2023
2023
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Record 277 of
Title:Epitaxial growth strategy for construction of Tm3+ doped and [hk1] oriented Sb2S3 nanorods S-scheme heterojunction with enhanced photoelectrochemical performance
Author(s):Liu, Xinyang(1); Zhang, Liyuan(1); Jin, Wei(1); Li, Qiujie(1); Sun, Qian(1); Wang, Yishan(2); Liu, Enzhou(3); Hu, Xiaoyun(1); Miao, Hui(1)Source: Chemical Engineering Journal Volume: 475 Issue: null Article Number: 146315 DOI: 10.1016/j.cej.2023.146315 Published: November 1, 2023Abstract:With the advantages of high absorption coefficient, non-toxicity and low cost, Sb2S3 shows great potential as a narrow bandgap photocathode in the field of PEC hydrogen production. However, the separation and transportation of photogenerated carriers in the reported Sb2S3 photocathode are inefficient due to its anisotropy and the Fermi level being pinned by deep-level defects. Therefore, Tm3+ doped Sb2S3 nanorods with the selective carrier transport orientation were epitaxially grown on SnSe2 film by a simple hydrothermal strategy to modulate the defect property of Sb2S3, optimize carrier transportation and separation efficiency, and improve the PEC performance of photoelectrodes. Experimental results showed that the doping of Tm3+ weakening the Fermi level pinning while achieving the conversion of Sb2S3 to n-type conducting property. The S-scheme heterojunction formed by Tm3+ doped Sb2S3 nanorods labeled as Sb2S3: Tm3+ and SnSe2 nanosheets provided a stronger driving force to optimize carrier interface transportation. The photocurrent density (?0.91 mA cm?2) is increased about 18 times compared to the pristine Sb2S3 photocathode. This work developed an effective doping strategy to weaken the Fermi level pinning and provided a novel idea for the epitaxial growth of Sb2S3 nanorods to optimize the carrier transportation. ? 2023 Elsevier B.V.Accession Number: 20234114849515 -
Record 278 of
Title:Research on high precision control algorithm
Author(s):Li, Hanlin(1,2); Ge, We(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12959 Issue: null Article Number: 129591J DOI: 10.1117/12.3007793 Published: 2023Abstract:With the rapid development of industry, semiconductor, aerospace and other industries, the device processing size is getting smaller and smaller, and the positioning accuracy of high-end equipment is becoming higher and higher in recent years, the development level of precision positioning technology, to a certain extent, characterizes a country's scientific and technological strength, and reflects the country's comprehensive national strength. From aviation and aerospace to the lithography industry directly related to various chips, precision engineering technology plays an important role in them. Control accuracy is often a very important indicator to measure whether the control environment meets the requirements. In this paper, permanent magnet synchronous linear motor is used to compare the influence of various algorithms on the control accuracy of the motor. This paper mainly conducts in-depth research on the control algorithms and compares various performance indicators of different algorithms in the same working environment. First of all, the control principle and core points of PID control algorithm, SMG sliding mode control algorithm and ADRC active disturbance rejection control algorithm are briefly described. The control system block diagram of these three control algorithms is given, and the advantages and disadvantages of these three control algorithms are expounded. The permanent magnet synchronous linear motor control system modeling is carried out on matlab/simulink. Then use matlab/simulink to carry out these three control algorithms for the motor control simulation and control experiment, modify the parameters and then compare the simulation results, and point out which algorithm is better in the control environment. ? 2023 SPIE.Accession Number: 20240215330036 -
Record 279 of
Title:Dim Target Detection Algorithm Based on Multi-Scale Feature Enhancement
Author(s):Ma, Zhen(1); Li, Peng(2); Liu, Wen(3)Source: 2023 4th International Conference on Information Science, Parallel and Distributed Systems, ISPDS 2023 Volume: null Issue: null Article Number: null DOI: 10.1109/ISPDS58840.2023.10235358 Published: 2023Abstract:Aiming at the problems of small and dim target with relatively few pixels, difficult to extract pixel features, low detection probability and high false alarm rate. In this paper, an algorithm based on multi-scale feature enhancement for dim target detection is proposed. Starting from the upper layer of detection task, the image high-resolution reconstruction network based on pyramid architecture is first used to strengthen the small and target region and distribution features, and then the reconstructed target features are sent as learning labels into the Yolo v5s detection framework containing multi-channel convolution kernel for self-supervised learning. Through the case test with different number of target points, it is proved that the mAP value of the enhanced image is more than 4% higher than that of the original image. ? 2023 IEEE.Accession Number: 20234014832730 -
Record 280 of
Title:Design and Research of a Compact Polarization Spectral Imaging Method Based on Double Gaussian
Author(s):Qi, Chen(1); Yu, Tao(1); Zhang, Zhou-Feng(1); Zhong, Jing-Jing(1); Liu, Yu-Yang(1); Wang, Xue-Ji(1); Hu, Bing-Liang(1)Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 43 Issue: 7 Article Number: null DOI: 10.3964/j.issn.1000-0593(2023)07-2082-08 Published: July 2023Abstract:Obtaining more attribute information about the target is the goal the optical sensor constantly pursues. Polarization spectral imaging technology, which combines polarization attribute detection and traditional spectral imaging technology, can distinguish "different objects with the same spectrum", and achieve "target highlighting"and "dynamic adjustment". The shortcomings of the current polarization spectral imaging system include complex structure, large volume, channel crosstalk, and cumbersome multi-dimensional information extraction. In this paper, a compact polarization spectral imaging method based on Linear Variable Filter (LVF) and pixelated polarization modulation is proposed to solve the above problems. The work includes: under the constraints of high spectral resolution and short focal length, the double Gaussian structure is used as the initial optical structure, and the simulation and implementation of the optical system are carried out at the same time; The polarization modulation detector is coupled on the image plane to achieve simultaneous acquisition of spectral information and polarization information. In the laboratory darkroom, the optical index test of the system prototype developed based on the above technical route is carried out. The final index is as follows: working band: 430~880 nm, spatial resolution: 0.22 mrad, spectral resolution: 10 nm, synchronous acquisition of four polarization states, System transfer function: 0.547, polarization detection accuracy: 89.4%, total size of optomechanical system: 45 mm×45 mm×80 mm. Experiments were carried out outdoors, and the conclusion was that the monochromatic images of different polarization states of the central wavelength have obvious intensity changes; the multi-dimensional information extraction and fusion of the global image show that the characteristic spectral curves of different objects have obvious spectral differences. This method breaks through the shortcomings of the traditional polarization spectral imaging technology route and provides a new and important application method for the multi-dimensional information acquisition of polarization spectral imaging. ? 2023 Science Press. All rights reserved.Accession Number: 20233414617219 -
Record 281 of
Title:Modified achromatic Savart polariscope for broadband spatially modulated snapshot imaging polarimeter
Author(s):Quan, Naicheng(1); Li, Siyuan(1,2); Zhang, Chunmin(2)Source: Optics and Lasers in Engineering Volume: 162 Issue: null Article Number: 107398 DOI: 10.1016/j.optlaseng.2022.107398 Published: March 2023Abstract:This paper presents the modified achromatic Savart Polariscope for constructing broadband spatially modulated snapshot imaging polarimeter. The modified achromatic Savart Polariscope can be made from two different birefringent crystals. The achievements and performances of the modified achromatic Savart Polariscope are demonstrated with numerical simulations. The chromatic variations in spatial carrier frequencies can be reduced by an order of magnitude. The spatially modulated snapshot imaging polarimeter constructed by the modified achromatic Savart Polariscopes can achieve the root mean square errors with a magnitude of 10?4 across the spectral range 0.48–0.96 μm as it does in monochromatic light conditions. ? 2022 Elsevier LtdAccession Number: 20224813193570 -
Record 282 of
Title:Research on the Key Technology of High Resolution Low-Light-Level Remote Sensing
Author(s):Bai, Zhe(1); Ma, Yilong(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12557 Issue: null Article Number: 125571X DOI: 10.1117/12.2651915 Published: 2023Abstract:In recent years, besides higher spatial resolution, higher temporal resolution and higher spectral resolution, extending the effective working time of satellite platform based aerospace paid much attention. And Low-light-level(LLL) remote sensing technology in visible band is one of the ways to achieve the goal. LLL remote-sensing camera has become a novel subject for the development of aerospace optical remote-sensing payloads. In this manuscript, first the status quo and trend of LLL remote sensing technology is made a comprehensive introduction. After that, centering on the crucial technique to realize the low-light-level sensing, several different implementation ways are made a comparison both from the theoretical viewpoint and experiment demonstration. Finally, some advices are given on how to develop aerospace LLL remote sensing techniques based on the existing research results. ? 2023 SPIE.Accession Number: 20230813600620 -
Record 283 of
Title:A Restricted Embedding Transfer Model for Hyperspectral Anomaly Detection
Author(s):Shi, Chenliang(1); Qiu, Shi(2)Source: 2023 4th International Conference on Big Data and Artificial Intelligence and Software Engineering, ICBASE 2023 Volume: null Issue: null Article Number: null DOI: 10.1109/ICBASE59196.2023.10303063 Published: 2023Abstract:The purpose of hyperspectral image anomaly detection is to overcome the problem of inconsistent background distribution, suppress background information as much as possible, and highlight anomalous target information. Many existing deep learning anomaly detection methods use generative algorithms, such as those based on generative adversarial networks and those based on automatic encoders, but these algorithms are inevitably accompanied by the problem of low reconstruction accuracy or poor calibration. In order to solve these problems, this paper proposes a restricted embedding transfer model for hyperspectral image anomaly detection, which transforms the anomaly detection problem into a feature regression problem through partial knowledge transfer learning. Thus it avoiding the need for reconstruction or probability distribution evaluation. The teacher network adaptively generates descriptive embedding vectors that are used as pseudo-labels to assist the training of the student network, and only part of the normal sample is needed to complete the training. In the experimental part, the performance of the proposed method is compared with seven existing methods on twelve hyperspectral datasets. The results show that the proposed method has better detection effect, and the AUC index reaches 0.9789, which is 0.0109 higher than the second place. ? 2023 IEEE.Accession Number: 20234915151193 -
Record 284 of
Title:Athermalization of Infrared Continuous Zoom Optical System Based on Wavefront Coding
Author(s):Kai, Jiang(1,2); Er-Rui, Chen(1,2); Liang, Zhou(1,2); Kai, Liu(1,2); Jing, Duan(1,2); Qiusha, Shan(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12617 Issue: null Article Number: 1261759 DOI: 10.1117/12.2666470 Published: 2023Abstract:Wavefront coding is a technology which combination of the optical design and digital image processing. By inserting a phase mask closed to the pupil plane of the continuous zoom optical system，the wavefront of the system is re-modulated. And the depth of focus is extended consequently. In reality the idea is same as the athermalization theory of infrared optical system. In this paper, an uncooled infrared continuous zoom optical system with effective focal as 38mm～19mm, F number as 1.2, operating wavelength varying from 8μm to 12μm was designed. A cubic phase mask was used at the pupil plane to re-modulate the wavefront. Then the performance of the infrared continuous zoom system was simulated with CODEV as the environment temperature varying from -40℃ to 60℃. MTF curve of the optical system with phase mask are compared with the traditional before using phase mask. Decode the image of the coding system, and the result show that wavefront coding technology can make the system not sensitive to thermal defocus, and then realize the athermal design of the infrared optical system. ? 2023 SPIE.Accession Number: 20232114130360 -
Record 285 of
Title:Optical testing of the primary mirror of the telescope of multispectral high-resolution imaging system
Author(s):Li, Jing(1); Sun, Guoyan(1); Xue, Xun(1); Yan, Zhou(1); Zhao, Jianke(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12507 Issue: null Article Number: 125071R DOI: 10.1117/12.2656049 Published: 2023Abstract:The multispectral high-resolution imaging system is composed of four wide-spectrum cameras, which can detect targets in the visible, short-wave infrared, medium-wave infrared and long-wave infrared spectrum simultaneously. In order to reduce the size of the system, the four wide-spectrum cameras use the same telescope. To achieve operating wavelengths covering four wavebands, the telescope uses a fully reflective design with a coaxial aspherical surface with a hole in the center of the primary mirror. If aberration-free testing is used, the central aperture will occur, resulting in incomplete aperture of surface shape detection. Thus, in this paper, a compensator is designed which can achieve the whole aperture of surface testing without centralized obscuration. At the same time, the impact of the misalignment of compensator in the optical path during the test is analyzed. The optical testing path adopts infinite conjugate working distance to reduce one adjustment amount of compensator. And the first surface of compensator is coordinated with the interferometer to adjust the angle of compensator quickly and accurately, which further reduces the measurement error introduced by the optical testing path. The design of the compensator can realize the control of sensitive misalignment, reduce the surface measuring error caused by the compensator misalignments, and eventually reduce the precise processing error. ? 2023 SPIE.Accession Number: 20230613537963 -
Record 286 of
Title:Research on Quantum Efficiency Calibration of SVOM VT CCDs
Author(s):Yue, Pan(1); Lijuna, Dan(1); Zhonghana, Sun(1); Chaoa, Huang(1); Weia, Li(1); Fengtaoa, Wang(1); Huia, Zhao(1); Jiana, Zhang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12965 Issue: null Article Number: 129650B DOI: 10.1117/12.3007801 Published: 2023Abstract:The successful achievement of the scientific objectives of the Visible Telescope (VT) in the Space Multi-band Variable Object Monitor (SVOM) mission relies heavily on high-precision quantum efficiency calibration. The calibration process for the VT CCD presents a challenge due to the requirement for extremely low radiation levels given the long integration time of the CCD. To address the difficulty in accurately measuring such low radiance, a two-step calibration method is employed. This method involves the use of two photodiodes, one positioned at the CCD location and the other in an integrating sphere. In the first step, the proportional relationship between the measured illuminance values of the two photodiodes is calibrated under high illumination conditions. This step establishes a reliable reference for subsequent calibrations. In the second step, the CCD is calibrated using the integrating sphere photodiode under low illumination conditions. The measured illuminance is then converted to the CCD position. Experimental results have demonstrated the effectiveness of this two-step calibration method, achieving a quantum efficiency calibration uncertainty of 1.7%. This approach provides a reliable and accurate means of calibrating the quantum efficiency of the CCD in the VT instrument. ? 2023 SPIE. All rights reserved.Accession Number: 20240215333276 -
Record 287 of
Title:A Coaxial Assembling Method of Dual Optical Path System based on Optical Centering Assembling
Author(s):Yin, Yamei(1); Lei, Yu(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12507 Issue: null Article Number: 125072L DOI: 10.1117/12.2656558 Published: 2023Abstract:As the most widely used optical structure, coaxial optical system has become the critical component of many elaborate compound machines. However, with the development of science and technology, aerospace and lithography technology has put forward higher requirements on the imaging quality of ultra-precision coaxial optical system. And the optical axis consistency condition plays a critical role in the system imaging quality. In this paper, the dual optical path system based on light splitting prism is introduced, in which the coaxiality of the dual optical path become a critical issue. For the high coaxiality assembly, the optical centering assembling technology based on optical imaging principle is applied to ensure the coaxiality among the optical axis of optical element, the rotation axis of corresponding machine part and the rotation axis of lathe. According to the optical auto-collimation imaging principle, the visualization and transmission of the main datum of the optical system is completed, which will ensure the datum conversion completed with high precision. Finally, the experiment has been conducted and the coaxiality of the actual dual optical system is better than 0.05mm. ? 2023 SPIE.Accession Number: 20230613537983 -
Record 288 of
Title:Analysis of assembly errors of optomechanical systems
Author(s):Chou, Xiaoquan(1); Li, Zhiguo(1); Li, Xiaoyan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12976 Issue: null Article Number: 129761L DOI: 10.1117/12.3009431 Published: 2023Abstract:Optomechanical system assembly is a complex process and serves as the final stage in implementing a system, playing a crucial role in determining the performance indicators of the Optomechanical system. The performance of the Optomechanical system is mainly affected by two factors: surface shape errors of optical elements and alignment errors of components, both of which are related to the assembly process. Stress is one of the main causes of surface shape errors in optical elements. During assembly, the coupling stress can cause changes in the shape of optical elements. These changes may result in surface shape deviations from the design requirements, thereby affecting the system's performance. Alignment errors of parts and components can cause assembly errors such as misalignment, tilt, and optical spacing in the optical system. These errors can have adverse effects on the optical performance of the system. The Optomechanical system assembly errors mainly include component-level assembly errors and system-level assembly errors. To accurately analyze and estimate the assembly errors of the Optomechanical system, a small displacement torsor theory and the technique of spatial pose transformation matrix have been used to construct an error analysis model for the Optomechanical system. These models can assist engineers in predicting and controlling assembly errors, improving the performance of the Optomechanical system, and guiding the design and production of the Optomechanical system. ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20240315402118