensing images based on Generative Adversarial Network (GAN) named "Restoration Generative Adversarial Network with ResNet and DenseNet" (RRDGAN) is proposed, which can acquire better quality images by incorporating denoising and SR into a unified framework. The generative network is implemented by fusing Residual Neural Network (ResNet) and Dense Convolutional Network (DenseNet) in order to consider denoising and SR problems at the same time. Then, total variation (TV) regularization is used to furthermore enhance the edge details, and the idea of Relativistic GAN is explored to make the whole network converge better. Our RRDGAN is implemented in wavelet transform (WT) domain, since different frequency parts could be handled separately in the wavelet domain. The experimental results on three different remote sensing datasets shows the feasibility of our proposed method in acquiring remote sensing images. | |||||||||
Accession Number: WOS:000650795000001 | |||||||||
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eISSN: 2072-4292 |
Record 187 of 318 | |||||||||||||||||||||||||||||||||
Title: Femtosecond Laser Drilling of Cylindrical Holes for Carbon Fiber-Reinforced Polymer (CFRP) Composites | |||||||||||||||||||||||||||||||||
Author(s): Jiang, H (Jiang, Hao); Ma, CW (Ma, Caiwen); Li, M (Li, Ming); Cao, ZL (Cao, Zhiliang) | |||||||||||||||||||||||||||||||||
Source: MOLECULES Volume: 26 Issue: 10 Article Number: 2953 DOI: 10.3390/molecules26102953 Published: MAY 2021 | |||||||||||||||||||||||||||||||||
Abstract: Ultrafast laser drilling has been proven to effectively reduce the heat-affected zone (HAZ) of carbon fiber-reinforced polymer (CFRP) composites. However, previous research mainly focused on the effects of picosecond laser parameters on CFRP drilling. Compared with a picosecond laser, a femtosecond laser can achieve higher quality CFRP drilling due to its smaller pulse width, but there are few studies on the effects of femtosecond laser parameters on CFRP drilling. Moreover, the cross-sectional taper of CFRP produced by laser drilling is very large. This paper introduces the use of the femtosecond laser to drill cylindrical holes in CFRP. The effect of laser power, rotational speed of the laser, and number of spiral passes on HAZ and ablation depth in circular laser drilling and spiral laser drilling mode was studied, respectively. It also analyzed the forming process of the drilling depth in the spiral drilling mode and studied the influence of laser energy and drilling feed depth on the holes' diameters and the taper. The experimental results show that the cylindrical hole of CFRP with a depth-to-diameter ratio of about 3:1 (taper < 0.32 degrees, HAZ < 10 mu m) was obtained by using femtosecond laser and a spiral drilling apparatus. | |||||||||||||||||||||||||||||||||
Accession Number: WOS:000655075300001 | |||||||||||||||||||||||||||||||||
PubMed ID: 34065643 | |||||||||||||||||||||||||||||||||
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eISSN: 1420-3049 |
Record 188 of 318 | ||||||
Title: Tunable Wettability Pattern Transfer Photothermally Achieved on Zinc with Microholes Fabricated by Femtosecond Laser | ||||||
Author(s): Li, FP (Li, Fengping); Feng, G (Feng, Guang); Yang, XJ (Yang, Xiaojun); Lu, CJ (Lu, Chengji); Ma, G (Ma, Guang); Li, XG (Li, Xiaogang); Xue, W (Xue, Wei); Sun, HR (Sun, Haoran) | ||||||
Source: MICROMACHINES Volume: 12 Issue: 5 Article Number: 547 DOI: 10.3390/mi12050547 Published: MAY 2021 | ||||||
Abstract: A quickly tunable wettability pattern plays an important role in regulating the surface behavior of liquids. Light irradiation can effectively control the pattern to achieve a specific wettability pattern on the photoresponsive material. However, metal oxide materials based on light adjustable wettability have a low regulation efficiency. In this paper, zinc (Zn) superhydrophobic surfaces can be obtained by femtosecond-laser-ablated microholes. Owing to ultraviolet (UV) irradiation increasing the surface energy of Zn and heating water temperature decreasing the surface energy of water, the wettability of Zn can be quickly tuned photothermally. Then, the Zn superhydrophobic surfaces can be restored by heating in the dark. Moreover, by tuning the pattern of UV irradiation, a specific wettability pattern can be transferred by the Zn microholes, which has a potential application value in the field of new location-controlled micro-/nanofluidic devices, such as microreactors and lab-on-chip devices. | ||||||
Accession Number: WOS:000662411400001 | ||||||
PubMed ID: 34064870 | ||||||
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eISSN: 2072-666X |
Record 189 of 318 |
Title: Star Identification Based on Multilayer Voting Algorithm for Star Sensors |
Author(s): Liu, MY (Liu, Meiying); Wei, X (Wei, Xin); Wen, DS (Wen, Desheng); Wang, H (Wang, Hu) |
Source: SENSORS Volume: 21 Issue: 9 Article Number: 3084 DOI: 10.3390/s21093084 Published: MAY 2021 |
Abstract: This paper describes the multilayer voting algorithm, a novel autonomous star identification method for spacecraft attitude determination. The proposed algorithm includes two processes: an initial match process and a verification process. In the initial match process, a triangle voting scheme is used to acquire candidates of the detected stars, in which the triangle unit is adopted as the basic voting unit. During the identification process, feature extraction is implemented, and each triangle unit is described by its singular values. Then the singular values are used to search for candidates of the imaged triangle units, which further improve the efficiency and robustness of the algorithm. After the initial match step, a verification method is applied to eliminate incorrect candidates from the initial results and then outputting the final match results of the imaged stars. Experiments show that our algorithm has more robustness to position noise, magnitude noise, and false stars than the other three algorithms, the identification speed of our algorithm is largely faster than the geometric voting algorithm and optimized grid algorithm. However, it takes more memory, and SVD also seems faster. |
Accession Number: WOS:000650757700001 |
PubMed ID: 33925177 |
eISSN: 1424-8220 |
Record 190 of 318 | |||||||||||||||
Title: Analysis of a wavelength-tunable D-shaped photonic crystal fiber filter with broad bandwidth | |||||||||||||||
Author(s): Meng, XJ (Meng, Xiaojian); Li, JS (Li, Jianshe); Guo, Y (Guo, Ying); Du, HJ (Du, Huijing); Liu, YD (Liu, Yundong); Li, SG (Li, Shuguang); Guo, HT (Guo, Haitao); Bi, WH (Bi, Weihong) | |||||||||||||||
Source: JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS Volume: 38 Issue: 5 Pages: 1525-1531 DOI: 10.1364/JOSAB.421792 Published: MAY 1 2021 | |||||||||||||||
Abstract: This paper has designed a D-shaped photonic crystal fiber filter based on surface plasmon resonance. The single-polarization filtering performance is analyzed systematically by the finite element method. It is found that the structural optimization process will modify the refractive index of the fundamental mode and the surface plasmon polarization mode, which results in a shift of the resonance wavelength. The proposed filter is able to indicate the wavelength-tunable function in the ranges of 1250-1350 nm and 1550-1750 nm by two methods. Moreover, at the communication windows of 1310 nm and 1550 nm, the corresponding filtering bandwidths are 170 and 550 nm, respectively. The flow chart of filter preparation reported in the study is promising for use in the field of optical devices. (C) 2021 Optical Society of America | |||||||||||||||
Accession Number: WOS:000645934500014 | |||||||||||||||
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ISSN: 0740-3224 | |||||||||||||||
eISSN: 1520-8540 |
Record 191 of 318 |
Title: Application and Research of NaYF<sub>4</sub> : Yb<SUP>3+</SUP>/Eu<SUP>3+</SUP> Upconverting Luminescent Micro-Nano Particles in Anti-Counterfeiting Identification |
Author(s): Wang, C (Wang Chong); Mo, JY (Mo Jian-ye); Li, DD (Li Dong-dong); She, JB (She Jiang-bo); Liu, Z (Liu Zhen) |
Source: SPECTROSCOPY AND SPECTRAL ANALYSIS Volume: 41 Issue: 5 Pages: 1525-1529 DOI: 10.3964/j.issn.1000-0593(2021)05-1525-05 Published: MAY 2021 |
Abstract: Rare earth doped upconversion luminescent micro-nano particles have great application prospects in anti-counterfeit identification. First of all, in the article NaYF4 : Yb3+/Eu3+ micro-nano particles prepared by hydrothermal synthesis method, The size, morphology and crystallinity of NaYF4 : Yb3+/Eu3+ micro-nano particles were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope, and the luminescence properties of NaYF4 : Yb3+/Eu3+ micro-nano particles were analyzed using a 980 nm pump source; Secondly, NaYF4 : Yb3+/Eu3+ micro-nano particles and alcohol were mixed in a certain proportion to make a screen printing agent and combined with a networkcustomized screen template, different anti-counterfeit patterns were printed on the paper. After air drying, the words were exposed to a 980 nm laser and camera were used to study it. Finally, the printed words were divided into two parts, one was stored indoors at a constant temperature of 25 degrees C, and the other was stored in the outdoor natural environment in January in winter. The storage locations are all Xi'an. After one week, in different environments the words were again tested with the same experimental instruments for imaging. The experiment and test results show that the diffraction peak of NaYF4 : Yb3+/Eu3+ micro nano particles is a completely consistent standard card of NaYF4, and no other impurities are generated. In this experiment, The synthesized micro-nano particles are all hexagonal in shape, and the average length and cross-sectional width are 209 and 175 nm respectively. The surface of the nanocrystal is smooth, defect-free, unbent, with high crystallinity and good dispersion. The electron diffraction ring corresponds to the 312, 300, and 302 crystal planes of NaYF4 : Yb3+/Eu3+ micro-nano particles. NaYF4 : Yb3+/Eu3+ micro-nano particles are affected by doped ions, it produces four visible lights of blue, green, yellow and red by different energy level transitions. Through fluorescence spectrum analysis of NaYF4 : Yb3+/Eu3+ micro-nano particles. The asymmetry ratio of Eu3+ ion is about 1. This result shows that the magnetic dipole transition is equivalent to the electric dipole transition. Screen printing agent of NaYF4 : Yb3+/Eu3+ micro-nano particles are good in different environments, the results are clear and easy to identify. However, affected by the storage environment, The results of indoor imaging have not changed much from the original imaging results. All characters of outdoor imaging are affected by moisture in the natural environment, the brightness is slightly reduced, but they can still be recognized. The imaging results show that the prepared NaYF4 Yb3+/Eu3+ micro-nano particles have the characteristics of stability and reliability in anti-counterfeiting identification, but they are still affected by natural environmental factors with a controllable degree. On the whole, it has great application prospects in anti-counterfeiting identification. |
Accession Number: WOS:000658891700032 |
ISSN: 1000-0593 |
Record 192 of 318 | ||||||
Title: Aperture-averaged scintillation index and fade statistics in weak oceanic turbulence* | ||||||
Author(s): Wang, H (Wang, Hao); Kang, FZ (Kang, Fu-Zeng); Wang, X (Wang, Xuan); Zhao, W (Zhao, Wei); Sun, SW (Sun, Shu-Wei) | ||||||
Source: CHINESE PHYSICS B Volume: 30 Issue: 6 Article Number: 064207 DOI: 10.1088/1674-1056/abd756 Published: MAY 2021 | ||||||
Abstract: With the rapid demand for underwater optical communication (UOC), studies of UOC degradation by oceanic turbulence have attached increasing attention worldwide and become a research hot-spot in recent years. Previous studies used a simplified and inaccurate oceanic turbulence spectrum, in which the eddy diffusivity ratio between temperature and salinity is assumed to be unity and the outer scale of turbulence is assumed to be infinite. However, both assumptions are not true in most of the actual marine environments. In this paper, based on the Rytov theory in weak turbulence, we derive analytical expressions of "the aperture-averaged scintillation index" (SI) for both plane and spherical waves, which can clearly demonstrate how SI is influenced by several key factors in UOC. Then, typical fade statistics of the UOC system in weak turbulence is discussed including the probability of fade, the expected number of fades per time, the mean fade time, signal-to-noise ratio and bit error rate. Our results show that spherical wave is preferable in the UOC system in weak turbulence compared to plane wave, and the aperture-averaged effect has a significant impact on UOC system's performance. Our results can be used to determine those key parameters for designing the UOC system over reasonable ranges. | ||||||
Accession Number: WOS:000657493300001 | ||||||
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ISSN: 1674-1056 | ||||||
eISSN: 1741-4199 |
Record 193 of 318 | ||||||
Title: High-power operation and lateral divergence angle reduction of broad-area laser diodes at 976 nm | ||||||
Author(s): Liu, YX (Liu, Yuxian); Yang, GW (Yang, Guowen); Wang, ZF (Wang, Zhenfu); Li, T (Li, Te); Tang, S (Tang, Song); Zhao, YL (Zhao, Yuliang); Lan, Y (Lan, Yu); Demir, A (Demir, Abdullah) | ||||||
Source: OPTICS AND LASER TECHNOLOGY Volume: 141 Article Number: 107145 DOI: 10.1016/j.optlastec.2021.107145 Early Access Date: APR 2021 Published: SEP 2021 | ||||||
Abstract: Broad-area diode lasers with high output power and low lateral divergence angle are highly desired for extensive scientific and industrial applications. Here, we report on the epitaxial design for higher output power and a flared waveguide design for reduced divergence, which leads to high power operation with a low lateral divergence angle. A vertically asymmetric epitaxial structure was employed and optimized for low internal optical loss and high efficiency to realize high output power operation. Using a flared waveguide design, the lateral divergence angle was efficiently reduced by decreasing the number of high-order lateral optical modes significantly. The flared waveguide design introduces a smooth modification of the ridge width along the cavity without deteriorating laser performance. Based on the optimized epitaxial and waveguide design, we scaled the waveguide width to realize high continuous-wave power of 34.5 W at 25 C. A low lateral divergence angle of 8 and high power conversion efficiency of 60% were achieved at the operating power level of 25 W. The life test data (30 A at 45 C for 39 units, 0 failures in 1000 h) demonstrated reliable operation illustrating the efficient design for reduced lateral divergence angle and high operating power. | ||||||
Accession Number: WOS:000663589200010 | ||||||
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ISSN: 0030-3992 | ||||||
eISSN: 1879-2545 |
Record 194 of 318 | |||||||||
Title: Spatio-Temporal Learning for Video Deblurring based on Two-Stream Generative Adversarial Network | |||||||||
Author(s): Song, LY (Song, Liyao); Wang, Q (Wang, Quan); Lie, HW (Lie, Haiwei); Fan, JC (Fan, Jiancun); Hu, BL (Hu, Bingliang) | |||||||||
Source: NEURAL PROCESSING LETTERS Volume: 53 Issue: 4 Special Issue: SI Pages: 2701-2714 DOI: 10.1007/s11063-021-10520-y Early Access Date: APR 2021 Published: AUG 2021 | |||||||||
Abstract: Video-deblurring has achieved excellent results by using deep learning approaches. How to capture the dynamic spatio-temporal information in the videos is crucial on deblurring. In this paper, we propose a two-stream DeblurGAN which combines a 3D stream with a 2D stream to deblur. The 3D convolution provides spatial and temporal invariance to restore the foreground of frames, while the 2D convolution is sufficient to deal with spatial features, given a relatively consistant background. Thus, our model takes advantage of the great processing power of the 3D stream to handle the foreground which usually contains more dynamical motion blur, and the advantage of the simplicity of the 2D stream to handle the mostly consistent background. We have the full advantage of combining both the 3D convolution and the 2D convolution. Then we take the two-stream model as the generator and adopt the adversarial learning. We test our model on the VideoDeblurring and GOPRO datasets, and compare with other methods which we have listed. Our method outperforms others in the Peak Signal-to-Noise Ratio (PSNR), especially shows a good performance handling the foreground with obvious motion blur. | |||||||||
Accession Number: WOS:000643175000003 | |||||||||
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ISSN: 1370-4621 | |||||||||
eISSN: 1573-773X |
Record 195 of 318 | |||||||||
Title: Grain-Orientation dependence about luminescence modulation behavior upon electric polarization in Sm<SUP>3+</SUP> doped KSr<sub>2</sub>Nb<sub>5</sub>O<sub>15</sub> textured ceramics | |||||||||
Author(s): Cao, SY (Cao, Shuyao); Chen, Q (Chen, Qian); Li, YP (Li, Yangping); Wu, CY (Wu, Changying); Feng, XY (Feng, Xiaoying); Xu, J (Xu, Jie); Cheng, GH (Cheng, Guanghua); Gao, F (Gao, Feng) | |||||||||
Source: MATERIALS LETTERS Volume: 295 Article Number: 129866 DOI: 10.1016/j.matlet.2021.129866 Early Access Date: APR 2021 Published: JUL 15 2021 | |||||||||
Abstract: Sm3+ doped KSr2Nb5O15 textured ceramics with grain-orientation were fabricated using tape casting technology. The influences of the grain orientation on the microstructures, dielectric and ferroelectric properties were characterized. Moreover, the samples possessed luminescence modulation behavior after polarization, which exhibited obvious grain-orientation dependence. A considerable modulation ratio of approximately 69% was obtained along the [00l] direction of textured ceramics, which was almost twice that of ceramics without grain orientation. This work provided a new strategy for the enhancement of luminescence modulation properties in rare-earth activator-doped ferroelectric oxides. (C) 2021 Elsevier B.V. All rights reserved. | |||||||||
Accession Number: WOS:000646237700003 | |||||||||
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ISSN: 0167-577X | |||||||||
eISSN: 1873-4979 |
Record 196 of 318 | |||||||||
Title: Terahertz signatures and quantitative analysis of glucose anhydrate and mixture | |||||||||
Author(s): Yan, H (Yan, Hui); Fan, WH (Fan, Wenhui); Chen, X (Chen, Xu); Liu, LT (Liu, Lutao); Wang, HQ (Wang, Hanqi); Jiang, XQ (Jiang, Xiaoqiang) | |||||||||
Source: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY Volume: 258 Article Number: 119825 DOI: 10.1016/j.saa.2021.119825 Early Access Date: APR 2021 Published: SEP 5 2021 | |||||||||
Abstract: Glucose, as the main energy carrier and significant source of nutrition, generally comes in two available forms of anhydrate and monohydrate in commercial production. Considering their respective application occasions, proper identification of glucose in single composition or binary-mixture and quantification of the mixture are crucial in industry monitoring to guarantee merchandise quality. Simultaneously, public confusions of glucose are rather ubiquitous partly due to anhydrate and monohydrate with identical white crystalline appearance. In this paper, utilizing the molecular fingerprints of terahertz (THz) technology that are corresponding to structural characteristics of anhydrous and hydrated form, THz signatures of glucose anhydrate, monohydrate and their mixture, as well as THz spectral transformation from monohydrate to anhydrate with the dehydrating process are systematically studied. Some visible peaks of monohydrate were noted at 1.82 and 1.99 THz signifying the presence of hydrated structure. However, with the dehydrating process, the peaks related to the hydrated structure are not very apparent when the peaks at 1.44 and 2.08 THz appear due to changes in the molecular structure of anhydrate, which provide clear indication for hydrogen-bond network reconstruction at the micro level. Furthermore, characteristic peaks at 1.44 and 1.82 THz can be specified as the main quantitative indicators for quantitative detection. The linear relationships between the amplitudes of characteristic peaks and the percentage compositions of anhydrate and monohydrate are revealed. Three commercially available brands of edible glucose powder A, B, C were effectively identified by THz signatures. While powder C was recognized as binary-mixture and the proportion of anhydrate and monohydrate was further quantified. THz spectroscopy technology has advantages of direct recognition, simple quantitative model based on THz absorption peaks, and no need for complicated chemical treatment. It may be potentially shed light on industrial monitoring of glucose production and other related mixture in the future. (c) 2021 Elsevier B.V. All rights reserved. | |||||||||
Accession Number: WOS:000663171000007 | |||||||||
PubMed ID: 33901947 | |||||||||
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ISSN: 1386-1425 | |||||||||
eISSN: 1873-3557 |
Record 197 of 318 | ||||||
Title: Adaptive multiscale feature for object detection | ||||||
Author(s): Yu, XY (Yu, Xiaoyong); Wu, SY (Wu, Siyuan); Lu, XQ (Lu, Xiaoqiang); Gao, GL (Gao, Guilong) | ||||||
Source: NEUROCOMPUTING Volume: 449 Pages: 146-158 DOI: 10.1016/j.neucom.2021.04.002 Early Access Date: APR 2021 Published: AUG 18 2021 | ||||||
Abstract: In object detection, multiscale features are necessary to deal with objects with different size. Using Feature Pyramid Network (FPN) as the backbone network is a very popular paradigm in existing object detectors, we call this paradigm FPN+. However, feature fusion of FPN is insufficient to express object of similar size but different appearance due to the unidirectional feature fusion. We motivate and present Adaptive Multiscale Feature (AMF), a new multiscale feature fusion method with bidirectional feature fusion, using to solve the one-direction fusion of FPN. AMF module fuses multiscale features from two aspects: (1) shattering features by the way of CLSM; (2) fusing features by the way of channel-wise attention. The proposed AMF improves the expression ability of multiscale features of the backbone network, and effectively improves the performance of the object detector. The proposed feature fusion method can be added to all object detector, such as the one-stage detector, the two-stage detector, anchor-based detector and anchor-free based detector. Experimental results on the COCO 2014 dataset show that the proposed AMF module performs the popular FPN based detector. Whether anchored-free based detectors or anchored based detectors, performance of detector can be improved through AMF. And the resulting best model can achieve a very competitive mAP on COCO 2014 dataset. | ||||||
Accession Number: WOS:000652818400013 | ||||||
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ISSN: 0925-2312 | ||||||
eISSN: 1872-8286 |
Record 198 of 318 | |||||||||
Title: Spectroscopic properties of ErF<sub>3</sub> doped tellurite-gallium oxyfluoride glass for ∼3<i>μ</i>m laser materials | |||||||||
Author(s): Wan, R (Wan, Rui); Wang, PF (Wang, Pengfei); Li, SW (Li, Shengwu); Ma, Y (Ma, Yuan); Zhang, GW (Zhang, Guangwei) | |||||||||
Source: JOURNAL OF APPLIED PHYSICS Volume: 129 Issue: 15 Article Number: 153105 DOI: 10.1063/5.0047010 Published: APR 21 2021 | |||||||||
Abstract: ErF3-doped TeO2-Ga2O3-BaF2-AlF3-Y2O3 (TGBAY) glasses with high fluorescence efficiency and a high thermal damage threshold were developed for potential mid-infrared fiber laser applications. A model 2.7-mu m fiber laser based on this material was analyzed using rate and propagation equations. Under 808 and 980nm laser pumping, fluorescence emissions with central wavelength at 1.55 and 2.73 mu m were detected. Based on the Judd-Ofelt (J-O) theory, the intensity parameters (Omega (lambda), lambda =2, 4, and 6) and radiative transition property were calculated and characterized through absorption and emission spectra. The results indicated that tellurite-gallium oxyfluoride glass had a high glass transition temperature (T-g, similar to 391 degrees C), large emission cross sections at 1.55 mu m (6.32x10(-21)cm(2)) and 2.73 mu m (9.68x10(-21)cm(2)) as well as a longer fluorescence lifetime (6.84ms at 1.55 mu m and 262 mu s at 2.73 mu m) relative to the conventional Er3+-doped tellurite glass. The temperature dependence of the emission spectra indicated that TGBAY-2Er glass was more favorable to achieve infrared emission at low temperatures. Numerical simulation revealed the feasibility of achieving a similar to 2.7 mu m fiber laser operation based on the developed Er3+-doped tellurite-gallium oxyfluoride glass fiber. | |||||||||
Accession Number: WOS:000641861700002 | |||||||||
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ISSN: 0021-8979 | |||||||||
eISSN: 1089-7550 |
Record 199 of 318 | ||||||
Title: Non-interferometric accurate phase imaging via linear-convergence iterative optimization | ||||||
Author(s): Huang, JH (Huang, Jianhui); Pan, A (Pan, An); Jin, HL (Jin, Huiliang); Meng, GX (Meng, Guoxiang); Ye, Q (Ye, Qian) | ||||||
Source: OPTICS AND LASERS IN ENGINEERING Volume: 144 Article Number: 106630 DOI: 10.1016/j.optlaseng.2021.106630 Early Access Date: APR 2021 Published: SEP 2021 | ||||||
Abstract: This paper reported a general non-interferometric high-accuracy quantitative phase imaging (QPI) method for arbitrary complex-valued objects. Given by a typical 4-f optical configuration as the imaging system, three frames of small-window phase modulation are applied on the object's Fourier spectrum so that redistributed intensity patterns are produced on the image plane, in which the object phase emerges at different degree. Then, an algebraic relationship that connects the object phase with the output intensity is established to provide us with an approximate closed-form phase recovery. Further, an efficient iterative optimization strategy is developed to turn that approximate solution into an accurate one. Due to the linear convergence property of the iteration, a high-accuracy phase recovery is achieved without requiring heavy iterations. The feasibility and accuracy of the proposed method are verified by both numerical simulations and experiments on diverse phase objects including biomedical tissues. | ||||||
Accession Number: WOS:000652509100002 | ||||||
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ISSN: 0143-8166 | ||||||
eISSN: 1873-0302 |
Record 200 of 318 | ||||||
Title: Infrared and visible image fusion based on edge-preserving guided filter and infrared feature decomposition | ||||||
Author(s): Ren, L (Ren, Long); Pan, ZB (Pan, Zhibin); Cao, JZ (Cao, Jianzhong); Zhang, H (Zhang, Hui); Wang, H (Wang, Hao) | ||||||
Source: SIGNAL PROCESSING Volume: 186 Article Number: 108108 DOI: 10.1016/j.sigpro.2021.108108 Early Access Date: APR 2021 Published: SEP 2021 | ||||||
Abstract: Infrared (IR) images can distinguish salient targets from their backgrounds based on the radiation difference in all-weather conditions. By contrast, visible (VIS) images can contain high-resolution texture and details information, which is more suitable for human observation. Therefore, it is quite necessary to combine both imaging advantages of these two kinds of images. Compared with the existing methods, we believe that scale decomposition based methods are the most active and efficient image fusion methods, which also have the best fusion effects. Inspired by the present scale decomposition methods, we propose a new feature decomposition method. Firstly, we propose an improved guided filter called edgepreserving guided filter (EPGF), which adopts the image gradient map for further improving the filtering effect. Subsequently, by using the EPGF, we decompose the IR and VIS images into three kinds of layers, including salient feature layers, luminance layers and detail layers. At the same time, we combine all the layers together to get an initial fusion result. Finally, we optimize the initial fusion image according to a new image fusion optimization model and ADMM, and the final fusion result will be obtained after several iterations. Compared with other scale decomposition methods, our proposed feature decomposition based method takes the IR salient targets, IR and VIS background illumination, as well as VIS details into consideration which is more in line with human visual observation, besides the computational efficiency is also superior. Experimental results indicate that this method has better subjective and objective evaluation results compared with other state-of-the-art methods. (C) 2021 Elsevier B.V. All rights reserved. | ||||||
Accession Number: WOS:000652606600008 | ||||||
Author Identifiers: | ||||||
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ISSN: 0165-1684 | ||||||
eISSN: 1872-7557 |
Record 201 of 318 | |||||||||
Title: Novel strategy for the enhancement of anti-counterfeiting ability of photochromic ceramics: Sm<SUP>3+</SUP> doped KSr<sub>2</sub>Nb<sub>5</sub>O<sub>15</sub> textured ceramics with anisotropic luminescence modulation behavior | |||||||||
Author(s): Cao, SY (Cao, Shuyao); Chen, Q (Chen, Qian); Li, YP (Li, Yangping); Wu, CY (Wu, Changying); Xu, J (Xu, Jie); Cheng, GH (Cheng, Guanghua); Gao, F (Gao, Feng) | |||||||||
Source: JOURNAL OF THE EUROPEAN CERAMIC SOCIETY Volume: 41 Issue: 9 Pages: 4924-4933 DOI: 10.1016/j.jeurceramsoc.2021.03.039 Early Access Date: APR 2021 Published: AUG 2021 | |||||||||
Abstract: Sm3+ doped KSr2Nb5O15 (KSN-Sm) textured ceramics with anisotropic photochromic and luminescence modulation behaviors provided a new strategy for the enhancement of anti-counterfeiting ability. The KSN-Sm textured ceramics were fabricated by the tape casting technology, which exhibited obvious grain-orientation, with Lotgering factor f((00l)) of 0.62. The textured sample possessed evident difference of reflectivity, photochromic, luminescent and luminescence modulation properties among various grain-orientated directions. The difference of luminescent emission intensity was over than 30 % and the luminescence modulation ratios Delta R-t are 75.3 % and 63.3 % along paralleled and vertical [00l] orientations, respectively. These optical anisotropies were attributed to the different refractive indexes, distributions of photochromic centers and energy transfer rates at various orientations. This work is hopeful to achieve the multidirectional data recording and enhancement of anti-counterfeiting ability of photochromic ceramics by the anisotropic properties of textured ceramics. | |||||||||
Accession Number: WOS:000640703200005 | |||||||||
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ISSN: 0955-2219 | |||||||||
eISSN: 1873-619X |
Record 202 of 318 | ||||||||||||||||||||||||||||||||||||||||||||||||
Title: Molybdenum Carbide Buried in D-Shaped Fibers as a Novel Saturable Absorber Device for Ultrafast Photonics Applications | ||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Liu, SC (Liu, Sicong); Shang, SG (Shang, Shiguang); Lv, RD (Lv, Ruidong); Wang, YG (Wang, Yonggang); Wang, J (Wang, Jiang); Ren, W (Ren, Wei); Wang, YS (Wang, Yishan) | ||||||||||||||||||||||||||||||||||||||||||||||||
Source: ACS APPLIED MATERIALS & INTERFACES Volume: 13 Issue: 16 Pages: 19128-19137 DOI: 10.1021/acsami.1c01345 Early Access Date: APR 2021 Published: APR 28 2021 | ||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: Study of nonlinear laser-matter interactions in 2D materials has promoted development of photonics applications. As a typical MXene material, molybdenum carbide (Mo2C) has attracted much attention because of its graphene-like structure. Here, a type of D-shaped fiber (DF)-buried Mo2C saturable absorber (SA) fabricated by magnetron-sputtering deposition (MSD) and sol-gel technique is reported. The Mo2C material was buried between the bottom DF and the upper amorphous silica fabricated by sol-gel technology. Therefore, the DF-based SA effectively solves the problem of material shedding and aging, thus improving the stability and damage threshold of the fiber laser. Application of the SA in erbium-doped fiber laser and stable passive Q-switched operation with a maximum pulse energy of 430.47 nJ is realized. By adjusting the polarization state and pump power, high-power mode-locked pulses are generated with a pulse duration and output power of 199 fs and 54.13 mW, respectively. Further, bound-state soliton pulses are obtained with a pulse width of 312 fs and soliton interval of 1.26 ps for the first time based on MXene materials. Moreover, by application of the SA in ytterbiumdoped fiber lasers, a stable dissipative soliton mode-locked pulse is obtained with a pulse width of 23 ps. These results indicate that the DF-based buried Mo2C as a novel SA provides a reliable method for all-fiber and multifunctional high-power ultrafast laser. | ||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000645520700074 | ||||||||||||||||||||||||||||||||||||||||||||||||
PubMed ID: 33847490 | ||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 1944-8244 | ||||||||||||||||||||||||||||||||||||||||||||||||
eISSN: 1944-8252 |
Record 203 of 318 |
Title: A comparison of neural networks algorithms for EEG and sEMG features based gait phases recognition |
Author(s): Wei, PN (Wei, Pengna); Zhang, JH (Zhang, Jinhua); Tian, FF (Tian, Feifei); Hong, J (Hong, Jun) |
Source: BIOMEDICAL SIGNAL PROCESSING AND CONTROL Volume: 68 Article Number: 102587 DOI: 10.1016/j.bspc.2021.102587 Early Access Date: APR 2021 Published: JUL 2021 |
Abstract: Surface electromyography (sEMG) and electroencephalogram (EEG) can be utilized to discriminate gait phases. However, the classification performance of various combination methods of the features extracted from sEMG and EEG channels for seven gait phase recognition has yet to be discussed. This study investigates the effectiveness of various dimensions of feature sets with different neural network algorithms in multiclass discrimination of gait phases. There are thirty-seven feature sets (slope sign change (SSC) of eight sEMG and twenty-one EEG channels, mean absolute value (MAV) of eight sEMG channels) and three classifiers (Linear Discriminant Analysis (LDA), K-nearest neighbor (KNN), Kernel Support Vector Machine (KSVM)) were utilized. The thirtyseven one-dimensional and six two-dimensional feature sets were applied to LDA and KNN, twenty-onedimensional and thirty-seven-dimensional feature sets were applied to three optimized KSVM for gait phase recognition. We found that thirty-seven-dimensional feature sets with grid search KSVM achieved the highest classification accuracy (98.56 +/- 1.34 %) and the time consumption was 26.37 s. The average time consumption of two-dimensional feature sets with KNN was the shortest (0.33 s). The SSC of sEMG with wider values distributions than others obtained a high performance. This indicates the wider the value distribution of features, the better accuracy of gait recognition. The findings suggest that a multi-dimensional feature set composed of EEG and sEMG features with KSVM achieved good performance. Considering execution time and recognition rate, two-dimensional feature sets with KNN are suitable for online gait recognition, thirty-seven-dimensional feature sets with KSVM are more likely to be used for off-line gait analysis. |
Accession Number: WOS:000674565400002 |
ISSN: 1746-8094 |
eISSN: 1746-8108 |
Record 204 of 318 | ||||||||||||
Title: Dispersed pulses created by aperiodic binary spectral phase jump and applications for pulse shaping | ||||||||||||
Author(s): Liu, X (Liu, Xin); Wang, HS (Wang, Hushan); Cao, HB (Cao, Huabao); Yuan, H (Yuan, Hao); Huang, P (Huang, Pei); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei); Fu, YX (Fu, Yuxi) | ||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 8 Pages: 12319-12329 DOI: 10.1364/OE.419450 Published: APR 12 2021 | ||||||||||||
Abstract: Inspired by pulse-pair generation with periodic phase jump, the generation of dispersed pulses with aperiodic binary spectral phase jump (ABSPJ) is proposed and theoretically investigated. It is presented by the numerical simulations that two dispersed pulses can be generated by ABSPJ of pi. The dispersion of one pulse is opposite to the other and can be tuned freely with engineering of the phase jump. The generated dispersed pulse-pair is potentially of great interest for various applications, such as two-dimensional spectroscopy, double pulses laser-wakefield acceleration (LWFA) and chirp management in dual-chirped optical parametric amplification (DC-OPA) system to generate TW single-cycle mid-infrared (MIR) pulses. Furthermore, a pulse shaper configured as a micro-electro-mechanical systems (MEMS) located at the Fourier plane of a 4-f dispersion-free compressor is suggested and the implementation in a high repetition optical parametric chirped pulse amplification (OPCPA) system with picosecond pump has been numerically studied. The simulations showed that MEMS of 900 pixels is enough to pre-compensate TOD of 200000 fs(3) for a pulse of 20 fs. Because pixel with only two piston-levels is necessary for such MEMS, the pulse shaper is expected to be compact and reliable. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||
Accession Number: WOS:000640033600078 | ||||||||||||
PubMed ID: 33984994 | ||||||||||||
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ISSN: 1094-4087 |
Record 205 of 318 | ||||||
Title: A Comprehensive Review of Fluorescence Correlation Spectroscopy | ||||||
Author(s): Yu, L (Yu, Lan); Lei, YZ (Lei, Yunze); Ma, Y (Ma, Ying); Liu, M (Liu, Min); Zheng, JJ (Zheng, Juanjuan); Dan, D (Dan, Dan); Gao, P (Gao, Peng) | ||||||
Source: FRONTIERS IN PHYSICS Volume: 9 Article Number: 644450 DOI: 10.3389/fphy.2021.644450 Published: APR 12 2021 | ||||||
Abstract: Fluorescence correlation spectroscopy (FCS) is a powerful technique for quantification of molecular dynamics, and it has been widely applied in diverse fields, e.g., biomedicine, biophysics, and chemistry. By time-correlation of the fluorescence fluctuations induced by molecules diffusing through a focused light, FCS can quantitatively evaluate the concentration, diffusion coefficient, and interaction of the molecules in vitro or in vivo. In this review, the basic principle and implementation of FCS are introduced. Then, the advances of FCS variants are reviewed, covering dual-color FCCS, multi-focus FCS, pair correlation function (pCF), scanning FCS, focus-reduced FCS, SPIM-FCS, and inverse-FCS. Besides, the applications of FCS are demonstrated with the measurement of local concentration, hydrodynamic radius, diffusion coefficient, and the interaction of different molecules. Lastly, a discussion is given by summarizing the pros and cons of different FCS techniques, as well as the outlooks and perspectives of FCS. | ||||||
Accession Number: WOS:000643701700001 | ||||||
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ISSN: 2296-424X |
Record 206 of 318 | |||||||||
Title: 2.86 μm emission and fluorescence enhancement through controlled precipitation of ZnTe nanocrystals in DyF<sub>3</sub> doped multicomponent tellurite oxyfluoride glass | |||||||||
Author(s): Wan, R (Wan, Rui); Wang, PF (Wang, Pengfei); Li, SW (Li, Shengwu); Ma, Y (Ma, Yuan) | |||||||||
Source: JOURNAL OF NON-CRYSTALLINE SOLIDS Volume: 564 Article Number: 120842 DOI: 10.1016/j.jnoncrysol.2021.120842 Early Access Date: APR 2021 Published: JUL 15 2021 | |||||||||
Abstract: Tellurite oxyfluoride glasses with composition of 71TeO(2)-10ZnO-10BaF(2)-4K(2)O-3Nb(2)O(5)-2TiO(2) doped with different concentrations of DyF3 (0.3, 0.4, 0.5, 0.7, 1 wt%) were prepared by melt-quenching method under dry O-2 atmosphere. Under 808 nm laser pumping, infrared (IR) fluorescence emission with central wavelength of 2.86 mu m was detected. Basing on the Judd-Ofelt (J-O) theory, the intensity parameters (Omega(lambda), lambda=2, 4 and 6) and radiative property were calculated and characterized through the transmission and fluorescence spectra. The tellurite oxyfluoride glass had high thermal stability and large emission cross-section at 2.86 mu m (7.82 x 10(-21) cm(2)). DyF3 doped tellurite oxyfluoride glass ceramic were prepared via in-situ crystallization of ZnTe nanocrystals through heat treatment to ameliorate the surrounding environment of rare earth (RE) ions. The tellurite oxyfluoride glass ceramic prepared by heat treatment at 390 degrees C had great enhancement in 2.86 mu m fluorescence intensity (about 7 times), longer fluorescence lifetime (126 mu s), indicating that the in-situ crystallization method may be helpful for exploring tellurite based high gain laser glass. | |||||||||
Accession Number: WOS:000663076700003 | |||||||||
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ISSN: 0022-3093 | |||||||||
eISSN: 1873-4812 |
Record 207 of 318 | ||||||
Title: Direct axial plane imaging of particle manipulation with nondiffracting Bessel beams | ||||||
Author(s): An, S (An, Sha); Peng, T (Peng, Tong); Yan, SH (Yan, Shaohui); Zhang, P (Zhang, Peng); Li, MM (Li, Manman); Yao, BL (Yao, Baoli) | ||||||
Source: APPLIED OPTICS Volume: 60 Issue: 11 Pages: 2974-2980 DOI: 10.1364/AO.417854 Published: APR 10 2021 | ||||||
Abstract: Optical manipulation with nondiffracting beams has been attracting great interest and finding widespread applications in many fields such as chemistry, physics, and biomedicine. Generally, optical manipulation is conducted in an optical microscopy system, which, in general, only allows for imaging motions of particles in the transverse plane, rendering the observation of dynamics processes occurring in the axial plane impractical. We propose and demonstrate an optical manipulation system that incorporates an axial plane imaging module. With this system, the trapping behavior in the transverse plane and the transportation process in the axial plane of a particle immersed in a Bessel beam were acquired simultaneously in real time. (C) 2021 Optical Society of America | ||||||
Accession Number: WOS:000639245900006 | ||||||
PubMed ID: 33983190 | ||||||
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ISSN: 1559-128X | ||||||
eISSN: 2155-3165 |
Record 208 of 318 | |||||||||
Title: Determination of the antibiotic minocycline by integrated optofluidic microstructured polymer optical fiber chemiluminescence | |||||||||
Author(s): Li, ZN (Li, Zhanao); Yang, XH (Yang, Xinghua); Teng, PP (Teng, Pingping); Kong, DP (Kong, Depeng); Gao, S (Gao, Shuai); Liu, ZH (Liu, Zhihai); Yang, J (Yang, Jun); Gao, DH (Gao, Danheng); Luo, M (Luo, Meng); Wen, XY (Wen, Xingyue); Yuan, LB (Yuan, Libo); Li, K (Li, Kang); Bowkett, M (Bowkett, Mark); Copner, N (Copner, Nigel) | |||||||||
Source: INSTRUMENTATION SCIENCE & TECHNOLOGY Volume: 49 Issue: 6 Pages: 571-584 DOI: 10.1080/10739149.2021.1912761 Early Access Date: APR 2021 Published: NOV 2 2021 | |||||||||
Abstract: An in-fiber optofluidic chemiluminescence (CL) device is reported based on a low-cost microstructured polymer optical fiber (mPOF). The mPOF is composed of a central hole for liquid delivery and a suspended core for optical coupling. Due to the lower processing temperature of mPOF, the difficulty of constructing microfluidic channels is greatly reduced. In addition, the large core diameter of mPOF is more conducive to optical coupling. The microholes are opened on the surface of the mPOF by partial melting to complete the construction of the microfluidic channel. Simultaneously, the response of the CL reaction is detected on-line by the optoelectronic device. Minocycline (MC) was employed as the analyte for on-line optofluidic CL detection. The results show that the device detects aqueous minocycline from 0.0001 to 0.1 g/L with a linear response between 0.001 and 0.01 g/L. The limit of detection is 0.0001 g/L. Moreover, the ability of the device to detect minocycline in blood serum is investigated. The relative deviation from the linear calibration value is within 3.2%. Furthermore, the low-cost in-fiber optofluidic CL device may be integrated with other devices and offers potential in drug safety and medical detection. | |||||||||
Accession Number: WOS:000640166100001 | |||||||||
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ISSN: 1073-9149 | |||||||||
eISSN: 1525-6030 |
Record 209 of 318 | |||||||||||||||
Title: Hyperspectral Image Super-Resolution with Self-Supervised Spectral-Spatial Residual Network | |||||||||||||||
Author(s): Chen, WJ (Chen, Wenjing); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang) | |||||||||||||||
Source: REMOTE SENSING Volume: 13 Issue: 7 Article Number: 1260 DOI: 10.3390/rs13071260 Published: APR 2021 | |||||||||||||||
Abstract: Recently, many convolutional networks have been built to fuse a low spatial resolution (LR) hyperspectral image (HSI) and a high spatial resolution (HR) multispectral image (MSI) to obtain HR HSIs. However, most deep learning-based methods are supervised methods, which require sufficient HR HSIs for supervised training. Collecting plenty of HR HSIs is laborious and time-consuming. In this paper, a self-supervised spectral-spatial residual network (SSRN) is proposed to alleviate dependence on a mass of HR HSIs. In SSRN, the fusion of HR MSIs and LR HSIs is considered a pixel-wise spectral mapping problem. Firstly, this paper assumes that the spectral mapping between HR MSIs and HR HSIs can be approximated by the spectral mapping between LR MSIs (derived from HR MSIs) and LR HSIs. Secondly, the spectral mapping between LR MSIs and LR HSIs is explored by SSRN. Finally, a self-supervised fine-tuning strategy is proposed to transfer the learned spectral mapping to generate HR HSIs. SSRN does not require HR HSIs as the supervised information in training. Simulated and real hyperspectral databases are utilized to verify the performance of SSRN. | |||||||||||||||
Accession Number: WOS:000638794300001 | |||||||||||||||
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eISSN: 2072-4292 |
Record 210 of 318 |
Title: Sparse Constrained Low Tensor Rank Representation Framework for Hyperspectral Unmixing |
Author(s): Dong, L (Dong, Le); Yuan, Y (Yuan, Yuan) |
Source: REMOTE SENSING Volume: 13 Issue: 8 Article Number: 1473 DOI: 10.3390/rs13081473 Published: APR 2021 |
Abstract: Recently, non-negative tensor factorization (NTF) as a very powerful tool has attracted the attention of researchers. It is used in the unmixing of hyperspectral images (HSI) due to its excellent expression ability without any information loss when describing data. However, most of the existing unmixing methods based on NTF fail to fully explore the unique properties of data, for example, low rank, that exists in both the spectral and spatial domains. To explore this low-rank structure, in this paper we learn the different low-rank representations of HSI in the spectral, spatial and non-local similarity modes. Firstly, HSI is divided into many patches, and these patches are clustered multiple groups according to the similarity. Each similarity group can constitute a 4-D tensor, including two spatial modes, a spectral mode and a non-local similarity mode, which has strong low-rank properties. Secondly, a low-rank regularization with logarithmic function is designed and embedded in the NTF framework, which simulates the spatial, spectral and non-local similarity modes of these 4-D tensors. In addition, the sparsity of the abundance tensor is also integrated into the unmixing framework to improve the unmixing performance through the L2,1 norm. Experiments on three real data sets illustrate the stability and effectiveness of our algorithm compared with five state-of-the-art methods. |
Accession Number: WOS:000644676100001 |
eISSN: 2072-4292 |
Record 211 of 318 | ||||||||||||
Title: Person Reidentification via Unsupervised Cross-View Metric Learning | ||||||||||||
Author(s): Feng, YC (Feng, Yachuang); Yuan, Y (Yuan, Yuan); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||
Source: IEEE TRANSACTIONS ON CYBERNETICS Volume: 51 Issue: 4 Pages: 1849-1859 DOI: 10.1109/TCYB.2019.2909480 Published: APR 2021 | ||||||||||||
Abstract: Person reidentification (Re-ID) aims to match observations of individuals across multiple nonoverlapping camera views. Recently, metric learning-based methods have played important roles in addressing this task. However, metrics are mostly learned in supervised manners, of which the performance relies heavily on the quantity and quality of manual annotations. Meanwhile, metric learning-based algorithms generally project person features into a common subspace, in which the extracted features are shared by all views. However, it may result in information loss since these algorithms neglect the view-specific features. Besides, they assume person samples of different views are taken from the same distribution. Conversely, these samples are more likely to obey different distributions due to view condition changes. To this end, this paper proposes an unsupervised cross-view metric learning method based on the properties of data distributions. Specifically, person samples in each view are taken from a mixture of two distributions: one models common prosperities among camera views and the other focuses on view-specific properties. Based on this, we introduce a shared mapping to explore the shared features. Meanwhile, we construct view-specific mappings to extract and project view-related features into a common subspace. As a result, samples in the transformed subspace follow the same distribution and are equipped with comprehensive representations. In this paper, these mappings are learned in an unsupervised manner by clustering samples in the projected space. Experimental results on five cross-view datasets validate the effectiveness of the proposed method. | ||||||||||||
Accession Number: WOS:000631201900010 | ||||||||||||
PubMed ID: 31021787 | ||||||||||||
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ISSN: 2168-2267 | ||||||||||||
eISSN: 2168-2275 |
Record 212 of 318 | ||||||||||||||||||
Title: Design of Multifunctional Janus Metasurface Based on Subwavelength Grating | ||||||||||||||||||
Author(s): Ji, RN (Ji, Ruonan); Jin, C (Jin, Chuan); Song, K (Song, Kun); Wang, SW (Wang, Shao-Wei); Zhao, XP (Zhao, Xiaopeng) | ||||||||||||||||||
Source: NANOMATERIALS Volume: 11 Issue: 4 Article Number: 1034 DOI: 10.3390/nano11041034 Published: APR 2021 | ||||||||||||||||||
Abstract: In this paper, a Janus metasurface is designed by breaking the structural symmetry based on the polarization selection property of subwavelength grating. The structure comprises three layers: a top layer having a metallic nanostructure, a dielectric spacer, and a bottom layer having subwavelength grating. For a forward incidence, the metal-insulator-metal (MIM) structure operates as a gap plasmonic cavity if the linearly polarized (LP) component is parallel to the grating wires. It also acts as a high-efficiency dual-layer grating polarizer for the orthogonal LP component. For the backward incidence, the high reflectance of the grating blocks the function of the gap plasmonic cavity, leading to its pure functioning as a polarizer. A bifunctional Janus metasurface for 45 degrees beam deflector and polarizer, with a transmission of 0.87 and extinction ratio of 3840, is designed at 1.55 mu m and is investigated to prove the validity of the proposed strategy. Moreover, the proposed metasurface can be cascaded to achieve more flexible functions since these functions are independent in terms of operational mechanism and structural parameters. A trifunctional Janus metasurface that acts as a focusing lens, as a reflector, and as a polarizer is designed based on this strategy. The proposed metasurface and the design strategy provide convenience and flexibility in the design of multifunctional, miniaturized, and integrated optical components for polarization-related analysis and for detection systems. | ||||||||||||||||||
Accession Number: WOS:000643371300001 | ||||||||||||||||||
PubMed ID: 33921569 | ||||||||||||||||||
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eISSN: 2079-4991 |
Record 213 of 318 | ||||||||||||||||||||||||
Title: All-optical RF spectrum analyzer with a 5 THz bandwidth based on CMOS-compatible high-index doped silica waveguides | ||||||||||||||||||||||||
Author(s): Li, YH (Li, Yuhua); Kang, Z (Kang, Zhe); Zhu, K (Zhu, Kun); Ai, SQ (Ai, Shiqi); Wang, X (Wang, Xiang); Davidson, RR (Davidson, Roy R.); Wu, Y (Wu, Yan); Morandotti, R (Morandotti, Roberto); Little, BE (Little, Brent E.); Moss, DJ (Moss, David J.); Chu, ST (Chu, Sai Tak) | ||||||||||||||||||||||||
Source: OPTICS LETTERS Volume: 46 Issue: 7 Pages: 1574-1577 DOI: 10.1364/OL.420716 Published: APR 1 2021 | ||||||||||||||||||||||||
Abstract: We report an all-optical radio-frequency (RF) spectrum analyzer with a bandwidth greater than 5 THz, based on a 50 cm long spiral waveguide in a CMOS-compatible high-index doped silica platform. By carefully mapping out the dispersion profile of the waveguides for different thicknesses, we identify the optimal design to achieve near-zero dispersion in the C-band. To demonstrate the capability of the RF spectrum analyzer, we measure the optical output of a femtosecond fiber laser with an ultrafast optical RF spectrum in the terahertz regime. (C) 2021 Optical Society of America | ||||||||||||||||||||||||
Accession Number: WOS:000636612700015 | ||||||||||||||||||||||||
PubMed ID: 33793489 | ||||||||||||||||||||||||
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ISSN: 0146-9592 | ||||||||||||||||||||||||
eISSN: 1539-4794 |
Record 214 of 318 |
Title: Accurate Determination of Conversion Gains of SVOM VT CCDs Based on a Signal-Dependent Charge-Sharing Mechanism |
Author(s): Pan, Y (Pan, Yue); Fan, XW (Fan, Xuewu); Wang, H (Wang, Hu); Zhao, H (Zhao, Hui); Qiu, YL (Qiu, Yulei); Gao, W (Gao, Wei); Zhang, J (Zhang, Jian) |
Source: ELECTRONICS Volume: 10 Issue: 8 Article Number: 931 DOI: 10.3390/electronics10080931 Published: APR 2021 |
Abstract: The signal-variance method and the photon transfer curve method are the most valuable tools for calculating the conversion gains of charge-coupled device (CCD) detectors. This paper describes the phenomena that arise in the conversion gain measurements of space multi-band variable object monitor (SVOM) visible telescope (VT) CCDs, where the results of the signal-variance method increase with the image gray level, and the results of the photon transfer curve method appear with nonlinearity, which is caused by the signal-dependent charge sharing mechanism of back-illuminated CCDs. A numerical simulation model based on random variables was adopted to analyze the influence of the mechanism on the gain determination. The model simulates all the signals and noise in the flat field image, including the photon signal and photon-shot noise, readout noise, fixed pattern noise, and the signal-dependent charge-sharing signal, and it demonstrated agreement with the experimental data. Then, we proposed a quadratic polynomial curve-fitting formula for the photon transfer curve, and we quantitatively analyzed the relationship between the fitting coefficients and the gain, the signal-dependent charge sharing coefficient, and the full well capacity using the control variable method. Finally, the formula was used to accurately determine the conversion gains of SVOM VT CCDs. |
Accession Number: WOS:000644013000001 |
eISSN: 2079-9292 |
Record 215 of 318 |
Title: Fast Dark Signal Measurements of SVOM VT CCDs Using the Vertical Gradient of Dark Field Images |
Author(s): Pan, Y (Pan, Yue); Fan, XW (Fan, Xuewu); Zhao, H (Zhao, Hui); Qiu, YL (Qiu, Yulei); Gao, W (Gao, Wei); Zhang, J (Zhang, Jian) |
Source: PHOTONICS Volume: 8 Issue: 4 Article Number: 132 DOI: 10.3390/photonics8040132 Published: APR 2021 |
Abstract: This paper describes a fast technique for estimating the dark signals of the charge coupled devices (CCDs) of the visible telescope (VT) onboard the space multi-band variable object monitor (SVOM). It is based on the vertical gradient in the dark field images of the frame transfer CCDs. During the process of frame clear, exposure, frame transfer and readout, the characteristic of dark signal accumulation is analyzed firstly. Next, the linear fitting method is used to fit the signal level of the dark field image in the vertical direction, and the slope of the fitting line represents the dark signal factor. This technique only needs one dark field image and can be used for simple and efficient dark signal measurements of frame transfer CCDs. Besides, an experiment of detecting dark signals as a function of temperature based on the fast technique has been carried out. Making use of the Shockley-Hall-Read theory, two curve fitting formulas are adopted to the experimental results for VT Advanced Inverted Mode Operation (AIMO) CCD and VT Non-Inverted Mode Operation (NIMO) CCD respectively. The experimental results and the formulas are used to determine the optimal on-orbit cooling temperature of VT CCDs. |
Accession Number: WOS:000643501200001 |
eISSN: 2304-6732 |
Record 216 of 318 | ||||||||||||
Title: Using CNN and HHT to Predict Blood Pressure Level Based on Photoplethysmography and Its Derivatives | ||||||||||||
Author(s): Sun, XX (Sun, Xiaoxiao); Zhou, L (Zhou, Liang); Chang, SD (Chang, Shendong); Liu, ZH (Liu, Zhaohui) | ||||||||||||
Source: BIOSENSORS-BASEL Volume: 11 Issue: 4 Article Number: 120 DOI: 10.3390/bios11040120 Published: APR 2021 | ||||||||||||
Abstract: According to the WTO, there were 1.13 billion hypertension patients worldwide in 2015. The WTO encouraged people to check the blood pressure regularly because a large amount of patients do not have any symptoms. However, traditional cuff measurement results are not enough to represent the patient ' s blood pressure status over a period of time. Therefore, there is an urgent need for portable, easy to operate, continuous measurement, and low-cost blood pressure measuring devices. In this paper, we adopted the convolutional neural network (CNN), based on the Hilbert-Huang Transform (HHT) method, to predict blood pressure (BP) risk level using photoplethysmography (PPG). Considering that the PPG ' s first and second derivative signals are related to atherosclerosis and vascular elasticity, we created a dataset called PPG+; the images of PPG+ carry information on PPG and its derivatives. We built three classification experiments by collecting 582 data records (the length of each record is 10 s) from the Medical Information Mart for Intensive Care (MIMIC) database: NT (normotension) vs. HT (hypertension), NT vs. PHT (prehypertension), and (NT + PHT) vs. HT; the F1 scores of the PPG + experiments using AlexNet were 98.90%, 85.80%, and 93.54%, respectively. We found that, first, the dataset established by the HHT method performed well in the BP grade prediction experiment. Second, because the Hilbert spectra of the PPG are simple and periodic, AlexNet, which has only 8 layers, got better results. More layers instead increased the cost and difficulty of training. | ||||||||||||
Accession Number: WOS:000642783800001 | ||||||||||||
PubMed ID: 33924324 | ||||||||||||
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eISSN: 2079-6374 |
Record 217 of 318 | |||||||||
Title: TTH-RNN: Tensor-Train Hierarchical Recurrent Neural Network for Video Summarization | |||||||||
Author(s): Zhao, B (Zhao, Bin); Li, XL (Li, Xuelong); Lu, XQ (Lu, Xiaoqiang) | |||||||||
Source: IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS Volume: 68 Issue: 4 Pages: 3629-3637 DOI: 10.1109/TIE.2020.2979573 Published: APR 2021 | |||||||||
Abstract: Although a recurrent neural network (RNN) has achieved tremendous advances in video summarization, there are still some problems remaining to be addressed. In this article, we focus on two intractable problems when applying an RNN to video summarization: first the extremely large feature-to-hidden matrices. Since video features are usually in a high-dimensional space, it leads to extremely large feature-to-hidden mapping matrices in the RNN model, which increases the training difficulty. Second, the deficiency in long-range temporal dependence exploration. Most videos contain thousands of frames at least, which is such a long sequence that traditional RNNs cannot deal well with. Facing the abovementioned two problems, we develop a tensor-train hierarchical recurrent neural network (TTH-RNN) for the video summarization task. It contains a tensor-train embedding layer to avert the large feature-to-hidden matrices, together with a hierarchical structure of an RNN to explore the long-range temporal dependence among video frames. Practically, the experimental results on four benchmark datasets, including SumMe, TVsum, MED, and VTW, have demonstrated the excellent performance of a TTH-RNN in video summarization. | |||||||||
Accession Number: WOS:000599525100082 | |||||||||
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ISSN: 0278-0046 | |||||||||
eISSN: 1557-9948 |
Record 218 of 318 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Title: Atmospheric diffuse plasma jet formation from positive-pseudo-streamer and negative pulseless glow discharges | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Li, J (Li, Jing); Lei, BY (Lei, Bingying); Wang, J (Wang, Jing); Xu, BP (Xu, Boping); Ran, S (Ran, Shuang); Wang, YS (Wang, Yishan); Zhang, TY (Zhang, Tongyi); Tang, J (Tang, Jie); Zhao, W (Zhao, Wei); Duan, YX (Duan, Yixiang) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Source: COMMUNICATIONS PHYSICS Volume: 4 Issue: 1 Article Number: 64 DOI: 10.1038/s42005-021-00566-8 Published: MAR 31 2021 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: Streamer coupling theory is traditionally used to engineer the generation of diffuse plasmas in the regime preceding filamentary discharge, but this method remains inefficient. Here, an alternative route to cost-efficient diffuse plasma generation is proposed, involving the expansion and quenching of existing filamentary discharge. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000636775700001 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 2399-3650 |
Record 219 of 318 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Title: Unobtrusive vital signs and activity monitoring based on dual mode fiber | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Xu, W (Xu, Wei); Bian, SH (Bian, Shihang); Dong, B (Dong, Bo); Shen, Y (Shen, Ying); Han, SY (Han, Shuying); Yu, CY (Yu, Changyuan); Zhao, W (Zhao, Wei); Wang, YS (Wang, Yishan) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Source: OPTICAL FIBER TECHNOLOGY Volume: 64 Article Number: 102530 DOI: 10.1016/j.yofte.2021.102530 Early Access Date: MAR 2021 Published: JUL 2021 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: A solid unobtrusive fiber-optic sensor based on modal interference in dual mode fiber (DMF) embedded in a thin mat is proposed and investigated theoretically and experimentally, realizing real-time vital signs and activity monitoring. The whole sensing setup only consists of one laser diode, one section of DMF, one photo-detector and few standard single mode fibers (SMFs). The DMF fiber is sandwiched into the SMFs using core-offset splicing, i. e., SMF-DMF-SMF structure. The optimal value of the core offset is numerically simulated and experimentally validated. It has to be noted that all the fibers used in the experiment are with 900-mu m protection jacket, which can effectively avoid fiber breaking. The proposed sensor is both investigated in different postures and different subjects. And the results of vital signs monitoring performance show great consistency compared with commercial monitors. Besides, the activity monitoring is also addressed with one-second discrimination resolution, identifying three basic states, i.e., on bed, body movement and off bed. It is easy to fabricate and shows great potential in future non-invasive vital signs and activity monitoring applications. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000660470600015 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 1068-5200 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
eISSN: 1095-9912 |
Record 220 of 318 | |||||||||
Title: A motor imagery EEG signal classification algorithm based on recurrence plot convolution neural network | |||||||||
Author(s): Meng, XJ (Meng, XianJia); Qiu, S (Qiu, Shi); Wan, SH (Wan, Shaohua); Cheng, KY (Cheng, Keyang); Cui, L (Cui, Lei) | |||||||||
Source: PATTERN RECOGNITION LETTERS Volume: 146 Pages: 134-141 DOI: 10.1016/j.patrec.2021.03.023 Early Access Date: MAR 2021 Published: JUN 2021 | |||||||||
Abstract: With the promotion of brain-computer interface technology, it is possible to study brain control system through EEG signals in recent years. In order to solve the problem of EEG signal classification effectively, a motor imagery classification algorithm based on recurrence plot convolution neural network is proposed. Firstly, EEG signals are preprocessed to enhance the signal intensity in the exercise interval. Secondly, time-domain and frequency-domain features are extracted respectively to construct the feature mode of recurrence plot. Finally, a new neural network is established to realize the accurate recognition of left and right movements. This research can also be transferred to other research fields. ? 2021 Elsevier B.V. All rights reserved. | |||||||||
Accession Number: WOS:000646018400018 | |||||||||
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ISSN: 0167-8655 | |||||||||
eISSN: 1872-7344 |
Record 221 of 318 | |||||||||||||||
Title: Simulation and analysis of the coherent-dispersion spectrometer for exoplanet detection | |||||||||||||||
Author(s): Wu, YH (Wu, Yinhua); Chen, SS (Chen, Shasha); Wang, PC (Wang, Pengchong); Zhou, S (Zhou, Shun); Feng, YT (Feng, Yutao); Zhang, WG (Zhang, Weiguang); Wei, RY (Wei, Ruyi) | |||||||||||||||
Source: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Volume: 503 Issue: 2 Pages: 3032-3043 DOI: 10.1093/mnras/stab656 Early Access Date: MAR 2021 Published: MAY 2021 | |||||||||||||||
Abstract: The coherent-dispersion spectrometer (CODES) is a new exoplanet detection instrument using the radial velocity (RV) method. This attempts mainly to improve environmental sensitivity and energy utilization by using an asymmetric, common-path Sagnac interferometer instead of a traditional Michelson interferometer. In order to verify its feasibility and to choose the appropriate key parameters to obtain the optimal performance, research on data processing for the design stage of the CODES is performed by systematic simulation and analysis. First, the instrument modelling is carried out for further data analysis according to the principle of the CODES, and the reliability of the model is verified by experiments. Second, the influence of key parameters on fringe visibility is analysed systematically, which provides a certain reference for the choice of the key parameters. Third, the RV inversion method for the CODES is proposed and optimized according to the related analysis results so as to promote RV inversion precision. Finally, the recommended values for the key parameters of the CODES are given. The experimental results show that the data processing error of RV inversion is less than 0.6 m s(-1) within the recommended range of key parameters. This indicates that the scheme of the CODES is reasonable and feasible, and that the proposed data processing method is effective and well matched with the instrument design. | |||||||||||||||
Accession Number: WOS:000648999700106 | |||||||||||||||
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ISSN: 0035-8711 | |||||||||||||||
eISSN: 1365-2966 |
Record 222 of 318 | |||||||||
Title: Laser-induced fluorescence and its effect on the damage resistance of fluoride-containing phosphate-based glasses | |||||||||
Author(s): Li, SW (Li, Shengwu); Yang, YQ (Yang, Yanqiang); Song, YF (Song, Yunfei); Wan, R (Wan, Rui); Ma, Y (Ma, Yuan); Peng, B (Peng, Bo); Zhang, GW (Zhang, Guangwei); Wang, PF (Wang, Pengfei) | |||||||||
Source: CERAMICS INTERNATIONAL Volume: 47 Issue: 9 Pages: 13164-13172 DOI: 10.1016/j.ceramint.2021.01.181 Early Access Date: MAR 2021 Published: MAY 1 2021 | |||||||||
Abstract: A series of multi-component fluoride-containing phosphate-based glasses prepared in a reducing atmosphere showed improved resistance to high-energy ultraviolet (UV) laser-induced damage and strong laser-induced fluorescence (LIF) within the glass bulk. The UV optical absorption, photoluminescence, and fluorescence decay properties of these glasses were investigated to explore the defect-related LIF mechanism and its underlying effect on the glasses? laser-induced damage threshold (LIDT). Seven laser wavelengths ranging from 253 nm to 532 nm were used to excite the LIF, and two characteristic fluorescence bands peaking at approximately 414 nm and 780?800 nm occurred in all three types of glasses. The LIF band at 414 nm was attributed to PO3-EC defects in the second harmonic frequency (2?) absorptive glass and third harmonic frequency (3?) transparent glass, but Fe2+ ions in the fundamental frequency (1?) absorptive glass. A later fluorescence band at 780?800 nm occurred due to POHC defects in the 2? absorptive and 3? transparent glasses and Fe3+ ions in the 1? absorptive glass. A detailed study on the dynamic decay processes of two additional dominant fluorescence peaks at 450 nm and 780 nm under 266 nm excitation revealed the potential effect of LIF on LIDT improvement. The relatively longer LIF lifetime, higher LIF intensity, and larger LIF peak area corresponded with and contributed to a higher LIDT, especially in the 3? transparent glass with a low UV absorption coefficient. This study provides strong evidence for the prior hypothesis between strong LIF and LIDT. | |||||||||
Accession Number: WOS:000632212800001 | |||||||||
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ISSN: 0272-8842 | |||||||||
eISSN: 1873-3956 |
Record 223 of 318 | ||||||
Title: Offline Signature Authentication Algorithm Based on the Fuzzy Set | ||||||
Author(s): Qiu, S (Qiu, Shi); Fei, FC (Fei, Fengchang); Cui, Y (Cui, Ying) | ||||||
Source: MATHEMATICAL PROBLEMS IN ENGINEERING Volume: 2021 Article Number: 5554341 DOI: 10.1155/2021/5554341 Published: MAR 19 2021 | ||||||
Abstract: There exists a problem that it is difficult to identify the authenticity of offline signatures. Firstly, a segmentation model is established based on the theory of fuzzy sets to extract signatures completely. Secondly, statistical shape model (SSM) and variance distance discretization of intraclass signatures are introduced for stability analysis and quantification. Finally, multilayer classifiers are constructed to realize signature authentication. The algorithm has low false detection rate and short authentication time. | ||||||
Accession Number: WOS:000636231900006 | ||||||
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ISSN: 1024-123X | ||||||
eISSN: 1563-5147 |
Record 224 of 318 | ||||||||||||
Title: Extraordinary Fast Forward and Backward Light in Transparent Non-Hermitian Systems | ||||||||||||
Author(s): Zhang, LX (Zhang, Lingxuan); Ying, L (Ying, Lei); Ge, L (Ge, Li); Zhao, W (Zhao, Wei); Zhang, WF (Zhang, Wenfu) | ||||||||||||
Source: LASER & PHOTONICS REVIEWS Volume: 15 Issue: 5 Article Number: 2000204 DOI: 10.1002/lpor.202000204 Early Access Date: MAR 2021 Published: MAY 2021 | ||||||||||||
Abstract: The phenomenon of fast forward and backward light pulse propagation in effectively transparent non-Hermitian photonic systems is reported. Specifically, the propagation eigenmodes are analyzed in several parity-time-symmetric coupled waveguides. In contrast to a previous finding that showed slow light due to an exceptional point in such systems, a critical point in its close proximity that displays a diverging dispersion is identified. Superluminal light pulse propagation in the forward and backward directions is then found and observed numerically on the two sides of the critical point, respectively. This abnormal phenomenon can be understood by a conservation relation of group velocities, which can be extended to other transparent non-Hermitian photonic systems with different symmetries. More importantly, the abrupt transition across the critical point between the fast forward and backward light can be tuned, indicating the possibility of detecting atom-scale movement of the waveguides with little time delay. In addition, bandwidth broadening and a passive superluminal propagation configuration are discussed. | ||||||||||||
Accession Number: WOS:000630234900001 | ||||||||||||
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ISSN: 1863-8880 | ||||||||||||
eISSN: 1863-8899 |
Record 225 of 318 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Title: Excitation of high-quality orbital angular momentum vortex beams in an adiabatically helical-twisted single-mode fiber | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Ren, KL (Ren, Kaili); Ren, LY (Ren, Liyong); Liang, J (Liang, Jian); Yang, L (Yang, Li); Xu, J (Xu, Jie); Han, DD (Han, Dongdong); Wang, YK (Wang, Yongkai); Liu, JH (Liu, Jihong); Dong, J (Dong, Jun); He, HY (He, Hanyu); Zhang, WF (Zhang, Wenfei) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 6 Pages: 8441-8450 DOI: 10.1364/OE.419668 Published: MAR 15 2021 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: A novel method to control the parameters of a chiral fiber grating structure is proposed. Mode couplings are controlled in real time during the twisting fabrication process. This chiral grating structure can satisfy the phase-matching condition for generating high-quality orbital angular momentum (OAM) beams, with an order mode of conversion efficiency over 99.9%. Both theoretical analysis and experimental results of this OAM mode conversion have been investigated, with good agreement. The results demonstrate a dual-OAM beam converter with a charge of +/- 1 for the right- and left-handed CLPGs, respectively. The high-quality OAM beam generated in this twisted single-mode fiber process may find excellent applications in optical communications. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000629298900040 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
PubMed ID: 33820291 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 1094-4087 |
Record 226 of 318 | ||||||
Title: Generation of Hybrid Optical Trap Array by Holographic Optical Tweezers | ||||||
Author(s): Li, X (Li, Xing); Zhou, Y (Zhou, Yuan); Cai, YN (Cai, Yanan); Zhang, YN (Zhang, Yanan); Yan, SH (Yan, Shaohui); Li, MM (Li, Manman); Li, RZ (Li, Runze); Yao, BL (Yao, Baoli) | ||||||
Source: FRONTIERS IN PHYSICS Volume: 9 Article Number: 591747 DOI: 10.3389/fphy.2021.591747 Published: MAR 9 2021 | ||||||
Abstract: Enabled by multiple optical traps, holographic optical tweezers can manipulate multiple particles in parallel flexibly. Spatial light modulators are widely used in holographic optical tweezers, in which Gaussian point (GP) trap arrays or special mode optical trap arrays including optical vortex (OV) arrays, perfect vortex (PV) arrays, and Airy beam arrays, etc., can be generated by addressing various phase holograms. However, the optical traps in these arrays are almost all of the same type. Here, we propose a new method for generating a hybrid optical trap array (HOTA), where optical traps such as GPs, OVs, PVs, and Airy beams in the focal plane are combined arbitrarily. Also, the axial position and peak intensity of each them can be adjusted independently. The energy efficiency of this method is theoretically studied, while different micro-manipulations on multiple particles have been realized with the support of HOTA experimentally. The proposed method expands holographic optical tweezers' capabilities and provides a new possibility of multi-functional optical micro-manipulation. | ||||||
Accession Number: WOS:000631422100001 | ||||||
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ISSN: 2296-424X |
Record 227 of 318 | ||||||||||||
Title: Investigation on secondary electron emission characteristics of double-layer structures | ||||||||||||
Author(s): Wang, D (Wang, Dan); He, YN (He, Yongning); Guo, JJ (Guo, Junjiang); Cai, YH (Cai, Yahui); Mao, ZS (Mao, Zhangsong); Ye, M (Ye, Ming) | ||||||||||||
Source: JOURNAL OF APPLIED PHYSICS Volume: 129 Issue: 9 Article Number: 093304 DOI: 10.1063/5.0023325 Published: MAR 7 2021 | ||||||||||||
Abstract: Secondary electron (SE) emission (SEE) from material surfaces is a frequent phenomenon in space and vacuum environments. SEE modulation is important since it governs the performance of some devices such as electronic multipliers or induces some detrimental effects such as multipactors. Surface coating has been reported to modulate SEE effectively, whereas SEE behaviors of coating structures are not clearly understood yet, and the appropriate theory to describe SEE characteristics quantitatively for coating structures is less developed so far. Here, we have prepared four alumina coatings possessing various thicknesses to research the SEE characteristics of coating structures and have shown how the coating thickness affects the SEE behaviors. Besides, by considering coating/substrate as an ideal double-layer structure, we have derived several equations to describe the producing, transmitting, and escaping processes of excited inner SEs and finally constructed a unidimensional SEE model for double-layer structures. The model is applicable to reveal the dependence of true SE yield (TSEY) on the top and bottom layers' physical properties and estimate TSEY proportions contributed by the top and bottom layers at random energy points. By employing the concept, SEE characteristics of Al2O3/Si, MgO/Si, and TiO2/Si double-layer structures have been quantitatively interpreted. Moreover, the abnormal SEY curve with a double-hump shape, which is induced by the peak position distinction of SiO2/Si structures, can also be explained. This work is of great significance to comprehend TSEY modulating regularities of various double-layer structures applied in surface engineering. Published under license by AIP Publishing. | ||||||||||||
Accession Number: WOS:000630435000001 | ||||||||||||
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ISSN: 0021-8979 | ||||||||||||
eISSN: 1089-7550 |
Record 228 of 318 | ||||||
Title: Fabrication and experimental characterization of precise high-efficiency 2D multi-mode fiber array coupler | ||||||
Author(s): Zhou, XJ (Zhou, Xiaojun); Song, AG (Song, Aiguo); Kong, DP (Kong, Depeng); Yu, WX (Yu, Weixing) | ||||||
Source: OPTICAL FIBER TECHNOLOGY Volume: 63 Article Number: 102488 DOI: 10.1016/j.yofte.2021.102488 Early Access Date: MAR 2021 Published: MAY 2021 | ||||||
Abstract: In this paper a method for fabricating precise high-efficiency 2D multi-mode fiber array coupler is proposed, and the coupler's performance is experimentally characterized. By improving the design of 2D fiber array coupler, the average concentricity error of the fiber array is down to 0.9 mu m. After coupling with microlens array, the average coupling efficiency of the coupler is up to 57.51%. It is demonstrated that the precise microhole position and fiber cladding diameter, supported by microlens array, can provide an excellent coupling performance. This 2D fiber array coupler can be widely applied in LIDAR, optical communication systems and microwave photonics systems, provide the functions of high-speed image capture, interconnection and optical signals time-space transformation. | ||||||
Accession Number: WOS:000647686700001 | ||||||
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ISSN: 1068-5200 | ||||||
eISSN: 1095-9912 |
Record 229 of 318 | |||||||||||||||
Title: Correction of the error induced by obscurations of Ritchey-Chretien collimators for high-resolution space camera MTF measured with the ISO 12233 slanted-edge method | |||||||||||||||
Author(s): Liu, SK (Liu, Shangkuo); Liu, K (Liu, Kai); E, KW (E, Kewei); Wang, T (Wang, Tao); Li, ZH (Li, Zhaohui); Yao, BL (Yao, Baoli) | |||||||||||||||
Source: OPTIK Volume: 235 Article Number: 166653 DOI: 10.1016/j.ijleo.2021.166653 Early Access Date: MAR 2021 Published: JUN 2021 | |||||||||||||||
Abstract: We propose a method to correct the error induced by the obscurations of Ritchey-Chretien (R-C) collimators, when measuring modulation transfer function (MTF) of high-resolution space cameras by the ISO 12,233 slanted-edge method. The obscurations of an R-C collimator include the secondary mirror (SM) and its supporting bars. Mathematical models are derived to simulate possible obscurations by virtual surfaces of Zemax, with which we get the correction function (CF) of the obscuration induced error (OIE). Simulated results manifest that the proposed method can correct the OIE. Furthermore, an experiment setup is established with the same system parameters of the previous Zemax modeled system. The experiment results verify the effectiveness of the proposed method again. Our method can guarantee the precision of the ISO 12,233 slanted-edge method when an R-C collimator is chosen. | |||||||||||||||
Accession Number: WOS:000636795600001 | |||||||||||||||
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ISSN: 0030-4026 | |||||||||||||||
eISSN: 1618-1336 |
Record 230 of 318 | ||||||
Title: Modified scaling angular spectrum method for numerical simulation in long-distance propagation* | ||||||
Author(s): Chen, XY (Chen, Xiao-Yi); Duan, YX (Duan, Ya-Xuan); Xiang, BB (Xiang, Bin-Bin); Li, M (Li, Ming); Da, ZS (Da, Zheng-Shang) | ||||||
Source: CHINESE PHYSICS B Volume: 30 Issue: 3 Article Number: 034203 DOI: 10.1088/1674-1056/abd38d Published: MAR 2021 | ||||||
Abstract: The angular method (AS) cannot be used in long-distance propagation because it produces severe numerical errors due to the sampling problem in the transfer function. Two ways can solve this problem in AS for long-distance propagation. One is zero-padding to make sure that the calculation window is wide enough, but it leads to a huge calculation burden. The other is a method called band-limited angular spectrum (BLAS), in which the transfer function is truncated and results in that the calculation accuracy decreases as the propagation distance increases. In this paper, a new method called modified scaling angular spectrum (MSAS) to solve the problem for long-distance propagation is proposed. A scaling factor is introduced in MSAS so that the sampling interval of the input plane can be adjusted arbitrarily unlike AS whose sampling interval is restricted by the detector's pixel size. The sampling interval of the input plane is larger than the detector's pixel size so the size of calculation window suitable for long-distance field propagation in the input plane is smaller than the size of the calculation window required by the zero-padding. Therefore, the method reduces the calculation redundancy and improves the calculation speed. The results from simulations and experiments show that MSAS has a good signal-to-noise ratio (SNR), and the calculation accuracy of MSAS is better than BLAS. | ||||||
Accession Number: WOS:000631808900001 | ||||||
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ISSN: 1674-1056 | ||||||
eISSN: 2058-3834 |
Record 231 of 318 | ||||||||||||||||||
Title: SpectralSpatial Joint Sparse NMF for Hyperspectral Unmixing | ||||||||||||||||||
Author(s): Dong, L (Dong, Le); Yuan, Y (Yuan, Yuan); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||||||||
Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Volume: 59 Issue: 3 Pages: 2391-2402 DOI: 10.1109/TGRS.2020.3006109 Published: MAR 2021 | ||||||||||||||||||
Abstract: The nonnegative matrix factorization (NMF) combining with spatial-spectral contextual information is an important technique for extracting endmembers and abundances of hyperspectral image (HSI). Most methods constrain unmixing by the local spatial position relationship of pixels or search spectral correlation globally by treating pixels as an independent point in HSI. Unfortunately, they ignore the complex distribution of substance and rich contextual information, which makes them effective in limited cases. In this article, we propose a novel unmixing method via two types of self-similarity to constrain sparse NMF. First, we explore the spatial similarity patch structure of data on the whole image to construct the spatial global self-similarity group between pixels. And according to the regional continuity of the feature distribution, the spectral local self-similarity group of pixels is created inside the superpixel. Then based on the sparse expression of the pixel in the subspace, we sparsely encode the pixels in the same spatial group and spectral group respectively. Finally, the abundance of pixels within each group is forced to be similar to constrain the NMF unmixing framework. Experiments on synthetic and real data fully demonstrate the superiority of our method over other existing methods. | ||||||||||||||||||
Accession Number: WOS:000622319000041 | ||||||||||||||||||
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ISSN: 0196-2892 | ||||||||||||||||||
eISSN: 1558-0644 |
Record 232 of 318 | ||||||
Title: Trapping performance of holographic optical tweezers generated with different hologram algorithms | ||||||
Author(s): He, MR (He, M. R.); Liang, YS (Liang, Y. S.); Bianco, PR (Bianco, P. R.); Wang, ZJ (Wang, Z. J.); Yun, X (Yun, X.); Cai, YN (Cai, Y. N.); Feng, K (Feng, K.); Lei, M (Lei, M.) | ||||||
Source: AIP ADVANCES Volume: 11 Issue: 3 Article Number: 035130 DOI: 10.1063/5.0033186 Published: MAR 1 2021 | ||||||
Abstract: Quantitative measurement of small forces and small displacement using holographic optical tweezers (HOTs) is finding increasing applications due to the features of non-contact and high accuracy manipulation. Although hologram optimization algorithms have been widely reported, the holographic optical trapping performance relying on the algorithms has not been studied systematically. In this paper, we investigated the force measuring the performance of various types of HOTs generated with six different hologram algorithms (GSW, GAA, GS, SR, S, and RM). To do this, we built up a HOT instrument and compared the light fields' intensity distribution, trap stiffness, efficiency, and calculation time of multi-point trap arrays generated by six hologram algorithms with this setup. Our work will provide a better understanding of the performance of different hologram algorithms in HOTs. | ||||||
Accession Number: WOS:000629874300001 | ||||||
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eISSN: 2158-3226 |
Record 233 of 318 | |||||||||||||||||||||||||||||||||||||||||||||
Title: Nonlinear calibration of frequency modulated continuous wave LIDAR based on a microresonator soliton comb | |||||||||||||||||||||||||||||||||||||||||||||
Author(s): Jia, LH (Jia, Linhua); Wang, Y (Wang, Yang); Wang, XY (Wang, Xinyu); Zhang, FM (Zhang, Fumin); Wang, WQ (Wang, Weiqiang); Wang, JD (Wang, Jindong); Zheng, JH (Zheng, Jihui); Chen, JW (Chen, Jiawei); Song, MY (Song, Mingyu); Ma, X (Ma, Xin); Yuan, MY (Yuan, Meiyan); Little, B (Little, Brent); Chu, ST (Chu, Sai Tek); Cheng, D (Cheng, Dong); Qu, XH (Qu, Xinghua); Zhao, W (Zhao, Wei); Zhang, WF (Zhang, Wenfu) | |||||||||||||||||||||||||||||||||||||||||||||
Source: OPTICS LETTERS Volume: 46 Issue: 5 Pages: 1025-1028 DOI: 10.1364/OL.415524 Published: MAR 1 2021 | |||||||||||||||||||||||||||||||||||||||||||||
Abstract: Traditional frequency modulated continuous wave (FMCW) LIDAR ranging is based on heterodyne detection, calculating unknown distance by extracting the frequency of the interference signal, while the main error source is frequency modulation (FM) nonlinearity. In this paper, a ranging system based on a microresonator soliton comb is demonstrated to correct the nonlinearity by sampling the ranging signals at equal frequency intervals, producing a ranging error lower than 20 mu m, while at the range of 2 m. Advantages of fast data acquisition, light computation requirements, and a simple optical path, without long optical fiber, give this method a high practical value in precision manufacturing. (C) 2021 Optical Society of America | |||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000625297100026 | |||||||||||||||||||||||||||||||||||||||||||||
PubMed ID: 33649648 | |||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 0146-9592 | |||||||||||||||||||||||||||||||||||||||||||||
eISSN: 1539-4794 |
Record 234 of 318 | |||||||||||||||||||||||||||
Title: The Lyman-alpha Solar Telescope (LST) for the ASO-S mission - I. Scientific objectives and overview (vol 19, 158, 2019) | |||||||||||||||||||||||||||
Author(s): Li, H (Li, Hui); Chen, B (Chen, Bo); Feng, L (Feng, Li); Li, Y (Li, Ying); Huang, Y (Huang, Yu); Li, JW (Li, Jing-Wei); Lu, L (Lu, Lei); Xue, JC (Xue, Jian-Chao); Ying, BL (Ying, Bei-Li); Zhao, J (Zhao, Jie); Yang, YT (Yang, Yu-Tong); Gan, WQ (Gan, Wei-Qun); Fang, C (Fang, Cheng); Song, KF (Song, Ke-Fei); Wang, H (Wang, Hong); Guo, QF (Guo, Quan-Feng); He, LP (He, Ling-Ping); Zhu, B (Zhu, Bo); Zhu, C (Zhu, Cheng); Deng, L (Deng, Lei); Bao, HC (Bao, Hai-Chao); Cao, CX (Cao, Cai-Xia); Yang, ZG (Yang, Zhong-Guang) | |||||||||||||||||||||||||||
Source: RESEARCH IN ASTRONOMY AND ASTROPHYSICS Volume: 21 Issue: 2 Article Number: 49 DOI: 10.1088/1674-4527/21/2/49 Published: MAR 2021 | |||||||||||||||||||||||||||
Accession Number: WOS:000631535400001 | |||||||||||||||||||||||||||
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ISSN: 1674-4527 | |||||||||||||||||||||||||||
eISSN: 2397-6209 |
Record 235 of 318 | |||||||||||||||||||||||||||||||||||||||||||||||||||
Title: Antireflective and Superhydrophilic Structure on Graphite Written by Femtosecond Laser | |||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Lou, R (Lou, Rui); Li, GY (Li, Guangying); Wang, X (Wang, Xu); Zhang, WF (Zhang, Wenfu); Wang, YS (Wang, Yishan); Zhang, GD (Zhang, Guodong); Wang, J (Wang, Jiang); Cheng, GH (Cheng, Guanghua) | |||||||||||||||||||||||||||||||||||||||||||||||||||
Source: MICROMACHINES Volume: 12 Issue: 3 Article Number: 236 DOI: 10.3390/mi12030236 Published: MAR 2021 | |||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: Antireflection and superhydrophilicity performance are desirable for improving the properties of electronic devices. Here, we experimentally provide a strategy of femtosecond laser preparation to create micro-nanostructures on the graphite surface in an air environment. The modified graphite surface is covered with abundant micro-nano structures, and its average reflectance is measured to be 2.7% in the ultraviolet, visible and near-infrared regions (250 to 2250 nm). The wettability transformation of the surface from hydrophilicity to superhydrophilicity is realized. Besides, graphene oxide (GO) and graphene are proved to be formed on the sample surface. This micro-nanostructuring method, which demonstrates features of high efficiency, high controllability, and hazardous substances zero discharge, exhibits the application for functional surface. | |||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000633889600001 | |||||||||||||||||||||||||||||||||||||||||||||||||||
PubMed ID: 33652965 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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eISSN: 2072-666X |
Record 236 of 318 | ||||||
Title: Calibration of geometrical aberration in transmitted wavefront testing of refractive optics with deflectometry | ||||||
Author(s): Wang, DD (Wang, Daodang); Yin, YM (Yin, Yamei); Dou, JC (Dou, Jinchao); Kong, M (Kong, Ming); Xu, XK (Xu, Xinke); Lei, LH (Lei, Lihua); Liang, RG (Liang, Rongguang) | ||||||
Source: APPLIED OPTICS Volume: 60 Issue: 7 Pages: 1973-1981 DOI: 10.1364/AO.415715 Published: MAR 1 2021 | ||||||
Abstract: Deflectometry, with its noticeable advantages such as simple structure, large dynamic range, and high accuracy comparable to interferometry, has been one of the powerful metrological techniques for optical surfaces in recent years. In the "null" deflectometric transmitted wavefront testing of refractive optics, ray tracing of the test system model is required, in which both the miscalibration of system geometrical parameters and optical tolerances on tested optics could introduce significant geometrical aberrations in the testing results. In this paper, the geometrical aberration introduced by a system modeling error in the transmitted wavefront testing is discussed. Besides, a calibration method based on polynomial optimization of geometrical aberration is presented for the geometrical aberration calibration. Both simulation and experiment have been performed to validate the feasibility of the proposed calibration method. The proposed method can calibrate the optical tolerances on tested optics effectively, and it is feasible even with a large geometric error, providing a viable way to address the uncertainty in system modeling in transmitted wavefront testing of freeform refractive optics with large dynamic range. (C) 2021 Optical Society of America | ||||||
Accession Number: WOS:000624969800024 | ||||||
PubMed ID: 33690289 | ||||||
Author Identifiers: | ||||||
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ISSN: 1559-128X | ||||||
eISSN: 2155-3165 |
Record 237 of 318 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Title: Numerical simulation of dielectric barrier discharge with asymmetrical electrode in atmospheric helium | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Author(s): Wang, J (Wang, Jing); Li, J (Li, Jing); Lei, BY (Lei, Bingying); Ran, S (Ran, Shuang); Xu, BP (Xu, Boping); Liu, YH (Liu, Yinghua); Li, XZ (Li, Xinzhong); Wang, YS (Wang, Yishan); Tang, J (Tang, Jie); Zhao, W (Zhao, Wei); Duan, YX (Duan, Yixiang) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Source: PLASMA SOURCES SCIENCE & TECHNOLOGY Volume: 30 Issue: 3 Article Number: 035012 DOI: 10.1088/1361-6595/abe613 Published: MAR 2021 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Abstract: The characteristics of the dielectric barrier discharge (DBD) equipped with asymmetrical electrode (ring electrode on the upper and disk electrode on the lower) in atmospheric helium are investigated by a two-dimensional self-consistent fluid model. Simulation results show that as the applied voltage increases, the discharge enhances and the onset of discharge advances, which is similar to the results of traditional DBD. However, with the applied voltage increasing, the symmetry of the discharge current pulses in the positive and negative half cycles disappears because of the asymmetric electrode configuration. In addition, only the spatial distribution of the electron density at the peak moments of the first and second current pulses satisfies the complementary characteristics, while the spatial distribution at other peak moments does not meet the complementary characteristics. Moreover, the electric field, near the upper dielectric barrier surface, presents a curtain-like distribution with considerable radial electric field components, which results from the non-uniform radial surface charge distribution and the ring electrode configuration. The relative variation of the radial distribution of surface charge density is largely determined by the geometry of the opposite electrode. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000629941100001 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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ISSN: 0963-0252 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
eISSN: 1361-6595 |
Record 238 of 318 | |||||||||||||||
Title: Thermal Analysis of Visible Emission From Micro-Ring Resonators by Third-Harmonic Generation | |||||||||||||||
Author(s): Wang, SH (Wang, Shao Hao); Li, YH (Li, Yuhua); Wang, LR (Wang, Leiran); Little, BE (Little, Brent E.); Chu, ST (Chu, Sai Tak) | |||||||||||||||
Source: IEEE PHOTONICS TECHNOLOGY LETTERS Volume: 33 Issue: 5 Pages: 235-238 DOI: 10.1109/LPT.2021.3054379 Published: MAR 1 2021 | |||||||||||||||
Abstract: We present a thermal model to describe the interaction between the visible modes in micro-ring resonators from the third harmonic generation (THG) nonlinear process. We demonstrate that the model can predict the thermal characteristics of the orthogonal THG modes from the interaction and of the resonance coupling between them in micro-ring resonators having a strong nonlinear thermo-optic coefficient. Furthermore, the model can be used to extract the THG efficiency, the linear and nonlinear thermo-optic coefficients and the polarization dependency of the THG modes from the measurement data. | |||||||||||||||
Accession Number: WOS:000615033300002 | |||||||||||||||
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ISSN: 1041-1135 | |||||||||||||||
eISSN: 1941-0174 |
Record 239 of 318 | |||||||||||||||||||||||||||
Title: Generative Adversarial Capsule Network With ConvLSTM for Hyperspectral Image Classification | |||||||||||||||||||||||||||
Author(s): Wang, WY (Wang, Wei-Ye); Li, HC (Li, Heng-Chao); Deng, YJ (Deng, Yang-Jun); Shao, LY (Shao, Li-Yang); Lu, XQ (Lu, Xiao-Qiang); Du, Q (Du, Qian) | |||||||||||||||||||||||||||
Source: IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Volume: 18 Issue: 3 Pages: 523-527 DOI: 10.1109/LGRS.2020.2976482 Published: MAR 2021 | |||||||||||||||||||||||||||
Abstract: Recently, deep learning has been widely applied in hyperspectral image (HSI) classification since it can extract high-level spatial-spectral features. However, deep learning methods are restricted due to the lack of sufficient annotated samples. To address this problem, this letter proposes a novel generative adversarial network (GAN) for HSI classification that can generate artificial samples for data augmentation to improve the HSI classification performance with few training samples. In the proposed network, a new discriminator is designed by exploiting capsule network (CapsNet) and convolutional long short-term memory (ConvLSTM), which extracts the low-level features and combines them together with local space sequence information to form the high-level contextual features. In addition, a structured sparse L-2(,1) constraint is imposed on sample generation to control the modes of data being generated and achieve more stable training. The experimental results on two real HSI data sets show that the proposed method can obtain better classification performance than the several state-of-the-art deep classification methods. | |||||||||||||||||||||||||||
Accession Number: WOS:000622098500031 | |||||||||||||||||||||||||||
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ISSN: 1545-598X | |||||||||||||||||||||||||||
eISSN: 1558-0571 |
Record 240 of 318 | ||||||||||||||||||||||||
Title: A compact bionic compound eye camera for imaging in a large field of view | ||||||||||||||||||||||||
Author(s): Wang, YY (Wang, Yuanyuan); Shi, CY (Shi, Chengyong); Xu, HR (Xu, Huangrong); Zhang, YJ (Zhang, Yuanjie); Yu, WX (Yu, Weixing) | ||||||||||||||||||||||||
Source: OPTICS AND LASER TECHNOLOGY Volume: 135 Article Number: 106705 DOI: 10.1016/j.optlastec.2020.106705 Published: MAR 2021 | ||||||||||||||||||||||||
Abstract: The traditional imaging technologies, such as two-dimensional imaging, have not been able to meet people's needs for higher technology. Inspired by the characteristics, such as small size, sensitivity to moving targets and large field of view, researchers began to study bionic compound eyes. In this paper, a hemispherical mounting surface with through holes to set the compound lens array is fabricated by 3-D printing technology. More than one hundred small lenses are mounted on the 3-D printed hemispherical surface to form a bionic curved compound eye, which is then integrated with an optical relay system and an CMOS imaging sensor to form a rather compact bionic compound eye camera. The addition of the optical relay system solves the problem that the mismatch between the curved focal plane formed by the curved compound eye and the flat focal plane of the CMOS imaging sensor. By employing this method, we design and analyze the curved lens array and optical relay system, and perform the related optical performance tests on the fabricated bionic curved compound eye imaging system. The results show that a good image quality can be achieved. The formed bionic compound eye imaging prototype system rather compact and has a weight of only 121 g, a volume of 34 mm x 44 mm x 80 mm, and a field of view of 120 degrees x 120 degrees. This system has great potential and value in military, medical, and engineering applications. | ||||||||||||||||||||||||
Accession Number: WOS:000597285300009 | ||||||||||||||||||||||||
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ISSN: 0030-3992 | ||||||||||||||||||||||||
eISSN: 1879-2545 |
Record 241 of 318 | ||||||||||||
Title: Free-carrier-assisted mid-infrared microcavity soliton generation | ||||||||||||
Author(s): Fan, WC (Fan, Weichen); Sun, QB (Sun, Qibing); Lu, ZZ (Lu, Zhizhou); Wang, LR (Wang, Leiran); Zhao, W (Zhao, Wei); Zhang, WF (Zhang, Wenfu) | ||||||||||||
Source: JOURNAL OF APPLIED PHYSICS Volume: 129 Issue: 8 Article Number: 083106 DOI: 10.1063/5.0037921 Published: FEB 28 2021 | ||||||||||||
Abstract: Multi-photon absorption (MPA) and free-carrier (FC) effects, usually considered to be detrimental to microcomb generation by introducing strong nonlinear loss, also offer opportunities to overwhelm the thermal-optic effect by modifying the refractive index. Here, we derive the theoretical expression of solitons expanded with MPA and FC effects, accompanied by numerical simulations to reveal the dynamics and mechanism for capturing steady mid-infrared solitons in both Si and Ge microcavities. It is found that with increased FC lifetime, the intensity-dependent MPA underlies non-monotonous variation of nonlinear detuning which enables soliton generation. More interestingly, proper control on the FC lifetime admits bidirectional switching of soliton states (i.e., both decreasing and increasing the number of solitons) as well as self-starting solitons, yielding different technique routes toward microcavity solitons. This research could contribute to a better understanding of nonlinear behaviors influenced by FC effects and find practical applications by releasing the demand on precise control of laser sources, which is especially meaningful for the mid-infrared region. | ||||||||||||
Accession Number: WOS:000630512900003 | ||||||||||||
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ISSN: 0021-8979 | ||||||||||||
eISSN: 1089-7550 |
Record 242 of 318 |
Title: Tumor imaging of a novel Ho3+-based biocompatible NIR fluorescent fluoride nanoparticle |
Author(s): Fan, Q (Fan, Q.); Zhang, GW (Zhang, G. W.); Peng, B (Peng, B.) |
Source: JOURNAL OF LUMINESCENCE Volume: 235 Article Number: 118007 DOI: 10.1016/j.jlumin.2021.118007 Early Access Date: FEB 2021 Published: JUL 2021 |
Abstract: Cancer has become the leading cause of death for its high incidence and mortality. Early diagnosis and treatment are essential for the inhibition of tumor growth. In this work, A biocompatible, nontoxic, near-infrared fluorescent tumor targeting nanoparticle KHLF(K5HoLi2F10) was prepared by a delicate method for the early diagnosis of tumor. The surface functionalization of the nanoparticle endows it with good water solubility and biocompatibility. Covalent binding to folic acid provides it with the ability to target HeLa cells. After modification, this nanoparticle can still maintain high fluorescence intensity and it can be detected in 2 cm thick pork tissue. We carried out biodistribution imaging, organs imaging and tumor targeting imaging experiments to characterize its imaging ability in vivo. The results show that this nanoparticle could accurately accumulate in HeLa tumor and generate significant fluorescence signal, which confirms the nanoparticle has great potential as a efficient biocompatible fluorescent contrast agent for tumor diagnosis. |
Accession Number: WOS:000641453200001 |
ISSN: 0022-2313 |
eISSN: 1872-7883 |
Record 243 of 318 | |||||||||||||||||||||
Title: Secondary electron emission characteristics of the Al<sub>2</sub>O<sub>3</sub>/MgO double-layer structure prepared by atomic layer deposition | |||||||||||||||||||||
Author(s): Cao, WW (Cao, Weiwei); Wang, B (Wang, Bo); Yang, Y (Yang, Yang); Zhu, BL (Zhu, Bingli); Guo, JJ (Guo, Junjiang); Xu, P (Xu, Peng); Bai, XH (Bai, Xiaohong); Qin, JJ (Qin, Junjun); Wang, C (Wang, Chao); Zhu, JP (Zhu, Jingping); Bai, YL (Bai, Yonglin) | |||||||||||||||||||||
Source: CERAMICS INTERNATIONAL Volume: 47 Issue: 7 Pages: 9866-9872 DOI: 10.1016/j.ceramint.2020.12.128 Early Access Date: FEB 2021 Part: A Published: APR 1 2021 | |||||||||||||||||||||
Abstract: As a secondary electron emission layer, an Al2O3/MgO double-layer structure is fabricated by atomic layer deposition (ALD) technology. The thickness range from 1 nm to 4 nm of the top Al2O3 layer deposited on 20 nm MgO creates a double-layer. The morphology of the cross section, element distribution, surface roughness, X-ray diffraction, and secondary electron yield (SEY) values were measured by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and secondary electron emission (SEE) measurement systems. The SEE characteristics of the MgO single layer, Al2O3 single layer and MgO/Al2O3 double-layer were measured. The maximum SEY of a single MgO layer reached 6.2@600 eV, and the maximum SEY of a single Al2O3 layer reached 3.92@400 eV. The SEY of the Al2O3/MgO double-layer decreased when the Al2O3 thickness ranged from 1 nm to 4 nm, and the SEY reduction value of the double-layer decreased as the Al2O3 thickness increased. Finally, Dionne's semiempirical SEE model was employed to explain the SEE yield of the prepared composite film structures. These results are useful for depositing a secondary electron emission layer in the channel of microchannel plates. | |||||||||||||||||||||
Accession Number: WOS:000623673900006 | |||||||||||||||||||||
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ISSN: 0272-8842 | |||||||||||||||||||||
eISSN: 1873-3956 |
Record 244 of 318 | |||||||||
Title: The nonlinear optical properties of two-dimensional metal-organic framework | |||||||||
Author(s): Cheng, XM (Cheng, Xuemei); Yao, JJ (Yao, Jingjing); Zhang, H (Zhang, Hui); Wang, X (Wang, Xing); Bai, JT (Bai, Jintao) | |||||||||
Source: JOURNAL OF ALLOYS AND COMPOUNDS Volume: 855 Article Number: 157433 DOI: 10.1016/j.jallcom.2020.157433 Part: 1 Published: FEB 25 2021 | |||||||||
Abstract: We report the investigation on the nonlinear optical properties of two typical two-dimensional metal-organic frameworks (2D MOFs) - 2D Cu-MOF and Zn-MOF (copper/zinc 1,4-benzene dicarboxylate, CuBDC and ZnBDC) using spatial self-phase modulation (SSPM) and spatial cross-phase modulation (SXPM) methods. It is found that 2D Cu-MOF exhibits a large nonlinear optical coefficient (n(2) = 5.20 x 10(-11) m(2)/W and chi(3) = 8.24 x 10(-11) (e.s.u)). By contrast, no nonlinear optical effect was observed from 2D Zn-MOF under the same condition. The main reason is the Cu center of Cu-MOF has variable valence electrons and a vacant 3d atom orbit, which can form a conjugated system with organic ligands through the d - pi interaction and therefore strengthen the nonlinear optical effect by the delocalization of pi electrons. However, the Zn ion of Zn-MOF with fixed valence electrons and fully occupied d orbit makes it hard to produce observable nonlinear optical effect. Furthermore, we demonstrated the ability of 2D Cu-MOF in all-optical spatial light modulation and optical switch based on the principle of SXPM. This work sheds light on the physics of 2D MOFs in all-optical light modulation, providing an insight for rational design of 2D MOFs with high nonlinear optical coefficients in future. (C) 2020 Elsevier B.V. All rights reserved. | |||||||||
Accession Number: WOS:000601001500057 | |||||||||
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ISSN: 0925-8388 | |||||||||
eISSN: 1873-4669 |
Record 245 of 318 | |||||||||||||||
Title: Human behaviour recognition with mid-level representations for crowd understanding and analysis | |||||||||||||||
Author(s): Sun, BY (Sun, Bangyong); Yuan, NZ (Yuan, Nianzeng); Li, SY (Li, Shuying); Wu, SY (Wu, Siyuan); Wang, N (Wang, Nan) | |||||||||||||||
Source: IET IMAGE PROCESSING Volume: 15 Issue: 14 Special Issue: SI Pages: 3414-3424 DOI: 10.1049/ipr2.12147 Early Access Date: FEB 2021 Published: DEC 2021 | |||||||||||||||
Abstract: Crowd understanding and analysis have received increasing attention for couples of decades, and development of human behaviour recognition strongly supports the application of crowd understanding and analysis. Human behaviour recognition usually seeks to automatically analyse ongoing movements and actions in different camera views by using various machine learning methodologies in unknown video clips or image sequences. Compared to other data modalities such as documents and images, processing video data demands much higher computational and storage resources. The idea of using middle level semantic concepts to represent human actions from videos is explored and it is argued that these semantic attributes enable the construction of more descriptive methods for human action recognition. The mid-level attributes, initialized by a cluster processing, are built upon low level features and fully utilize the discrepancies in different action classes, which can capture the importance of each attribute for each action class. In this way, the representation is constructed to be semantically rich and capable of highly discriminative performance even paired with simple linear classifiers. The method is verified on three challenging datasets (KTH, UCF50 and HMDB51), and the experimental results demonstrate that our method achieves better results than the baseline methods on human action recognition. | |||||||||||||||
Accession Number: WOS:000624128900001 | |||||||||||||||
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ISSN: 1751-9659 | |||||||||||||||
eISSN: 1751-9667 |
Record 246 of 318 | ||||||
Title: A 4F optical diffuser system with spatial light modulators for image data augmentation | ||||||
Author(s): Li, BP (Li, Baopeng); Ersoy, OK (Ersoy, Okan K.); Ma, CW (Ma, Caiwen); Pan, ZB (Pan, Zhibin); Wen, WS (Wen, Wansha); Song, ZX (Song, Zongxi) | ||||||
Source: OPTICS COMMUNICATIONS Volume: 488 Article Number: 126859 DOI: 10.1016/j.optcom.2021.126859 Early Access Date: FEB 2021 Published: JUN 1 2021 | ||||||
Abstract: This paper proposes a novel image data augmentation method based on the 4F optical diffuser system with two spatial light modulators. The method combines data augmentation methods based on geometric transformations with optical phase diffuser, resulting in a system which is effective and easy-to-use. This method can be used in an all-optical machine learning system or in a hybrid digital-optical system, and its digital implementation can also be used in learning-based computer vision applications. The method was tested in image classification of MNIST dataset. It was demonstrated that the augmented dataset significantly improves the classification accuracy. | ||||||
Accession Number: WOS:000632325100005 | ||||||
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ISSN: 0030-4018 | ||||||
eISSN: 1873-0310 |
Record 247 of 318 | |||||||||
Title: Deep neural network oriented evolutionary parametric eye modeling | |||||||||
Author(s): Zheng, Y (Zheng, Yang); Fu, H (Fu, Hong); Li, RM (Li, Ruimin); Hsung, TC (Hsung, Tai-Chiu); Song, ZX (Song, Zongxi); Wen, DS (Wen, Desheng) | |||||||||
Source: PATTERN RECOGNITION Volume: 113 DOI: 10.1016/j.patcog.2020.107755 Early Access Date: FEB 2021 Published: MAY 2021 | |||||||||
Abstract: Comprehensive and accurate eye modeling is crucial to a variety of applications, including human computer interaction, assistive technologies, and medical diagnosis. However, most studies focus on the localization of one or two components of eyes, such as pupil or iris, lacking a comprehensive eye model. We propose to model an eye image by a set of parametric curves. The set of curves are plotted on an eye image to form a Contour-Eye image. A deep neural network is trained to evaluate the fitness of the Contour-Eye image. Then an evolutionary process is conducted to search the best fitting curve set, guided by the trained deep neural network. Finally, an accurate eye model with optimized parametric curves is obtained. For the algorithm evaluation, a finely annotated eye dataset denoted as FAED-50 is established by us, which contains 2,498 eye images from 50 subjects. The experimental results on the FAED-50 and the relabeled CASIA datasets and comparison with the state-of-the-art methods demonstrate the effectiveness and accuracy of the proposed parametric model. (c) 2020 Published by Elsevier Ltd. | |||||||||
Accession Number: WOS:000626268400008 | |||||||||
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ISSN: 0031-3203 | |||||||||
eISSN: 1873-5142 |
Record 248 of 318 | |||||||||||||||||||||
Title: Super-resolution and optical sectioning integrated structured illumination microscopy | |||||||||||||||||||||
Author(s): Dan, D (Dan, Dan); Gao, P (Gao, Peng); Zhao, TY (Zhao, Tianyu); Dang, SP (Dang, Shipei); Qian, J (Qian, Jia); Lei, M (Lei, Ming); Min, JW (Min, Junwei); Yu, XH (Yu, Xianghua); Yao, BL (Yao, Baoli) | |||||||||||||||||||||
Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS Volume: 54 Issue: 7 Article Number: 074004 DOI: 10.1088/1361-6463/abc4a8 Published: FEB 18 2021 | |||||||||||||||||||||
Abstract: Super-resolution structured illumination microscopy (SR-SIM) has attracted a great deal of attention in the past few decades. As a wide-field imaging technique, SR-SIM usually suffers from issues relating to out-of-focus background, particularly when imaging thick samples. In this study, we develop an integrated SIM with simultaneous SR and optical sectioning (OS) capabilities, facilitating SR imaging of stacked optical sections, with the out-of-focus background suppressed. The combination of the merits of SR and OS is realized by means of a new image reconstruction algorithm. We confirm the validity of the integrated SIM, both experimentally and in simulation. We anticipate that this integrated SIM will assist biologists in obtaining much clearer SR images in relation to thick specimens. | |||||||||||||||||||||
Accession Number: WOS:000595248500001 | |||||||||||||||||||||
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ISSN: 0022-3727 | |||||||||||||||||||||
eISSN: 1361-6463 |
Record 249 of 318 | ||||||
Title: Infrared and visible image fusion based on weighted variance guided filter and image contrast enhancement | ||||||
Author(s): Ren, L (Ren, Long); Pan, ZB (Pan, Zhibin); Cao, JZ (Cao, Jianzhong); Liao, JW (Liao, Jiawen); Wang, Y (Wang, Yang) | ||||||
Source: INFRARED PHYSICS & TECHNOLOGY Volume: 114 Article Number: 103662 DOI: 10.1016/j.infrared.2021.103662 Early Access Date: FEB 2021 Published: MAY 2021 | ||||||
Abstract: With extraordinary advances in sensor technology, infrared and visible image fusion has been widely used in both military and civilian applications. In this paper, we propose a novel image fusion method based on decomposition and division based strategy. The proposed method improves the guided filter to better decompose images and restrict artifacts around image boundaries. Furthermore, because the quality of visible images is easily affected by low light conditions and noises, it is necessary to enhance the contrast of visible images to improve the visual quality before applying image fusion. Subsequently, we divide the infrared and visible image into several sub-images in vertical direction, because there is more similar image content in this direction such as the sky and land. Additionally, each sub-image is decomposed into a base layer and a detail layer. Different from previous methods, the fusion in our proposed method is executed by two different strategies, one takes the sub infrared base layer as the main image to get the fusion result, while the other one takes the sub visible base layer as the main image, and two different sub-fusion results are obtained. We also propose a new fusion strategy called gradient-brightness criterion to adaptively output the final fused image. As a result, the fused image preserves more details of visible image and clearer infrared objects at the same time, which is well suited for human visual perception. Experimental results indicate that our proposed method achieves a superior performance compared with previous fusion methods in both subjective and objective assessments. | ||||||
Accession Number: WOS:000634644700001 | ||||||
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ISSN: 1350-4495 | ||||||
eISSN: 1879-0275 |
Record 250 of 318 | ||||||||||||
Title: Sub-7 fs radially-polarized pulses by post-compression in thin fused silica plates | ||||||||||||
Author(s): Cao, HB (Cao, Huabao); Nagymihaly, RS (Nagymihaly, Roland S.); Khodakovskiy, N (Khodakovskiy, Nikita); Pajer, V (Pajer, Viktor); Bohus, J (Bohus, Janos); Lopez-Martens, R (Lopez-Martens, Rodrigo); Borzsonyi, A (Borzsonyi, Adam); Kalashnikov, M (Kalashnikov, Mikhail) | ||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 4 Pages: 5915-5922 DOI: 10.1364/OE.416201 Published: FEB 15 2021 | ||||||||||||
Abstract: We experimentally demonstrate the post-compression of radially polarized 25 fs pulses at 800 nm central wavelength in a multiple thin plate arrangement for the first time, to the best of our knowledge. Sub-7 fs pulses with 90 mu J energy were obtained after dispersion compensation, corresponding to a compression factor of more than 3.5. Preservation of radial polarization state was confirmed by polarized intensity distribution measurements. Linear projections of the radially polarized pulses were also fully characterized in the temporal domain. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | ||||||||||||
Accession Number: WOS:000619209800101 | ||||||||||||
PubMed ID: 33726123 | ||||||||||||
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ISSN: 1094-4087 |
Record 251 of 318 | |||||||||
Title: Corrigendum: Investigations on Average Fluorescence Lifetimes for Visualizing Multi-Exponential Decays (vol 8, 576862, 2020) | |||||||||
Author(s): Li, YH (Li, Yahui); Natakorn, S (Natakorn, Sapermsap); Chen, Y (Chen, Yu); Safar, M (Safar, Mohammed); Cunningham, M (Cunningham, Margaret); Tian, JS (Tian, Jinshou); Li, DDU (Li, David Day-Uei) | |||||||||
Source: FRONTIERS IN PHYSICS Volume: 8 Article Number: 637953 DOI: 10.3389/fphy.2020.637953 Published: FEB 15 2021 | |||||||||
Accession Number: WOS:000623322600001 | |||||||||
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ISSN: 2296-424X |
Record 252 of 318 | |||||||||||||||
Title: Extended field of view of light-sheet fluorescence microscopy by scanning multiple focus-shifted Gaussian beam arrays | |||||||||||||||
Author(s): Liu, C (Liu, Chao); Bai, C (Bai, Chen); Yu, XH (Yu, Xianghua); Yan, SH (Yan, Shaohui); Zhou, Y (Zhou, Yuan); Li, X (Li, Xing); Min, JW (Min, Junwei); Yang, YL (Yang, Yanlong); Dan, D (Dan, Dan); Yao, BL (Yao, Baoli) | |||||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 4 Pages: 6158-6168 DOI: 10.1364/OE.418707 Published: FEB 15 2021 | |||||||||||||||
Abstract: Light-sheet fluorescence microscopy (LSFM) facilitates high temporal-spatial resolution, low photobleaching and phototoxicity for long-term volumetric imaging. However, when a high axial resolution or optical sectioning capability is required, the field of view (FOV) is limited. Here, we propose to generate a large FOV of light-sheet by scanning multiple focus-shifted Gaussian beam arrays (MGBA) while keeping the high axial resolution. The positions of the beam waists of the multiple Gaussian beam arrays are shifted in both axial and lateral directions in an optimized arranged pattern, and then scanned along the direction perpendicular to the propagation axis to form an extended FOV of light-sheet. Complementary beam subtraction method is also adopted to further improve axial resolution. Compared with the single Gaussian light-sheet method, the proposed method extends the FOV from 12 mu m to 200 mu m while sustaining the axial resolution of 0.73 mu m. Both numerical simulation and experiment on samples are performed to verify the effectiveness of the method. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | |||||||||||||||
Accession Number: WOS:000619209800120 | |||||||||||||||
PubMed ID: 33726142 | |||||||||||||||
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ISSN: 1094-4087 |
Record 253 of 318 | ||||||
Title: Theoretical investigations of a modified compressed ultrafast photography method suitable for single-shot fluorescence lifetime imaging | ||||||
Author(s): Li, YH (Li, Yahui); Tian, JS (Tian, Jinshou); Li, DDU (Li, David Day-Uei) | ||||||
Source: APPLIED OPTICS Volume: 60 Issue: 5 Pages: 1476-1483 DOI: 10.1364/AO.415594 Published: FEB 10 2021 | ||||||
Abstract: A single-shot fluorescence lifetime imaging (FLIM) method based on the compressed ultrafast photography (CUP) is proposed, named space-restricted CUP (srCUP). srCUP is suitable for imaging objects moving slowly (<similar to 150/Mmm/s, M is the magnification of the objective lens) in the field of view with the intensity changing within nanoseconds in a measurement window around 10 ns. We used synthetic datasets to explore the performances of srCUP compared with CUP and TCUP (a variant of CUP). srCUP not only provides superior reconstruction performances, but its reconstruction speed is also twofold and threefold faster than CUP and TCUP, respectively. The lifetime determination performances were assessed by estimating lifetime components, amplitude- and intensity-weighted average lifetimes (tau(A) and tau(I)), with the reconstructed scenes using the least squares method based on a bi-exponential model. srCUP has the best accuracy and precision for lifetime determinations with a relative bias less than 7% and a coefficient of variation less than 7% for tau(A), and a relative bias less than 10% and a coefficient of variation less than 11% for tau(I). (C) 2021 Optical Society of America | ||||||
Accession Number: WOS:000617545500051 | ||||||
PubMed ID: 33690594 | ||||||
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ISSN: 1559-128X | ||||||
eISSN: 2155-3165 |
Record 254 of 318 | |||||||||
Title: Quantitative atmospheric rendering for real-time infrared scene simulation | |||||||||
Author(s): Wu, X (Wu, Xin); Zhang, C (Zhang, Chi); Huang, ML (Huang, Melin); Yang, C (Yang, Chen); Ding, GP (Ding, Guopeng) | |||||||||
Source: INFRARED PHYSICS & TECHNOLOGY Volume: 114 Article Number: 103610 DOI: 10.1016/j.infrared.2020.103610 Early Access Date: FEB 2021 Published: MAY 2021 | |||||||||
Abstract: The radiation transfer of the Earth?s atmosphere is a complex progress, which involves electromagnetic propagation, thermodynamics, and molecular spectroscopy. Atmospheric effects on an infrared scene were presented as transmission, absorption, and scattering. Atmospheric rendering thus aims to visually display these effects of the radiation through the Earth?s atmosphere. In this paper, a quantitative atmospheric rendering method was proposed for real-time infrared scene simulation. By counting the selective absorption of water, carbon dioxide, and ozone on an infrared spectrum, transmittance was calculated using Lambert?Beer?s law, the steady-state path radiation was precomputed according to Kirchhoff?s law, and the Rayleigh and Mie scattering effects were calculated with GPU when an infrared scene was rendered in real-time. Simulations were conducted to verify the performance of the proposed method by comparing our results with those obtained from the MODTRAN program. | |||||||||
Accession Number: WOS:000634635600003 | |||||||||
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ISSN: 1350-4495 | |||||||||
eISSN: 1879-0275 |
Record 255 of 318 | ||||||||||||
Title: High-performance solid-state photon-enhanced thermionic emission solar energy converters with graded bandgap window-layer | ||||||||||||
Author(s): Yang, Y (Yang, Yang); Xu, P (Xu, Peng); Cao, WW (Cao, Weiwei); Zhu, BL (Zhu, Bingli); Wang, B (Wang, Bo); Bai, YL (Bai, Yonglin); Qin, JJ (Qin, Junjun); Bai, XH (Bai, Xiaohong); Chen, Z (Chen, Zhen) | ||||||||||||
Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS Volume: 54 Issue: 5 Article Number: 055502 DOI: 10.1088/1361-6463/abbb04 Published: FEB 4 2021 | ||||||||||||
Abstract: To realize a high-performance solid-state photon-enhanced thermionic emission (SPETE) solar energy converter, in this study, a graded bandgap window layer is therefore adopted, throughout which the bandgap gradation is generated via the variation of Al composition in the AlxGa1-xAs layer in the SPETE converter with a GaAs absorber. Based on one-dimension steady-state equation, an analytical model is formed in analyzing performance of the proposed device in our study. Theoretical simulation results indicate that not only are the losses of contact surface recombination being decreased via the bandgap-gradation-induced build-in electric field of the window layer, but also the photon-generated electrons are effectively collected, thereby improving the conversion efficiency. Moreover, the effect of bandgap energy of the contact surface and the width of the window layer on device performance is discussed. A trade-off of high-efficient SPETE converters is therefore realized between large contact surface bandgap and thin window layer width, to which the rationale lies in the improved process of electron collection facilitated by the enhanced build-in electric field rather than reducing the photon absorption in the window layer. Threshold values for barrier height at the emitting interface are presented to guarantee the ideal voltage-current characteristic. It is found that the threshold values of barrier increase with the increase in temperatures. | ||||||||||||
Accession Number: WOS:000589880400001 | ||||||||||||
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ISSN: 0022-3727 | ||||||||||||
eISSN: 1361-6463 |
Record 256 of 318 | |||||||||||||||
Title: Stable and oscillating solitons of <i>PT</i>-symmetric couplers with gain and loss in fractional dimension | |||||||||||||||
Author(s): Zeng, LW (Zeng, Liangwei); Shi, JC (Shi, Jincheng); Lu, XW (Lu, Xiaowei); Cai, Y (Cai, Yi); Zhu, QF (Zhu, Qifan); Chen, HY (Chen, Hongyi); Long, H (Long, Hu); Li, JZ (Li, Jingzhen) | |||||||||||||||
Source: NONLINEAR DYNAMICS Volume: 103 Issue: 2 Pages: 1831-1840 DOI: 10.1007/s11071-020-06180-7 Early Access Date: FEB 2021 Published: JAN 2021 | |||||||||||||||
Abstract: Families of coupled solitons of PT-symmetric physical models with gain and loss in fractional dimension and in settings with and without cross-interactions modulation (CIM) are reported. Profiles, powers, stability areas, and propagation dynamics of the obtained PT-symmetric coupled solitons are investigated. By comparing the results of the models with and without CIM, we find that the stability area of the model with CIM is much broader than the one without CIM. Remarkably, oscillating PT-symmetric coupled solitons can also exist in the model of CIM with the same coefficients of the self- and cross-interactions modulations. In addition, the period of these oscillating coupled solitons can be controlled by the linear coupling coefficient. | |||||||||||||||
Accession Number: WOS:000614687200004 | |||||||||||||||
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ISSN: 0924-090X | |||||||||||||||
eISSN: 1573-269X |
Record 257 of 318 | ||||||
Title: Optimization of the focusing characteristics of Fresnel zone plates fabricated with a femtosecond laser | ||||||
Author(s): Zhou, F (Zhou, Fang); Sun, XY (Sun, Xiaoyan); Zhong, HM (Zhong, Hongmin); Duan, L (Duan, Lian); Hu, YW (Hu, Youwang); Duan, J (Duan, Ji'an); Li, M (Li, Ming) | ||||||
Source: JOURNAL OF MODERN OPTICS Volume: 68 Issue: 2 Pages: 100-107 DOI: 10.1080/09500340.2021.1879300 Early Access Date: FEB 2021 Published: JAN 19 2021 | ||||||
Abstract: In this research, amplitude Fresnel zone plates (FZPs) were fabricated on fused silica glass with femtosecond laser. The focusing characteristics including focal length, diffraction efficiency, geometric concentrator ratio, spot energy uniformity, depth of focus and resolution were studied by simulations and experiments. To optimize the focusing characteristics of FZP, we proposed an optimized machining process, an extended FZP and an fractal FZP. The optimized machining process increased the diffraction efficiency of the amplitude FZP from 6.96% to 8.14%, the extended FZP broke through the limit of minimum line width in processing and improved the resolution, and the fractal FZP increased the focus depth from 4 mm to 10 mm. In addition, we wrote a FZP on the end face of multi mode fiber, the divergent annular beam converged and formed an focus ring at the focal plane. This research will provide broad applications in fiber tweezers, beam coupling and optical communication. | ||||||
Accession Number: WOS:000614500900001 | ||||||
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ISSN: 0950-0340 | ||||||
eISSN: 1362-3044 |
Record 258 of 318 | |||||||||||||||
Title: A New Robust Adaptive Fusion Method for Double-Modality Medical Image PET/CT | |||||||||||||||
Author(s): Zhou, T (Zhou, Tao); Lu, HL (Lu, Huiling); Hu, FY (Hu, Fuyuan); Shi, HB (Shi, Hongbin); Qiu, S (Qiu, Shi); Wang, HQ (Wang, Huiqun) | |||||||||||||||
Source: BIOMED RESEARCH INTERNATIONAL Volume: 2021 Article Number: 8824395 DOI: 10.1155/2021/8824395 Published: FEB 4 2021 | |||||||||||||||
Abstract: A new robust adaptive fusion method for double-modality medical image PET/CT is proposed according to the Piella framework. The algorithm consists of the following three steps. Firstly, the registered PET and CT images are decomposed using the nonsubsampled contourlet transform (NSCT). Secondly, in order to highlight the lesions of the low-frequency image, low-frequency components are fused by pulse-coupled neural network (PCNN) that has a higher sensitivity to featured area with low intensities. With regard to high-frequency subbands, the Gauss random matrix is used for compression measurements, histogram distance between the every two corresponding subblocks of high coefficient is employed as match measure, and regional energy is used as activity measure. The fusion factor d is then calculated by using the match measure and the activity measure. The high-frequency measurement value is fused according to the fusion factor, and high-frequency fusion image is reconstructed by using the orthogonal matching pursuit algorithm of the high-frequency measurement after fusion. Thirdly, the final image is acquired through the NSCT inverse transformation of the low-frequency fusion image and the reconstructed high-frequency fusion image. To validate the proposed algorithm, four comparative experiments were performed: comparative experiment with other image fusion algorithms, comparison of different activity measures, different match measures, and PET/CT fusion results of lung cancer (20 groups). The experimental results showed that the proposed algorithm could better retain and show the lesion information, and is superior to other fusion algorithms based on both the subjective and objective evaluations. | |||||||||||||||
Accession Number: WOS:000620154800007 | |||||||||||||||
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ISSN: 2314-6133 | |||||||||||||||
eISSN: 2314-6141 |
Record 259 of 318 | ||||||||||||
Title: Novel Method Based on Hollow Laser Trapping-LIBS-Machine Learning for Simultaneous Quantitative Analysis of Multiple Metal Elements in a Single Microsized Particle in Air | ||||||||||||
Author(s): Niu, C (Niu, Chen); Cheng, XM (Cheng, Xuemei); Zhang, TL (Zhang, Tianlong); Wang, X (Wang, Xing); He, B (He, Bo); Zhang, WD (Zhang, Wending); Feng, YZ (Feng, Yaozhou); Bai, JT (Bai, Jintao); Li, H (Li, Hua) | ||||||||||||
Source: ANALYTICAL CHEMISTRY Volume: 93 Issue: 4 Pages: 2281-2290 DOI: 10.1021/acs.analchem.0c04155 Published: FEB 2 2021 | ||||||||||||
Abstract: Elemental identification of individual microsized aerosol particles is an important topic in air pollution studies. However, simultaneous and quantitative analysis of multiple constituents in a single aerosol particle with the noncontact in situ manner is still a challenging task. In this work, we explore the laser trapping-LIBS-machine learning to analyze four elements (Zn, Ni, Cu, and Cr) absorbed in a single micro-carbon black particle in air. By employing a hollow laser beam for trapping, the particle can be restricted in a range as small as similar to 1.72 mu m, which is much smaller than the focal diameter of the flat-topped LIBS exciting laser (similar to 20 mu m). Therefore, the particle can be entirely and homogeneously radiated, and the LIBS spectrum with a high signal-to-noise ratio (SNR) is correspondingly achieved. Then, two types of calibration models, i.e., the univariate method (calibration curve) and the multivariate calibration method (random forests (RF) regression), are employed for data processing. The results indicate that the RF calibration model shows a better prediction performance. The mean relative error (MRE), relative standard deviation (RSD), and root-mean-squared error (RMSE) are reduced from 0.1854, 363.7, and 434.7 to 0.0866, 179.8, and 216.2 ppm, respectively. Finally, simultaneous and quantitative determination of the four metal contents with high accuracy is realized based on the RF model. The method proposed in this work has the potential for online single aerosol particle analysis and further provides a theoretical basis and technical support for the precise prevention and control of composite air pollution. | ||||||||||||
Accession Number: WOS:000618089100050 | ||||||||||||
PubMed ID: 33401900 | ||||||||||||
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ISSN: 0003-2700 | ||||||||||||
eISSN: 1520-6882 |
Record 260 of 318 |
Title: Multi-scale joint network based on Retinex theory for low-light enhancement |
Author(s): Song, XJ (Song, Xijuan); Huang, JJ (Huang, Jijiang); Cao, JZ (Cao, Jianzhong); Song, DW (Song, Dawei) |
Source: SIGNAL IMAGE AND VIDEO PROCESSING Volume: 15 Issue: 6 Pages: 1257-1264 DOI: 10.1007/s11760-021-01856-y Early Access Date: FEB 2021 Published: SEP 2021 |
Abstract: Due to the limitations of devices, images taken in low-light environments are of low contrast and high noise without any manual intervention. Such images will affect the visual experience and hinder further visual processing tasks, such as target detection and target tracking. To alleviate this issue, we propose a multi-scale joint low-light enhancement network based on the Retinex theory. The network consists of a decomposition part and an enhancement part. As a joint network, the decomposition and enhancement parts are mutually constrained, and the parameters are updated at the same time so that the image processing results are more excellent in detail. Our algorithm avoids the separation and recombination of decomposition and enhancement. Therefore, less information is lost in the processing of low-light images, and the enhancement result of the proposed algorithm is very close to the ground truth. In addition, in the enhancement part, we adopt a multi-scale network to fully extract image features. The multi-scale network maintains a balance between the global and local luminance of the illumination image. Retinex theory can effectively solve the problem of noise amplification and color distortion. At the same time, we have added color loss to solve the problem of color distortion, so that the enhancement result is closer to the normal-light image in color. The enhancement results are intuitively excellent, and the peak signal-to-noise ratio and structural similarity index results also reflect the reliability of the algorithm. |
Accession Number: WOS:000613979300001 |
ISSN: 1863-1703 |
eISSN: 1863-1711 |
Record 261 of 318 | |||||||||||||||||||||
Title: Localized gap modes of coherently trapped atoms in an optical lattice | |||||||||||||||||||||
Author(s): Chen, ZM (Chen, Zhiming); Zeng, JH (Zeng, Jianhua) | |||||||||||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 3 Pages: 3011-3025 DOI: 10.1364/OE.412554 Published: FEB 1 2021 | |||||||||||||||||||||
Abstract: We theoretically investigate one-dimensional localized gap modes in a coherent atomic gas where an optical lattice is formed by a pair of counterpropagating far-detuned Stark laser fields. The atomic ensembles under study emerge as Lambda-type three-level configuration accompanying the effect of electromagnetically induced transparency (EIT). Based on Maxwell-Bloch equations and the multiple scales method, we derive a nonlinear equation governing the spatial-temporal evolution of the probe-field envelope. We then uncover the formation and properties of optical localized gap modes of two kinds, such as the fundamental gap solitons and dipole gap modes. Furthermore, we confirm the (in)stability regions of both localized gap modes in the respective band-gap spectrum with systematic numerical simulations relying on linear-stability analysis and direct perturbed propagation. The predicted results may enrich the nonlinear horizon to the realm of coherent atomic gases and open up a new door for optical communication and information processing. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | |||||||||||||||||||||
Accession Number: WOS:000614617700006 | |||||||||||||||||||||
PubMed ID: 33770909 | |||||||||||||||||||||
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ISSN: 1094-4087 |
Record 262 of 318 |
Title: The dual-injection Ge-on-Si photodetectors with high saturation power by optimizing light field distribution |
Author(s): Cui, JS (Cui, Jishi); Li, TT (Li, Tiantian); Yang, FH (Yang, Fenghe); Cui, WJ (Cui, Wenjing); Chen, HM (Chen, Hongmin) |
Source: OPTICS COMMUNICATIONS Volume: 480 Article Number: 126467 DOI: 10.1016/j.optcom.2020.126467 Published: FEB 1 2021 |
Abstract: In this work, we put forward the length design principle of the dual-injection integrated Ge-on-Si photodetectors based on the characteristics of the light field distribution. When the length of the absorption layer makes the maximum intensity of the incident light from both ends are alternately distributed, the light field distribution is more uniform. Based on this principle, the shorter photodetector could get better saturation performance. Two dual-injection photodetectors with the length of 6 mu m and 10 mu m have been investigated, the experimental results show that the saturation current of 6 mu m length device is 18.33% higher, and the bandwidth is 138.60% higher at 10 mW incident power comparing with the 10 mu m length device. The 6 mu m length photodetector realized a responsivity of 1.07 A/W, a bandwidth of 37.3 GHz at 50 mu W luminous power @1550 nm. |
Accession Number: WOS:000588332200013 |
ISSN: 0030-4018 |
eISSN: 1873-0310 |
Record 263 of 318 | ||||||||||||||||||
Title: Rapid Image Reconstruction of Structured Illumination Microscopy Directly in the Spatial Domain | ||||||||||||||||||
Author(s): Dan, D (Dan, Dan); Wang, ZJ (Wang, Zhaojun); Zhou, X (Zhou, Xing); Lei, M (Lei, Ming); Zhao, TY (Zhao, Tianyu); Qian, J (Qian, Jia); Yu, XH (Yu, Xianghua); Yan, SH (Yan, Shaohui); Min, JW (Min, Junwei); Bianco, P (Bianco, Piero); Yao, BL (Yao, Baoli) | ||||||||||||||||||
Source: IEEE PHOTONICS JOURNAL Volume: 13 Issue: 1 Article Number: 3900411 DOI: 10.1109/JPHOT.2021.3053110 Published: FEB 2021 | ||||||||||||||||||
Abstract: Super-resolution structured illumination microscopy (SIM) routinely performs image reconstruction in the frequency domain using an approach termed frequency-domain reconstruction (FDR). Due to multiple Fourier transforms between the spatial and frequency domains, SIM suffers from low reconstruction speed, constraining its applications in real-time, dynamic imaging. To overcome this limitation, we developed a new method for SIM image reconstruction, termed spatial domain reconstruction (SDR). SDR is intrinsically simpler than FDR, does not require Fourier transforms and the theory predicts it to be a rapid image reconstruction method. Results show that SDR reconstructs a super-resolution image 7-fold faster than FDR, producing images that are equal to either FDR or the widely-used FairSIM. We provide a proof-of-principle using mobile fluorescent beads to demonstrate the utility of SDR in imaging moving objects. Consequently, replacement of the FDR approach with SDR significantly enhances SIM as the desired method for live-cell, instant super-resolution imaging. This means that SDR-SIM is a "What You See Is What You Get" approach to super-resolution imaging. | ||||||||||||||||||
Accession Number: WOS:000617366600006 | ||||||||||||||||||
PubMed ID: 33880138 | ||||||||||||||||||
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ISSN: 1943-0655 | ||||||||||||||||||
eISSN: 1943-0647 |
Record 264 of 318 |
Title: Small Moving Target Recognition in Star Image with TRM |
Author(s): Du, Y (Du, Yun); Wen, DS (Wen, Desheng); Liu, GZ (Liu, Guizhong); Qiu, S (Qiu, Shi) |
Source: INTERNATIONAL JOURNAL OF PATTERN RECOGNITION AND ARTIFICIAL INTELLIGENCE Volume: 35 Issue: 2 Article Number: 2150004 DOI: 10.1142/S021800142150004X Published: FEB 2021 |
Abstract: Recognition of small moving targets in space has become one of the frontier scientific researches in recent decade. Most of them focus on detection and recognition in star image with sidereal stare mode. However, in this research field, few researches are about detection and recognition in star image with track rate mode. In this paper, a novel approach is proposed to recognize the moving target in single frame by machine learning method based on elliptical characteristic extraction of star points. The technical path about recognition of moving target in space is redesigned instead of traditional processing approaches. Elliptical characteristics of each star point can be successfully extracted from single image. Machine learning can achieve the classification goal in order to make sure that all moving targets can be extracted. The experiments show that our proposed approach can have better performance in star images with different qualities. |
Accession Number: WOS:000627311000014 |
ISSN: 0218-0014 |
eISSN: 1793-6381 |
Record 265 of 318 | ||||||
Title: High-speed focusing and scanning light through a multimode fiber based on binary phase-only spatial light modulation | ||||||
Author(s): Geng, Y (Geng, Yi); Chen, H (Chen, Hui); Zhang, ZK (Zhang, Zaikun); Zhuang, B (Zhuang, Bin); Guo, HT (Guo, Haitao); He, ZQ (He, Zhengquan); Kong, DP (Kong, Depeng) | ||||||
Source: APPLIED PHYSICS B-LASERS AND OPTICS Volume: 127 Issue: 2 Article Number: 25 DOI: 10.1007/s00340-021-07573-1 Published: FEB 2021 | ||||||
Abstract: A binary phase-only modulation technique was proposed to focus and scan light through a multimode fiber (MMF) based on spatial light modulator (SLM). For the same number of modulation modes, the number of iterations using this method is only 1/256 of that using phase-only iterative optimization or 1/3 of that using phase-only computation optimization, and the modulation time is at least one to two orders of magnitude shorter than previous wavefront shaping systems. Focusing and scanning light through an MMF with a 105 mu m core diameter and 5 m length was achieved experimentally. This method can be extended to focus and scan light at multiple planes along the axial direction by modifying the input wavefront accordingly. | ||||||
Accession Number: WOS:000613223500001 | ||||||
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ISSN: 0946-2171 | ||||||
eISSN: 1432-0649 |
Record 266 of 318 |
Title: Peregrine combs and rogue waves on a bright soliton background |
Author(s): Guo, LH (Guo, Lehui); Chen, P (Chen, Ping); Tian, JS (Tian, Jinshou) |
Source: OPTIK Volume: 227 Article Number: 165455 DOI: 10.1016/j.ijleo.2020.165455 Published: FEB 2021 |
Abstract: The dynamics of the modulation rogue waves in an inhomogeneous nonlinear optical fiber with the periodic modulation are studied. We find that for different modulation amplitudes and modulation frequencies, the modulation rogue wave solution can be Peregrine comb, rogue wave, or the transition state in between, respectively. In particular, the phase diagram of the three kinds of nonlinear states is given at the modulation amplitude and modulation frequency plane. Moreover, the dynamics characteristics of the Peregrine comb and the rogue wave are discussed on the localized soliton background. It is interesting that the main excitation characteristics of the Peregrine combs and the rogue waves on an infinitely wide plane wave background are well maintained on the soliton background. These results pave the way for exciting and manipulating the rogue waves on a local background. |
Accession Number: WOS:000651297900009 |
ISSN: 0030-4026 |
eISSN: 1618-1336 |
Record 267 of 318 | |||||||||||||||||||||||||||
Title: Optical design and simulation of Einstein Probe satellite follow-up x-ray telescope | |||||||||||||||||||||||||||
Author(s): Li, MS (Li, Maoshun); Zhu, YX (Zhu, Yuxuan); Lu, JB (Lu, Jingbin); Yang, YJ (Yang, Yangji); Cong, M (Cong, Min); Sheng, LZ (Sheng, Lizhi); Qiang, PF (Qiang, Pengfei); Cui, WW (Cui, Weiwei); Zhang, ZL (Zhang, Ziliang); Wang, YS (Wang, Yusa); Han, DW (Han, Dawei); Li, W (Li, Wei); Wang, J (Wang, Juan); Huo, J (Huo, Jia); Zhao, XF (Zhao, Xiaofan); Yu, N (Yu, Nian); Song, ZY (Song, Zeyu); Ma, J (Ma, Jia); Lv, ZH (Lv, Zhonghua); Zhao, ZJ (Zhao, Zijian); Wang, H (Wang, Hao); Hou, DJ (Hou, Dongjie); Chen, C (Chen, Can); Chen, TX (Chen, Tianxiang); Yang, XT (Yang, Xiongtao); Luo, LD (Luo, Laidan); Lu, B (Lu, Bing); Xu, JJ (Xu, Jingjing); Chen, YH (Chen, Yehai); Chen, Y (Chen, Yong) | |||||||||||||||||||||||||||
Source: OPTICAL ENGINEERING Volume: 60 Issue: 2 Article Number: 025102 DOI: 10.1117/1.OE.60.2.025102 Published: FEB 2021 | |||||||||||||||||||||||||||
Abstract: The Follow-up X-ray Telescope (FXT), a key payload onboard the Einstein Probe sallite (EP), is equipped with a Wolter-I x-ray focusing mirror system. We introduce the principle of such a mirror system and analyze the influence of the mirror gap in the multishell nested mirror of the FXT on the effective area, stray-light ratio, and vignetting. To ensure that no occlusion occurs within adjacent shells and minimize stray-light ratio, the size of the gap is set to a optimized value for corresponding shell. We finished a design of a 54-shell mirror system according to these results. The optical performance of the design was then simulated using a Monte Carlo algorithm and the ray-tracing principle. The simulation shows that the effective area is 414.5 +/- 0.2 cm(2) at 1.25 keV (considering the spider), and the field of view is 64 arcmin in diameter. These parameters meet the optical requirements of the FXT. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE) | |||||||||||||||||||||||||||
Accession Number: WOS:000625363000019 | |||||||||||||||||||||||||||
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ISSN: 0091-3286 | |||||||||||||||||||||||||||
eISSN: 1560-2303 |
Record 268 of 318 | ||||||||||||
Title: Vision-to-Language Tasks Based on Attributes and Attention Mechanism | ||||||||||||
Author(s): Li, XL (Li, Xuelong); Yuan, AH (Yuan, Aihong); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||
Source: IEEE TRANSACTIONS ON CYBERNETICS Volume: 51 Issue: 2 Pages: 913-926 DOI: 10.1109/TCYB.2019.2914351 Published: FEB 2021 | ||||||||||||
Abstract: Vision-to-language tasks aim to integrate computer vision and natural language processing together, which has attracted the attention of many researchers. For typical approaches, they encode image into feature representations and decode it into natural language sentences. While they neglect high-level semantic concepts and subtle relationships between image regions and natural language elements. To make full use of these information, this paper attempt to exploit the text-guided attention and semantic-guided attention (SA) to find the more correlated spatial information and reduce the semantic gap between vision and language. Our method includes two-level attention networks. One is the text-guided attention network which is used to select the text-related regions. The other is SA network which is used to highlight the concept-related regions and the region-related concepts. At last, all these information are incorporated to generate captions or answers. Practically, image captioning and visual question answering experiments have been carried out, and the experimental results have shown the excellent performance of the proposed approach. | ||||||||||||
Accession Number: WOS:000608690900036 | ||||||||||||
PubMed ID: 31107679 | ||||||||||||
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ISSN: 2168-2267 | ||||||||||||
eISSN: 2168-2275 |
Record 269 of 318 | |||||||||
Title: Pixel-wise ordinal classification for salient object grading | |||||||||
Author(s): Liu, YZ (Liu, Yanzhu); Wang, YN (Wang, Yanan); Kong, AWK (Kong, Adams Wai Kin) | |||||||||
Source: IMAGE AND VISION COMPUTING Volume: 106 Article Number: 104086 DOI: 10.1016/j.imavis.2020.104086 Published: FEB 2021 | |||||||||
Abstract: Driven by business intelligence applications for rating attraction of products in shops, a new problem - salient object grading is studied in this paper. In computer vision, plenty of salient object detection approaches have been proposed, while most existing studies detect objects in a binary manner: salient or not. This paper focuses on a new problem setting that requires detecting all salient objects and categorizing them into different salient levels. Based on that, a pixel-wise ordinal classification method is proposed. It consists of a multi-resolution saliency detector which detects and segments objects, an ordinal classifier which grades pixels into different salient levels, and a binary saliency enhancer which sharpens the difference between non-saliency and all other salient levels. Two new image datasets with salient level labels are constructed. Experimental results demonstrate that, on the one hand, the proposed method provides effective salient level predictions and on the other hand, offers very comparable performance with state-of-the-art salient object detection methods in the traditional problem setting. (C) 2020 Elsevier B.V. All rights reserved. | |||||||||
Accession Number: WOS:000620292700002 | |||||||||
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ISSN: 0262-8856 | |||||||||
eISSN: 1872-8138 |
Record 270 of 318 |
Title: Data Augmentation and Spectral Structure Features for Limited Samples Hyperspectral Classification |
Author(s): Wang, WN (Wang, Wenning); Liu, XB (Liu, Xuebin); Mou, XQ (Mou, Xuanqin) |
Source: REMOTE SENSING Volume: 13 Issue: 4 Article Number: 547 DOI: 10.3390/rs13040547 Published: FEB 2021 |
Abstract: For both traditional classification and current popular deep learning methods, the limited sample classification problem is very challenging, and the lack of samples is an important factor affecting the classification performance. Our work includes two aspects. First, the unsupervised data augmentation for all hyperspectral samples not only improves the classification accuracy greatly with the newly added training samples, but also further improves the classification accuracy of the classifier by optimizing the augmented test samples. Second, an effective spectral structure extraction method is designed, and the effective spectral structure features have a better classification accuracy than the true spectral features. |
Accession Number: WOS:000624451200001 |
eISSN: 2072-4292 |
Record 271 of 318 | |||||||||||||||||||||||||||
Title: Optical spectroscopic characterizations of laser irradiated olivine grains (vol 597, A50, 2017) | |||||||||||||||||||||||||||
Author(s): Yang, YZ (Yang, Yazhou); Zhang, H (Zhang, Hao); Wang, ZW (Wang, Ziwei); Yuan, Y (Yuan, Ye); Li, SL (Li, Shaolin); Hsu, WB (Hsu, Weibiao); Liu, CJ (Liu, Chujian) | |||||||||||||||||||||||||||
Source: ASTRONOMY & ASTROPHYSICS Volume: 646 Article Number: C1 DOI: 10.1051/0004-6361/201629327e Published: FEB 1 2021 | |||||||||||||||||||||||||||
Accession Number: WOS:000616489400001 | |||||||||||||||||||||||||||
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ISSN: 0004-6361 | |||||||||||||||||||||||||||
eISSN: 1432-0746 |
Record 272 of 318 | ||||||||||||
Title: Low loss and polarization-insensitive coupling length for a terahertz fiber directional coupler with symmetric dual-suspended core structure | ||||||||||||
Author(s): Zhu, YF (Zhu, Yuan-Feng); Huang, X (Huang, Xu); Ke, Q (Ke, Qiang); Liu, GQ (Liu, Guiqiang); Rao, CF (Rao, Chun-Fang); Kong, DP (Kong, Depeng); Mei, S (Mei, Sen); Liu, YQ (Liu, Yunqi); Wang, H (Wang, Hua) | ||||||||||||
Source: OPTICS COMMUNICATIONS Volume: 480 Article Number: 126497 DOI: 10.1016/j.optcom.2020.126497 Published: FEB 1 2021 | ||||||||||||
Abstract: In this work, a terahertz (THz) fiber directional coupler with a symmetric dual-suspended core structure has been proposed for realizing low loss and polarization-insensitive coupling length in the THz frequency region. The fiber core of the directional coupler consists of two round solid dielectric rods supported by two intersecting thin dielectric layers. Numerical simulations performed using the full-vector finite element method show that a short polarization-independent coupling length can be obtained by adjusting the geometric parameters of the fiber. Moreover, a low-loss THz fiber directional coupling performance can also be achieved at a central frequency of 1.00-THz and approximately 0.16 THz of bandwidth. For example, a coupler with a length of 0.421 cm has a transmission loss of 0.30 dB and 0.26 dB for the xand y-polarization modes, respectively. | ||||||||||||
Accession Number: WOS:000588332800011 | ||||||||||||
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ISSN: 0030-4018 | ||||||||||||
eISSN: 1873-0310 |
Record 273 of 318 | |||||||||||||||||||||
Title: In situ lunar phase curves measured by Chang'E-4 in the Von Karman Crater, South Pole-Aitken basin | |||||||||||||||||||||
Author(s): Jiang, T (Jiang, Te); Hu, XY (Hu, Xiaoyi); Zhang, H (Zhang, Hao); Ma, P (Ma, Pei); Li, CL (Li, Chunlai); Ren, X (Ren, Xin); Liu, B (Liu, Bin); Liu, DW (Liu, Dawei); Yang, JF (Yang, Jianfeng); Xue, B (Xue, Bin); Jin, WD (Jin, Weidong); Zhu, MH (Zhu, Meng-Hua); Huang, CN (Huang, Changning); Lin, HY (Lin, Hongyu) | |||||||||||||||||||||
Source: ASTRONOMY & ASTROPHYSICS Volume: 646 Article Number: A2 DOI: 10.1051/0004-6361/202039252 Published: JAN 29 2021 | |||||||||||||||||||||
Abstract: Context. The Yutu-2 rover of the Chang'E-4 (CE-4) mission measured the lunar phase curves in the Von Karman crater, South Pole-Aitken basin. | |||||||||||||||||||||
Accession Number: WOS:000615916800001 | |||||||||||||||||||||
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ISSN: 0004-6361 | |||||||||||||||||||||
eISSN: 1432-0746 |
Record 274 of 318 | |||||||||||||||||||||
Title: Generation and Conversion Dynamics of Dual Bessel Beams with a Photonic Spin-Dependent Dielectric Metasurface | |||||||||||||||||||||
Author(s): Li, TY (Li, Tianyue); Li, XY (Li, Xingyi); Yan, SH (Yan, Shaohui); Xu, XH (Xu, Xiaohao); Wang, SM (Wang, Shuming); Yao, BL (Yao, Baoli); Wang, ZL (Wang, Zhenlin); Zhu, SN (Zhu, Shining) | |||||||||||||||||||||
Source: PHYSICAL REVIEW APPLIED Volume: 15 Issue: 1 Article Number: 014059 DOI: 10.1103/PhysRevApplied.15.014059 Published: JAN 29 2021 | |||||||||||||||||||||
Abstract: A Bessel beam has the properties of propagation invariance and a self-healing effect, leading to a variety of interesting phenomena and applications. Recently, as a planar diffractive element with miniaturized size, metasurfaces are widely employed to manipulate light in the subwavelength region, including generating a Bessel beam. However, such a metasurface-generated Bessel beam allows output light with no tunable functions. Here, with the interplay of the geometric phase and the dynamic phase, we propose a method to generate and allow conversion from any orthogonal polarizations to independent Bessel beams with a single-layer dielectric metasurface. The simulation results indicate that the arbitrary conversion between different Bessel beams is related to the spin-dependent orbit motion caused by the tight-focusing effect, leading to the singularity of the spot. This physical mechanism is well studied and the theoretical model for revealing the dependence of different incident polarization on the conversion dynamics is presented. Our approach paves a way for efficient generation and multifunctional applications, ranging from high-numerical-aperture devices to compact nanophotonic platforms for spin-dependent structured beams. | |||||||||||||||||||||
Accession Number: WOS:000613148600001 | |||||||||||||||||||||
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ISSN: 2331-7019 |
Record 275 of 318 | ||||||
Title: The mutual influence between rare earth element doping and femtosecond laser-induced effects in Ga-As-Sb-S chalcogenide glass | ||||||
Author(s): Liu, LT (Liu, Lutao); Chen, FY (Chen, Fengyi); Cui, J (Cui, Jian); Xiao, XS (Xiao, Xusheng); Xu, YT (Xu, Yantao); Hou, CQ (Hou, Chaoqi); Cui, XX (Cui, Xiaoxia); Guo, HT (Guo, Haitao) | ||||||
Source: CERAMICS INTERNATIONAL Volume: 47 Issue: 5 Pages: 6388-6396 DOI: 10.1016/j.ceramint.2020.10.219 Early Access Date: JAN 2021 Published: MAR 1 2021 | ||||||
Abstract: Femtosecond laser-induced damage thresholds (LIDTs) of Ga0.8As29.2Sb10S60 glasses doped with gradient Tm3+ concentrations and the effects of laser-induced damage on the glass' luminescence properties were studied in this work. Tm3+ doping in the glass considerably decreased the LIDT, from 3394.8 to 1881.8 mJ/cm(2), when the Tm3+ concentration increased from 0 to 5000 ppmw. This was related to the absorption of Tm3+ around the femtosecond laser's wavelength and microstructural changes caused by the Tm3+ doping. On the other hand, the femtosecond laser changed the glass matrix's elemental distribution and microstructure. Although the laser damaged the glass, the luminescence properties were barely affected. Based on the changes, femtosecond laser damage mechanism of chalcogenide glass doped with rare earth element was firstly proposed. | ||||||
Accession Number: WOS:000615233200004 | ||||||
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ISSN: 0272-8842 | ||||||
eISSN: 1873-3956 |
Record 276 of 318 | ||||||||||||||||||
Title: Audio description from image by modal translation network | ||||||||||||||||||
Author(s): Ning, HL (Ning, Hailong); Zheng, XT (Zheng, Xiangtao); Yuan, Y (Yuan, Yuan); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||||||||
Source: NEUROCOMPUTING Volume: 423 Pages: 124-134 DOI: 10.1016/j.neucom.2020.10.053 Published: JAN 29 2021 | ||||||||||||||||||
Abstract: Audio is the main form for the visually impaired to obtain information. In reality, all kinds of visual data always exist, but audio data does not exist in many cases. In order to help the visually impaired people to better perceive the information around them, an image-to-audio-description (I2AD) task is proposed to generate audio descriptions from images in this paper. To complete this totally new task, a modal translation network (MT-Net) from visual to auditory sense is proposed. The proposed MT-Net includes three progressive sub-networks: 1) feature learning, 2) cross-modal mapping, and 3) audio generation. First, the feature learning sub-network aims to learn semantic features from image and audio, including image feature learning and audio feature learning. Second, the cross-modal mapping sub-network transforms the image feature into a cross-modal representation with the same semantic concept as the audio feature. In this way, the correlation of inter-modal data is effectively mined for easing the heterogeneous gap between image and audio. Finally, the audio generation sub-network is designed to generate the audio waveform from the cross-modal representation. The generated audio waveform is interpolated to obtain the corresponding audio file according to the sample frequency. Being the first attempt to explore the I2AD task, three large-scale datasets with plenty of manual audio descriptions are built. Experiments on the datasets verify the feasibility of generating intelligible audio from an image directly and the effectiveness of proposed method. (c) 2020 Elsevier B.V. All rights reserved. | ||||||||||||||||||
Accession Number: WOS:000599837600012 | ||||||||||||||||||
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ISSN: 0925-2312 | ||||||||||||||||||
eISSN: 1872-8286 |
Record 277 of 318 | ||||||||||||||||||
Title: Determination of the photoemission position in single-photon ionization with attosecond streaking spectroscopy | ||||||||||||||||||
Author(s): Wang, F (Wang, Feng); Liao, Q (Liao, Qing); Liu, K (Liu, Kai); Qin, MY (Qin, Meiyan); Zhang, XF (Zhang, Xiaofan); Zhang, QB (Zhang, Qingbin); Cao, W (Cao, Wei); Pi, LW (Pi, Liang-Wen); Zhou, YM (Zhou, Yueming); Lu, PX (Lu, Peixiang) | ||||||||||||||||||
Source: PHYSICAL REVIEW A Volume: 103 Issue: 1 Article Number: 013115 DOI: 10.1103/PhysRevA.103.013115 Published: JAN 29 2021 | ||||||||||||||||||
Abstract: Attosecond metrology can directly measure attosecond emission time of photoexcited electrons from matter, providing unprecedented understanding of transition processes of electrons from bound to continuum states. However, some fundamental details of the electron dynamics in the entire emission process upon photoexcitation still remain debatable or unknown. The photoemission time delays deduced from attosecond streaking spectroscopy originate from photoelectron propagation in the coupled Coulomb-laser fields, encoding the spatial and spectral information of electrons upon photoexcitation. Here we demonstrate that attosecond photoemission delays can be used to image picometer-resolved photoemission position via a classical model. The electronic dynamics in the laser-assisted single-photon ionization process is fully captured by a quantum path-integral model. We trace the imaged photoemission position to the average position of spatially coherent superposition of electron waves upon photoexcitation and, in particular, predict emission position coinciding with the orbital radius of the ground state of hydrogen-like atoms, in contrast with previous predictions. | ||||||||||||||||||
Accession Number: WOS:000613140400006 | ||||||||||||||||||
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ISSN: 2469-9926 | ||||||||||||||||||
eISSN: 2469-9934 |
Record 278 of 318 | |||||||||
Title: Tunable all-optical AND logic gates via four-wave mixing based on graphene-on-silicon slot microring resonators | |||||||||
Author(s): Wu, W (Wu, Wei); Sun, QB (Sun, Qibing); Wang, GX (Wang, Guoxi); Zhang, LX (Zhang, Lingxuan); Zhao, W (Zhao, Wei) | |||||||||
Source: OPTICS AND LASER TECHNOLOGY Volume: 138 Article Number: 106926 DOI: 10.1016/j.optlastec.2021.106926 Early Access Date: JAN 2021 Published: JUN 2021 | |||||||||
Abstract: We propose a novel graphene-on-silicon organic hybrid slot microring resonator (GSHMIR) for tunable all-optical logic gates, which could offer broadband ultra-flattened dispersion with multiple zero-dispersion wavelengths (ZDWs) and high nonlinearity coefficient of 1.67 x 10(4) W(-1)m(-1). Further investigations on temporal evolution dynamics for all-optical logic function suggest that the third-order dispersion will induce the temporal drift and tail oscillation of output pulses. The tunable all-optical AND logic function over the wavelength range from 1536 nm to 1569 nm could be obtained for 40 Gb/s signals with the conversion efficiency as high as -6.4 dB. These results are essential for all-optical wavelength division multiplexer (WDM) technology of future integrated optoelectronic systems, as well as providing a novel architecture for on-chip optical communications. | |||||||||
Accession Number: WOS:000620283500002 | |||||||||
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ISSN: 0030-3992 | |||||||||
eISSN: 1879-2545 |
Record 279 of 318 | |||||||||
Title: On-line SERS detection of adenine in DNA based on the optofluidic in-fiber integrated GO/PDDA/Ag NPs | |||||||||
Author(s): Gao, DH (Gao, Danheng); Yang, XH (Yang, Xinghua); Teng, PP (Teng, Pingping); Kong, DP (Kong, Depeng); Liu, ZH (Liu, Zhihai); Yang, J (Yang, Jun); Luo, M (Luo, Meng); Li, ZN (Li, Zhanao); Wen, XY (Wen, Xingyue); Yuan, LB (Yuan, Libo); Li, K (Li, Kang); Bowkett, M (Bowkett, Mark); Copner, N (Copner, Nigel); Wang, XZ (Wang, Xiaozhang) | |||||||||
Source: SENSORS AND ACTUATORS B-CHEMICAL Volume: 332 Article Number: 129517 DOI: 10.1016/j.snb.2021.129517 Early Access Date: JAN 2021 Published: APR 1 2021 | |||||||||
Abstract: In this paper, a novel type of in-fiber optofluidic Raman self-assembly graphene oxide (GO)/PDDA/Ag NPs SERS sensor for the adenine in DNA is proposed. The microstructured hollow fiber (MHF) has a channel and a suspended core in microscale, which allows the sample to flow into the fiber. Meanwhile, the GO/PDDA/Ag NPs SERS substrates are modified on the MHF core by chemical bond. When the sample is interacted with the evanescent field excited by the suspended core, the on-line SERS signals can be coupled back to the core and be detected. Here, we carry out on-line optofluidic detection on the adenine samples. The results show that the detection limit (LOD) of the samples of is about 1 x 10(-14) M. The unwound DNA solution extracted from biological blood is injected into the MHF. Under the action of the hydrogen bond between PDDA with adenine, the adenine base in DNA is successfully detected and the interference of guanine, cytosine and thymine is eliminated. Significantly, this work provides an integrated self-assembled GO/PDDA/Ag NPs SERS adenine sensor in an optofluidic fiber. This rapid, convenient and sensitive Raman detection sensor of adenine in DNA is expected to have more potential applications in HIV, genetics and other fields. | |||||||||
Accession Number: WOS:000618771800006 | |||||||||
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eISSN: 0925-4005 |
Record 280 of 318 | |||||||||||||||
Title: Dark matter-wave gap solitons in dense ultracold atoms trapped by a one-dimensional optical lattice | |||||||||||||||
Author(s): Li, JW (Li, Jiawei); Zeng, JH (Zeng, Jianhua) | |||||||||||||||
Source: PHYSICAL REVIEW A Volume: 103 Issue: 1 Article Number: 013320 DOI: 10.1103/PhysRevA.103.013320 Published: JAN 27 2021 | |||||||||||||||
Abstract: Optical lattices have been used as a versatile toolbox to control Bose-Einstein condensates (BECs) in recent years, and a wealth of emergent nonlinear phenomena have been found, including bright gap solitons and dark ones, among which the former has been realized in experiments. The latter, however, has only theoretical results and its fundamental properties are still not well understood. Here we theoretically and numerically explore an open issue of creating stable matter-wave dark gap solitons in a one-dimensional optical lattice, onto which the BECs with self-defocusing quintic nonlinearity are loaded. Using linear-stability analysis and direct simulations, the formation, structures, and properties of dark gap solitons in quintic nonlinearity have been compared to those upheld by cubic Kerr nonlinearity. In particular, we uncover that the dark gap solitons and soliton clusters are robustly stable in the first finite band gap of the underlying linear spectrum, and are hard to be stabilized in the second gap. The predicted dark gap solitons are observable in current experiments on dense ultracold atoms, using an optical lattice technique, and in the optics domain for nonlinear light propagation in periodic optical media with quintic nonlinearity. | |||||||||||||||
Accession Number: WOS:000612208200005 | |||||||||||||||
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ISSN: 2469-9926 | |||||||||||||||
eISSN: 2469-9934 |
Record 281 of 318 | |||||||||
Title: Extended focused imaging in microscopy using structure tensor and guided filtering | |||||||||
Author(s): Ren, ZB (Ren, Zhenbo); Guan, PY (Guan, Peiyan); Lam, EY (Lam, Edmund Y.); Zhao, JL (Zhao, Jianlin) | |||||||||
Source: OPTICS AND LASERS IN ENGINEERING Volume: 140 Article Number: 106549 DOI: 10.1016/j.optlaseng.2021.106549 Early Access Date: JAN 2021 Published: MAY 2021 | |||||||||
Abstract: The limited depth-of-field (DOF) in optical microscopic imaging systems prevents them from capturing an entirely focused images when the imaged scene is thick and covers a wide range of depth. Specimens lying outside the DOF is defocused and thus blurred, hindering the subsequent observation and analysis. Extended focused imaging aims at yielding a single all-in-focus image by combining the in-focus information from a stack of partially focused images. In this paper, we present a new algorithm for digitally extending the low DOF of a microscopic imaging system. The method is based on the two-scale decomposition of an image into a base layer and a detail layer, both of which contain information of different scales. Then, with the structure tensor, which is uniquely advantageous for autofocusing multi-focal planes, as the focus measure, initial weight maps are generated. The guided filtering is then employed to optimize the weighted averaging scheme for the fusion of the base and detail layers. We examine the proposed algorithm under incoherent and coherent imaging modalities, i.e., bright-field microscopy and digital holographic microscopy. Qualitative and quantitative comparisons with the existing approaches are carried out using extensive experimental data. The results show the advantages and superior performance of the proposed scheme even in the presence of coherent noise. | |||||||||
Accession Number: WOS:000640981300029 | |||||||||
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ISSN: 0143-8166 | |||||||||
eISSN: 1873-0302 |
Record 282 of 318 |
Title: A MOSFET-based high voltage nanosecond pulse module for the gating of proximity-focused microchannel plate image-intensifier |
Author(s): Fang, YM (Fang, Yuman); Gou, YS (Gou, Yongsheng); Zhang, MR (Zhang, Minrui); Wang, JF (Wang, Junfeng); Tian, JS (Tian, Jinshou) |
Source: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Volume: 987 Article Number: 164799 DOI: 10.1016/j.nima.2020.164799 Published: JAN 21 2021 |
Abstract: Gate modules based on avalanche technology for photocathode gating to proximity-focused microchannel-plate image intensifier (MCPII) are often limited to short gate exposures. A nanosecond pulse module based on MOSFET devices has been demonstrated at our lab, which is capable of generating pulses of adjustable full width at half maximum (FWHM) from 3 ns to D.C. operation with 1 ns switching time and a burst repetition rate up to 4 MHz. A method of supplying gate-current pulses to the MOSFET device is adopted to increase the switching speed based on the totem pole driver. Nanosecond optical gating time of an 18-mm proximity-focused MCPII with a metallic underlay photocathode was obtained. A MCPII with standard multi-alkali photocathode was analyzed for comparison. Moreover, a photocathode-MCP model based on the Finite Integral Technique (FIT) is developed to investigate the dependence of the gating time on the sheet resistance of the photocathode. |
Accession Number: WOS:000597318400010 |
ISSN: 0168-9002 |
eISSN: 1872-9576 |
Record 283 of 318 | ||||||
Title: High-side mode suppression ratio with a high-stability external-cavity diode laser array at 976 nm in a wide temperature and current range | ||||||
Author(s): Liu, B (Liu, Bin); Liu, H (Liu, Hui); Zhu, PF (Zhu, Pengfei); Liu, XS (Liu, Xingsheng) | ||||||
Source: OPTICS COMMUNICATIONS Volume: 486 Article Number: 126792 DOI: 10.1016/j.optcom.2021.126792 Early Access Date: JAN 2021 Published: MAY 1 2021 | ||||||
Abstract: A high-side mode suppression ratio (SMSR) and high-stability external-cavity diode laser array employing optical feedback from a volume Bragg grating (VBG) with 15% diffraction efficiency at 976 nm was investigated. Based on the transfer matrix method and on the multimode rate equation, the theoretical model for an external-cavity diode laser at 976 nm was built for different temperature and current values. Both the simulated and the experimental results show that the temperature and the current range of such laser array with a front end reflectivity (R-f) of 0.5% are 10 degrees C and 15 A broader than that for an external cavity with R-f = 2%. As a result, the external-cavity diode laser array at 976 nm with a R-f value of 0.5% exhibits a high stability in the temperature range of 15-35 degrees C and from 15 to 50 A. Moreover, it shows an SMSR higher than 30 dB and a power larger than 33.9 W at 50A. | ||||||
Accession Number: WOS:000618210800003 | ||||||
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ISSN: 0030-4018 | ||||||
eISSN: 1873-0310 |
Record 284 of 318 | ||||||||||||||||||
Title: Flower-Shaped Optical Vortex Array | ||||||||||||||||||
Author(s): Fan, HH (Fan, Haihao); Zhang, H (Zhang, Hao); Cai, CY (Cai, Chenyuan); Tang, MM (Tang, Miaomiao); Li, HH (Li, Hehe); Tang, J (Tang, Jie); Li, XZ (Li, Xinzhong) | ||||||||||||||||||
Source: ANNALEN DER PHYSIK Volume: 533 Issue: 4 Article Number: 2000575 DOI: 10.1002/andp.202000575 Early Access Date: JAN 2021 Published: APR 2021 | ||||||||||||||||||
Abstract: Herein, the generation of an optical vortex array dubbed the flower-shaped optical vortex array (FOVA) is proposed and experimentally demonstrated using a single optical path interference method. FOVA is generated by the superposition of even and odd Ince-Gaussian (IG) beams, which have the same degree m and different order p. The number of optical vortices (OVs) in the FOVA is determined based on the values of order p and degree m of the even and odd IG beams. Furthermore, the positive sign of the OVs in the array can be transformed to negative by adding a specific initial phase difference. The OVs vanish and then recover as the initial phase difference increases from 0 to 2 pi. Moreover, the gradient force and energy flow distribution of the FOVA are studied. The OVA with flower-shaped structure generated herein has potential significance in applications, such as microparticle manipulation and optical measurements. | ||||||||||||||||||
Accession Number: WOS:000608844900001 | ||||||||||||||||||
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ISSN: 0003-3804 | ||||||||||||||||||
eISSN: 1521-3889 |
Record 285 of 318 | ||||||
Title: Distribution equalization learning mechanism for road crack detection | ||||||
Author(s): Fang, J (Fang, Jie); Qu, B (Qu, Bo); Yuan, Y (Yuan, Yuan) | ||||||
Source: NEUROCOMPUTING Volume: 424 Pages: 193-204 DOI: 10.1016/j.neucom.2019.12.057 Early Access Date: JAN 2021 Published: FEB 1 2021 | ||||||
Abstract: Visual-based road crack detection becomes a hot research topic over the last decade because of its huge application demands. Road crack detection is actually a special form of salient object detection task, whose objects are small and distribute randomly in the image compared to the traditional ones, which increase the difficulty of detecting. Most conventional methods utilize bottom information, such as color, texture, and contrast, to extract the crack regions in the image. Even though these methods can achieve satisfactory performances for images with simple scenarios, they are easily interfered by some factors such as light and shadow, which may decrease the detection result directly. Inspired by the competitive performances of deep convolutional neural networks on many visual tasks, we propose a distribution equalization learning mechanism for road crack detection in this paper. Firstly, we consider the crack detection task as a pixel-level classification and use a U-Net based architecture to finalize it. Secondly, the occurrence probability of crack and non-crack are so different, which results in the ill-conditioned classifier and undesirable detection performance, especially the high false detection rate. In this case, we propose a weighted cross entropy loss term and a data augmentation strategy to avoid influence from imbalanced samples through emphasizing the crack regions. Additionally, we propose an auxiliary interaction loss, and combine it with the popular self-attention strategy to alleviate the fracture situations through considering relationships among different local regions in the image. Finally, we tested the proposed method on three public and challenging datasets, and the experimental results demonstrate its effectiveness. (c) 2019 Elsevier B.V. All rights reserved. | ||||||
Accession Number: WOS:000611084200019 | ||||||
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ISSN: 0925-2312 | ||||||
eISSN: 1872-8286 |
Record 286 of 318 | |||||||||||||||
Title: Precise dynamic characterization of microcombs assisted by an RF spectrum analyzer with THz bandwidth and MHz resolution | |||||||||||||||
Author(s): Wang, RL (Wang, Ruolan); Chen, L (Chen, Liao); Hu, H (Hu, Hao); Zhao, YJ (Zhao, Yanjing); Zhang, C (Zhang, Chi); Zhang, WF (Zhang, Wenfu); Zhang, XL (Zhang, Xinliang) | |||||||||||||||
Source: OPTICS EXPRESS Volume: 29 Issue: 2 Pages: 2153-2161 DOI: 10.1364/OE.415933 Published: JAN 18 2021 | |||||||||||||||
Abstract: The radio frequency (RF) spectrum of microcombs can be used to evaluate its phase noise features and coherence between microcomb teeth. Since microcombs possess characteristics such as high repetition rate, narrow linewidth and ultrafast dynamical evolution, there exists strict requirement on the bandwidth, resolution and frame rate of RF measurement system. In this work, a scheme with 1.8-THz bandwidth, 7.5-MHz spectral resolution, and 100-Hz frame rate is presented for RF spectrum measurement of microcombs by using an all-optical RF spectrum analyzer based on cross-phase modulation and Fabry Perot (FP) spectrometer, namely FP-assisted light intensity spectrum analyzer (FP-assisted LISA). However, extra dispersion introduced by amplifying the microcombs will deteriorate the bandwidth performance of measured RF spectrum. After compensating the extra dispersion through monitoring the dispersion curves measured by FP-assisted LISA, the more precise RF spectra of microcombs are measured. Then, the system is used to measure the noise sidebands and line shape evolution of microcombs within 2s temporal window, in which dynamic RF combs variation at different harmonic frequencies up to 1.96 THz in modulation instability (MI) state and soliton state are recorded firstly. Therefore, the improved bandwidth and resolution of FP-assisted LISA enable more precise measurement of RF spectrum, paving a reliable way for researches on physical mechanism of microcombs. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement | |||||||||||||||
Accession Number: WOS:000609227300128 | |||||||||||||||
PubMed ID: 33726416 | |||||||||||||||
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ISSN: 1094-4087 |
Record 287 of 318 |
Title: Development of a self-calibration method for real-time monitoring of SO<sub>2</sub> ship emissions with UV cameras |
Author(s): Wu, KJ (Wu, Kuijun); Xiong, YH (Xiong, Yuanhui); Feng, YT (Feng, Yutao); Yu, Y (Yu, Yi); Li, FQ (Li, Faquan) |
Source: OPTICS EXPRESS Volume: 29 Issue: 2 Pages: 1813-1823 DOI: 10.1364/OE.415156 Published: JAN 18 2021 |
Abstract: Self-calibration of UV cameras was demonstrated for the first time. This novel method has the capability of real-time continuous calibration by using the raw images at 310 nm and 330 nm without changing the viewing direction or adding any additional equipment. The methodology was verified through simulations and experiments and demonstrated to be of greatly improved effectiveness and accuracy. The errors of self-calibration mothed are estimated by comparison with the differential optical absorption spectroscopy (DOAS) approach, and it can be reduced to 1.8% after filter transmittance corrections. The results show that the self-calibration method appears to have great potential as a future technique for quantitative and visual real-time monitoring of SO2 emissions from ships and other point sources (such as oil refineries, power plants, or more broadly, any industrial stack) when the field of view (FOV) of the system is not completely covered by the SO2 plumes. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement |
Accession Number: WOS:000609227300107 |
PubMed ID: 33726387 |
ISSN: 1094-4087 |
Record 288 of 318 | |||||||||
Title: Small Infrared Target Detection Based on Fast Adaptive Masking and Scaling With Iterative Segmentation | |||||||||
Author(s): Chen, YH (Chen, Yaohong); Zhang, GP (Zhang, Gaopeng); Ma, YJ (Ma, Yingjun); Kang, JU (Kang, Jin U.); Kwan, C (Kwan, Chiman) | |||||||||
Source: IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Volume: 19 DOI: 10.1109/LGRS.2020.3047524 Early Access Date: JAN 2021 Published: 2022 | |||||||||
Abstract: Fast and robust small infrared (IR) target detection is a challenging task and critical to the performance of IR searching and tracking (IRST) systems. However, the current algorithms generally have difficulty in striking a good balance between speed and performance. In this letter, we propose a new approach to small IR target detection that can significantly accelerate the detection process by first performing a fast adaptive masking and scaling algorithm. We then propose to enhance the target characteristics and suppress the background clutter using both contrast and gradient information. Finally, we propose to accurately extract the targets via iterative segmentation. The experimental results demonstrated that our proposed method yields the best and the most robust performance, with a speed of at least two times faster than the state-of-the-art methods. | |||||||||
Accession Number: WOS:000732290500001 | |||||||||
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ISSN: 1545-598X | |||||||||
eISSN: 1558-0571 |
Record 289 of 318 | ||||||||||||||||||||||||||||||
Title: Theoretical and Experimental Analysis of the Directional RI Sensing Property of Tilted Fiber Grating | ||||||||||||||||||||||||||||||
Author(s): Sun, YZ (Sun, Yuezhen); Lu, TA (Lu, Tean); Moreno, Y (Moreno, Yarien); Li, LY (Li, Liangye); Wang, HS (Wang, Hushan); Zhou, KM (Zhou, Kaiming); Sun, QZ (Sun, Qizhen); Liu, DM (Liu, Deming); Yan, ZJ (Yan, Zhijun); Zhang, L (Zhang, Lin) | ||||||||||||||||||||||||||||||
Source: JOURNAL OF LIGHTWAVE TECHNOLOGY Volume: 39 Issue: 2 Pages: 674-681 DOI: 10.1109/JLT.2020.3027947 Published: JAN 15 2021 | ||||||||||||||||||||||||||||||
Abstract: In this article, we have theoretically and experimentally investigated the unique vector refractive index (RI) sensing property of tilted fiber grating (TFG). Due to the orthogonal symmetric grating structure, TFGs would mainly achieve the coupling between the fiber core mode and the two orthogonal polarization LP1m of cladding mode. And the numerical simulation results showed that the coupling coefficient between fundamental core mode to the LP1m cladding mode is higher than the others. In the experiment, we have furthermore observed the cladding mode field distribution of excessively TFG (Ex-TFG) and long period fiber grating (LPFG), which indicated that the evanescent field distribution of cladding mode of TFG shows an asymmetric near field distribution with two lobes oriented along the fast axis of TFG, and the one of LPFG has a circularly symmetric cladding mode field distribution. In addition, by employing side-immersion method, we have measured the azimuth RI sensitivities of Ex-TFG, tilted fiber Bragg grating (TFBG) and LPFG, which exhibited that both Ex-TFG and TFBG have shown a direction-dependency RI sensitivity, and the RI sensitivity with side-immersion along fast axis is almost half of the one along slow axis, and the RI sensitivity of LPFG is azimuth independent. Overall, the experiment results show that the TFGs inherently show unique directional RI sensing property, which could be potentially applied in vector sensing area. | ||||||||||||||||||||||||||||||
Accession Number: WOS:000604853500040 | ||||||||||||||||||||||||||||||
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ISSN: 0733-8724 | ||||||||||||||||||||||||||||||
eISSN: 1558-2213 |
Record 290 of 318 | |||||||||
Title: Study on the performance of polarization maintaining fiber temperature sensor based on tilted fiber grating | |||||||||
Author(s): Zhao, J (Zhao, Jun); Wang, HS (Wang, Hushan); Sun, XH (Sun, Xiaohan) | |||||||||
Source: MEASUREMENT Volume: 168 Article Number: 108421 DOI: 10.1016/j.measurement.2020.108421 Published: JAN 15 2021 | |||||||||
Abstract: A novel functional-type high integration polarization interference fiber temperature sensor based on 45 degrees tilted fiber Bragg grating in-fiber polarizer (TFBG-PIF-TS) is proposed. The accuracy, resolution, stability, linearity and sensitivity of the prototype are tested and compared with PT100, 18B20 as well as polarizing plate based polarization interferometric fiber temperature sensor (PP-PIF-TS). The feasibility of the scheme in the transformer winding temperature monitoring is verified. The results show that the accuracy and resolution of TFBG-PIF-TS reach +/- 0.1 degrees C and 0.01 degrees C respectively, which has higher resolution, better integration and reliability, and has simple structure, strong anti-vibration and anti-electromagnetic interference abilities. Therefore, the proposed scheme can meet the needs of high voltage, strong magnetic field and other passive precise temperature measurement occasions. | |||||||||
Accession Number: WOS:000582271500082 | |||||||||
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ISSN: 0263-2241 | |||||||||
eISSN: 1873-412X |
Record 291 of 318 | ||||||||||||
Title: Scientific objectives and payloads of Tianwen-1, China's first Mars exploration mission | ||||||||||||
Author(s): Zou, YL (Zou Yongliao); Zhu, Y (Zhu Yan); Bai, YF (Bai Yunfei); Wang, LG (Wang Lianguo); Jia, YZ (Jia Yingzhuo); Shen, WH (Shen Weihua); Fan, Y (Fan Yu); Liu, Y (Liu Yang); Wang, C (Wang Chi); Zhang, AB (Zhang Aibing); Yu, GB (Yu Guobin); Dong, JH (Dong Jihong); Shu, R (Shu Rong); He, ZP (He Zhiping); Zhang, TL (Zhang Tielong); Du, AM (Du Aimin); Fan, MY (Fan Mingyi); Yang, JF (Yang Jianfeng); Zhou, B (Zhou Bin); Wang, Y (Wang Yi); Peng, YQ (Peng Yongqing) | ||||||||||||
Source: ADVANCES IN SPACE RESEARCH Volume: 67 Issue: 2 Pages: 812-823 DOI: 10.1016/j.asr.2020.11.005 Published: JAN 15 2021 | ||||||||||||
Abstract: This paper describes the scientific objectives and payloads of Tianwen-1, China's first exploration mission to Mars. An orbiter, carrying a lander and a rover, lifted-off in July 2020 for a journey to Mars where it should arrive in February 2021. A suite of 13 scientific payloads, for in-situ and remote sensing, autonomously commanded by integrated payload controllers and mounted on the orbiter and the rover will study the magnetosphere and ionosphere of Mars and the relation with the solar wind, the atmosphere, surface and subsurface of the planet, looking at the topography, composition and structure and in particular for subsurface ice. The mission will also investigate Mars climate history. It is expected that Tianwen-1 will contribute significantly to advance our scientific knowledge of Mars. (C) 2020 COSPAR. Published by Elsevier Ltd. | ||||||||||||
Accession Number: WOS:000603416600010 | ||||||||||||
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ISSN: 0273-1177 | ||||||||||||
eISSN: 1879-1948 |
Record 292 of 318 | ||||||
Title: Accelerating patch-based low-rank image restoration using kd-forest and Lanczos approximation | ||||||
Author(s): Guo, Q (Guo, Qiang); Zhang, YX (Zhang, Yongxia); Qiu, S (Qiu, Shi); Zhang, CM (Zhang, Caiming) | ||||||
Source: INFORMATION SCIENCES Volume: 556 Pages: 177-193 DOI: 10.1016/j.ins.2020.12.066 Early Access Date: JAN 2021 Published: MAY 2021 | ||||||
Abstract: Patch-based low-rank approximation (PLRA) via truncated singular value decomposition is a powerful and effective tool for recovering the underlying low-rank structure in images. Generally, it first performs an approximate nearest neighbors (ANN) search algorithm to group similar patches into a collection of matrices with reshaping them as vectors. The inherent correlation among similar patches makes these matrices have a low-rank structure. Then the singular value decomposition (SVD) is used to derive a low-rank approximation of each matrix by truncating small singular values. However, the conventional implementation of patch-based low-rank image restoration suffers from high computational cost of the ANN search and full SVD. To address this limitation, we propose a fast approximation method that accelerates the computation of PLRA using multiple kd-trees and Lanczos approximation. The basic idea of this method is to exploit an index kd-tree built from patch samples of the observed image and several small kd-trees built from overlapping regions of the image to accelerate the search for similar patches, and apply the Lanczos bidiagonalization procedure to obtain a fast low-rank approximation of patch matrix without computing the full SVD. Experimental results on image denoising and inpainting tasks demonstrate the efficiency and accuracy of our method. (C) 2020 Elsevier Inc. All rights reserved. | ||||||
Accession Number: WOS:000626586900011 | ||||||
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ISSN: 0020-0255 | ||||||
eISSN: 1872-6291 |
Record 293 of 318 | |||||||||
Title: Numerical study of the influence of thermal radiation on measuring semi-transparent thermal insulation material with hot wire method | |||||||||
Author(s): Zhang, H (Zhang, H.); Ma, YX (Ma, Y. X.); Wang, X (Wang, X.); Tang, GH (Tang, G. H.) | |||||||||
Source: INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER Volume: 121 Article Number: 105120 DOI: 10.1016/j.icheatmasstransfer.2021.105120 Early Access Date: JAN 2021 Published: FEB 2021 | |||||||||
Abstract: Semi-transparent thermal insulation material has very low extinction coefficient and will transmit infrared spectrum within some wavelength range. When measuring the thermal conductivity (TC) of such kinds of material with transient methods, both heat conduction and thermal radiation occur within material. Transient hot wire (HW) method is a widely used method for thermal insulation measurement. It is developed with the assumption that heat only transfers via conduction. Since thermal radiation within low density thermal insulation material is a pronounced heat transfer mode at high temperature, the TC of radiation participating medium measured by HW method might be incorrect. To reveal the inconsistency between test theory and practical heat transfer process when measuring semi-transparent thermal insulation material with HW method, the transient conduction and radiation coupled heat transfer process is simulated numerically. The uncertainty caused by thermal radiation is investigated for material with different extinction coefficient at various temperature. The deviation increases with the increment of temperature and decreases with increment of extinction coefficient compared to results obtained from the one dimensional (1D) steady state method. The numerical analysis indicates that the TC of thermal insulation material with low extinction ability measured by HW method is overestimated at high temperature. | |||||||||
Accession Number: WOS:000614147700035 | |||||||||
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ISSN: 0735-1933 | |||||||||
eISSN: 1879-0178 |
Record 294 of 318 | |||||||||
Title: One-dimensional quantum droplets under space-periodic nonlinear management | |||||||||
Author(s): Chen, JB (Chen, Junbo); Zeng, JH (Zeng, Jianhua) | |||||||||
Source: RESULTS IN PHYSICS Volume: 21 Article Number: 103781 DOI: 10.1016/j.rinp.2020.103781 Early Access Date: JAN 2021 Published: FEB 2021 | |||||||||
Abstract: Quantum droplets have recently emerged as a novel liquid state of matter in a mixture of two-component ultracold Bose gases under the equilibrium condition between the competing attractive inter- and repulsive intraspecies forces. Quantum droplets represent a self-bound liquid state in purely nonlinear systems and as such there is not any management applied to their study up to now. We here introduce the nonlinear management via space-periodic Feshbach resonance technique to a binary Bose-Einstein condensate and investigate theoretically the structure, property and dynamics of the one-dimensional quantum droplets therein, three findings are made: small droplets with single hump (solitonlike), moderate droplets composed of two solitons, large droplets feature a modulated flat-top shape. Particularly, by means of linear-stability and direct perturbed simulations, we prove that the droplets have a much wider stable region than their counterparts without taking the nonlinear management. The variational approximation is adopted and validated with numerical results in terms of small droplets. The results predicted here may be realized in the frontier ultracold atoms experiments aided by Feshbach-resonance, opening up a new channel to the quantum droplets studies. | |||||||||
Accession Number: WOS:000630949400015 | |||||||||
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ISSN: 2211-3797 |
Record 295 of 318 |
Title: Controlled asymmetric bidirectional quantum teleportation of two- and three-qubit states |
Author(s): Huo, GW (Huo, Guangwen); Zhang, TY (Zhang, Tongyi); Zha, XW (Zha, Xinwei); Zhang, XX (Zhang, Xiuxing); Zhang, MZ (Zhang, Meizhi) |
Source: QUANTUM INFORMATION PROCESSING Volume: 20 Issue: 1 Article Number: 24 DOI: 10.1007/s11128-020-02956-3 Published: JAN 11 2021 |
Abstract: We propose a protocol of asymmetric controlled bidirectional quantum teleportation of two- and three-qubit states. That is to say, Alice wants to teleport an arbitrary two-qubit state to Bob, and Bob wants to teleport an arbitrary three-qubit state for Alice via the control of supervisor Charlie. By using the eleven-qubit entangled state as the quantum channel, Alice can teleport an arbitrary two-qubit state for Bob and Bob can teleport an arbitrary three-qubit state for Alice simultaneously. |
Accession Number: WOS:000610572400002 |
ISSN: 1570-0755 |
eISSN: 1573-1332 |
Record 296 of 318 | ||||||
Title: Indium selenide saturable absorber for high-energy nanosecond <i>Q</i>-switched pulse generation | ||||||
Author(s): Li, L (Li, Lu); Wang, Y (Wang, Yao); Jin, W (Jin, Wei); Zhao, QY (Zhao, Qiyi); Su, YL (Su, Yulong) | ||||||
Source: APPLIED OPTICS Volume: 60 Issue: 2 Pages: 427-432 DOI: 10.1364/AO.414750 Published: JAN 10 2021 | ||||||
Abstract: As a kind of III/VI group compound 2D layered material, indium selenide (In2Se3) has attracted tremendous interest because of its favorable optoelectronic characteristics. Here, magnetron sputtering deposition (MSD) technology was employed to prepare an In2Se3-based saturable absorber (SA). The nonlinear optical properties of this SA, whose modulation depth (1T) is 6.18%, were studied. With the aid of its saturable absorption, a stable two-wavelength Q-switching Er-doped fiber (EDF) laser was established. When pump power was adjusted to 900 mW, the output power was increased to 63.84 mW. The shortest pulse duration and maximum pulse energy were estimated to be 556 ns and 376 nJ, respectively. The signal-to-noise ratio of 70 dB proves this fiber laser has high stability. In comparison with previous works, the laser performance in this study is improved significantly. These results indicate that the In2Se3 holds promise as an outstanding candidate for high-energy pulse generation and will advance the development of In2Se3-based nonlinear photonics devices. (C) 2021 Optical Society of America. | ||||||
Accession Number: WOS:000606795800027 | ||||||
PubMed ID: 33448968 | ||||||
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ISSN: 1559-128X | ||||||
eISSN: 2155-3165 |
Record 297 of 318 | ||||||
Title: Simulation and analysis of atmospheric scattering in stray light testing for point source transmittance | ||||||
Author(s): Ma, ZP (Ma, Zhanpeng); Chen, QF (Chen, Qinfang); Wang, H (Wang, Hu) | ||||||
Source: APPLIED OPTICS Volume: 60 Issue: 2 Pages: 232-238 DOI: 10.1364/AO.409656 Published: JAN 10 2021 | ||||||
Abstract: We propose a full-band model to quantitatively calculate terrestrial atmospheric scattering in stray light testing based on the Monte Carlo algorithm. Measurements are conducted using two classifications of air cleanliness at off-axis angles from 35 degrees to 90 degrees. Corresponding simulations of Mie scattering and Rayleigh scattering are used for a comparison with the measured values. The relative root mean square deviation of the simulation from the measurement result is 3.72% and 24.1% for Mie scattering and Rayleigh scattering, respectively. This exhibits excellent agreement between the measured and predicted values for a 26 degrees full-angle baffle when illuminated by a 550 mm diameter collimated beam. (C) 2021 Optical Society of America | ||||||
Accession Number: WOS:000606795800003 | ||||||
PubMed ID: 33448944 | ||||||
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ISSN: 1559-128X | ||||||
eISSN: 2155-3165 |
Record 298 of 318 | ||||||||||||||||||||||||||||||||||||
Title: 11 TOPS photonic convolutional accelerator for optical neural networks | ||||||||||||||||||||||||||||||||||||
Author(s): Xu, XY (Xu, Xingyuan); Tan, MX (Tan, Mengxi); Corcoran, B (Corcoran, Bill); Wu, JY (Wu, Jiayang); Boes, A (Boes, Andreas); Nguyen, TG (Nguyen, Thach G.); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Hicks, DG (Hicks, Damien G.); Morandotti, R (Morandotti, Roberto); Mitchell, A (Mitchell, Arnan); Moss, DJ (Moss, David J.) | ||||||||||||||||||||||||||||||||||||
Source: NATURE Volume: 589 Issue: 7840 Pages: 44-+ DOI: 10.1038/s41586-020-03063-0 Published: JAN 7 2021 | ||||||||||||||||||||||||||||||||||||
Abstract: Convolutional neural networks, inspired by biological visual cortex systems, are a powerful category of artificial neural networks that can extract the hierarchical features of raw data to provide greatly reduced parametric complexity and to enhance the accuracy of prediction. They are of great interest for machine learning tasks such as computer vision, speech recognition, playing board games and medical diagnosis(1-7). Optical neural networks offer the promise of dramatically accelerating computing speed using the broad optical bandwidths available. Here we demonstrate a universal optical vector convolutional accelerator operating at more than ten TOPS (trillions (10(12)) of operations per second, or tera-ops per second), generating convolutions of images with 250,000 pixels-sufficiently large for facial image recognition. We use the same hardware to sequentially form an optical convolutional neural network with ten output neurons, achieving successful recognition of handwritten digit images at 88 per cent accuracy. Our results are based on simultaneously interleaving temporal, wavelength and spatial dimensions enabled by an integrated microcomb source. This approach is scalable and trainable to much more complex networks for demanding applications such as autonomous vehicles and real-time video recognition. | ||||||||||||||||||||||||||||||||||||
Accession Number: WOS:000606497700007 | ||||||||||||||||||||||||||||||||||||
PubMed ID: 33408378 | ||||||||||||||||||||||||||||||||||||
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ISSN: 0028-0836 | ||||||||||||||||||||||||||||||||||||
eISSN: 1476-4687 |
Record 299 of 318 | ||||||||||||
Title: Modified snapshot spectroscopic ellipsometry based on optical frequency-domain interferometry | ||||||||||||
Author(s): Li, SY (Li, Siyuan); Zhang, CM (Zhang, Chunmin); Quan, NC (Quan, Naicheng) | ||||||||||||
Source: OPTIK Volume: 228 Article Number: 166165 DOI: 10.1016/j.ijleo.2020.166165 Early Access Date: JAN 2021 Published: FEB 2021 | ||||||||||||
Abstract: We propose a modified snapshot spectroscopic ellipsometry based on optical frequency-domain interferometry. The proposed system employs only one high-order retarder and a Wollaston prism to analyze the changed state of polarization of the reflected light and can provide the maximum channel bandwidth of the channeled spectroscopic ellipsometry. The spectroscopic ellipsometric parameters of isotropic samples can be accurately measured in a measurement speed of 40 ms without mechanical or active modulation devices. The feasibility of the proposed spectroscopic ellipsometry is demonstrated by experiments. | ||||||||||||
Accession Number: WOS:000615935900011 | ||||||||||||
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ISSN: 0030-4026 | ||||||||||||
eISSN: 1618-1336 |
Record 300 of 318 | |||||||||||||||||||||
Title: Analysis of corrected Cerenkov emission during electron radiotherapy by Monte Carlo method | |||||||||||||||||||||
Author(s): Li, Y (Li, Yi); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Zhang, CM (Zhang, Chunmin) | |||||||||||||||||||||
Source: APPLIED RADIATION AND ISOTOPES Volume: 168 Article Number: 109481 DOI: 10.1016/j.apradiso.2020.109481 Early Access Date: JAN 2021 Published: FEB 2021 | |||||||||||||||||||||
Abstract: Cerenkov emission during electron radiotherapy had been emerging as a new dose assessment approach for clinical radiotherapy and could be imaged through a standard commercial camera. The purpose of this work aimed to study the accuracy of corrected Cerenkov emission method during electron radiotherapy by Monte Carlo (MC) method. GAMOS MC software was used to model the physics of electron therapy and calculated dose and Cerenkov photon distribution in water phantom. Compared to ionization chamber and diode measurement, MC simulated dose discrepancy was less than 1% in percentage depth dose (PDD) curves and less than. | |||||||||||||||||||||
Accession Number: WOS:000605532900026 | |||||||||||||||||||||
PubMed ID: 33658131 | |||||||||||||||||||||
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ISSN: 0969-8043 | |||||||||||||||||||||
eISSN: 1872-9800 |
Record 301 of 318 | ||||||
Title: An uncoupled theory of FG nanobeams with the small size effects and its exact solutions | ||||||
Author(s): Pei, YL (Pei, Y. L.); Li, LX (Li, L. X.) | ||||||
Source: ARCHIVE OF APPLIED MECHANICS Volume: 91 Issue: 4 Pages: 1713-1728 DOI: 10.1007/s00419-020-01849-2 Early Access Date: JAN 2021 Published: APR 2021 | ||||||
Abstract: Due to unphysical coupling induced by the material inhomogeneity, FG (functionally graded) nanobeam problems were formulated in a very complex way so that they cannot be analytically solved. In this paper, an uncoupled theory is proposed for FG nanobeams considering their small size effects. First, with the aid of the neutral axis, the axial displacement is expressed in terms of generalized displacements for FG nanobeams. Based on the nonlocal strain gradient theory, the generalized stresses and strains are accordingly defined and uncoupled constitutive relations are derived. Based on the principle of virtual work, an uncoupled theory is eventually established, including governing equations and boundary conditions. Within the present framework, analytical solutions to FG nanobeams are obtained for the first time for general boundary conditions. These solutions not only re-evaluate the previous results but shed light on the small size effects of FG nanobeams. | ||||||
Accession Number: WOS:000604445000003 | ||||||
Author Identifiers: | ||||||
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ISSN: 0939-1533 | ||||||
eISSN: 1432-0681 |
Record 302 of 318 | ||||||||||||
Title: Bidirectional Interaction Network for Person Re-Identification | ||||||||||||
Author(s): Chen, XM (Chen, Xiumei); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||
Source: IEEE TRANSACTIONS ON IMAGE PROCESSING Volume: 30 Pages: 1935-1948 DOI: 10.1109/TIP.2021.3049943 Published: 2021 | ||||||||||||
Abstract: Person re-identification (ReID) task aims to retrieve the same person across multiple spatially disjoint camera views. Due to huge image changes caused by various factors such as posture variation and illumination transformation, images of different persons may share the more similar appearances than images of the same one. Learning discriminative representations to distinguish details of different persons is significant for person ReID. Many existing methods learn discriminative representations resorting to a human body part location branch which requires cumbersome expert human annotations or complex network designs. In this article, a novel bidirectional interaction network is proposed to explore discriminative representations for person ReID without any human body part detection. The proposed method regards multiple convolutional features as responses to various body part properties and exploits the inter-layer interaction to mine discriminative representations for person identities. Firstly, an inter-layer bilinear pooling strategy is proposed to feasibly exploit the pairwise feature relations between two convolution layers. Secondly, to explore interaction of multiple layers, an effective bidirectional integration strategy consisting of two different multi-layer interaction processes is designed to aggregate bilinear pooling interaction of multiple convolution layers. The interaction of multiple layers is implemented in a layer-by-layer nesting policy to ensure the two interaction processes are different and complementary. Extensive experiments validate the superiority of the proposed method on four popular person ReID datasets including Market-1501, DukeMTMC-ReID, CUHK03-NP and MSMT17. Specifically, the proposed method achieves a rank-1 accuracy of 95.1% and 88.2% on Market-1501 and DukeMTMC-ReID, respectively. | ||||||||||||
Accession Number: WOS:000611077900010 | ||||||||||||
PubMed ID: 33439839 | ||||||||||||
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ISSN: 1057-7149 | ||||||||||||
eISSN: 1941-0042 |
Record 303 of 318 |
Title: A Fog Covered Object Recognition Algorithm Based On Space And Frequency Network |
Author(s): Cui, Y (Cui, Ying); Qiu, S (Qiu, Shi); Li, T (Li, Tong) |
Source: INTELLIGENT AUTOMATION AND SOFT COMPUTING Volume: 28 Issue: 2 Pages: 417-428 DOI: 10.32604/iasc.2021.016802 Published: 2021 |
Abstract: It is difficult to recognize a target object from foggy images. Aiming at solving this problem, a new algorithm is thereby proposed. Fog concentration estimation is the prerequisite for image defogging. Due to the uncertainty of fog distribution, a fog concentration estimation model is accordingly proposed. Establish the brightness and gradient model in the spatial domain, and establish the FFT model in the frequency domain. Also, a multiple branch network framework is established to realize the qualitative estimation of the fog concentration in images based on comprehensive analysis from spatial and frequency domain levels. In the aspect of foggy image target recognition, a residual network is introduced based on Fast RCNN network structure. The fog concentration information is added into the target recognition function to realize accurate recognition of target from foggy images. Experimental results show that the accuracy of AOM is higher than 81 under different fog concentration indoors and outdoors. |
Accession Number: WOS:000640542700009 |
ISSN: 1079-8587 |
eISSN: 2326-005X |
Record 304 of 318 |
Title: Effect of pupil matching of cold shield on the fringe contrast of long-wave infrared spatial heterodyne spectroscopy |
Author(s): Han, B (Han, Bin); Feng, YT (Feng, Yutao); Zhang, ZH (Zhang, Zhaohui); Wu, JQ (Wu, Junqiang); Wu, Y (Wu, Yang); Sun, J (Sun, Jian); Wang, PC (Wang, Pengchong); Chang, CG (Chang, Chenguang); Li, J (Li, Juan); Zhao, YD (Zhao, Yudi); Hu, BL (Hu, Bingliang) |
Source: APPLIED OPTICS Volume: 60 Issue: 29 Pages: 9241-9248 DOI: 10.1364/AO.439482 Published: 2021 |
Abstract: Matching the cold shield with the exit pupil of the fringe-imaging system of long-wave infrared (LWIR) spatial heterodyne spectroscopy (SHS) damages illumination uniformity of the interferogram and affects the fringe contrast, which is a significant parameter for LWIR SHS. The optical models of the fringe-imaging system considering and not considering the pupil matching of the cold shield are built to illustrate the effect on the fringe contrast. Simulations based on the optical design software ASAP are conducted to verify the fringe contrast loss for field-widened, LWIR SHS. The result shows that the pupil matching of the cold shield decreases the fringe contrast of LWIR SHS and field-widened LWIR SHS by 0.049% and 0.053%, respectively, and the fringe contrast loss increases with the degree of deviation from the telecentric condition of the fringe-imaging system. (C) 2021 Optical Society of America |
Accession Number: WOS:000705391200033 |
PubMed ID: 34624011 |
ISSN: 1559-128X |
eISSN: 2155-3165 |
Record 305 of 318 | |||||||||||||||
Title: Background Purification Framework With Extended Morphological Attribute Profile for Hyperspectral Anomaly Detection | |||||||||||||||
Author(s): Huang, J (Huang, Ju); Liu, K (Liu, Kang); Xu, ML (Xu, Mingliang); Perc, M (Perc, Matjaz); Li, XL (Li, Xuelong) | |||||||||||||||
Source: IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING Volume: 14 Pages: 8113-8124 DOI: 10.1109/JSTARS.2021.3103858 Published: 2021 | |||||||||||||||
Abstract: Hyperspectral anomaly detection has attracted extensive interests for its wide use in military and civilian fields, and three main categories of detection methods have been developed successively over past few decades, including statistical model-based, representation-based, and deep-learning-based methods. Most of these algorithms are essentially trying to construct proper background profiles, which describe the characteristics of background and then identify the pixels that do not conform to the profiles as anomalies. Apparently, the crucial issue is how to build an accurate background profile; however, the background profiles constructed by existing methods are not accurate enough. In this article, a novel and universal background purification framework with extended morphological attribute profiles is proposed. It explores the spatial characteristic of image and removes suspect anomaly pixels from the image to obtain a purified background. Moreover, three detectors with this framework covering different categories are also developed. The experiments implemented on four real hyperspectral images demonstrate that the background purification framework is effective, universal, and suitable. Furthermore, compared with other popular algorithms, the detectors with the framework perform well in terms of accuracy and efficiency. | |||||||||||||||
Accession Number: WOS:000690441600011 | |||||||||||||||
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ISSN: 1939-1404 | |||||||||||||||
eISSN: 2151-1535 |
Record 306 of 318 | |||||||||||||||
Title: A Novel Negative-Transfer-Resistant Fuzzy Clustering Model With a Shared Cross-Domain Transfer Latent Space and its Application to Brain CT Image Segmentation | |||||||||||||||
Author(s): Jiang, YZ (Jiang, Yizhang); Gu, XQ (Gu, Xiaoqing); Wu, DR (Wu, Dongrui); Hang, WL (Hang, Wenlong); Xue, J (Xue, Jing); Qiu, S (Qiu, Shi); Lin, CT (Lin, Chin-Teng) | |||||||||||||||
Source: IEEE-ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS Volume: 18 Issue: 1 Pages: 40-52 DOI: 10.1109/TCBB.2019.2963873 Published: JAN 1 2021 | |||||||||||||||
Abstract: Traditional clustering algorithms for medical image segmentation can only achieve satisfactory clustering performance under relatively ideal conditions, in which there is adequate data from the same distribution, and the data is rarely disturbed by noise or outliers. However, a sufficient amount of medical images with representative manual labels are often not available, because medical images are frequently acquired with different scanners (or different scan protocols) or polluted by various noises. Transfer learning improves learning in the target domain by leveraging knowledge from related domains. Given some target data, the performance of transfer learning is determined by the degree of relevance between the source and target domains. To achieve positive transfer and avoid negative transfer, a negative-transfer-resistant mechanism is proposed by computing the weight of transferred knowledge. Extracting a negative-transfer-resistant fuzzy clustering model with a shared cross-domain transfer latent space (called NTR-FC-SCT) is proposed by integrating negative-transfer-resistant and maximum mean discrepancy (MMD) into the framework of fuzzy c-means clustering. Experimental results show that the proposed NTR-FC-SCT model outperformed several traditional non-transfer and related transfer clustering algorithms. | |||||||||||||||
Accession Number: WOS:000615042600005 | |||||||||||||||
PubMed ID: 31905144 | |||||||||||||||
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ISSN: 1545-5963 | |||||||||||||||
eISSN: 1557-9964 |
Record 307 of 318 | |||||||||
Title: Dependence of Field Splitting Characteristics on Metallic Components Topological Configuration in Multilaminar Plasmonic Films | |||||||||
Author(s): Kang, YF (Kang, Yifan); Yang, HT (Yang, Hongtao); Wang, C (Wang, Chao); Li, YF (Li, Yongfeng); Cao, WW (Cao, Weiwei) | |||||||||
Source: IEEE TRANSACTIONS ON NANOTECHNOLOGY Volume: 20 Pages: 715-725 DOI: 10.1109/TNANO.2021.3112704 Published: 2021 | |||||||||
Abstract: The dependence of field splitting characteristics of multilaminar plasmonic structure on its metallic components topology is analyzed. It is found that the coupling interaction between metallic-particle-centered localized surface plasmons generates a collective effect, collective metallic-particles-centered plasmons, to dominantly determine the plasmonic resonances of the structure. When the metallic particles filling ratio within the matrix is high, this collective effect may cause resonance splitting phenomenon and greatly enlarge the frequency range of field splitting enhancement, which is the physical mechanism and also the designing guideline for multilaminar plasmonic broadband perfect absorber. The surface plasmon polaritons are concurrently superimposed on the metallic-particles-centered collective effect to establish an inter-group coupling competition effect, which may strengthen or weaken the preexisting resonance processes through constructive or destructive field interference in between. This serves as the theoretical base for narrowband field splitting enhancement applications. Moreover, we have revealed the existence of the corresponding relationship between the specific field splitting resonance and those participating or dominating metallic particles involved, which provides the advantages to finely tailor field splitting characteristics through precise implantation of nanoparticles. | |||||||||
Accession Number: WOS:000702563400001 | |||||||||
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ISSN: 1536-125X | |||||||||
eISSN: 1941-0085 |
Record 308 of 318 | ||||||
Title: Temporal Constraint Background-Aware Correlation Filter With Saliency Map | ||||||
Author(s): Liao, JW (Liao, Jiawen); Qi, C (Qi, Chun); Cao, JZ (Cao, Jianzhong) | ||||||
Source: IEEE TRANSACTIONS ON MULTIMEDIA Volume: 23 Pages: 3346-3361 DOI: 10.1109/TMM.2020.3023794 Published: 2021 | ||||||
Abstract: Correlation filter (CF) based trackers have recently drawn great attention in visual tracking community due to their impressive performance, and computational efficiency on benchmark datasets. However, the performance of most existing trackers using correlation filter is hampered by two aspects: i) Included background information in the selected rectangular target patch is considered as part of the target, and they are treated as important as the real target in training new filter model, it causes the filter easily drift when target shape changes dramatically. ii) Existing filters use a moving average operation with an empirical weight to update the filter model in each frame, such per frame adaptation constantly introduces new information of the target patch, but never consider the consistence of the historical information, and the newly obtained one, further increases the risk of drifting. This paper presents a new framework including saliency map, and a novel CF regression model. We reformulate the original optimization problem, and provide a closed form solution for multidimensional features which is solved efficiently using alternating direction method of multipliers (ADMM), and accelerated using Sherman-Morrison lemma, our algorithm as a new framework can be easily integrated into CF base trackers to boost their tracking performance. We perform comprehensive experiments on five benchmarks: OTB-2015, VOT2016, VOT2018, UAV123, and TempleColor-128. Results show that the proposed method performs favorably against lots of state-of-the-art methods with a speed close to real-time. Our method with deep features performs much better on all 5 datasets. | ||||||
Accession Number: WOS:000698902000031 | ||||||
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ISSN: 1520-9210 | ||||||
eISSN: 1941-0077 |
Record 309 of 318 | |||||||||||||||
Title: Tilt Correction Toward Building Detection of Remote Sensing Images | |||||||||||||||
Author(s): Liu, K (Liu, Kang); Jiang, ZY (Jiang, Zhiyu); Xu, ML (Xu, Mingliang); Perc, M (Perc, Matjaz); Li, XL (Li, Xuelong) | |||||||||||||||
Source: IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING Volume: 14 Pages: 5854-5866 DOI: 10.1109/JSTARS.2021.3083481 Published: 2021 | |||||||||||||||
Abstract: Building detection is a crucial task in the field of remote sensing, which can facilitate urban construction planning, disaster survey, and emergency landing. However, for large-size remote sensing images, the great majority of existing works have ignored the image tilt problem. This problem can result in partitioning buildings into separately oblique parts when the large-size images are partitioned. This is not beneficial to preserve semantic completeness of the building objects. Motivated by the above fact, we first propose a framework for detecting objects in a large-size image, particularly for building detection. The framework mainly consists of two phases. In the first phase, we particularly propose a tilt correction (TC) algorithm, which contains three steps: texture mapping, tilt angle assessment, and image rotation. In the second phase, building detection is performed with object detectors, especially deep-neural-network-based methods. Last but not least, the detection results will be inversely mapped to the original large-size image. Furthermore, a challenging dataset named Aerial Image Building Detection is contributed for the public research. To evaluate the TC method, we also define an evaluation metric to compute the cost of building partition. The experimental results demonstrate the effects of the proposed method for building detection. | |||||||||||||||
Accession Number: WOS:000663535500017 | |||||||||||||||
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ISSN: 1939-1404 | |||||||||||||||
eISSN: 2151-1535 |
Record 310 of 318 | ||||||
Title: Hierarchical Edge Refinement Network for Saliency Detection | ||||||
Author(s): Song, DW (Song, Dawei); Dong, YS (Dong, Yongsheng); Li, XL (Li, Xuelong) | ||||||
Source: IEEE TRANSACTIONS ON IMAGE PROCESSING Volume: 30 Pages: 7567-7577 DOI: 10.1109/TIP.2021.3106798 Published: 2021 | ||||||
Abstract: At present, most saliency detection methods are based on fully convolutional neural networks (FCNs). However, FCNs usually blur the edges of salient objects. Due to that, the multiple convolution and pooling operations of the FCNs will limit the spatial resolution of the feature maps. To alleviate this issue and obtain accurate edges, we propose a hierarchical edge refinement network (HERNet) for accurate saliency detection. In detail, the HERNet is mainly composed of a saliency prediction network and an edge preserving network. Firstly, the saliency prediction network is used to roughly detect the regions of salient objects and is based on a modified U-Net structure. Then, the edge preserving network is used to accurately detect the edges of salient objects, and this network is mainly composed of the atrous spatial pyramid pooling (ASPP) module. Different from the previous indiscriminate supervision strategy, we adopt a new one-to-one hierarchical supervision strategy to supervise the different outputs of the entire network. Experimental results on five traditional benchmark datasets demonstrate that the proposed HERNet performs well when compared with the state-of-the-art methods. | ||||||
Accession Number: WOS:000693758500004 | ||||||
PubMed ID: 34464260 | ||||||
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ISSN: 1057-7149 | ||||||
eISSN: 1941-0042 |
Record 311 of 318 | ||||||||||||
Title: A Supervised Segmentation Network for Hyperspectral Image Classification | ||||||||||||
Author(s): Sun, H (Sun, Hao); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||
Source: IEEE TRANSACTIONS ON IMAGE PROCESSING Volume: 30 Pages: 2810-2825 DOI: 10.1109/TIP.2021.3055613 Published: 2021 | ||||||||||||
Abstract: Recently, deep learning has drawn broad attention in the hyperspectral image (HSI) classification task. Many works have focused on elaborately designing various spectral-spatial networks, where convolutional neural network (CNN) is one of the most popular structures. To explore the spatial information for HSI classification, pixels with its adjacent pixels are usually directly cropped from hyperspectral data to form HSI cubes in CNN-based methods. However, the spatial land-cover distributions of cropped HSI cubes are usually complicated. The land-cover label of a cropped HSI cube cannot simply be determined by its center pixel. In addition, the spatial land-cover distribution of a cropped HSI cube is fixed and has less diversity. For CNN-based methods, training with cropped HSI cubes will result in poor generalization to the changes of spatial land-cover distributions. In this paper, an end-to-end fully convolutional segmentation network (FCSN) is proposed to simultaneously identify land-cover labels of all pixels in a HSI cube. First, several experiments are conducted to demonstrate that recent CNN-based methods show the weak generalization capabilities. Second, a fine label style is proposed to label all pixels of HSI cubes to provide detailed spatial land-cover distributions of HSI cubes. Third, a HSI cube generation method is proposed to generate plentiful HSI cubes with fine labels to improve the diversity of spatial land-cover distributions. Finally, a FCSN is proposed to explore spectral-spatial features from finely labeled HSI cubes for HSI classification. Experimental results show that FCSN has the superior generalization capability to the changes of spatial land-cover distributions. | ||||||||||||
Accession Number: WOS:000617758400007 | ||||||||||||
PubMed ID: 33539293 | ||||||||||||
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ISSN: 1057-7149 | ||||||||||||
eISSN: 1941-0042 |
Record 312 of 318 | ||||||||||||
Title: Program-controlled single soliton microcomb source | ||||||||||||
Author(s): Wang, XY (Wang, Xinyu); Xie, P (Xie, Peng); Wang, WQ (Wang, Weiqiang); Wang, Y (Wang, Yang); Lu, ZZ (Lu, Zhizhou); Wang, LR (Wang, Leiran); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Zhao, W (Zhao, Wei); Zhang, WF (Zhang, Wenfu) | ||||||||||||
Source: PHOTONICS RESEARCH Volume: 9 Issue: 1 Pages: 66-72 DOI: 10.1364/PRJ.408612 Published: JAN 1 2021 | ||||||||||||
Abstract: Soliton microcombs (SMCs) are spontaneously formed in a coherently pumped high-quality microresonator, which provides a new tool for use as an on-chip frequency comb for applications of high-precision metrology and spectroscopy. However, generation of SMCs seriously relies on advanced experimental techniques from professional scientists. Here, we experimentally demonstrate a program-controlled single SMC source where the intracavity thermal effect is timely balanced using an auxiliary laser during single SMC generation. The microcomb power is adopted as the criteria for microcomb states discrimination and a forward and backward thermal tuning technique is employed for the deterministic single SMC generation. Further, based on a closed-loop control system, the repetition rate stability of the SMC source improved more than 20 times and the pump frequency can be continuously tuned by simply changing the operation temperature. The reliability of the SMC source is verified by consecutive 200 generation trials and maintaining over 10 h. We believe the proposed SMC source will have significant promising influences in future SMC-based application development. (C) 2020 Chinese Laser Press | ||||||||||||
Accession Number: WOS:000603599400012 | ||||||||||||
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ISSN: 2327-9125 |
Record 313 of 318 | ||||||||||||
Title: Scalable Wide Neural Network: A Parallel, Incremental Learning Model Using Splitting Iterative Least Squares | ||||||||||||
Author(s): Xi, JB (Xi, Jiangbo); Ersoy, OK (Ersoy, Okan K.); Fang, JW (Fang, Jianwu); Cong, M (Cong, Ming); Wei, X (Wei, Xin); Wu, TJ (Wu, Tianjun) | ||||||||||||
Source: IEEE ACCESS Volume: 9 Pages: 50767-50781 DOI: 10.1109/ACCESS.2021.3068880 Published: 2021 | ||||||||||||
Abstract: With the rapid development of research on machine learning models, especially deep learning, more and more endeavors have been made on designing new learning models with properties such as fast training with good convergence, and incremental learning to overcome catastrophic forgetting. In this paper, we propose a scalable wide neural network (SWNN), composed of multiple multi-channel wide RBF neural networks (MWRBF). The MWRBF neural network focuses on different regions of data and nonlinear transformations can be performed with Gaussian kernels. The number of MWRBFs for proposed SWNN is decided by the scale and difficulty of learning tasks. The splitting and iterative least squares (SILS) training method is proposed to make the training process easy with large and high dimensional data. Because the least squares method can find pretty good weights during the first iteration, only a few succeeding iterations are needed to fine tune the SWNN. Experiments were performed on different datasets including gray and colored MNIST data, hyperspectral remote sensing data (KSC, Pavia Center, Pavia University, and Salinas), and compared with main stream learning models. The results show that the proposed SWNN is highly competitive with the other models. | ||||||||||||
Accession Number: WOS:000638390700001 | ||||||||||||
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ISSN: 2169-3536 |
Record 314 of 318 | |||||||||
Title: Coherent synthetic aperture imaging for visible remote sensing via reflective Fourier ptychography | |||||||||
Author(s): Xiang, M (Xiang, Meng); Pan, A (Pan, An); Zhao, YY (Zhao, Yiyi); Fan, XW (Fan, Xuewu); Zhao, H (Zhao, Hui); Li, C (Li, Chuang); Yao, BL (Yao, Baoli) | |||||||||
Source: OPTICS LETTERS Volume: 46 Issue: 1 Pages: 29-32 DOI: 10.1364/OL.409258 Published: JAN 1 2021 | |||||||||
Abstract: Synthetic aperture radar can measure the phase of a microwave with an antenna, which cannot be directly extended to visible light imaging due to phase lost. In this Letter, we report an active remote sensing with visible light via reflective Fourier ptychography, termed coherent synthetic aperture imaging (CSAI), achieving high resolution, a wide field-of-view (FOV), and phase recovery. A proof-of-concept experiment is reported with laser scanning and a collimator for the infinite object. Both smooth and rough objects are tested, and the spatial resolution increased from 15.6 to 3.48 mu M with a factor of 4.5. The speckle noise can be suppressed obviously, which is important for coherent imaging. Meanwhile, the CSAI method can tackle the aberration induced from the optical system by one-step deconvolution and shows the potential to replace the adaptive optics for aberration removal of atmospheric turbulence. (C) 2020 Optical Society of America | |||||||||
Accession Number: WOS:000603399900008 | |||||||||
PubMed ID: 33362005 | |||||||||
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ISSN: 0146-9592 | |||||||||
eISSN: 1539-4794 |
Record 315 of 318 |
Title: Analysis and correction of geometrical error-induced pointing errors of a space laser communication APT system |
Author(s): Zhang, FR (Zhang, Furui); Ruan, P (Ruan, Ping); Han, JF (Han, Junfeng); Li, Y (Li, Yao) |
Source: INTERNATIONAL JOURNAL OF OPTOMECHATRONICS Volume: 15 Issue: 1 DOI: 10.1080/15599612.2021.1895923 Published: JAN 1 2021 |
Abstract: The geometrical error caused pointing error is an inevitable problem in space satellite laser communication terminals which can affect the pointing accuracy of the APT (acquisition pointing and tracking) system greatly, in order to facilitate the assembling of the APT system and improve the performance of the laser communication system, the geometrical error sensitivity about the APT pointing accuracy is analyzed based on multi-body kinematics method in this paper, the error transformation matrix is derived and the geometrical error is analyzed, the simulation results provide some pointing error distribution regulars which are conductive to assembling. Based on the above research, the geometrical error correction experiment is performed and the pointing accuracy of the APT system is tested, the expectation value of the pointing error can reach 29.9 mu rad which is greatly improved. This research can provide technical references for the design and analysis of space laser communication terminals. |
Accession Number: WOS:000646038800001 |
ISSN: 1559-9612 |
eISSN: 1559-9620 |
Record 316 of 318 |
Title: Optical path pointing error and coaxiality analysis of APT system of space laser communication terminal |
Author(s): Zhang, FR (Zhang Furui); Ruan, P (Ruan Ping); Han, JF (Han Junfeng) |
Source: OPTICA APPLICATA Volume: 51 Issue: 2 Pages: 203-222 DOI: 10.37190/oa210205 Published: 2021 |
Abstract: Precision beam pointing is the key indicator for APT (acquisition, pointing and tracking) system in space laser communication. The laser travels inside the optical system and the pointing vector will be affected by an assembly error of the axis and reflectors. In this paper, the model of the optical path pointing error and coaxiality error induced by the assembly error are established; the error distribution is given and a quantitative analysis is performed. The results show that the magnitude of pointing error is affected by the axis assembling error greatly but its distribution is susceptible to the reflector assembly error. Finally, the correction of coaxiality is performed and tested. The experimental results show that the coaxiality error can be greatly improved and the mean value of the coaxiality error of a beacon path and a signal path are 14 and 9.6 mu rad, respectively, which meets the requirements. This work can provide guidance for design and assembly of the APT and contribute to the improvement of its pointing performance. |
Accession Number: WOS:000674668900005 |
ISSN: 0078-5466 |
eISSN: 1899-7015 |
Record 317 of 318 | ||||||||||||
Title: Fine-Grained Visual Categorization by Localizing Object Parts With Single Image | ||||||||||||
Author(s): Zheng, XT (Zheng, Xiangtao); Qi, L (Qi, Lei); Ren, YT (Ren, Yutao); Lu, XQ (Lu, Xiaoqiang) | ||||||||||||
Source: IEEE TRANSACTIONS ON MULTIMEDIA Volume: 23 Pages: 1187-1199 DOI: 10.1109/TMM.2020.2993960 Published: 2021 | ||||||||||||
Abstract: Fine-grained visual categorization (FGVC) refers to assigning fine-grained labels to images which belong to the same base category. Due to the high inter-class similarity, it is challenging to distinguish fine-grained images under different subcategories. Recently, researchers have proposed to firstly localize key object parts within images and then find discriminative clues on object parts. To localize object parts, existing methods train detectors for different kinds of object parts. However, due to the fact that the same kind of object part in different images often changes intensely in appearance, the existing methods face two shortages: 1) Training part detector for object parts with diverse appearance is laborious; 2) Discriminative parts with unusual appearance may be neglected by the trained part detectors. To localize the key object parts efficiently and accurately, a novel FGVC method is proposed in the paper. The main novelty is that the proposed method localizes the key object parts within each image only depending on a single image and hence avoid the influence of diversity between parts in different images. The proposed FGVC method consists of two key steps. Firstly, the proposed method localizes the key parts in each image independently. To this end, potential object parts in each image are identified and then these potential parts are merged to generate the final representative object parts. Secondly, two kinds of features are extracted for simultaneously describing the discriminative clues within each part and the relationship between object parts. In addition, a part based dropout learning technique is adopted to boost the classification performance further in the paper. The proposed method is evaluated in comparison experiments and the experiment results show that the proposed method can achieve comparable or better performance than state-of-the-art methods. | ||||||||||||
Accession Number: WOS:000645068200003 | ||||||||||||
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ISSN: 1520-9210 | ||||||||||||
eISSN: 1941-0077 |
Record 318 of 318 | |||||||||||||||
Title: The ensemble deep learning model for novel COVID-19 on CT images | |||||||||||||||
Author(s): Zhou, T (Zhou Tao); Lu, HL (Lu Huiling); Yang, ZL (Yang Zaoli); Qiu, S (Qiu Shi); Huo, BQ (Huo Bingqiang); Dong, YL (Dong Yali) | |||||||||||||||
Source: APPLIED SOFT COMPUTING Volume: 98 Article Number: 106885 DOI: 10.1016/j.asoc.2020.106885 Published: JAN 2021 | |||||||||||||||
Abstract: The rapid detection of the novel coronavirus disease, COVID-19, has a positive effect on preventing propagation and enhancing therapeutic outcomes. This article focuses on the rapid detection of COVID-19. We propose an ensemble deep learning model for novel COVID-19 detection from CT images. 2933 lung CT images from COVID-19 patients were obtained from previous publications, authoritative media reports, and public databases. The images were preprocessed to obtain 2500 high-quality images. 2500 CT images of lung tumor and 2500 from normal lung were obtained from a hospital. Transfer learning was used to initialize model parameters and pretrain three deep convolutional neural network models: AlexNet, GoogleNet, and ResNet. These models were used for feature extraction on all images. Softmax was used as the classification algorithm of the fully connected layer. The ensemble classifier EDL-COVID was obtained via relative majority voting. Finally, the ensemble classifier was compared with three component classifiers to evaluate accuracy, sensitivity, specificity, F value, and Matthews correlation coefficient. The results showed that the overall classification performance of the ensemble model was better than that of the component classifier. The evaluation indexes were also higher. This algorithm can better meet the rapid detection requirements of the novel coronavirus disease COVID-19. (C) 2020 Elsevier B.V. All rights reserved. | |||||||||||||||
Accession Number: WOS:000603366000004 | |||||||||||||||
PubMed ID: 33192206 | |||||||||||||||
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ISSN: 1568-4946 | |||||||||||||||
eISSN: 1872-9681 |