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IET International Radar Conference 2020, IET IRC 2020

作者： Zhou, Jian Pang, Chen Li, Yongzhen Wang, Xuesong State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System National University of Defense Technology Hunan Changsha410073 China College of Electronic Science and Engineering National University of Defense Technology Hunan Changsha410073 China

ISBN: (纸本)9781839535635

This paper aims to eliminate the polarimetric biases of V-dipole phased array antennas using lower measurement cost. We analyze the polarization characteristics of the V-dipole with the integration method. An alternate-arranged 8×8 V-dipole array is designed and simulated. Based on the analysis of mutual coupling, the polarimetric performance of the array is presented. To correct the polarimetric biases using lower measurement cost, a cluster-based method is proposed to reconstruct the array pattern. The method uses partial elements to design polarimetric correction and treats the selection of elements as a clustering problem. The results prove the method helpful to minimize the biases using limited measurement cost. © 2020 Institution of Engineering and technology. All rights reserved.

关键词： Polarimeters

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Evaluation of surface wind speed over East Asia and the adjacent ocean in three reanalyses using satellite and in-situ observations

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Atmospheric and Oceanic science Letters 2025年

作者： Li, Siyuan Wang, Kai Miao, Hao Zhu, Xuedan Liu, Yanjie Li, Jinxiao Wang, Wei Zheng, Xiao Feng, Juan Wang, Xiaocong Shanghai Investigation Design and Research Institute Co. Ltd. Shanghai China College of Atmospheric Science Nanjing University of Information Science and Technology Nanjing China China Meteorological Administration Transportation Meteorology Key Laboratory Nanjing Joint Institute for Atmospheric Sciences Nanjing China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

Surface wind speed (SWS) not only plays a crucial role in regulating the Earth's energy and hydrological cycle, but also is an important source of sustainable renewable energy. This study assesses the credibility of SWSs in three reanalyses (ERA5, MERRA2, and JRA-55) in East Asia using both satellite and in-situ observations. Results show all three reanalyses can capture the spatial pattern of SWS as in observations, yet there are notable differences in magnitude. On land, ERA5 and MERRA2 overestimate the SWS by about 0.6 and 1.5 m s⁻¹, respectively, whereas JRA-55 underestimates it. The biases over the oceans are opposite to those on land and are relatively small due to the assimilation of observations of oceanic surface winds. Overall, JRA-55 and ERA5 offer better estimates of seasonal means and variances of SWS than MERRA2. The observed SWS shows a negative trend of −0.08 m s⁻¹/10 yr on land and a positive trend of 0.09 m s⁻¹/10 yr in the western North Pacific. Only JRA-55 shows similar trends to observations over both land and ocean, while ERA5 and MERRA2 show varying degrees of deviation from the observations. Further investigation shows that there is a strong link between the trend of SWS and that of the large-scale circulation, and that a large part of the SWS trend can be attributed to changes in large-scale circulations. 摘要利用卫星和地面站点观测数据, 本文对再分析产品中的地表风速 (SWS) 进行了可信度评估. 研究结果表明, 再分析产品能够较好地再现SWS的观测分布特征, 但在风速的量级上则存在显著差异. 具体而言, 在陆地区域, ERA5和MERRA2分别高估了约0.6 m s⁻¹和1.5 m s⁻¹, 而JRA-55则存在低估现象;而在海洋区域, 偏差情况与陆地相反. 总体来看, JRA-55和ERA5在模拟SWS的气候态及其变率方面, 更加接近观测数据. 其中, JRA-55中SWS的年代际趋势与观测数据最为一致. © 2024

关键词： ASCAT East Asia Reanalysis Surface wind speed Trend analysis

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Compression and thermal conduction performance of bioinspired sandwich structures fabricated by laser powder bed fusion

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Additive Manufacturing Frontiers 2025年第1期4卷

作者： Lin, Kaijie Hu, Kaiming Gu, Dongdong Yang, Jiankai Zhou, Mingdong Xiong, Yi College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Jiangsu Provincial Research Center for Laser Additive Manufacturing of High-Performance Components Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Shanghai Aircraft Manufacturing Co. Ltd. Shanghai 201324 China School of Mechanical Engineering University of Shanghai for Science and Technology Shanghai 200093 China Shanghai Key Laboratory of Digital Manufacture for Thin-walled Structures School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen 518055 China

After millions of years of natural evolution, horsetails have evolved unique stem structures that enable survival in harsh environments. Inspired by the cross-sectional characteristics of horsetail stems, a series of bioinspired sandwich structures were designed and fabricated using the laser powder bed fusion (LPBF) process. By combining experimental and finite element simulation methods, the formability, mechanical properties, deformation behavior, and thermal conduction performance of these structures were determined. Results show that the surface morphology of the bioinspired sandwich structures was smooth, with no cracks observed. The bioinspired sandwich structure with an inner tube diameter of 1.9 mm (D_1.9) exhibited optimal comprehensive mechanical properties, with a specific strength of 64.2 MPa/(g/cm³), and specific energy absorption of 3.3 J/g. Stress distribution results revealed that the D_1.9 structures had the most uniform stress distribution. Furthermore, increasing the internal conduction paths improved heat transfer;therefore, the thermal conductivities of the D_1.4, D_1.9, and D_2.4 structures were higher than that of the D₀ structure. This study demonstrates that a bioinspired design approach, combined with additive manufacturing technology, enables the development of high-performance structures with both load-bearing and thermally insulating capabilities. © 2025

关键词： Additive manufacturing Bioinspired Laser powder bed fusion Mechanical properties Thermal conduction

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Channel Modeling and Multi-User Precoding for Tri-Polarized Holographic MIMO Communications

arXiv

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arXiv 2023年

作者： Wei, Li Huang, Chongwen Alexandropoulos, George C. Yang, Zhaohui Yang, Jun Sha, Wei E.I. Debbah, Mérouane Yuen, Chau Singapore University of Technology and Design Singapore College of Information Science and Electronic Engineering Zhejiang University China Department of Informatics and Telecommunications National and Kapodistrian University of Athens Greece Technology Innovation Institute Abu Dhabi United Arab Emirates State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen China Wireless Product R&D Institute ZTE Corporation Shenzhen China CentraleSupelec University Paris-Saclay Gif-sur-Yvette France

This paper studies the exploitation of triple polarization (TP) for multi-user (MU) holographic multiple-input multiple-output surface (HMIMOS) wireless communication systems, aiming at capacity boosting without enlarging the antenna array size. We specifically consider that both the transmitter and receiver are equipped with an HMIMOS comprising compact sub-wavelength TP patch antennas. To characterize TP MU-HMIMOS systems, a TP near-field channel model is proposed using the dyadic Green's function, whose characteristics are leveraged to design a user-cluster-based precoding scheme for mitigating the cross-polarization and inter-user interference contributions. A theoretical correlation analysis for HMIMOS with infinitely small patch antennas is also presented. According to the proposed scheme, the users are assigned to one of the three polarizations, which is easy to implement, at the cost, however, of reducing the system's diversity. Our numerical results showcase that the cross-polarization channel components have a non-negligible impact on the system performance, which is efficiently eliminated with the proposed MU precoding scheme. Copyright © 2023, The Authors. All rights reserved.

关键词： Polarization

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Research on in-plane fluid-elastic instability of heat transfer tube in steam generator 48

Research on in-plane fluid-elastic instability of heat trans...

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48th International Congress and Exhibition on Noise Control Engineering, INTER-NOISE 2019 MADRID

作者： Qi, Huan-Huan Jiang, Nai-Bin Huang, Xuan Feng, Zhi-Peng Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China 328 Changshun Avenue Chengdu China

ISBN: (纸本)9788487985317

Due to a small gap between the anti-vibration bars (AVBs) and the heat transfer tubes, and according to the position of AVBs and the number of continuous failures of the in-plane support, the in-plane restraint failure analysis of AVB is divided into 13 cases. The influence of the restraint failure on the in-plane mode of the heat transfer tube under different cases is analysed. The mode damping ratio was calculated by performing a weighted average method based on the mode shape function, and then the effects of different restraints by AVBs on fluid-elastic instability of steam generator tubes are studied. The analysis results show that with the increase of the continuous failure position of the in-plane support, the first-order modal frequency in the elbow zone decreases continuously, and the mode shape appearing in the elbow zone becomes more obvious. The first-order mode in the elbow zone is not necessarily the mode in which the largest fluidelastic instability ratio occurs. The vibration mode with the largest ratio of the fluid-elastic instability appears almost in the elbow zone. With the increase of the continuous failure position of the in-plane support, the fluid-elastic instability ratio increases continuously. When three or more continuous AVBs fail in-plane, fluidelastic instability will occur. © INTER-NOISE 2019 MADRID - 48th International Congress and Exhibition on Noise Control Engineering. All Rights Reserved.

关键词： Tubes (components)

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Alternating Direction Method of Multipliers Improved Online Power Management in a Fuel Cell Hybrid Bus

Alternating Direction Method of Multipliers Improved Online ...

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第33届中国控制与决策会议

作者： Xiaodong Wei Chao Sun Weiwei Huo Fengchun Sun State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University National Engineering Laboratory for Electric Vehicles Beijing Institute of Technology School of Mechanical and Electrical BeijingInformation Science and Technology University

ADMM is an important convex optimization method in solving complex control *** fuel cell and battery hybrid vehicles,the power distribution control of fuel cell engine and the battery is critical,which is called energy *** paper,for the first time,proposed an ADMM-based energy management strategy for a fuel cell hybrid *** augmented lagrangian equation and scaled dual form of the system model are established,to satisfy the standard form of *** are developed to validate the performance of proposed method under the driving cycles CHTC-HT and *** results show that the ADMM-based energy management approach is able to realize real-time implementation,while maintaining over 95% optimality of hydrogen consumption compared to DP offline results.

关键词： Fuel cell hybrid bus Energy management Convex optimization Alternating Direction Method of Multipliers

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Long-distance OPGW Optical Cable Monitoring system Based on φ-OTDR technology

Long-distance OPGW Optical Cable Monitoring System Based on ...

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Asia Communications and Photonics Conference and Exhibition (ACP)

作者： Ying Wang Yanyang Lei Xing Liu Can Li Xiaomeng Xia Tong Chen Yue Deng Jing Zhang Xiaohui Tang Information Communication Dispatching Monitoring Center State Grid Information & Telecommunication Branch Beijing China National Key Laboratory of Science and Technology on Tunable Laser Harbin Institute of Technology Harbin China Energy Planning Institute Southwest Electric Power Design Institute Co. Ltd Chengdu China

In this paper, a long-range phase-sensitive optical time-domain reflectometer (φ-OTDR) system is proposed, which is based on the direct detection type φ-OTDR system, combined with the first-order forward Raman distributed amplification technology and remote pump amplification technology, to achieve 130km vibration monitoring range and 20m spatial resolution. Compared with relay EDFA amplification technology and bidirectional distributed amplification technology, the system eliminates the necessity of a remote power supply, which is of great significance in the monitoring application of long-distance OPGW optical cable.

关键词： Vibrations Stimulated emission Power supplies Optical pumping Communication cables Optical sensors Optical reflection

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Communication-Assisted Sensing in 6G Networks

arXiv

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arXiv 2023年

作者： Dong, Fuwang Liu, Fan Lu, Shihang Xiong, Yifeng Zhang, Qixun Feng, Zhiyong Gao, Feifei School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China School of Information and Electronic Engineering Beijing University of Posts and Telecommunications Beijing100876 China Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing100876 China Department of Automation Tsinghua University Beijing100876 China

Exploring the mutual benefit and reciprocity of sensing and communication (S&C) functions is fundamental to realizing deeper integration for integrated sensing and communication (ISAC) systems. This paper investigates a novel communication-assisted sensing (CAS) system within 6G perceptive networks, where the base station actively senses the targets through device-free wireless sensing and simultaneously transmits the estimated information to end-users. In such a CAS system, we first establish an optimal waveform design framework based on the rate-distortion (RD) and source-channel separation (SCT) theorems. After analyzing the relationships between the sensing distortion, coding rate, and communication channel capacity, we propose two distinct waveform design strategies in the scenario of target impulse response estimation. In the separated S&C waveforms scheme, we equivalently transform the original problem into a power allocation problem and develop a low-complexity one-dimensional search algorithm, shedding light on a notable power allocation tradeoff between the S&C waveform. In the dual-functional waveform scheme, we conceive a heuristic mutual information optimization algorithm for the general case, alongside a modified gradient projection algorithm tailored for the scenarios with independent sensing sub-channels. Additionally, we identify the presence of both subspace tradeoff and water-filling tradeoff in this scheme. Finally, we validate the effectiveness of the proposed algorithms through numerical simulations. Copyright © 2023, The Authors. All rights reserved.

关键词： Optimization

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design and polarization scattering characteristics of L-shape reflector 5

Design and polarization scattering characteristics of L-shap...

引用

IET International Radar Conference 2020, IET IRC 2020

作者： Huang, Jiankai Wang, ZhanLing Pang, Chen Li, Jianbing Li, Yongzhen State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and Engineering National University of Defense Technology Hunan Changsha410073 China

ISBN: (纸本)9781839535635

This paper presents a new L-shape reflector to enhance the cross-polarization radar cross section (RCS). Cross-polarization component can increase the jamming effect against the polarization radars. Such L-shape reflectors can also be used as radar tags in cars, books and so on for radar target detection. By bending the structure of traditional dipole reflector to L shape, the direction of surface current is changed, which produces the cross-polarization component. We have simulated L-shape reflector with different lengths of branches in X-band. Compared with the scattering characteristics of traditional dipole reflector, the linear depolarization ratio (LDRvh) of the L-shape reflector can be easily controlled by changing the length of two branches. © 2020 Institution of Engineering and technology. All rights reserved.

关键词： Radar cross section

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3-DOF decoupled magnetic platform for optical low-frequency vibration isolation

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International Journal of Mechanical sciences 2025年 300卷

作者： Wen-Hao Qi Tian-Yu Zhao Qiu-Hua Gao Jia-Jia Lu Long-Qi Cai Yang Li Ge Yan Wen-Ming Zhang State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China National Key Laboratory of Nuclear Reactor Technology Nuclear Power Institute of China Chengdu 610213 China

Optical instruments, such as atomic force microscopes (AFM), are susceptible to interference from external vibrations, which can diminish imaging clarity and hinder optimal performance. A three-degree-of-freedom (3-DOF) decoupled magnetic platform (DMP) is proposed for optical low-frequency vibration isolation. The specially developed platform attains vibration decoupling through an orthogonal structural design and utilizes six identical vibration isolation units that are specially configured to achieve low dynamic stiffness and significantly low-frequency vibration isolation performance in both horizontal and vertical directions simultaneously. Different from the traditional realization of positive and negative stiffness combination, the novel isolation unit is designed using the constant magnetic force, which is generated from the magnetic field distortion. This implementation is revealed through magnetic field analysis and verified via static calibration. The dynamic model is established by considering viscous damping and dry friction, and the Runge-Kutta Method is applied to calculate the vibration response. Theoretical analyses are conducted to guide the design of the DMP and predict dynamic responses under different structural parameters, damping settings, and excitation conditions. Experiments are implemented to demonstrate the vibration isolation performance of the prototype. The result reveals the different effects of viscous damping and dry friction and demonstrates that the developed DMP has a broad frequency decoupled vibration isolation capability. The magnetic platform achieved by reusing the newly designed quasi-zero stiffness (QZS) unit provides a new option for optical vibration isolation, with the advantages of a large stroke and strong vibration decoupling.

关键词： constant magnetic force decoupled platform large stroke Nonlinear dynamics optical vibration isolation quasi-zero stiffness

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