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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yumeng Wang Lu Gao Pei Zheng Lingnan Song School of Electronic and Information Engineering Beihang University Beijing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

In this article, a radiation patternreconfigurable patch antenna with tunable complementary split-ring resonators (CSRR) based on liquid metal (LM) and 3-D printed microfluidics is presented. The antenna is composed of three layers, a top coaxial fed rectangular patch, a middle ground plane with two CSRRs etched symmetrically, and two bottom microfluidics channels each adhered underneath the corresponding CSRR. Pattern reconfiguration is achieved by filling the microfluidic channels with the liquid metal plugs to change the physical parameters of the CSRR structure. By adjusting the length of the slot stubs in CSRRs, the main beam of the double CSRR-loaded antenna can be continuously scanned from -46° to 46° in elevation plane.

关键词： Liquids Slot antennas Patch antennas Simulation Metals Filling Resonators

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Evaluation of multidimensional simulations of summer air temperature in China from CMIP5 to CMIP6 by the BCC models: From trends to modes

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Advances in Climate Change Research 2022年第1期13卷 28-41页

作者： Yun-Wen LIU Liang ZHAO Gui-Rong TAN Xin-Yong SHEN Su-Ping NIE Qing-Quan LI Li ZHANG Key Lciboratoiy of Meteorological Disaster Ministry of EducationJoint International Research Laboratory'of Climate and Environment ChangeCollaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Numerical Modeling for Atmosphere Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China Laboratory for Climate Studies National Climate CenterChina Meteorological AdministrationBeijing 100081China

To determine whether the capability of the CMIP6 version of Beijing Climate Center(BCC)models(BCC-ESMI and BCC-CSM2-MR)in simulating China summer surface air temperature(SAT)has improved,we presented a multidimensional evaluation of the summer SAT in China including the trends,modes,and influencing *** comparisons are also made with the results of CMIP5(BCC-CSM1.1 and ***).In general,the CMIP6,especially BCC-CSM2-MR,has smaller deviations in the trends,the means,the mutations,the maximum centers,the variances,and the spatial patterns of the dominant modes from observatio relative to those of ***,the BCC CMIP6 models still underestimate the SAT variation in the Qinghai-Tibetan Plateau and the northeastern regions of China,and the performance is unsatisfactory with respect to the physical drivers of the dominant ***,all the BCC models can capture the spatio-temporal characteristics of the first mode well and can,in general,characterize the spatial pattern of the second mode,but none of the models perform well in the principal component of the second mode(PC2)due to the low performance with respect to the interannual variation of ***,the factors influencing the leading two modes are *** two CMIP6 can simulate better the Northern Hemisphere subtropical high northern boundary affecting the first *** factor,the Asia polar vortex area,can only be simulated better by two low-resolution models(BCC-CSM1.1 and BCC-ESM I).For the second mode,all four models simulate the influence of Asian zonal circulation well,but poorly simulate that of the southern Indian Ocean dipole due to a large deviation in the Indian Ocean surface temperature.

关键词： Summer mean temperature China Dominant mode CMIP6 BCC

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UAV Track Planning Algorithm Based on Graph Attention Network and Deep Q Network 11th

UAV Track Planning Algorithm Based on Graph Attention Networ...

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11th International Conference on Image and Graphics, ICIG 2021

作者： Hu, Xinyu Gao, Jingpeng Jiang, Zhiye 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)9783030873578

To solve the problem that the deviation of the Unmanned Aerial Vehicle (UAV) flight status data collected by the equipment during flight leads to the failure of the mission, this paper proposes a UAV track planning algorithm based on Graph Attention Network and Deep Q Network (DQN). Firstly, we use the camera to collect images and apply pre-trained ResNet to extract image features. Secondly, we adopt the Graph Attention Network to establish the connection between the sensor-measured flight state information and the actual flight state information. Thirdly, we build the optimization model of flight state. Moreover, based on the Deep Reinforcement Learning (DRL) theory, the DQN-based UAV track planning system is trained. Finally, the system combined the optimized flight state to complete the optimal flight action output to realize the track planning. Simulation results show that, compared with the original algorithm which is under the same flight conditions as the proposed algorithm, the velocity deviation rate of the proposed algorithm is improved by 46.79%, which can plan a high-quality track and has good engineering application value. © 2021, Springer Nature Switzerland AG.

关键词： Image processing

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DFT study of elastic, structural, and optical properties of K2InAgZ6 (Z = Cl, Br, I) perovskites: potential for optoelectronic applications

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Optical and Quantum Electronics 2024年第12期56卷 1-17页

作者： Ahmad, Sohail Zakria, Muhammad Alotaibi, Khalid M. Huma, Tabasum Hakimi, Nadimullah Ali, Rawaid Qasimullah Safeen, Akif Feng, Jing Shah, Syed Hatim Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming650093 China Pakistan Institute of Engineering and Applied Sciences National Institute of Lasers and Optronics College Nilore Islamabad45650 Pakistan Department of Chemistry Collage of Science King Saud University PO Box 2455 Riyadh11541 Saudi Arabia Faculty of Metallurgical and Energy Engineering Kunming University of Science and Technology Kunming650093 China College of Physical and Electronic Information Technology Key Laboratory of Advanced Techniques for Renewable Energy Materials Ministry of Education Yunnan Normal University Kunming650500 China Faculty of Physical and Numerical Sciences Qurtuba University of Science and Information Technology Peshawar Peshawar25100 Pakistan Department of Physics University of Poonch Rawalakot AJK Poonch12350 Pakistan

In this article, a comprehensive research was carried out to investigate the elastic, structural, and optoelectronic properties of double perovskite compounds K2InAgCl6, K2InAgBr6, and K2InAgI6 by using density functional theory. Goldsmith’s tolerance factor (tG), whose values are near to unity, was used to assess the structural stability of the cubic perovskite structure. According to the analysis of electronic characteristic, K2InAgCl6, K2InAgBr6, and K2InAgI6 are semiconductors with a tiny band gap, calculated using the mBJ-PBE sol potential with band gap values of 2.48 eV, 1.47 eV, and 0.23 eV, respectively. A comprehensive analysis of the optical characteristics of these compounds was conducted across an energy range from 0 to 10 eV. The results revealed that K2InAgCl6, K2InAgBr6, and K2InAgI6 exhibit significant conductivity and absorbance properties in wide energy ranges, which is confirmed by density of states analysis. Moreover, the optical characteristics shows that lower photon energy relates to high optical transmission, while higher energies result in more optical absorption of material. These results demonstrate that K2InAgCl6, K2InAgBr6, and K2InAgI6 are viable material candidates for use in high-frequency UV optical devices. © The Author(s), under exclusive licence to Springer science+Business Media, LLC, part of Springer Nature 2024.

关键词： Perovskite

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A Radar Signal Modulation Recognition Algorithm Based on Multi-branch Fusion Difference

A Radar Signal Modulation Recognition Algorithm Based on Mul...

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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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Effects of Dropsonde Data in Field Campaigns on Forecasts of Tropical Cyclones over the Western North Pacific in 2020 and the Role of CNOP Sensitivity

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Advances in Atmospheric sciences 2023年第5期40卷 791-803页

作者： Xiaohao QIN Wansuo DUAN Pak-Wai CHAN Boyu CHEN Kang-Ning HUANG State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China Hong Kong Observatory Hong KongChina Weather Forecasting Office National Meteorological CenterChina Meteorological AdministrationBeijing 100081China Research and Development Center Central Weather BureauTaipei 100006China

Valuable dropsonde data were obtained from multiple field campaigns targeting tropical cyclones,namely Higos,Nangka,Saudel,and Atsani,over the western North Pacific by the Hong Kong Observatory and Taiwan Central Weather Bureau in *** conditional nonlinear optimal perturbation(CNOP)method has been utilized in real-time to identify the sensitive regions for targeting observations adhering to the procedure of real-time field campaigns for the first *** observing system experiments were conducted to evaluate the effect of dropsonde data and CNOP sensitivity on TC forecasts in terms of track and intensity,using the Weather Research and Forecasting *** is shown that the impact of assimilating all dropsonde data on both track and intensity forecasts is ***,assimilation using only the dropsonde data inside the sensitive regions displays unanimously positive effects on both the track and intensity forecast,either of which obtains comparable benefits to or greatly reduces deterioration of the skill when assimilating all dropsonde ***,these results encourage us to further carry out targeting observations for the forecast of tropical cyclones according to CNOP sensitivity.

关键词： tropical cyclones targeting observation field campaign CNOP sensitivity dropsonde intensity forecasts

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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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On the metric resolvent: nonexpansiveness, convergence rates and applications

arXiv

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arXiv 2021年

作者： Xue, Feng National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

In this paper, we study the nonexpansive properties of metric resolvent, and present a convergence rate analysis for the associated fixed-point iterations (Banach-Picard and Krasnosel’skii-Mann types). Equipped with a variable metric, we develop the global ergodic and non-ergodic iteration-complexity bounds in terms of both solution distance and objective value. A byproduct of our expositions also extends the proximity operator and Moreau’s decomposition identity to arbitrary variable metric. It is further shown that many classes of the first-order operator splitting algorithms, including alternating direction methods of multipliers, primal-dual hybrid gradient and Bregman iterations, can be expressed by the fixed-point iterations of a simple metric resolvent, and thus, the convergence can be analyzed within this unified *** Codes 68Q25, 47H05, 90C25, 47H09 Copyright © 2021, The Authors. All rights reserved.

关键词： Iterative methods

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Seamless Prediction in China: A Review

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Advances in Atmospheric sciences 2023年第8期40卷 1501-1520页

作者： Hong-Li REN Qing BAO Chenguang ZHOU Jie WU Li GAO Lin WANG Jieru MA Yao TANG Yangke LIU Yujun WANG Zuosen ZHAO State Key Laboratory of Severe Weather and Institute of Tibetan Plateau MeteorologyChinese Academy of Meteorological SciencesBeijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Department of Atmospheric Science School of Environmental StudiesChina University of GeosciencesWuhan 430074China China Meteorological Administration Key Laboratory for Climate Prediction Studies National Climate CenterChina Meteorological AdministrationBeijing 100081China Ensemble Forecasting Division CMA Earth System Modeling and Prediction Center(CEMC)Beijing 100081China School of Atmospheric Sciences Chengdu University of Information TechnologyChengdu 610225China

Seamless prediction is a weather-climate integrated prediction covering multiple time scales that include days,weeks,months,seasons,years,and *** prediction can provide different industries with information such as weather conditions and climate variations from the next few days to years,which have important impacts on economic and social development and important reference value for short-,medium-and long-term decision-making and planning of the ***,seamless prediction has received widespread attention from the international scientific community *** Chinese scientists have also carried out relevant research,this paper reviews the research in China on developments and applications of seamless prediction methods and prediction systems in recent *** them,the main progress of seamless prediction methods studies is reviewed from four aspects:short-and medium-range weather forecasting,subseasonal-to-seasonal,seasonal-to-interannual,and decadal climate *** terms of development and application of seamless prediction systems,the main achievements made by meteorological operational departments,scientific institutes,and universities in China in recent years are ***,some of the issues in seamless prediction that need further study are discussed.

关键词： seamless prediction weather-climate integrated prediction prediction system

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Periodic Structures and Its Interaction to EM Wave Spectrum, Ideas From X-Ray to MW Wave

Periodic Structures and Its Interaction to EM Wave Spectrum,...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yunhui Tang Lu Gao Ruzhi Wang Shengjun Zhang Hang Song Yuning Zhang Xia Ai Lei Xie Luting Jiao Xiaoling Zhang Jing He Jiaqi Liu Beijing University of Technology Beijing China National Key Laboratory of Science & Technology on Test Physics and Numerical Mathematics Beijing China Beijing Institute of Space Long March Vehicle Beijing China

X-ray is an important tool for characterizing materials, which is based on the idea that all crystals are composed of atoms or molecules stacking in a particular type, basically expressing as unit cell, diffracting the incident ray with a proper type. In analogue, the periodic structures which are mostly constructed artificially show special desired properties, such as the properties of grating, frequency selective surfaces, metamaterials and metasurface. In this paper, A study was done on the insight of the relation of wave interaction with periodic structures based on X-ray diffraction and control of electromagnetic waves.

关键词： Frequency selective surfaces Stacking Electromagnetic scattering Crystals X-ray diffraction Metasurfaces Computational electromagnetics

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