2023
2023
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Record 121 of
Title:Optimal Design of Rectangular Mirror Based on Topology and Size Optimization
Author(s):Zeng, Aoxiong(1,2); Li, Fu(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12555 Issue: null Article Number: 125550I DOI: 10.1117/12.2651749 Published: 2023Abstract:In this paper, a lightweight design is carried out for the rectangular reflector of a small space telescope project. This study suggests a lightweight optimization design strategy based on three-point support in accordance with the high surface figure accuracy and low weight requirements of the project's rectangle reflective mirror. The fundamental structure of the mirror based on SiC material is first obtained, starting from the features of material selection and support method. Then, we get some parameters such as the radius-thickness ratio of the mirror through theoretical calculation and analysis, and preliminarily optimized these parameters. By using the maximization of the overall stiffness as the objective function, and the mirror RMS value as the design restraint, the topology optimization of the mirror is carried out. Finally, considering factors such as processing and manufacturing, we take the methods of size optimization to get an optimal structural model. Through simulation analysis, it can be measured that the weight of the mirror is only 3.94kg, the lightweight rate is 58%, and the RMS value in the X, Y, Z three axes under 1 g gravity condition is far less than 1/25λ(632.8nm) of the design index. This optimization method can well meet the design requirements. ? 2023 SPIE.Accession Number: 20230613559943 -
Record 122 of
Title:Cu-MOFs derived three-dimensional Cu1.81S@C for high energy storage performance
Author(s):Chen, Yanan(2); Zhao, Yuanbo(2); He, Weijun(2); Liu, Yanan(2); Xing, Hongna(2); Zhu, Xiuhong(1,2); Guo, Yanqun(3); Feng, Juan(2); Liao, Chunyan(2); Zong, Yan(2); Li, Xinghua(2); Zheng, Xinliang(2)Source: Materials Today Communications Volume: 37 Issue: null Article Number: 106955 DOI: 10.1016/j.mtcomm.2023.106955 Published: December 2023Abstract:Significant volume changes and slow ionic transport during charge/discharge processes restrict the improvement of electrochemical performance for CuxS (x = 1–2). Herein, a new strategy by introducing Cu-BTC (copper(II)-benzene-1,3,5-tricarboxylate) as a processor to derive three-dimensional Cu1.81S@C using green sulfurization and calcination methods is proposed. Benefiting from the high electrical conductivity, multistage pore size structure and stable structure brought by the conductive carbon skeleton after calcination, Cu1.81S@C-650oC exhibits a high specific capacitance of 291.1 F g-1 at a current density of 1 A g-1 and a superior rate capability of 83.6 % at a current density of 10 A g-1. In addition, the assembled asymmetric supercapacitor (Cu1.81S@C-650oC//AC ASC) also shows impressive performances, such as an energy density up to 16 Wh kg-1 at a power density of 352 W kg-1 and an excellent cycling stability of 93.1 % over 5000 cycles at a current density of 2 A g-1. This work demonstrates that the Cu-BTC-derived Cu1.81S@C is an attractive material with potential applications in energy storage devices. ? 2023 Elsevier LtdAccession Number: 20233614672458 -
Record 123 of
Title:Beam Scanning and Capture of Micro Laser Communication Terminal Based on MEMS Micromirrors
Author(s):Wang, Xuan(1,2); Han, Junfeng(1,2); Wang, Chen(1,2); Xie, Meilin(1,2); Liu, Peng(1,2); Cao, Yu(1,2); Jing, Feng(1,2); Wang, Fan(1,2); Su, Yunhao(1,2); Meng, Xiangsheng(1,2)Source: Micromachines Volume: 14 Issue: 7 Article Number: 1317 DOI: 10.3390/mi14071317 Published: July 2023Abstract:With the development of space laser communication and the planned deployment of satellite Internet constellations, there is a growing demand for microminiature laser communication terminals. To meet the requirements of size, weight and power (SWaP), miniaturized terminals require smaller drive components to complete on-orbit scanning and capture, which must be fast and efficient to enable satellite laser communication networks. These miniaturized laser communication terminals are highly susceptible to the impact of the initial pointing accuracy of the laser beam and microvibrations of the satellite platform. Therefore, this paper proposes a laser scanning-capture model based on a Micro-electromechanical Systems (MEMS) micromirror that can provide a fast, large-scale scanning analysis. A scanning overlap factor is introduced to improve the capture probability under the influence of microvibrations. Finally, experimental analysis was carried out to verify the effectiveness of the proposed model, which can establish a theoretical basis for future ultra-long-distance microspace laser communication. ? 2023 by the authors.Accession Number: 20233114472644 -
Record 124 of
Title:Progress of Raman spectroscopy technology for the detection of material composition on the surface of Mars
Author(s):Xie, Xinmei(1,2); Yang, Jianfeng(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12558 Issue: null Article Number: 125580C DOI: 10.1117/12.2651495 Published: 2023Abstract:Mars exploration is the biggest hot spot of deep space exploration after lunar exploration, and it is also an important target of manned planetary exploration in the future. For Mars exploration, the detection of its surface material composition is one of the important scientific tasks. This paper mainly introduces a new method for the detection of material components on the surface of Mars-Raman spectroscopy technology, briefly explains the principle of Raman scattering, summarizes the research progress of Raman spectroscopy technology for the detection of material components on the surface of Mars at home and abroad, and analyzes the development prospect of Raman spectroscopy technology in the field of Mars exploration. ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20230713574398 -
Record 125 of
Title:Design of reflective Fizeau optical synthetic aperture imaging system
Author(s):Zhang, Wenmao(1,2); Yang, Jianfeng(1); Zhao, Yiyi(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12964 Issue: null Article Number: 129640M DOI: 10.1117/12.3007833 Published: 2023Abstract:In the development of astronomy, high spatial resolution imaging technology plays a crucial role in astronomical observations. The introduction of the optical synthetic aperture concept satisfies the demand for high spatial resolution imaging, gradually becoming a novel direction in the advancement of optical interferometry. This study focuses on the investigation of Fizeau-type synthetic aperture imaging system and presents the design and performance analysis of a system based on requirements. The Fizeau-type synthetic aperture imaging system designed in this paper adopts reflective structure. The system operates in the visible light band (400nm~700nm), with a full field of view angle of 0.3°, an entrance pupil diameter of 300mm, and a focal length of 3598 mm. The sub-telescopes adopt the structure of coaxial two-mirror telescope system. The optical delay line adopts a parallel mirror structure. The beam combiner adopts an off-axis three-mirror structure. The performance of each sub-system and the whole system is analyzed. The results demonstrate that the synthetic aperture imaging system enhances the spatial resolution compared with the single sub-aperture system. ? 2023 SPIE.Accession Number: 20240315394901 -
Record 126 of
Title:Design of 50000 fps camera system for shooting of high-speed collision process
Author(s):Shi, Kui(1,2); Yang, Hong-Tao(1); Peng, Jian-Wei(1); Wang, Hao(1); Yan, A-Qi(1)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 31 Issue: 1 Article Number: null DOI: 10.37188/OPE.20233101.0069 Published: January 2023Abstract:In this study，a high-frame-frequency camera system is investigated to closely capture the colli-sion process of a high-speed moving target. As debris from the collision may get stuck to the front of the lens，a protective window assembly is considered. A thermal conduction device is also investigated be-cause the temperature of an FPGA installed in the imaging unit is too high，with a maximum temperature of 70℃ . A method for continuous photography with seven image units under the control of a sequence pulse is proposed，and the camera system achieved high frame-frequency imaging of 50，000 fps. The pro-tective window assembly includes three sets of self-locking protective window glasses that move automati-cally. A worm gear is utilized to realize a large transmission ratio and self-locking function，and a Hall sen-sor is used to report the position of the protection window in real time. The middle part of the heat conduc-tion device comprises flexible graphite plate with high thermal conductivity. Thus，the heat of the FPGA is transmitted effectively to the shell，and the problem of over-positioning of rigid heat conduction devices is solved during the installation and adjustment of the device. Vibration and heat tests were carried out on the assembled model camera. During and after the tests，the self-locking，movement and switching of the protective window component functioned properly，the camera worked normally，and the measured frame rate was 50050 frames/s. Hence，the camera system meets the requirements for clearly recording high-speed collisions，and provides a certain protection ability as well as adaptability to different thermal envi-ronments. ? 2023 Chinese Academy of Sciences. All rights reserved.Accession Number: 20230313385396 -
Record 127 of
Title:A New Medical Image Transfer and Process Platform
Author(s):Shen, Chao(1,2); Li, Wei(1); Huang, Chao(1); Gao, Wei(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12557 Issue: null Article Number: 1255707 DOI: 10.1117/12.2643681 Published: 2023Abstract:This paper designs a new platform for medical image transfer and process. The hardware part of the platform is based on FPGA, USB and RS232. The software part is based on Windows platform, basing on MFC dialog application developed with C + + programming tools in Microsoft Visual Studio 2010. The platform collects images from medical devices and uses the hardware platform to transmit them to PC for display, the application program on PC can realize the image data process and analysis. ? 2023 SPIE.Accession Number: 20230813600550 -
Record 128 of
Title:Application of satellite platform angular velocity prediction based on Kalman filter in optical image stabilization system
Author(s):Cheng, Qifan(1,2); Wen, Yan(1); Li, Wencan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12963 Issue: null Article Number: 129630Z DOI: 10.1117/12.3007599 Published: 2023Abstract:With the rapid advancement of space astronomical observation technology, there is an increasing demand for higher camera imaging quality. The micro-vibrations generated by internal disturbances of the satellite platform are the primary factors affecting encircled energy of disc of confusion in star image point.The traditional optical image stabilization system compensates for the disturbance by acquiring the variation of the centroid coordinates of the image point as an error feedback of the system, which has the problems of obvious lag and insufficient rapid response ability.To overcome the problem,a method based on optical image stabilization system for predicting angular velocity was proposed and on the basis of measuring the angular velocity of the Satellite bus as the error feedback of the system in this paper.The measured data are predicted using a combination of current statistical model (CS) and Kalman filtering algorithm.The simulation results in MATLAB demonstrate that the image stabilization system's line of sight stabilization is better than 1".It is shown that the method proposed in this paper has feasibility in the optical image stabilization system,the proposed algorithm has the characteristics of high robust and low computing load,and can accurately and effectively predict the vibration information of satellite platform in advance, and provide help for the rapid implementation of vibration suppression measures. ? 2023 SPIE. All rights reserved.Accession Number: 20240215330725 -
Record 129 of
Title:High precision grinding of large-aperture off-axis aspheric mirror with contour-performance controlling methodology (invited)
Author(s):Sun, Guoyan(1,2); Ji, Xiabin(1); Ding, Jiaoteng(1); Zhang, Jigong(1); Cheng, Hang(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 52 Issue: 9 Article Number: 20230454 DOI: 10.3788/IRLA20230454 Published: September 2023Abstract:Objective Large Aperture Off-axis Aspherical Optical Elements (LAOAOE) have been increasingly demanded, such as space/ground-based large aperture telescopes, aerial optoelectronics or ground tracking & sighting instruments. Moreover, the requirements for the larger aperture and shorter processing cycle make it be the core problem to manufacture the large aperture off-axis aspheric optical elements with the highly efficient and high-precision manufacturing. For instance, the processing cycle for the LAOAOE with the diameter of 1 meter is required to be 2-3 months. As the highly efficient removal process for the LAOAOE, surface form accuracy and damage depth of precision grinding having directly determined the processing difficulty and processing cycle of the subsequent polishing processing. Therefore, the high precision grinding process of shape-performance control for LAOAOE are investigated in this paper. In other words, it is required to improve the surface form accuracy and reduce the depth of grinding damage, simultaneously. The numerical collaborative approximation of both items is needed to be achieved in the end. Methods In terms of the surface form control, it was identified the main factors for the machine tool structure, which affect the surface form accuracy of low-frequency surfaces. To achieve collaborative control and accuracy optimization of process parameters, the investigations were conducted to explore the influence laws between the surface shape accuracy and the A-axis zero error, Y-axis alignment error, shape and size error of grinding wheel, grinding wheel path, Z-axis surface compensation and so on. For the performance control, the influence laws between the grinding damage depth and grinding parameters were obtained, and the mapping relationship between the grinding damage depth and grinding surface roughness were established. The suppression strategy of the subsurface damage strategies for LAOAOE was proposed in the end. Results and Discussions Firstly, the form accuracy (PV) of the grinding surface was significantly affected by multiple factors. The A-axis zero error variation of 0.001° had led to the change of 5.47 μm (the theoretical value)/6.9 μm (the experimental value) in surface form accuracy (PV). The Y-axis alignment error variation of 0.07 mm had caused the change of 7.9 μm (the theoretical value)/9 μm (the experimental value) in surface form accuracy (PV). Surface form accuracy had also been significantly affected by the profile error of grinding wheel, grinding method and approach as well as the Z-axis error compensation. For the reasons as above, the improvement of grinding surface form accuracy is subject to the collaborative control and optimization of the above factors. Moreover analysis based on indentation fracture mechanics revealed that there was a corresponding relationship between the grinding subsurface damage depth and surface roughness. When the damage depth was less than 5 μm in the experiment, the surface roughness Ra was below 30 nm and Rz lower than 0.25 μm, all of which could be used as the basis to control the grinding damage. Finally, after the shape and property-controlled grinding of off-axis aspheric lens with an aperture of 640 nm, the surface form accuracy could reach 3.1 μm with the surface roughness Ra less than 24 nm, Rz lower than 0.2 μm. According to the relationship between the surface roughness and the depth of the subsurface damage, the estimated depth of damaged layer was lower than 5 μm. It was verified that the subsequent polishing duration had been significantly shortened. Conclusions For the LAOAOE, the grinding surface form accuracy can be efficiently improved by the deterministic analysis, control and compensation on the various factors affecting surface form accuracy. By mastering the mapping law between the grinding subsurface damage depth and surface roughness, the measurement on surface roughness can realize the indirect control of subsurface damage depth. Also, the combinatorial optimization of grinding process can achieve the efficient improvement and collaborative control of form property precision, which will lead to the significant reduction of polishing period for the optical elements with large aperture. It will be of great reference value for the efficient high-precision processing of optical elements with large aperture. ? 2023 Chinese Society of Astronautics. All rights reserved.Accession Number: 20234214885558 -
Record 130 of
Title:Visual group target tracking algorithm based on MeanShift-PCA-PF
Author(s):Li, Jianing(1); Tian, Yan(2); Guo, Min(2); Zuo, Kaige(3); Wang, Xin(2)Source: 2023 8th International Conference on Intelligent Computing and Signal Processing, ICSP 2023 Volume: null Issue: null Article Number: null DOI: 10.1109/ICSP58490.2023.10248590 Published: 2023Abstract:In recent years, target tracking has been widely studied and applied in intelligent video surveillance, human-machine interaction, radar early warning and tracking, and other fields. With the emergence of the new combat concept of unmanned aerial vehicle (UAV) swarm operations, and the maturity of large-area, high-resolution visible light COMS imaging device technology, the imaging detection and visualization of UAV swarm targets in large observation fields will greatly improve the efficiency of command systems. Therefore, the research on the group target detection, tracking, and recognition based on video image is very urgent and crucial. Group targets are collections of densely packed multiple objects with certain group characteristics that meet the given distance criterion. Due to the large number of targets, limited image resolution, and waste of communication resources, multiple target tracking techniques are challenging to implement effectively. In this paper, based on the characteristics of group targets, we propose a group target tracking framework based on optical measurement equipment. By dividing groups according to the density feature of group targets, we obtain the structural properties and spatial geometric features of the group and implement tracking using a particle filter. Finally, we validate the effectiveness of the group target tracking technique through simulation experiments in group target tracking. ? 2023 IEEE.Accession Number: 20234314942395 -
Record 131 of
Title:Generation of Femtosecond Magnetic Pulses by Circularly Polarized Vortex Laser-driven Plasma
Author(s):Wen, Han(1,2); Xu, Peng(1); Pi, Liangwen(1); Fu, Yuxi(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 52 Issue: 9 Article Number: 0932001 DOI: 10.3788/gzxb20235209.0932001 Published: September 2023Abstract:Research on pulsed magnetic fields dates back to the early 20th century. Nowadays， ultra-short pulsed magnetic fields are being utilized to better understand ultrafast physical microprocesses， such as domain motion and spin-orbit interaction， with time scales ranging from microseconds to femtoseconds. In particular， femtosecond magnetic field pulses are of great significance for studying ultrafast magnetization， ultrafast demagnetization， ultrafast magnetic storage， and spin ultrafast dynamics. However， traditional pulsed magnetic fields are limited by the performance of the pulse power supply and the mechanical strength of the coil and cannot achieve higher pulsed magnetic field strengths. Additionally， the pulse length of the magnetic pulse generated by the pulse power supply is at the millisecond level， which makes it unsuitable for studying faster magnetic dynamics processes. Fortunately， recent studies have shown that when ultra-short pulse lasers interact with plasmas， hot electrons are produced on the surface of the plasma target. These hot electrons are then excited and pass through the target material， producing strong charge separation on the back surface of the target material. Under the action of the laser， these excited electrons are accelerated， generating strong electromagnetic radiation. Consequently， using ultra-short pulse lasers to drive electron flows is currently the most promising method for generating femtosecond magnetic field pulses. Thus， the goal of this paper is to use a three-dimensional model to simulate the interaction between the driving optical field and the plasma target. This simulation will help to study the physical processes involved， such as the propagation of the optical field， the movement of free electrons， vortex currents， and pulse magnetic field generation. By optimizing the relevant parameters， this research aims to generate femtosecond magnetic field pulses. In this paper， we employ the Particle-In-Cell （PIC） method as our simulation approach. This method utilizes the Vlasov-Maxwell equation set to accurately describe the self-consistent dynamics in plasma simulation. The electrons in the plasma are subject to the Lorenz force， which generates new current density as they move. This equation effectively corrects the electric and magnetic fields through the charge density and current density. The driving light described is a circularly polarized vortex beam， with a wavelength of 800 nm and an optical field intensity of approximately 1016 to 1021 W/cm2. The pulse width of the beam is roughly 10 fs. The plasma density ranges from 1018 to 1020 cm-3， and is confined within a cubic space with a side length of 30 λ0. During the simulation process， we only consider refractive index changes due to electron density and do not account for non-linear effects. Additionally， we assume that the ions are stationary and that the initial velocity and temperature of the plasma are both 0. During theoretical simulation， a proportionality gradient between momentum potential and the strength of the light field is created due to the lowest intensity of the vortex beam at its center. This gradient then forms a potential well， preventing electrons from escaping outward and producing a structured electron beam with a femtosecond duration. In addition， particles acquire angular momentum in their radial motion within the laser field， generating a vortex current. This in turn produces a pulsed magnetic field based on the current magnetic effect. The simulation results indicate that when circularly polarized vortex beams， with light field intensities of the order of 1016 to 1021 W/cm2， interact with plasma densities ranging from 1018 to 1020 cm-3， they can generate ultra-short magnetic pulses with peak intensities of 0.5~50 tesla and pulse time widths of about 10 fs. The effects of driving laser intensity and plasma density on these magnetic pulses are discussed through a simulated system calculation. The results show that the pulsed magnetic field intensity is proportional to the square root of both laser intensity and plasma density. Increasing electron density and laser intensity may facilitate the generation of ultra-short strong magnetic fields， providing numerical references for the production of femtosecond magnetic pulses in experiments. We expect that the simulation results above will facilitate the introduction of ultra-strong， ultra-short magnetic pulses into the femtosecond ultrafast realm， thereby supporting the advancement of research on ultrafast magnetic and spin dynamics， electronic motion and spin microprocessing control， ultrafast spin-electron magnetic storage applications， and magnetic switching. ? 2023 Chinese Optical Society. All rights reserved.Accession Number: 20234014824806 -
Record 132 of
Title:Multi-constraint Coupling Optimization for Salient Object Detection
Author(s):Zhu, Zhijie(1); Fang, Jie(1); Wang, Nan(2); Guan, Jiaqiu(1)Source: Proceedings - 2023 5th International Conference on Natural Language Processing, ICNLP 2023 Volume: null Issue: null Article Number: null DOI: 10.1109/ICNLP58431.2023.00012 Published: 2023Abstract:In this paper, we propose a lightweight salient object detection framework called Multi-Constraint Coupling optimization Network (MCONet) to address the conflict between model scale and inference ability, which can learn more knowledge with fewer parameters through embedding feature priors. Specifically, we build a lightweight encoder as the backbone network to represent the image, and then use two parallel decoders to infer salient mask features and salient edge features respectively. Besides, we fuse the output features of different decoders by a convolutional block attention module (CBAM) module. In addition, we adopt a multi-constraint coupling optimization strategy to increase the soft constraints in the training phase, and improve the prior guidance of the edge to the inference results. Experimental results on 5 public benchmark datasets show that the proposed MCONet can reach comparable even better performance of state-of-the-art lightweight salient object detection models. ? 2023 IEEE.Accession Number: 20234014837598