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Coupling of the Calculated Freezing and Thawing Front Parameterization in the Earth System Model CAS-ESM

Advances in Atmospheric sciences 2023年第9期40卷 1671-1688页

作者： Ruichao LI Jinbo XIE Zhenghui XIE Binghao JIA Junqiang GAO Peihua QIN Longhuan WANG Si CHEN State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 101408China School of Mathematics and Statistics Nanjing University of Information Science and TechnologyNanjing 210044China

The soil freezing and thawing process affects soil physical properties,such as heat conductivity,heat capacity,and hydraulic conductivity in frozen ground regions,and further affects the processes of soil energy,hydrology,and carbon and nitrogen *** this study,the calculation of freezing and thawing front parameterization was implemented into the earth system model of the Chinese Academy of sciences(CAS-ESM)and its land component,the Common Land Model(CoLM),to investigate the dynamic change of freezing and thawing fronts and their *** results showed that the developed models could reproduce the soil freezing and thawing process and the dynamic change of freezing and thawing *** regionally averaged value of active layer thickness in the permafrost regions was 1.92 m,and the regionally averaged trend value was 0.35 cm yr–*** regionally averaged value of maximum freezing depth in the seasonally frozen ground regions was 2.15 m,and the regionally averaged trend value was–0.48 cm yr–*** active layer thickness increased while the maximum freezing depth decreased year by *** results contribute to a better understanding of the freezing and thawing cycle process.

关键词： frozen ground freezing and thawing fronts maximum freezing depth active layer thickness earth system model CAS-ESM

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Source-Configured Microwave Plasmonic Vortices Based on Single Meta-Particle

Source-Configured Microwave Plasmonic Vortices Based on Sing...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Xianglin Kong Lei Zhao Xiaopeng Shen Yinfang Xu School of Information and Control Engineering School of Materials Science and Physics China University Mining and Technology Xuzhou China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China

In this paper, generation of plasmonic vortices with tunable topologic charges is proposed in the microwave regime. Tunable vortices with topologic charges of 0, +1 and -1 can be configured by illuminating incident plane waves with linearly polarization (LP), left-circularly polarization (LHCP) and right-circularly polarization (RHCP) on a single meta-particle, respectively. A spiral meta-particle operating at 2.94 GHz is designed, fabricated and measured to demonstrate the source-configured characteristics. The results showed that simulation and test are consistent with the theoretical ones.

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

作者： Kong, Xianglin Zhao, Lei Wang, Fengjun Zhang, Shengjun Fu, Yixiang Pang, Xiaoyu Liu, Xiaochun Shen, Xiaopeng China University of Mining and Technology School of Information and Control Engineering XuZhou 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 China University of Mining and Technology School of Materials and Physics Xuzhou China

ISBN: (纸本)9781665452366

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. © 2022 IEEE.

关键词： Multilayers

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Simulation of a dual-polarized printed dipole antenna with a rectagular cavity 11

Simulation of a dual-polarized printed dipole antenna with a...

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11th IEEE Asia-Pacific Conference on Antennas and Propagation, APCAP 2023 - Proceedings

作者： Wang, Qian Zhang, Jianchuan Liu, Jiaqi Fang, Zhongyi Fang, Liang Zhang, Junrui The Research Institute for Special Structures of Aeronautical Composite Avic The Aeronautical Science Key Lab for High Performance Electromagnetic Windows Shandong Ji'nan China School of Information Science and Engineering Harbin Institute of Technology at Weihai Weihai264209 China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing100076 China Shandong University at Weihai Weihai264209 China

ISBN: (纸本)9798350326277

This paper presents the design of a dual-polarized printed dipole antenna operating at 2GHz. In order to enhance the radiation characteristics of the antenna, a rectangular metallic cavity is positioned beneath the printed dipole *** antenna utilizes an exponentially tapered geometric shape for the printed dipole radiator, and it is fed using CPW technology. To mitigate mutual interference between the feeding structures, a bridge structure is implemented for one of the polarization ports. Electromagnetic simulation is conducted to evaluate the performance of the dual-polarized antenna. © 2023 IEEE.

关键词： dipole antenna dual-polarized antenna printed antenna rectangular cavity

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Spiral Antenna Loaded with Directors for GPR Application 13

Spiral Antenna Loaded with Directors for GPR Application

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13th International Conference on Microwave and Millimeter Wave technology, ICMMT 2021

作者： Jiang, Zhiye Liu, Yaokun Liu, Shufang Shi, Xiaowei National Key Laboratory Of Science And Technology On Test Physics And Numerical Mathematics Beijing100076 China School Of Electronic Engineering Xidian University Xi'an710071 China

ISBN: (纸本)9781665434379

The antenna is one of the most critical components in the ground penetrating radar system. The spiral Antenna has the characteristics of ultra-wideband, circular polarization and small size, making it suitable for underground target detection. In this paper, a high-gain helical antenna is designed. Its |S11| is less than -10dB from 380MHz to 4GHz and the bandwidth is greater than 10:1, while a unidirectional radiation is achieved by embedding the antenna into a cylindrical cavity. At the same time, directors are loaded in the maximum radiation direction of the antenna to increase the gain of the antenna. The peak gain is 11.5dBi. The size of the antenna is 240mm×240mm×97mm. © 2021 IEEE.

关键词： Helical antennas

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Digital Nonlinear Self-Interference Cancellation Using Sw-Gru-Tpa

SSRN

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SSRN 2024年

作者： Zhao, Zhongkai Xia, Shijie Gao, Lu Zheng, Pei Jiang, Yilin College of Information and Communication Engineering Harbin Engineering University Harbin150000 China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematic Beijing100876 China

In order to enhance spectrum utilization and decrease transmission delay, the 6G system adopts full-duplex(FD) mode. Simultaneous operation of the same frequency inevitably causes the receiver to receive the signal sent by the transmitter, leading to serious nonlinear self-interference due to the nonlinear distortion generated by the power amplifier(PA). This paper proposes hybrid layer structures SW-GRU-TPA for the implementation of digital self-interference cancellation(SIC), combined with Sliding Window (SW), Gated Recurrent Unit (GRU) , and Temporal Pattern Attention (TPA).The model can not only effectively utilize the influence of historical information on the signal, but also capture the spatial and temporal dependencies in the data to fit the nonlinear characteristics of the PA and the delay effect in multipath transmission. Meanwhile, by utilizing the L1 norm model pruning, the model parameters can be optimized, leading to improved processing efficiency, enhanced practicality, and increased convenience in real-world applications. Through the verification of the actual data, the performance of the SW-GRU-TPA network has improved by 7.95 dB, 7.79 dB, 3.45 dB and 3.13 dB respectively, compared to the RVTDNN, SW-GRU, HCRDNN and SW-GRU-AM *** the TPA is compressed by 42.17%, the ICR is only reduced by 1.58%. © 2024, The Authors. All rights reserved.

关键词： Power amplifiers

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Doffnet: A Distant Objects Rgb-T Semantic Segmentation Method Based on Cross-Level Interaction Fusion Network

SSRN

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SSRN 2024年

作者： Chen, Yu Li, Xiang Luan, Chao Hou, Weimin Liu, Haochen Xue, Lian Zhu, Zihui Zhang, Jianqi Liu, Delian Wu, Xin Wei, Linfang Jian, Chaochao Li, Jinze Academy of Military Sciences School of Physics and Optoelectronic Engineering Xidian University Xi’an710071 China Beijing Institute of Control & Electronics Technology Beijing100038 China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing100076 China

RGB-T segmentation represents an innovative approach driven by advancements in multi-spectral detection, poised to replace traditional RGB segmentation methods. An effective cross-modality feature fusion module is essential for this technology;simultaneously, the precise segmentation of distant objects is likewise a significant challenge. Building on these two focuses, we propose an end-to-end distant object feature fusion network (DOFFNet) for RGB-T segmentation. Initially, we introduce a cross-level interaction fusion strategy (CLIF) and an inter-correlation fusion method (IFFM) in the encoder to enhance multi-scale feature expression and improve fusion accuracy. Subsequently, we propose a residual-dense pixel convolution (R-DPC) in the decoder with a trainable upsampling unit, which dynamically reconstructs information lost during encoding, particularly for distant objects whose features may vanish after pooling. Experimental results demonstrate that DOFFNet improves accuracy across five classes and effectively segments distant objects occupying 0.2-2% of total pixels, enhancing overall segmentation quality and detailed understanding of RGB-T scenes. © 2024, The Authors. All rights reserved.

关键词： Semantic Segmentation

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Application of Graphic Electromagnetic Computing in Electrically Large Scale Composite Target Scattering

Application of Graphic Electromagnetic Computing in Electric...

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International Applied Computational Electromagnetics Society Symposium (ACES)

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

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.

关键词： Graphics Optical diffraction Laser radar Diffraction Computational modeling Lighting Optical computing

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Dynamic failure of aramid paper honeycomb under intermediate strain rate loading

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Thin-Walled Structures 2025年 215卷

作者： Chen, Meiduo Zhang, Xianglin Xu, Songlin Ma, Hao Yuan, Liangzhu Xie, Yushan Zhang, Xiaoman Wang, Pengfei University of Science and Technology of China Department of Modern Mechanics CAS Key Laboratory for Mechanical Behavior and Design of Materials Anhui Hefei230027 China Beijing Institute of Space Long March Vehicle Beijing100076 China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

Investigation of the transformation process of failure mechanism for materials and structures under intermediate strain rate loading is of great significance. To achieve intermediate strain rate loading, a novel experimental technique is proposed using a high-speed-rotating eccentric cam to compress the specimen. The particle velocities and the stresses at both ends of the specimen are measured by the velocity interferometer system for any reflector (VISAR) and by the semiconductor strain gauges, respectively. The paper honeycomb specimens with four thicknesses (i.e. 2 mm, 3 mm, 5 mm, and 10 mm) are tested under strain rates ranging from 0.1 to 15 s-1. Local deformation evolution in the specimen is captured based on high-speed photography and analyzed by the digital image correlation method (DIC). The deformation under intermediate strain rate loading is distinguished by higher particle velocity and lower particle acceleration, which is different from those under the static compression (at lower strain rates) and the Split Hopkinson Pressure bar (SHPB) impacting (at higher lower strain rates). Based on the DIC results, the abnormal size effect of specimen 2 mm is due to the competition between in-plane shear failure and out-of-plane buckling. The theoretical model is then established by introducing two main parameters, i.e. the lateral weakening factor ξ and the dynamic parameter k, to describe respectively the effects of in-plane shearing and strain rate on the out-of-plane wall buckling, and the critical stress for specimen buckling is obtained. The results show that the buckling deformation and the half-wave number for buckling are sensitive to the two parameters. This work provides theoretical and experimental references for the study of thin-walled structures under intermediate strain rate. © 2025 Elsevier Ltd

关键词： Fracture mechanics

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Design and Simulation of a Planar Printed Slot Array Antenna

Design and Simulation of a Planar Printed Slot Array Antenna

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2023 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition, iWEM 2023

作者： Xiaofei, Shi Jiaxin, Shi Jiaqi, Liu Zhongyi, Fang Lei, Wang Lizhong, Song Shandong Institute of Space Electronic Technology Yantai264003 China Harbin Institute of Technology School of Electronics and Information Engineering Harbin150001 China Harbin Institute of Technology at Weihai School of Information Science and Engineering Weihai264209 China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing100076 China Shandong Huayu Aerospace Technology Co. Ltd Yantai264003 China

ISBN: (纸本)9798350336740

This paper designs an array antenna with a planar printed structure. The antenna element adopts a rectangular slot antenna, and the antenna element is excited by a T-shaped feeding structure. The microstrip power distribution network is used to feed the antenna radiator array with equal power. The microstrip power distribution network and slot radiator array are located on top and bottom of dielectric substrate, and the array antenna is implemented by use of the printed circuit technology. In order to improve the gain, a metal reflector ground is placed below the dielectric substrate. A planar printed slot array antenna working in X band is designed. The coaxial line is used to feed the array antenna at the bottom. The whole antenna structure is easy to feed and suitable for fabrication. The designed array antenna was numerically calculated using full wave electromagnetic simulation software. At a working frequency of 10.1GHz, the voltage standing wave ratio (VSWR) of the antenna is about 1.35, and the gain is about 21.46dB. The design of the antenna scheme can be used as a reference for the actual application of engineering. © 2023 IEEE.

关键词： Slot antennas

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