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IEEE International Conference on Electronic Information and Communication technology (ICEICT)

作者： Sisi Jiang Jingpeng Gao Zhiye Jiang Fang Ye College of Information and Communication Engineering Harbin Engineering University Haibin China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China National Key Laboratory of Underwater Acoustic Technology College of Information and Communication Engineering Harbin Engineering University Harbin China

The time-frequency images of radar modulation signals are similar at low signal-to-noise ratios, which will lead to lower recognition accuracy. This paper proposes an algorithm based on multi-branch fusion differences to identify radar modulation signals. The algorithm designs a multi-branch fusion differential module based on the attention mechanism and differential thinking, to extract time-frequency image fine-grained features and improve the Convolution Neural Network characterization ability. After that, a dual-branch differential network is proposed by combining vanilla convolution and multi-branch fusion difference module. The network can fuse global and detailed features of time-frequency images, which can achieve radar signal modulation recognition. The simulation results show that the recognition accuracy of the algorithm can reach 93.17% at 0dB. Therefore, the algorithm can obtain high recognition accuracy and has high recognition performance.

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An Experimental Study on the Object Shielding Performance of Discrete Metal Wire Array

An Experimental Study on the Object Shielding Performance of...

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IEEE International Conference on Computational Electromagnetics (ICCEM)

作者： Weidong Wang Xin Liu Mingliang Wang Jiaqi Liu Gang Meng Zhiyong Gao Lei Mu Xia Ai Shengjun Zhang Jianbing Li National Key Laboratory of Science and Technology on Test Physics Beijing Institute of Space Long March Vehicle Beijing China

ISBN: (纸本)9781538612422

In this paper, a method of shielding the object behind a discrete metal wire array is proposed and verified by anechoic chamber experiments. Results show that if the metal wire array is dense enough (cell size is smaller than half of the wavelength), the object behind it can be effectually shielded by the discrete metal wire array. The principle can be applied to electromagnetic camouflage and protection.

关键词： anechoic chambers (electromagnetic) electromagnetic shielding Electromagnetic shielding half-wave ELECTRIC WIRE shielding properties Metals Cell Size Dense arrays

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Verification of Seasonal Prediction by the Upgraded China Multi-Model Ensemble Prediction System (CMMEv2.0)

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Journal of Meteorological Research 2024年第5期38卷 880-900页

作者： Jie WU Hong-Li REN Jianghua WAN Jingpeng LIU Jinqing ZUO Changzheng LIU Ying LIU Yu NIE Chongbo ZHAO Li GUO Bo LU Lijuan CHEN Qing BAO Jingzhi SU Lin WANG Jing-Jia LUO Xiaolong JIA Qingchen CHAO CMA Key Laboratory of Climate Prediction Studies National Climate CentreChina Meteorological Administration(CMA)Beijing 100081 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044 State Key Laboratory of Severe Weather and Institute of Tibetan Plateau Meteorology Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 CMA Earth System Modeling and Prediction Centre China Meteorological AdministrationBeijing 100081

Based on a combination of six Chinese climate models and three international operational models,the China multimodel ensemble(CMME)prediction system has been upgraded into its version 2(CMMEv2.0)at the national Climate Centre(NCC)of the China Meteorological Administration(CMA)by including new model members and expanding prediction products.A comprehensive assessment of the performance of the upgraded CMME during its hindcast(1993–2016)and real-time prediction(2021–present)periods is conducted in this *** results demonstrate that CMMEv2.0 outperforms all the individual models by capturing more realistic equatorial sea surface temperature(SST)*** exhibits better prediction skills for precipitation and 2-m temperature anomalies,and the improvements in prediction skill of CMMEv2.0 are significant over East *** superiority of CMMEv2.0 can be attributed to its better projection of El Niño–Southern Oscillation(ENSO;with the temporal correlation coefficient score for Niño3.4 index reaching 0.87 at 6-month lead)and ENSO-related *** for the real-time prediction in recent three years,CMMEv2.0 has also yielded relatively stable skills;it successfully predicted the primary rainbelt over northern China in summers of 2021–2023 and the warm conditions in winters of 2022/*** that,ensemble sampling experiments indicate that the CMMEv2.0 skills become saturated after the ensemble model number increased to 5–6,indicating that selection of only an optimal subgroup of ensemble models could benefit the prediction performance,especially over the extratropics,yet the underlying reasons await future investigation.

关键词： China multi-model ensemble(CMME)prediction system predictability source El Niño-Southern Oscillation(ENSO) real-time forecast verification

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Modified k-ω model using kinematic vorticity for corner separation in compressor cascades

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science China(Technological sciences) 2016年第5期59卷 795-806页

作者： LIU YangWei YAN Hao FANG Le LULiPeng LI QiuShi SHAO Liang National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Energy and Power Engineering Beihang University Beijing 100191 China Collaborative Innovation Center of Advanced Aero-Engine Beihang University Beijing 100191 China Laboratory of Mathematics and Physics Ecole Centrale de Pekin Beihang University Beijing 100191 China Laboratoire de Mecanique ties Fluides et d'Acoustique Ecole Centrale de Lyon Ecullv 69134 France

A new method of modifying the conventional k-w turbulence model for comer separation is proposed in this paper. The production term in the w equation is modified using kinematic vorticity considering fluid rotation and deformation in complex geometric boundary conditions. The corner separation flow in linear compressor cascades is calculated using the original k-w model, the modified k-w model and the Reynolds stress model （RSM）. The numerical results of the modified model are compared with the available experimental data, as well as the corresponding results of the original k-w model and RSM. In terms of accuracy, the modified model, which significantly improves the performance of the original k-w model for predicting comer separation, is quite competitive with the RSM. However, the modified model, which has considerably lower computational cost is more robust than the RSM.

关键词： k-w comodel kinematic vorticity corner separation compressor cascades

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Derivation of the thermal characteristics of mesoscale eddies

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Acta Oceanologica Sinica 2017年第3期36卷 8-13页

作者： CHEN Xuan PAN Jing ZHENG Chongwei ZHANG Xi HE Ming The 75839 Army People's Liberation Army Guangzhou 510510 China National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Dalian Naval Academy People's Liberation Army Dalian 116018 China College of Meteorology and Oceanography People's Liberation Army University of Science and Technology Nanjing 211101 China College of Marine Life Science Ocean University of China Qingdao 266003 China

This study aims at explaining the relationship between thermodynamic characteristics and direction of rotation of mesoscale eddies（MEs）. The geometric characteristics of the MEs are under the following assumptions： the structure of the MEs is symmetrical, and changes of oceanic physical variables are close to linear features in the radial direction in the ME regions. Based on these assumptions, by using primitive equations without friction under a cylindrical coordinate system, the thermodynamic characteristics of the MEs are derived, showing that the conventional relationship of warm anticyclonic eddies with high sea surface height（SSH） and cold cyclonic eddies with low SSH is not consistent with the SSH and sea surface temperature（SST） observations of eddies. The results show that the symmetrical form is an ideal approximation for the geometric characteristics of MEs. In consideration of the above assumptions, there are advantages for derivation of the characteristics of the MEs under a cylindrical coordinate.

关键词： mesoscale eddies thermodynamic characteristics symmetry

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A Fast Design Method for Ultra Broadband Absorbers Using RC Equivalent Circuit Model

A Fast Design Method for Ultra Broadband Absorbers Using RC ...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Xianglin Kong Lei Zhao Fengjun Wang Shengjun Zhang Yixiang Fu Xiaoyu Pang Xiaochun Liu Xiaopeng Shen School of Information and Control Engineering China University of Mining and Technology Xu Zhou CA China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical Beijing China Key Laboratory of Aeronautical Science and Technology for High Performance Electromagnetic Window Jinan China School of Materials and Physics China University of Mining and Technology Xuzhou China

An accuracy and efficient approach is proposed to fast design ultra-wideband microwave absorbers. The RC equivalent circuit model of absorbers is established according to impedance matching and transmission line theory. The model is suitable for low and high-frequency absorbers composed of multilayer square high impendence surface (HIS) and air layers of impendence matching. Absorbers with different parameters can be fast designed by utilizing the proposed model and genetic algorithm. The reflection coefficient of RC circuit and full-simulation are in good agreement, both of them are lower than -10 dB within 2-18 GHz or 4-50 GHz (fractional bandwidth of 160% or 170.37%), with the total thickness close to the Rozanov limit. An absorber is fabricated and measured to further verify the accuracy of the model. The measured results have a good agreement with the RC circuit model, which indicates the proposed method is an efficient way for fast designing ultra-broadband thin absorbers using double-layer (or multilayer) square HIS.

关键词： Microwave measurement Atmospheric modeling Transmission line measurements Nonhomogeneous media Microwave theory and techniques Microwave circuits Frequency measurement

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Laser-sub-cycle two-dimensional electron-momentum mapping using orthogonal two-color fields

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Physical Review A 2014年第6期90卷 061401(R)-061401(R)页

作者： Li Zhang Xinhua Xie Stefan Roither Daniil Kartashov YanLan Wang ChuanLiang Wang Markus Schöffler Dror Shafir Paul B. Corkum Andrius Baltuška Igor Ivanov Anatoli Kheifets XiaoJun Liu André Staudte Markus Kitzler Photonics Institute Vienna University of Technology 1040 Vienna Austria State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China Joint Laboratory for Attosecond Science of the National Research Council and the University of Ottawa 100 Sussex Drive Ottawa Ontario Canada K1A 0R6 Department of Physics of Complex Systems Weizmann Institute of Science Rehovot 76100 Israel Research School of Physical Sciences The Australian University Canberra ACT 0200 Australia

We study laser-sub-cycle control over electron trajectories concomitantly in space and time using orthogonally polarized two-color laser fields. We compare experimental photoelectron spectra of neon recorded by coincidence momentum imaging with photoelectron spectra obtained by semiclassical and numerical solutions of the time-dependent Schrödinger equation. We find that a resolution of a quarter optical cycle in the photoelectron trajectories can be achieved. It is shown that depending on their sub-cycle birth time the trajectories of photoelectrons are affected differently by the ion's Coulomb field.

关键词： ELECTRON optics PARTICLE tracks (Nuclear physics) TIME-dependent Schrodinger equations PHOTOELECTRON spectroscopy COULOMB potential GAUSSIAN distribution

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Spectral–spatial attention fusion transformer for hyperspectral image classification

Spectral–spatial attention fusion transformer for hyperspec...

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IET International Radar Conference (IRC 2023)

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

ISBN: (数字)9781837240982

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.

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The Warm Arctic-Cold Eurasia Pattern and Its key Region in Winter in CMIP6 Model Simulations

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Advances in Atmospheric sciences 2023年第12期40卷 2138-2153,I0002-I0006页

作者： Liang ZHAO Yunwen LIU Yihui DING Qingquan LI Wei DONG Xinyong SHEN Wei CHENG Haoxin YAO Ziniu XIAO State Key Laboratory of Numerical Modeling for Atmosphere Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjing 210044China Neijiang Meteorological Bureau Neijiang 641000China China Meteorological Administration National Climate CenterBeijing 100081China Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province School of Earth SciencesZhejiang UniversityHangzhou 310058China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China Beijing Institute of the Applied Meteorology Beijing 100029China

An enhanced Warm Arctic-Cold Eurasia(WACE)pattern has been a notable feature in recent winters of the Northern ***,divergent results between model and observational studies of the WACE still *** study evaluates the performance of 39 climate models participating in the Coupled Model Intercomparison Project Phase 6(CMIP6)in simulating the WACE pattern in winter of 1980-2014 and explores the key factors causing the differences in the simulation capability among the *** results show that the multimodel ensemble(MME)can better simulate the spatial distribution of the WACE pattern than most single *** that can/cannot simulate both the climatology and the standard deviation of the Eurasian winter surface air temperature well,especially the latter,usually can/cannot simulate the WACE pattern *** mainly results from the different abilities of the models to simulate the range and intensity of the warm anomaly in the Barents Sea-Kara seas(BKS)*** analysis shows that a good performance of the models in the BKS area is usually related to their ability to simulate location and persistence of Ural blocking(UB),which can transport heat to the BKS region,causing the warm Arctic,and strengthen the westerly trough downstream,cooling central ***,simulation of UB is key and significantly affects the model’s performance in simulating the WACE.

关键词： warm Arctic-cold Eurasia pattern Arctic amplification CMIP6 simulation evaluation extreme climate blocking highs

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Electroextraction of neodymium from LiCl-KCl melt using binary liquid Ga-Al cathode

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Journal of Rare Earths 2023年第8期41卷 1250-1257,I0005页

作者： Li Ding Xuepeng Wang Yongde Yan Valeri Smolenski Wenda Xu Alena Novoselova Yun Xue Fuqiu Ma Xingmei Zhang Key Laboratory of Superlight Materials and Surface Technology Ministry of EducationCollege of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China Yantai Research Institute of Harbin Engineering University Yantai 264006China Institute of High-Temperature Electrochemistry UB RAS Ekaterinburg 620990Russia Department of Rare Metals and Nanomaterials Institute of Physics and TechnologyUral Federal UniversityEkaterinburg 620990Russia Yantai Standard Metrology Inspection&Test Center National Steam Flowrate Measurement StationYantai 264000China

The electrochemical behaviour of Nd(Ⅲ)ion was investigated on inert W,active Ga and Ga-AI *** is established that the reduction of Nd(Ⅲ)ion on the inert electrode is a consecutive two-step process while that on the active electrodes is a one-step *** apparent standard potential of the Nd(Ⅲ)/Nd redox couple at different temperatures was determined by open-circuit chronopotentiometry and semi-differential method,and the relationship between temperature and apparent standard potential was further *** thermodynamic properties of Nd in Ga and Ga-Al electrodes such as activity coefficient and activity were evaluated via intermittent coulomb titration and temperature dependence test,and the effect of temperature on activity coefficient was ***,Nd was successfully extracted in form of alloy from molten salt by galvanostatic electrolysis,in which the current efficiency of91.7%for the electroextraction indicates that the binary liquid Ga-Al electrode has favorable performance.

关键词： Rareearths Electroextraction Spent nuclear fuel Pyrochemical processing Lanthanides Binary liquid cathode

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