2024

• Record 85 of
  
  Title:Rapid Solidification of Invar Alloy
  
  Author(s):He, Hanxin(1); Yao, Zhirui(2); Li, Xuyang(3); Xu, Junfeng(2)
  Source:Materials
  Volume: 17  Issue: 1  DOI: 10.3390/ma17010231  Published: January 2024  
  Abstract:The Invar alloy has excellent properties, such as a low coefficient of thermal expansion, but there are few reports about the rapid solidification of this alloy. In this study, Invar alloy solidification at different undercooling (ΔT) was investigated via glass melt-flux techniques. The sample with the highest undercooling of ΔT = 231 K (recalescence height 140 K) was obtained. The thermal history curve, microstructure, hardness, grain number, and sample density of the alloy were analyzed. The results show that with the increase in solidification undercooling, the XRD peak of the sample shifted to the left, indicating that the lattice constant increased and the solid solubility increased. As the solidification of undercooling increases, the microstructure changes from large dendrites to small columnar grains and then to fine equiaxed grains. At the same time, the number of grains also increases with the increase in the undercooling. The hardness of the sample increases with increasing undercooling. If ΔT ≥ 181 K (128 K), the grain number and the hardness do not increase with undercooling. © 2023 by the authors.
  Accession Number: 20240315384601
• Record 86 of
  
  Title:Parameter-free super-resolution structured illumination microscopy via a physics-enhanced neural network
  
  Author(s):Wang, Siying(1,2); Bai, Chen(1,2); Li, Xing(1,2); Qian, Jia(1); Li, Runze(1); Peng, Tong(1); Tian, Xuan(1,2); Ma, Wang(1,2); Ma, Rui(1,2); An, Sha(3); Gao, Peng(3); Dan, Dan(1,2); Yao, Baoli(1,2)
  Source:Optics Letters
  Volume: 49  Issue: 17  DOI: 10.1364/OL.533164  Published: September 1, 2024  
  Abstract:With full-field imaging and high photon efficiency advantages, structured illumination microscopy (SIM) is one of the most potent super-resolution (SR) modalities in bioscience. Regarding SR reconstruction for SIM, spatial domain reconstruction (SDR) has been proven to be faster than traditional frequency domain reconstruction (FDR), facilitating real-time imaging of live cells. Nevertheless, SDR relies on high-precision parameter estimation for reconstruction, which tends to suffer from low signal-to-noise ratio (SNR) conditions and inevitably leads to artifacts that seriously affect the accuracy of SR reconstruction. In this Letter, a physics-enhanced neural network-based parameter-free SDR (PNNP-SDR) is proposed, which can achieve SR reconstruction directly in the spatial domain. As a result, the peak-SNR (PSNR) of PNNP-SDR is improved by about 4 dB compared to the cross-correlation (COR) SR reconstruction; meanwhile, the reconstruction speed of PNNP-SDR is even about five times faster than the fast approach based on principal component analysis (PCA). Given its capability of achieving parameter-free imaging, noise robustness, and high-fidelity and high-speed SR reconstruction over conventional SIM microscope hardware, the proposed PNNP-SDR is expected to be widely adopted in biomedical SR imaging scenarios. © 2024 Optica Publishing Group. All rights
  Accession Number: 20243516948264
• Record 87 of
  
  Title:Graph Representation Learning-Guided Diffusion Model for Hyperspectral Change Detection
  
  Author(s):Ding, Xinyu(1); Qu, Jiahui(1); Dong, Wenqian(1,2); Zhang, Tongzhen(1); Li, Nan(3); Yang, Yufei(1)
  Source:IEEE Geoscience and Remote Sensing Letters
  Volume: 21  Issue:   DOI: 10.1109/LGRS.2024.3405635  Published: 2024  
  Abstract:Due to its capability to monitor subtle changes occurring on the Earth's surface, hyperspectral images change detection (HSI-CD) has emerged as a focal research area in the field of remote sensing. Recently, diffusion models have demonstrated remarkable performance in the field of HSI-CD. However, vanilla diffusion models are mostly constructed by CNN, which struggles to model global context relationships in complex scenes to result in limited change detection accuracy. In order to overcome the shortcomings about vanilla diffusion models, we innovatively design graph representation learning-guided diffusion model (GDM) and propose the GDM-based HSI-CD network (GDMCD). Specially, we utilize graph convolutional to construct the GDM as the feature extractor, which can adequately extract global difference features of HSIs. Then, we design the difference perception amplification module (DPAM) to increase the distinction between difference features extracted by GDM. Finally, we obtain the change map by classifying difference features which are processed by DPAM. Experiments conducted on three publicly available datasets with 1% sample size demonstrate that the proposed method outperforms the other state-of-the-art methods in terms of Overall Accuracy (OA), Kappa Coefficient (KC) achieving improvements of approximately 0.006%, 1.61%, and 0.34%, respectively. © 2004-2012 IEEE.
  Accession Number: 20242316205002
• Record 88 of
  
  Title:Material removal and surface generation mechanisms in rotary ultrasonic vibration–assisted aspheric grinding of glass ceramics
  
  Author(s):Sun, Guoyan(1,2); Wang, Sheng(3); Zhao, Qingliang(3); Ji, Xiabin(1); Ding, Jiaoteng(1)
  Source:International Journal of Advanced Manufacturing Technology
  Volume: 130  Issue: 7-8  DOI: 10.1007/s00170-023-12904-x  Published: February 2024  
  Abstract:High-efficiency precision grinding can shorten the machining cycle of aspheric optical elements by a factor of 2–10. To achieve this objective, ultrasonic vibration (UV)–assisted grinding (UVG) has been increasingly applied to manufacture aspheric optics. However, the mechanisms of material removal and surface formation in UV-assisted aspheric grinding of glass ceramics have rarely been studied. Herein, rotary UV-assisted vertical grinding (RUVG) was used to explore the machining mechanism of coaxial curved surfaces. First, RUV-assisted scratch experiments were conducted on aspheric surface of glass ceramics, which exhibited multiple benefits over conventional scratching. These include a reduction in the scratch force by 37.83–44.55% for tangential component and 3.87–28.15% for normal component, an increase in plastic removal length by 43.75%, and an increase in material removal rate by almost a factor of 2. Moreover, grinding marks on the aspheric surface in RUVG were accurately simulated and optimized by adjusting grinding parameters. RUVG experiments were performed to verify the accuracy of grinding texture simulations and investigate the UV effect. The results demonstrate that UV can improve the surface quality of aspheric grinding when compared with conventional vertical grinding. In particular, the total height of the profile of form accuracy and its root mean square were significantly improved by a factor of 3.38–4.54 and 7.15–10.82, respectively, and the surface roughness reduced by 10.03–12.10%. This study provides deeper insight into material removal and surface generation mechanisms for RUVG of aspheric surfaces, and it is thus envisaged that these results will be useful in engineering applications. © 2024, The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.
  Accession Number: 20240215352394
• Record 89 of
  
  Title:Modeling and Analysis of Electromechanical Automatic Leveling Mechanism for High-Mobility Vehicle-Mounted Theodolites
  
  Author(s):Li, Xiangyu(1,2,3); Ruan, Ping(1,2); Hao, Wei(1,2); Xie, Meilin(1,2); Lv, Tao(1,2,3)
  Source:IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
  Volume: E107.A  Issue: 7  DOI: 10.1587/transfun.2023EAP1058  Published: July 1, 2024  
  Abstract:To achieve precise measurement without landing, the high-mobility vehicle-mounted theodolite needs to be leveled quickly with high precision and ensure sufficient support stability before work. After the measurement, it is also necessary to ensure that the high-mobility vehicle-mounted theodolite can be quickly withdrawn. Therefore, this paper proposes a hierarchical automatic leveling strategy and establishes a two-stage electromechanical automatic leveling mechanism model. Using coarse leveling of the first-stage automatic leveling mechanism and fine leveling of the second-stage automatic leveling mechanism, the model realizes high-precision and fast leveling of the vehicle-mounted theodolites. Then, the leveling control method based on repeated positioning is proposed for the first-stage automatic leveling mechanism. To realize the rapid withdrawal for high-mobility vehicle-mounted theodolites, the method ensures the coincidence of spatial movement paths when the structural parts are unfolded and withdrawn. Next, the leg static balance equation is constructed in the leveling state, and the support force detection method is discussed in realizing the stable support for vehicle-mounted theodolites. Furthermore, a mathematical model for "false leg" detection is established furtherly, and a "false leg" detection scheme based on the support force detection method is analyzed to significantly improve the support stability of vehicle-mounted theodolites. Finally, an experimental platform is constructed to perform the performance test for automatic leveling mechanisms. The experimental results show that the leveling accuracy of established two-stage electromechanical automatic leveling mechanism can reach 3.600, and the leveling time is no more than 2 mins. The maximum support force error of the support force detection method is less than 15%, and the average support force error is less than 10%. In contrast, the maximum support force error of the drive motor torque detection method reaches 80.12%, and its leg support stability is much less than the support force detection method. The model and analysis method proposed in this paper can also be used for vehicle-mounted radar, vehicle-mounted laser measurement devices, vehicle-mounted artillery launchers and other types of vehicle-mounted equipment with high-precision and high-mobility working requirements. © 2024 The Institute of Electronics, Information and Communication Engineers.
  Accession Number: 20242716644921
• Record 90 of
  
  Title:Cognitive Fusion of Graph Neural Network and Convolutional Neural Network for Enhanced Hyperspectral Target Detection
  
  Author(s):Xu, Shufang(1,2); Geng, Sijie(3); Xu, Pengfei(4); Chen, Zhonghao(3); Gao, Hongmin(1)
  Source:IEEE Transactions on Geoscience and Remote Sensing
  Volume: 62  Issue:   DOI: 10.1109/TGRS.2024.3392188  Published: 2024  
  Abstract:In recent years, deep learning has emerged as a prominent technique in hyperspectral target detection (HTD). Extensive research has highlighted the potential of graph neural network (GNN) as a promising framework for exploring non-Euclidean dependencies within hyperspectral imagery (HSI). However, GNN has not been introduced to HTD. Additionally, achieving a balanced training set while effectively suppressing background remains a challenge. Therefore, we propose the cognitive fusion of GNN and convolutional neural network (CNN) for enhanced HTD (named as CFGC), which marks the first integration of GNN and CNN in HTD. Initially, using sparse subspace clustering (SSC) and a similarity measurement strategy, we select the most representative background samples for HTD. Subsequently, linear interpolation combines the prior target with the Laplacian-weighted prior target, yielding abundant targets with meaningful transformations. Finally, a fused network of CNN and GNN is utilized for training both the prior target and the constructed training set. Significantly, the incorporation of attention mechanism in both the CNN and GNN branches stands out as a noteworthy advantage, augmenting the models' ability to selectively prioritize crucial information. Four benchmark hyperspectral images have been used in extensive experiments, and the results demonstrate that CFGC exhibits superior performance in HTD. © 1980-2012 IEEE.
  Accession Number: 20241815997563
• Record 91 of
  
  Title:Adaptive location method for film cooling holes based on the design intent of the turbine blade
  
  Author(s):Hou, Yaohua(1); Wang, Jing(1); Mei, Jiawei(2); Zhao, Hualong(1)
  Source:International Journal of Advanced Manufacturing Technology
  Volume: 132  Issue: 3-4  DOI: 10.1007/s00170-024-13456-4  Published: May 2024  
  Abstract:Due to the inevitable deviation of the casting process, the dimensional error of the turbine blade is introduced. As a result, the location datum of the film cooling holes is changed, which has an impact on the machining accuracy. The majority of pertinent studies concentrate on the rigid location approach for the entire blade, which results in a modest relative position error of the blade surface but still fails to give the exact position and axial direction of the film cooling holes of the deformed blade. In this paper, the entire deformation of the blade cross-section curve is divided into a number of deformation combinations of the mean line curve based on the construction method of the blade design intent. The exact location of the film cooling holes in the turbine blade with deviation is therefore efficiently solved by a flexible deformation of the blade that optimises the position and axial direction of the holes. The verification demonstrates that the novel method can significantly reduce both the contour deviation of the blade surface and the location issue of the film cooling holes. After machining experiments, the maximum position deviation of the holes is reduced by approximately 80% compared to the rigid location method of the entire blade, and the average value and standard deviation are also decreased by about 70%. © The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature 2024.
  Accession Number: 20241215791556
• Record 92 of
  
  Title:Calibration method of relative spectral response function of indirect imaging spectrometer
  
  Author(s):Li, Xiao-Xiao(1,2); Li, Juan(1); Bai, Cai-Xun(3); Chang, Chen-Guang(1,2); Hao, Xiong-Bo(1); Wen, Zhen-Qing(1,2); Wang, Peng-Chong(1); Feng, Yu-Tao(1)
  Source:Wuli Xuebao/Acta Physica Sinica
  Volume: 73  Issue: 12  DOI: 10.7498/aps.73.20240200  Published: June 2024  
  Abstract:In imaging spectrometers, area array detectors are usually used as photoelectric conversion devices, but the inconsistency of the spectral response among pixels can distort the collected target spectra. To improve the spectral radiometric accuracy of imaging spectrometers, calibrating and correcting the inconsistency of the spectral response among pixels is essential. The signal received by each pixel of area array detector of the indirect imaging spectrometer is usually the superposition of the target multi-spectral radiation signals or full-spectral radiation signals. Therefore, its relative spectral radiometric calibration requires measuring the spectral response of each pixel at different wavelengths on the array detector. Under the ideal conditions, the response values of each pixel in the area array detector are different, so the indirect imaging spectrometer cannot simply calibrate the relative spectral response (RSR) function between pixels by using the method of "monochromator + integrating sphere". In this work, taking the interferometric imaging spectrometer for example, we analyze the influence of the inconsistency of the RSR among pixels on the target spectral radiation measurement accuracy, and propose a system-level RSR function measurement method for the indirect imaging spectrometer based on the Fourier transform modulation calibration source. In addition, we establish a mathematical model for calibrating the RSR function,and provide guidelines for selecting calibration system parameters such as light source, spectral resolution, and OPD sampling interval. The simulation results show that under the ideal noise-free condition, the 1% spectral response inconsistency among pixels results in a relative error of 1.02% to the recovered spectra. After RSR correction, the relative error of the recovered spectra of different rows decreases to 0.08%. Furthermore, in this work we simulate and analyse the influence of spectral signal-to-noise ratio on the calibration accuracy of the RSR function, and point out that increasing the brightness of the calibration light source, extending exposure time, and combining multi-frame interferograms can enhance RSR function calibration accuracy in practical applications. The research result can provide a theoretical basis for realizing the relative spectral radiometric calibration of indirect imaging spectrometer, which is of great significance in promoting quantitative spectral remote sensing. © 2024 Chinese Physical Society.
  Accession Number: 20242616443379
• Record 93 of
  
  Title:Biomimetic Curved Artificial Compound Eyes: A Review
  
  Author(s):Jiang, Heng(1,2); Tsoi, Chi Chung(1,2); Sun, Lanrui(1,2); Yu, Weixing(3); Fan, Hao(3); Ma, Mengchao(4); Jia, Yanwei(5); Zhang, Xuming(1,2)
  Source:Advanced Devices and Instrumentation
  Volume: 5  Issue:   DOI: 10.34133/adi.0034  Published: January 2024  
  Abstract:Natural compound eyes (NCEs) are the most abundant and successful eye designs in the animal kingdom. An NCE consists of a number of ommatidia, which are distributed along a curved surface to receive light. This curved feature is critical to the functions of NCE, and it ensures that different ommatidia point to slightly different directions and thus enables panoramic vision, depth perception, and efficient motion tracking while minimizing aberration. Consequently, biomimetic curved artificial compound eyes (BCACEs) have garnered substantial research attention in replicating the anatomical configuration of their natural counterparts by distributing ommatidia across a curved surface. The reported BCACEs could be briefly categorized into 2 groups: fixed focal lengths and tunable focal lengths. The former could be further subcategorized into simplified BCACEs, BCACEs with photodetector arrays within curved surfaces, and BCACEs with light guides. The latter encompasses other tuning techniques such as fluidic pressure modulation, thermal effects, and pH adjustments. This work starts with a simple classification of NCEs and then provides a comprehensive review of main parameters, operational mechanisms, recent advancements, fabrication methodologies, and potential applications of BCACEs. Finally, discussions are provided on future research and development. Compared with other available review articles on artificial compound eyes, our work is distinctive since we focus especially on the "curved" ones, which are difficult to fabricate but closely resemble the architecture and functions of NCEs, and could potentially revolutionize the imaging systems in surveillance, machine vision, and unmanned vehicles. Copyright © 2024 Heng Jiang et al.
  Accession Number: 20243016763510
• Record 94 of
  
  Title:Progressive Multi-Iteration Registration-Fusion Co-Optimization Network for Unregistered Hyperspectral Image Super-Resolution
  
  Author(s):Qu, Jiahui(1); Liu, Xuyao(1); Dong, Wenqian(1,2); Liu, Yang(3); Zhang, Tongzhen(1); Xu, Yang(1); Li, Yunsong(1)
  Source:IEEE Transactions on Geoscience and Remote Sensing
  Volume: 62  Issue:   DOI: 10.1109/TGRS.2024.3408424  Published: 2024  
  Abstract:Existing fusion-based hyperspectral image super-resolution (fusion-based HSI-SR) methods usually reconstruct high-resolution hyperspectral image (HR-HSI) by integrating the complementary information of low-resolution hyperspectral image (LR-HSI) and high-resolution multispectral image (HR-MSI). However, most of such methods rely on accurately registered images or consider registration and fusion as a two-stage task, which means that fusion must tolerate the accumulation of errors due to misregistration. In this article, we propose a progressive multi-iteration registration-fusion co-optimization network (PMI-RFCoNet) for unregistered HSI-SR, which progressively refines the registration and fusion result over multiple levels to reconstruct registered HR-HSI. To achieve registration-fusion co-optimization, the registration-fusion co-optimization block (Co-RFB) is designed to iterate continuously over multiple levels. We embed the interactive registration module (IRM) and the spectral recalibration and fusion module (SRFU) in Co-RFB, which can facilitate the network utilizing spatial and spectral features at different levels to generate more accurate HR-HSI. Specifically, IRM generates deformation field based on spatial correlations captured at long distances to repair non-rigid pixel offsets, and SRFU further performs adaptive high-fidelity spectral correction and spatial information fusion on the registration results. We conduct experimental verification on four widely used datasets, and the results show that PMI-RFCoNet can flexibly cope with different types and degrees of non-rigid deformation and achieve superior performance. Code is available at https://github.com/Jiahuiqu/PMI-RFCoNet. © 1980-2012 IEEE.
  Accession Number: 20242416235762
• Record 95 of
  
  Title:Linear-space-variant model for Fourier ptychographic microscopy
  
  Author(s):Feng, Tianci(1,2); Wang, Aiye(1,2); Wang, Zhiping(1,3); Liao, Yizheng(1,2); Pan, An(1,2)
  Source:Optics Letters
  Volume: 49  Issue: 10  DOI: 10.1364/OL.522745  Published: May 15, 2024  
  Abstract:Fourier ptychographic microscopy (FPM) needs to realize well-accepted reconstruction by image segmentation and discarding problematic data due to artifacts caused by vignetting. However, the imaging results have long suffered from uneven color blocks and the consequent digital stitching artifacts, failing to bring satisfying experiences to researchers and users over the past decade since the invention of FPM. In fact, the fundamental reason for vignetting artifacts lies in that the acquired data does not match the adopted linear-space-invariant (LSI) forward model, i.e., the actual object function is modulated by a quadratic phase factor during data acquisition, which has been neglected in the advancement of FPM. In this Letter, we rederive a linear-space-variant (LSV) model for FPM and design the corresponding loss function for FPM, termed LSV-FPM. Utilizing LSV-FPM for optimization enables the efficient removal of wrinkle artifacts caused by vignetting in the reconstruction results, without the need of segmenting or discarding images. The effectiveness of LSV-FPM is validated through data acquired in both 4f and finite conjugate single-lens systems. © 2024 Optica Publishing Group (formerly OSA). All rights reserved.
  Accession Number: 20242116112682
• Record 96 of
  
  Title:In-line attosecond photoelectron holography for single photon ionization
  
  Author(s):Liu, Yanhong(1); Cao, Wei(1); Yao, Ling-Hui(2); Pi, Liang-Wen(2); Zhou, Yueming(1); Lu, Peixiang(1,3)
  Source:Physical Chemistry Chemical Physics
  Volume: 26  Issue: 25  DOI: 10.1039/d3cp05919g  Published: June 18, 2024  
  Abstract:The momentum distribution of photoelectrons in H2+ molecules subjected to an attosecond pulse is theoretically investigated. To better understand the laser-molecule interaction, we develop an in-line photoelectron holography approach that is analogous to optical holography. This approach is specifically suitable for extracting the amplitude and phase of the forward-scattered electron wave packet in a dissociating molecule with atomic precision. We also extend this approach to imaging the transient scattering cross-section of a molecule dressed by a near infrared laser field. This attosecond photoelectron holography sheds light on structural microscopy of dissociating molecules with high spatial-temporal resolution. © 2024 The Royal Society of Chemistry.
  Accession Number: 20242516295916