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Generating multiple-folding-geometry freeform reflective imaging systems based on optical design model-informed neural network

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Optics & Laser technology 2025年 191卷

作者： Guogen Chen Tong Yang Dewen Cheng Yongtian Wang Beijing Engineering Research Center of Mixed Reality and Advanced Display School of Optics and Photonics Beijing Institute of Technology Beijing 100081 China National Key Laboratory on Near-surface Detection Beijing 100072 China Beijing Ned+AR Ltd. Beijing 100081 China

Freeform systems play important roles in modern optical systems, but their design remains challenging due to the complexity of freeform surfaces and lack of efficient methods as well as reference designs. This paper presents a framework that leverages an optical design model-informed neural network (ODMINN) to automatically generate multiple-folding-geometry freeform reflective imaging systems. The network is trained by both the data-driven loss and the physics-informed loss. An automatic training dataset generation method, combined with a fast light-obstruction evaluation method based on equivalent spherical systems, is proposed for obtaining dataset containing systems with various parameters and folding geometries. The real optical design model is integrated into the training process, by directly calculating the physics-informed loss related to imaging performance and optical design constraints using differential ray tracing. Freeform systems can be generated immediately by the network based on the design requirements. Compared with previous network which can only generate systems with one specific folding geometry, multiple-folding-geometry freeform systems can be generated using the proposed framework. We demonstrate the framework by designing freeform off-axis three-mirror systems with all eight different folding geometries. Our approach can significantly reduce human involvement and dependency on existing reference systems in the design of freeform optics, while dramatically improving the design efficiency.

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UAV trajectory planning algorithmfor data collection in wireless sensor networks

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Journal of Southeast University(English Edition) 2020年第4期36卷 376-384页

作者： Yan Feng Chen Jiahui Wu Tao Li Hao Pang Jingming Liu Wanzhu Xia Weiwei Shen Lianfeng National Mobile Communications Research Laboratory Southeast UniversityNanjing 210096China Jiangsu Zhongli Electronic Information Sci-Tech Co. Ltd.Changshu 215542China Science and Technology on Near-Surface Detection Laboratory Wuxi 214035China

In order to maximize the value of information(VoI)of collected data in unmanned aerial vehicle(UAV)-aided wireless sensor networks(WSNs),a UAV trajectory planning algorithm named maximum VoI first and successive convex approximation(MVF-SCA)is ***,the Rician channel model is adopted in the system and sensor nodes(SNs)are divided into key nodes and common ***,the data collection problem is formulated as a mixed integer non-linear program(MINLP)*** problem is divided into two sub-problems according to the different types of SNs to seek a sub-optimal solution with a low ***,the MVF-SCA algorithm for UAV trajectory planning is proposed,which can not only be used for daily data collection in the target area,but also collect time-sensitive abnormal data in time when the exception *** results show that,compared with the existing classic traveling salesman problem(TSP)algorithm and greedy path planning algorithm,the VoI collected by the proposed algorithm can be improved by about 15%to 30%.

关键词： unmanned aerial vehicle wireless sensor networks trajectory planning data collection value of information

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Optimal Design of End Suspension Electromagnet for Medium Speed Maglev Train

Optimal Design of End Suspension Electromagnet for Medium Sp...

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Chinese Control Conference (CCC)

作者： Peichang Yu Shelin Chen Ming Gao Qing Yang Lianchun Wang Jinhui Li College of Intelligence Science and Technology National University of Defense Technology Changsha China CRRC Tangshan Co. Ltd Tangshan China Science and Technology on Near-surface Detection Laboratory Wuxi China

ISBN: (数字)9789881563903

ISBN: (纸本)9781728165233

In order to solve the discernment of bearing capacity and system controllable of end-suspension electromagnet caused by eddy current effect of the medium-speed maglev train, the optimal design of the end-electromagnet is carried out. First of all, the suspension force of the electromagnet is analyzed based on basic electromagnetic theory. The theoretical equation of electromagnetic force considering the eddy current effect is established, and the characteristics of the eddy current effect in the speed range of 0 to 200 km/h are analysed. Then, this article discussed the optimal design of the end electromagnet for medium-speed maglev train. On the one hand, from the perspective of the existing electromagnet, the relationship between the loss of magnetic flux density and speed, length of the electromagnet was studied to clarify the feasibility of the optimal scheme. On the other hand, from the perspective of the dynamics of the suspension module, an optimization scheme for load capacity of the suspension module is proposed by considering the effects of magnetic saturation. At last, the dynamical and electric model of the optimal end electromagnet were established, and the controllability analysis was performed. The research and simulation show that the optimal design of the end electromagnet combined with the adjustment of the bearing force from the vehicle can meet the requirements of the medium speed maglev train operating in the whole range speed of 0-200km/h.

关键词： Electromagnets Suspensions Magnetic levitation Magnetic flux Force Coils

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Speckle suppression of SAR image using boundary and contextual constraint

Speckle suppression of SAR image using boundary and contextu...

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IET International Radar Conference (IET IRC 2020)

作者： W. Yuming L. Chaopeng J. Tian Z. Yansong College of Information Science and Engineering Hunan Normal University Changsha China Science and Technology on Near-Surface Detection Laboratory Wuxi China College of Electronic Science and Technology National University of Defense Technology Changsha China

Speckle suppression is a important preprocessing step for synthetic aperture radar (SAR). In this paper, a speckle suppression algorithm based boundary and contextual constraint is studied for enhancing image, which includes the establishment of speckle model based on boundary constraint, the analysis of speckle factor weighted constraint model based on contextual regularization, and the process of speckle factor estimation. The performance of this algorithm is validated by using the data acquired over an airship mounted SAR system.

关键词： airships speckle synthetic aperture radar radar imaging

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Electromagnetic radiation analysis and synthesize of UAV target with the theory of characteristic modes

Electromagnetic radiation analysis and synthesize of UAV tar...

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IET International Radar Conference (IET IRC 2020)

作者： Y. Chen Y. Wang Q. Tang H. Zhou Science and Technology on Near-Surface Detection Laboratory China School of Electronic and Optical Engineering Nanjing University of Science and Technology Nanjing China Shanghai Spaceflight Electronic and Communication Equipment Research Institute China

The theory of Characteristic Modes can better express the physical concept of radiator. In this paper, a fast method for synthesizing the radiation pattern of an unmanned aerial vehicle (UAV) platform is presented based on the characteristic mode theory. We can synthesize specific radiation patterns of the target to reduce or increase radiation energy in specific directions.

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PLAM system-mediated optimization of 808 nm low-level laser power density for enhanced bioactivity in human umbilical cord mesenchymal stem cells

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Optics and Lasers in Engineering 2025年 194卷

作者： Xiuwen Guo Liquan Dong Xin Wang Rujun Dai Jinyu Li Shujun Liu Lingqin Kong Ming Liu Yuejin Zhao Mei Hui Xuhong Chu School of Optics and Photonics Beijing Institute of Technology Beijing 100081 PR China National Key Laboratory on Near-surface Detection Beijing 100072 PR China Yangtze Delta Region Academy of Beijing Institute of Technology Jiaxing 314019 PR China Changchun University of Science and Technology Changchun 130022 China Spectra Vigor Technology (Beijing) Ltd Beijing 100029 PR China School of Medical Technology Beijing Institute of Technology Beijing 100081 PR China

Low-level laser therapy (LLLT) has significant potential in regenerative medicine for enhancing mesenchymal stem cells (MSCs) function. However, the optimal irradiation parameters, particularly power density, remain unclear. In this study, we developed an automated Precision Laser Adjustment and Motion (PLAM) system to investigate the effects of an 808 nm power-adjustable laser on human umbilical cord mesenchymal stem cells (HUMSCs). The laser was applied at power densities ranging from 10 to 500 mW/cm², with a constant energy density of 4 J/cm². Under these irradiation conditions, the biological responses showed clear power-dependence, with optimal effects observed at 100 and 250 mW/cm², consistent with the Arndt-Schulz law. Specifically, the 250 mW/cm² irradiation significantly accelerated cell migration at 24 hours and achieved the highest cell viability at 48 hours ( P < 0.01). Notably, the 100 mW/cm² protocol demonstrated superior biosafety, maintaining sustained ATP production ( p < 0.001 at 24 hours; p < 0.01 at 48 hours) and moderate reactive oxygen species (ROS) levels ( p < 0.0001), making it reliable for long-term stem cells expansion. Real-time temperature monitoring showed ΔT ≤1 °C, ruling out thermal damage. The results emphasize the importance of optimizing power density in LLLT and identify 100 mW/cm² as the optimal balance between therapeutic efficacy and safety. Furthermore, the PLAM system simplifies the irradiation procedure, reduces operational errors, and enhances experimental repeatability. These findings provide a scientific basis for standardizing LLLT parameters in regenerative medicine and introduce the PLAM automated experimental platform for future photobiomodulation research.

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Structure patterns of one-step synthesis of CuNi nanopowders in air environment: Experiment and atomistic simulations

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Nano-Structures and Nano-Objects 2024年 40卷

作者： Romanovski, Valentin Sdobnyakov, Nickolay Kolosov, Andrey Savina, Kseniya Nepsha, Nikita Moskovskikh, Dmitry Dobryden, Illia Zhang, Zhaowei Beletskii, Evgenii Romanovskaia, Elena Department of Materials Science and Engineering University of Virginia Charlottesville 22904 VA United States Department of General Physics Tver State University Tver 170002 Russian Federation Science and Research Centre of Functional Nano-Ceramics National University of Science and Technology “MISIS” Lenin av. 4 Moscow 119049 Russian Federation KTH Royal Institute of Technology Department of Chemistry Division of Surface and Corrosion Science Drottning Kristinas väg 51 Stockholm SE-100 44 Sweden Oil Crops Research Institute of Chinese Academy of Agricultural Sciences Wuhan 430062 China Key Laboratory of Biology and Genetic Improvement of Oil Crops Key Laboratory of Detection for Mycotoxins National Reference Laboratory for Agricultural Testing Wuhan 430062 China Hubei Hongshan Laboratory Wuhan 430000 China Institute of Chemistry St. Petersburg University Universitetskaya Emb.7/9 St. Petersburg 199034 Russian Federation

A possibility for one-step synthesis of bimetallic CuNi nanopowders in a different ratio of Ni to Cu by solution combustion synthesis technique under normal air atmosphere without any post reduction is reported. The effect of different types of fuels like citric acid and glycine on the combustion process and characteristics of resultant solid products were investigated. XRD results showed the existing of CuNi as a main phase and small amounts of CuO and (Ni,Cu)₄N. Determined CuNi particle sizes were in the range of up to 50 nm. Computer simulation was performed using the molecular dynamics method for similar concentration compositions, but in size range of 4.5–5.5 nm, as a result of cooling the system from 1700 K to 300 K. In addition, two types of melting scenario of binary CuNi NPs were studied: 1) heterogeneous melting of monocrystalline Cu and Ni NPs;2) melting of the crystallization products of binary NPs. Melting temperatures weakly depend on the choice of the above-mentioned melting scenario. However, the nature of subsequent crystallization can be influenced by the initial energy of the system, which is higher for case 1. The characteristic temperatures of phase transitions of melting and crystallization are determined based on the analysis of hysteresis loops of the specific potential part of the internal energy of NPs. The patterns of atomic and structural segregation in binary CuNi NPs were studied. © 2024 Elsevier B.V.

关键词： CuNi nanoparticles Homogeneous composites Molecular dynamics simulation Segregation Solution combustion synthesis

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Improved Capon Beamformer Using Fourier Integral Method (FIM)

Improved Capon Beamformer Using Fourier Integral Method (FIM...

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OCEANS

作者： Xionghou LIU Cong Wang Chao Sun Yixin Yang Jie Zhuo Guoqing Jiang Wenjun Duan Science and Technology on Near-Surface Detection Laboratory Wu Xi P. R. China School of Marine Science and Technology Northwestern Polytechnical University Xi'an P. R. China

ISBN: (数字)9781728154466

ISBN: (纸本)9781728184098

When compared to the conventional beamformer (CBF), the Capon beamformer often shows a better target detection performance. However, when the array aperture (or, the degrees of freedoms-DOFs) is limited and the signal-to-noise ratio (SNR) is relatively low, the performance of the Capon beamformer will degrade severely. Unfortunately, for the practical application the target of interest is often submerged in loud interferences and high-level fluctuated noises. Thus, it is very hard for a small-aperture array to find the target of interest. In this paper, to improve the beamforming performance of the small-aperture linear array, we propose an improved Capon beamformer based on Fourier integral method (FIM), which is termed as FIM-Capon for short. FIM-Capon firstly uses the basic theory of FIM to obtain 2N-1 outputs (the number of hydrophones in the array is N), which is actually the Toeplitz averaged covariance matrix calculated from the sampled array covariance matrix. And then, FIM-Capon uses the subarray smoothing and the Capon beamformer to process the 2N-1 outputs of the Toeplitz averaged covariance matrix to produce the final beamforming output. The proposed FIM-Capon method have two advantages; one is making use of the noise suppression ability of FIM, and the other is using the extended DOFs coming from the Toeplitz averaging. Hence, FIM-Capon has a higher input SNR and a larger DOF than the traditional Capon beamformer. As a result, when the aperture is limited and the input SNR is low, FIM-Capon shows a better weak target detection performance than the traditional Capon beamformer. Numerical simulations validate the effectiveness of the proposed FIM-Capon method.

关键词： Smoothing methods Array signal processing Sonar equipment Object detection Apertures Covariance matrices Signal to noise ratio

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A Co-offset GPR Data Inversion Based on Ray Theory

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IOP Conference Series: Earth and Environmental science 2021年第1期660卷

作者： Meiqi Xue Sixin Liu Qi Lu Hongqing Li Yuanxin Wang School of Earth Exploration Science and Technology Jilin University Changchun China Science and Technology on Near-Surface Detection Laboratory Wuxi

We use Monte Carlo method to establish a randomly undulating homogeneous layered medium model. Then the co-offset GPR data for the built geological model is simulated by FDTD. The ray-tracing based inversion is applied for interval velocity estimation. During the inversion, the offset between antennas, the velocity value of the first layer, the picked amplitudes values of each reflection layer and reference amplitude are the input data. The thickness and velocity of each layer are calculated by this recursive method. It is proved that this inversion method is feasible for the layered geological model with random undulation, and the fact that undulation, i.e. RMS height and correlation length, influences the inversion results is discussed.

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On Range-dimensional Performance Improvement of FD-MIMO Sonar Using Deconvolution

On Range-dimensional Performance Improvement of FD-MIMO Sona...

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OCEANS

作者： Jingrong WU Xionghou Liu Chao Sun Guangyu Jiang Dezhi Kong Kuan Fan School of Marine Science and Technology Northwestern Polytechnical University Xi'an P. R. China Science and Technology on Near-Surface Detection Laboratory Wu Xi P. R. China

ISBN: (数字)9781728154466

ISBN: (纸本)9781728184098

The frequency diverse multiple-input multiple-output (FD-MIMO) sonar can achieve improved detection performance in the range dimension by synthesizing echoes at different frequency bands without over-demanding system bandwidth. However, the existing bandwidth synthesis (BS) method suffers from high-level range sidelobes caused by the spectral leakage of the subband signals and the discontinuity of the synthesized spectrum. Hence, it is hard to detect a weak target in the range dimension. To address this problem, a deconvolved bandwidth synthesis (DBS) method is proposed, which can suppress the range-dimensional sidelobes by post-processing the beam output of the synthesized spectrum. To be specific, we first employ the narrowband frequency diverse linear frequency modulated (FD-LFM) pulses to construct the range-dimensional point spread function (PSF), and then apply the PSF and the Richardson-Lucy (R-L) algorithm to deconvolve the data obtained by synthesizing spectra of the subband signals. Simulation results indicate that for the FD-MIMO sonar the proposed DBS method shows a better interference rejection ability and a higher range resolution in the range dimension than the BS method.

关键词： Sonar Satellite broadcasting Signal to noise ratio Frequency diversity Frequency modulation Deconvolution Array signal processing

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