2013
2013
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Record 157 of
Title:Adaptive cancellation of light relative intensity noise for fiber optic gyroscope
Author(s):Ji, Zhongxiao(1,2)Source: Telkomnika - Indonesian Journal of Electrical Engineering Volume: 11 Issue: 12 DOI: Published: December 2013Abstract:In order to reduce the relative intensity noise (RIN) in the interferometric signal of the fiber opticgyroscope (FOG), an adaptive noise subtraction method is presented, which aims to overcome to the drawbacks that the fixed delay time and gain of the digital noise subtraction method. The drawbacks willmake the performance of FOG to be degraded greatly in the changing environment. In the paper theadaptive noise subtraction system based on the recursive least squares algorithm (RLS) is formed inFPGA, in which the interferometric signal is regarded as the signal source, and RIN in the free end of theoptical fiber coupler of FOG is looked as the noise reference signal. The two critical parameters that minimum delay time and its varying range result from measuring the minimum and maximum delay times of the interferometric signal in a certain temperature range. The off-line and on-line temperature experimental results verify the capability of adapting to the environmental temperature. © 2013 Universitas Ahmad Dahlan.Accession Number: 20134616987924 -
Record 158 of
Title:The new design and veri cation based on the coordinate rotation digital computer
Author(s):Li, Tiefeng(1,2); Ma, Caiwen(1); Li, Wenhua(1)Source: Journal of Information and Computational Science Volume: 10 Issue: 16 DOI: 10.12733/jics20102430 Published: November 1, 2013Abstract:The Coordinate Rotation Digital Computer (CORDIC) is an effective convergence algorithm that is used to compute many trigonometric functions using shifts and additions. However, it is difficult to be completely implemented in Integrated Circuit (IC) field because the CORDIC has six complex operating modes. Currently the shortcoming of CORDIC in the IC field are the low precision and the long calculation time so that it can't meet the actual needs. To over this, a new CORDIC algorithm that mainly adopts the iteration and the Looking-up Table (LUT) is introduced in this paper, which not only supports circular, linear and hyperbolic trigonometric function but it also has the interruption and overflowing functions. Most important is that it has higher precision and faster calculation speed than the conventional design. For example, the calculation speed of new CORDIC is up to 120 MHz. Using this frequency, it takes about 40 clock cycles to finish a trigonometric calculation. Moreover, the random verification model is firstly applied in the process of CORDIC design, which may automatically verify the definition domains of all input data and quickly analyze the precision errors of the calculated results. Finally, the precision errors between the expected results and the actual results are fully recorded by the verification model. © 2013 Binary Information Press.Accession Number: 20134917048380 -
Record 159 of
Title:Design of the objective lens for endoscope with imaging fiber bundle
Author(s):Yan, Xingtao(1,2); Yang, Jianfeng(1); Xue, Bin(1); Zhou, Ke(1,2); Zhao, Yiyi(1,2); Bu, Fan(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 42 Issue: 2 DOI: Published: February 2013Abstract:For the endoscope with imaging fiber bundle, either the configuration or the imaging quality of its objective lens should satisfy some new requirements. Firstly, the fundamental of the objective lens design was analyzed, and the retrofocus objective lens was chosen as an initial structure for this design. Then an objective lens for the fiber-optic endoscope was designed with the software Zemax. The operation wavelength, focal length, FOV (field of view) and relative aperture of the designed lens are 0.38-0.78 μm, 0.921 mm, 100° and 1/4 respectively. Its total length is 10.32 mm. It's telecentric in image space. The MTF value of the lens is greater than 0.85 at the spatial frequency of 38 lp/mm. Furthermore, a model of the designed lens combined with the imaging fiber bundle was established in the software Tracepro. The coupling efficiency of the simulated system is about 96% and the illumination of output end is uniform. All the results show that the designed lens has the peculiarity of wide FOV, short focal length, logical configuration, high coupling efficiency and uniformity illumination at image plane. It is suitable for the fiber-optic endoscope.Accession Number: 20131616213960 -
Record 160 of
Title:Erratum: Empirical mode decomposition based background removal and de-noising in polarization interference imaging spectrometer (Optics Express (2013) 21:3 (2592-2605))
Author(s):Ren, Wenyi(1,2,3); Zhang, Chunmin(1,2); Mu, Tingkui(1,2); Fu, Lili(1,3); Jia, Chenling(1,2)Source: Optics Express Volume: 21 Issue: 8 DOI: 10.1364/OE.21.010207 Published: April 22, 2013Abstract:nullAccession Number: 20131916321362 -
Record 161 of
Title:Precise spectrum reconstruction of the Fourier transforms imaging spectrometer based on polarization beam splitters
Author(s):Ren, Wenyi(1,2,3); Zhang, Chunmin(1,2); Jia, Chenling(1,2); Mu, Tingkui(1,2); Li, Qiwei(1,2); Zhang, Lin(1,2)Source: Optics Letters Volume: 38 Issue: 8 DOI: 10.1364/OL.38.001295 Published: April 15, 2013Abstract:A method was proposed to precisely reconstruct the spectrum from the interferogram taken by the Fourier transform imaging spectrometer (FTIS) based on the polarization beam splitters. Taken the FTISs based on the Savart polariscope and Wollaston prism as examples, the distorted spectrums were corrected via the proposed method effectively. The feasibility of the method was verified via simulation. The distorted spectrum, recovered from the interferogram taken by the polarization imaging spectrometer developed by us, was corrected. © 2013 Optical Society of America.Accession Number: 20131816287588 -
Record 162 of
Title:Multiple frequency bands of square split resonant rings and metal wire metamaterial
Author(s):Gao, Peng(1,2,3); Zhang, Chunmin(1,2); Ai, Jingjing(1,2,3); Kang, Yongqiang(1,2,3); Li, Gang(1,2,3)Source: Applied Optics Volume: 52 Issue: 25 DOI: 10.1364/AO.52.006309 Published: September 1, 2013Abstract:This work presents experimental measurements of two square split resonant ring and metal wire (SSRR-MW) samples with different cell sizes at microwave frequencies. The geometrical sizes of the metamaterial cells are found to play an important role in the resonant frequency. Cells with different geometrical sizes are chosen to stack into a two-layer or three-layer metamaterial unit to realize the multiple negative passbands. The effective parameters of three separate SSRR-MW models (a one-layer unit, a two-layer unit, and a three-layer unit) are retrieved from the simulation data. The composed models exhibit two or three negative bands by overlapping the passbands of original cells and broadening the overall bandwidth. The recovered parameters show good agreement with the theoretical analysis. © 2013 Optical Society of America.Accession Number: 20133816764219 -
Record 163 of
Title:Higher quantum efficiency GaAs photocathode material with exponential-doping structure
Author(s):Chen, Huailin(1); Yang, Wenzheng(2); Tang, Weidong(2); Fu, Xiaoqian(1); Du, Yujie(1); Zhang, Junju(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8761 Issue: DOI: 10.1117/12.2020136 Published: 2013Abstract:To improve the performance of GaAs NEA photocathodes, an exponential-doping structure GaAs material has been put forward, in which from the GaAs bulk-to-surface doping concentration is distributed exponentially from high to low. We apply this exponential-doping GaAs structure to the transmission-mode GaAs photocathodes. This sample was grown on the high quality p-type Be-doped GaAs (100) substrate by MBE. We have calculated the band-bending energy in exponential-doping GaAs emission-layer, and the total band-bending energy is 59 meV which helps to improve the photoexcited electrons movement towards surface for the thin epilayer. The integrated sensitivity of the exponential-doping GaAs photocathode samples reaches 1547uA/lm. © 2013 SPIE.Accession Number: 20133016522178 -
Record 164 of
Title:Prediction of welding residual stress by using thermo-metallurgical-mechanical constitute model
Author(s):Sun, Yu Jie(1); Lu, Yu(2); Xu, Jian(1); Shi, Chun Ming(1)Source: Advanced Materials Research Volume: 834-836 Issue: DOI: 10.4028/www.scientific.net/AMR.834-836.791 Published: 2013Abstract:The objective of this paper is to investigate the effects of solid-state phase transformation on welding residual stress in high stress low alloy steel. In this study, based on commercial finite element software, a sequentially coupled thermal, metallurgical, mechanical plane strain finite element model is developed. The main effort is to develop a series of subroutines which consider the heat transfer from welding arc and numerical implementation of a thermo-metallurgical-mechanical constitutes equation. The effectiveness of developed computational method is confirmed by a butt welding simulation. Simulation of butt welding demonstrates that the distribution pattern of longitudinal residual stresses perpendicular to weld centerline at the upper surface of weldment has two peaks and transformation plasticity has significant effect on the evolution of residual stress. © (2014) Trans Tech Publicutions, Switzerland.Accession Number: 20134616986790 -
Record 165 of
Title:Laboratory radiation calibration method of Hadamard transform imaging spectrometer
Author(s):Bai, Junke(1,2); Liu, Xuebin(1); Yan, Peng(1); Hu, Bingliang(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 42 Issue: 2 DOI: Published: February 2013Abstract:Hadamard transform imaging spectrometer is a multi-channel detection digital transform spectrometer detection technology. The spectromter used this technology to achieving spectral imaging. Based on the digital micromirror array device of the Hadamard transform spectrometer working principles and the instrument, a series of precision laboratory calibration methods were researched and employed for the Hadamard transform imaging spectrometer. A point light source in long distance was used for the pixel response nonuniformity correction of the CMOS detector. The uncertainty of the relative calibration was 4.6%. Solar simulator and spectral radiometer were used in absolute radiation calibration of the whole system, and the uncertainty of the absolute radiation calibration was 8.92%. Both of the uncertainty of relative calibration and the uncertainty of the absolute radiation calibration met the requirements of the projection. By actual objects imaging, the laboratory calibration methods of the Hadamard transform imaging spectrometer are proved accurate.Accession Number: 20131616213975 -
Record 166 of
Title:Design of fore telescope system for Offner imaging spectrometer
Author(s):Yan, Xingtao(1,2); Yang, Jianfeng(1); Xue, Bin(1); Ma, Xiaolong(1); Zhao, Yiyi(1,2); Bu, Fan(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 42 Issue: 10 DOI: Published: 2013Abstract:In allusion to the specific structural characters of Offner imaging spectrometer, the fundamental design principles of its fore telescope were analyzed. A novel method to design the wide FOV, long focal length and telecentric off-axis three-mirror anastigmatic (TMA) optical system was presented. For the projective demand, a fore telescope system for Offner imaging spectrometer was designed. Its focal length was 800 mm. Its FOV was 8.6°×0.148°, and the operation spectrum band was from 0.9 μm to 5 μm. The evaluation results of its imaging quality demonstrate that the MTF of each spectrum band is higher than 0.65 at the Nyquist frequency 16.7 lp/mm. The imaging quality has reached the diffraction-limitation, which satisfies the pre-designed requirement. Therefore, the design method is feasible. The designed telescope system is compact, easy to be fabricated and suitable for space borne Offner imaging spectrometer.Accession Number: 20135217144567 -
Record 167 of
Title:A novel laser gain medium: Micro-sphere array cooled by refractive index-matched coolant
Author(s):Gui, Luo(1); Ding, Jianyong(2); She, Jiangbo(3); Peng, Bo(3,4); Wei, Wei(2,3); Fan, Dianyuan(1)Source: Optics Communications Volume: 305 Issue: DOI: 10.1016/j.optcom.2013.04.072 Published: 2013Abstract:A micro-sphere array laser gain medium cooled by refractive index-matched coolant was demonstrated for the first time to our knowledge. The new concept is possessed of potential to improve thermal management, to increase the thermal load capacity and to build large scale laser medium with small-sized solid laser materials. The feasibility was experimentally proved with an oscillator experiment in which reliable laser output was observed: the maximum output was 113.3 mJ for the pump energy of 765.8 mJ, the threshold was 131.7 mJ and the slope efficiency was 19%. Promising improvement could be achieved by employing methods for maintaining accurate refractive index matching during the lasing process. © 2013 Elsevier B.V.Accession Number: 20132416411989 -
Record 168 of
Title:Erratum: Multiple frequency bands of square split resonant rings and metal wire metamaterial (Applied Optics (2013) 52 (6309-6315))
Author(s):Gao, Peng(1,2,3); Zhang, Chunmin(1,2); Jia, Zongwei(1,2,3); Kang, Yongqiang(1,2,3)Source: Applied Optics Volume: 52 Issue: 31 DOI: 10.1364/AO.52.007523 Published: November 1, 2013Abstract:nullAccession Number: 20134616972710