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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Gao, Lu Fang, Ning Wang, Mingliang Liu, Jiaqi Li, Yanan Wu, Runhui Xu, Yinfang National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China Beihang University Academy of Electronic Information Engineering Beijing China National Key Laboratory of Science and Technology on Test Physics Beijing China

ISBN: (纸本)9781665452366

The radar cross section(RCS) calculation model of electrically large-scale composite target is established by combining graphic electromagnetic computing(GRECO) with high-frequency optical approximation and physical diffraction. Using different illumination modes, the normal vector at each point on the target surface is obtained, and the total scattering field of the target is acquired by the coherent superposition of the scattering field and the diffraction field at each point on the target surface. © 2022 IEEE.

关键词： Radar cross section

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1-bit Coding Metasurface for Wideband RCS Reduction

1-bit Coding Metasurface for Wideband RCS Reduction

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Xu, Yinfang Liu, Jiaqi Gao, Lu Ai, Xia Zhang, Zhongjie Liang, Huan Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China

ISBN: (纸本)9781665452366

This paper achieve efficient RCS reduction over a wide frequency range by exploiting the reflection properties of the coding metasurface. The metasurface consists of '0' cells and '1' cells, and the reflection phase difference is close to 180° over a wide frequency range. By designing the spatial random coding arrangement of '0' units and '1' units, the electromagnetic waves incident on the metasurface form diffuse reflection, so as to achieve the purpose of broadband RCS reduction. The simulation results show that when the incident wave is irradiated vertically, the metasurface can basically achieve a RCS reduction of more than 10dB in a wide frequency band of 10-20.5GHz compared to a metal plate of the same size. In the case of oblique incidence, the RCS reduction still has a good effect, which is basically the same as the curve at normal incidence, and has the characteristics of wide-angle incidence RCS reduction. The reduced bandwidth of the broadband RCS of the coding metasurface is basically consistent with the 10 dB polarization bandwidth of the cell structure. The design of the metasurface is simple and efficient, so it has great application potential in stealth new technologies and new materials. © 2022 IEEE.

关键词： Plate metal

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Frequency hopping signal parameter estimation algorithm based on time-frequency point correlation 10

Frequency hopping signal parameter estimation algorithm base...

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10th IEEE Joint International Information technology and Artificial Intelligence Conference, ITAIC 2022

作者： Jiang, Zhiye Wang, Shangyue Chen, Yang Wang, Peng Gao, Lu Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (数字)9781665422079

ISBN: (纸本)9781665422079

Aiming at the low accuracy of frequency hopping signal parameter estimation under the influence of complex noise and interference, a frequency-hopping signal parameter estimation algorithm based on time-frequency point correlation is proposed. First, we design the kernel function to obtain the time-frequency distribution of the frequency-hopping signal. Then, we use the correlation of the time-frequency points to establish the target transfer relationship model. Besides, the feature quantity combines density screening is used for hierarchical clustering, and ridge queuing methods filter out the interference ridge label. Finally, we perform parameter estimation on the frequency hopping ridge. The simulation results show that the parameter error estimated by the proposed algorithm continues to decrease with the improvement of the signal-to-noise ratio. In the case of -6dB, the error of each parameter is as low as about 0.1. This algorithm can completely extract the frequency hopping ridge under the condition of a low signal-to-noise ratio, achieve an excellent parameter estimation effect, and provide a reference for communication signal parameter estimation. © 2022 IEEE.

关键词： Frequency hopping

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Supertetragonal BaZrS_(3):A promising perovskite sulphide with giant ferroelectricity and low band gap

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science China(physics,Mechanics & Astronomy) 2024年第8期67卷 126-133页

作者： Menglu Li Sa Zhang Chenhan Liu Xiaotao Zu Liang Qiao Haiyan Xiao School of Physics University of Electronic Science and Technology of ChinaChengdu 611731China College of Mathematics and Physics Chengdu University of TechnologyChengdu 610059China Micro-and Nano-scale Thermal Measurement and Thermal Management Laboratory Ministry of Education Key Laboratory of Numerical Simulation of Large-Scale Complex SystemsSchool of Energy and Mechanical EngineeringNanjing Normal UniversityNanjing 210023China

Over the past century,ferroelectricity has offered exciting opportunities for fundamental research and device ***,most of the discovered excellent ferroelectrics are oxide materials with large band gaps,limiting their potential for optoelectronics *** using first-principles calculations we identify a new narrow-gap ferroelectric beyond oxides,i.e.,ferroelectric perovskite sulphide BaZrS_(3).Under large compressive strains,BaZrS_(3)can be stabilized into a unique supertetragonal phase with an extraordinary polarization of 67.16μC/cm^(2),which is even stronger than that of conventional oxide ***,the supertetragonal BaZrS_(3)exhibits a direct narrow band gap of 1.2 eV and excellent electronic *** on the chemical bonding analysis,we attribute the formation of supertetragonal phase to charge re-ordering in which theπbond overlap along the long〈Zr-S〉bond completely vanishes and the antibonding states of theσbond appear below the Fermi *** work provides a conceptual strategy for designing new ferroelectrics for electronic and photovoltaic applications.

关键词： supertetragonal phase perovskite sulphide ferroelectricity

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Study on 2D Plasma Photonic Crystals with Defect Modes Using FDTD Method

Study on 2D Plasma Photonic Crystals with Defect Modes Using...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Song, Hang Zhang, Yuning Liu, Jiaqi Ai, Lihong Zhang, Shengiun National Key Laboratory of Science & Technology on Test Physics and Numerical Mathematics Beijing China Captial Aerospace Machinery Coporation Limited Beijing China

ISBN: (纸本)9781665452366

In this paper, a typical uniform unmagnetized two-dimensional plasma photonic crystal with a single linear defect mode is simulated based on the finite difference time domain method, and the effects of defect mode position and size on its photonic band gaps characteristics are explored respectively. the research can provide an idea for tuning the electromagnetic properties of two-dimensional plasma photonic crystals. © 2022 IEEE.

关键词： Finite difference time domain method

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A New One-Dimensional Photonic Crystals for Infrared Emission Modulation

A New One-Dimensional Photonic Crystals for Infrared Emissio...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Zhang, Yuning Zhang, Shengjun Song, Hang Cui, Yichun Liu, Jiaqi Ai, Lihong National Key Laboratory of Science & Technology on Test Physics and Numerical Mathematics Beijing China Capital Aerospace Machinery Corporation Limited Beijing China

ISBN: (纸本)9781665452366

With the wide application of infrared detection in the military field, the problem of how to reduce the probability of military targets being detected and identified has become urgent. In this paper, one-dimensional photonic crystals with wide incidence angle range are analyzed and simulated. The reflectance and transmittance properties of different structures are discussed with application in modulation of infrared emission. © 2022 IEEE.

关键词： Photonic crystals

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Contrasts of bimodal tropical instability waves(TIWs)-induced wind stress perturbations in the Pacific Ocean among observations,ocean models,and coupled climate models

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Journal of Oceanology and Limnology 2024年第1期42卷 1-23页

作者： Kai MA Chuanyu LIU Junli XU Fan WANG School of Mathematics and Physics Research Institute for Mathematics and Interdisciplinary SciencesQingdao University of Science and TechnologyQingdao 266100China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao 266237China

The coupling between wind stress perturbations and sea surface temperature(SST)perturbations induced by tropical instability waves(TIWs)in the Pacific Ocean has been revealed previously and proven crucial to both the atmosphere and ***,an overlooked fact by previous studies is that the loosely defined“TIWs”actually consist of two modes,including the Yanai wave-based TIW on the equator(hereafter eTIW)and the Rossby wave-based TIW off the equator(hereafter vTIW).Hence,the individual feedbacks of the wind stress to the bimodal TIWs remain *** this study,individual coupling relationships are established for both eTIW and v TIW,including the relationship between the TIW-induced SST perturbations and two components of wind stress perturbations,and the relationship between the TIW-induced wind stress perturbation divergence(curl)and the downwind(crosswind)TIW-induced SST *** show that,due to different distributions of eTIW and vTIW,the coupling strength induced by the eTIW is stronger on the equator,and that by the vTIW is stronger off the *** results of any of eTIW and vTIW are higher than those of the loosely defined *** further investigated how well the coupling relationships remained in several widely recognized oceanic general circulation models and fully coupled climate ***,the coupling relationships cannot be well represented in most numerical ***,we confirmed that higher resolution usually corresponds to more accurate ***,the coupling models established in this study are complementary to previous research and can be used to refine the oceanic and coupled climate models.

关键词： bimodal tropical instability waves mesoscale air-sea interaction coupled models Yanai wave

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SPECTRAL-SPATIAL ATTENTION FUSION TRANSFORMER FOR HYPERSPECTRAL IMAGE CLASSIFICATION

SPECTRAL-SPATIAL ATTENTION FUSION TRANSFORMER FOR HYPERSPECT...

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IET International Radar Conference 2023, IRC 2023

作者： Ji, Xiangyu Gao, Jingpeng Chen, Geng Gao, Lu College of Information and Communication Engineering Harbin Engineering University Harbin China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

ISBN: (纸本)9781839539954

In view of the limited generalization and poor local feature information modeling ability of vision transformer model(ViT) in hyperspectral image classification, a Spectral-Spatial Attention Fusion Transformer (SAFT) method for hyperspectral image classification is proposed in this paper. The proposed method includes two key modules: Spectral-Spatial Feature Extraction Module (SSFE) and Multi-Head Attention Fusion Transformer Module (MAFT). The SSFE module is a lightweight network. It contains a 3D convolution block and a 2D convolution block, which can efficiently obtain local feature information. Based on the proposed attention fusion structure, the MAFT module designs an improved transformer encoder. It improves the generalization ability of the model on the premise of obtaining global information. In this paper, two datasets of HyRANK are used for experiments. The experimental results show that this method is superior to other HSI classification methods. © The Institution of Engineering & technology 2023.

关键词： Convolutional neural networks

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Analysis of infrared radiation properties of SiC particles with different microstructures

Analysis of infrared radiation properties of SiC particles w...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Li, Yanan Wang, Qun Dong, Shikui Cui, Yichun Gao, Lu Ai, Xia Beijing University of Technology Beijing China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China Harbin Institute of Technology Harbin China

ISBN: (纸本)9781665452366

In order to control the infrared radiation properties by adjusting the micro morphology of SiC particles, we analyze the radiation characteristics of solid and hollow SiC particles with different scales. The results show that the particle size has a great influence on the radiation characteristics of SiC spherical solid particles, and the particle thickness directly affects the amplitude changes of extinction and scattering absorption peaks of SiC spherical hollow particles with small scale (d=100nm). © 2022 IEEE.

关键词： Particle size

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Influence of clusters on radiation properties of Si3N4particles

Influence of clusters on radiation properties of Si3N4partic...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

ISBN: (纸本)9781665452366

We analyze the radiation characteristics of Si3N4 elementary particles based on Mie theory, and Si3N4 cluster particles by GMM theory. The results show that the larger the Si3N4 cluster particles, the larger the extinction factor and scattering factor, which variation trend is similar to that of the elementary particles with the same scale, and the position of the scattering peak is also similar to that of the elementary particles. The influence of cluster particles on the amplitude of absorption factor is relatively small, but some absorption characteristic peaks disappear, which is very different from the elementary particles with the same scale. © 2022 IEEE.

关键词： Silicon compounds

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