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IEEE International Conference on Radar

作者： Hao Li Xueli Fang Lei Zhang Hui Kang Wei Zhang School of Information and Communication Engineering University of Electronic Science and Technology of China Chengdu China Key Laboratory of complex aviation simulation system Beijing China

ISBN: (纸本)9781665468893

With the emergence of various kinds of complex radar jamming, radar jamming intelligent recognition technology has increasingly become the key to electronic counter-counter measures. To achieve radar jamming open-set recognition with a small number of tagged samples, Generative adversarial network-based pseudolabeled convolutional neural network (GAN-PL-CNN) model is proposed in this paper. Firstly, radar jamming is modelled, and the radar jamming datasets with known and unknown types are established after time-frequency transformation and image processing. Then, the adaptive pseudolabeling method is used to achieve semi-supervised recognition of radar jamming by combining the learning capability of convolutional neural networks and the characteristics of pseudolabeling to increase labeled samples intelligently. Finally, generative adversarial networks are introduced to enhance the recognition ability of the model and the discrimination ability of the unknown type through the game between the generator and the discriminator in the iterative process. Experimental results show that the GAN-PL-CNN model achieves 89.7%-95.1% for known types and 30.7%-86.8% for unknown types at 3%-6% labeling rate. As the number of labeled samples increases, the recognition effect becomes better and has a greater ability to exclude unknown type.

关键词： Adaptation models Time-frequency analysis Radar measurements Neural networks Radar Radar imaging Convolutional neural networks

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Reconstructing the Nanoscale Porous Structures in Coal-Based Membranes by Ultrafast High-Temperature Sintering for Solar-Driven Water Treatment

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SSRN 2023年

作者： Liu, Chih-Chin Chen, Rong Wei, Yanzhuo Huang, Yang Zhang, Zhijun Zhao, Yixin Fu, Tairan Hu, Chuxiong Huang, Xia Zang, Xining Department of Mechanical Engineering Tsinghua University Beijing100084 China Key Laboratory for Advanced Materials Processing Technology Ministry of Education Tsinghua University Beijing100084 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China Department of Thermal Engineering Tsinghua University Beijing100084 China School of Chemical and Environmental Engineering China University of Mining and Technology Beijing100083 China Key Laboratory for Thermal Science and Power Engineering Ministry of Education China Beijing Key Laboratory for Precise Mining of Inter grown Energy and Resources China

Lignite, a low-grade coal, accounts for over 40% of the global coal reserves. The use of lignite has been limited compared to other grades due to its low calorific value, high impurities content, and elevated volatile matter. Exploring a scalable and environment-friendly approach to upgrade lignite will offer new opportunities. In this work, Ultrafast High-Temperature Carbonization (UHC) has been developed to carbonize lignite and modify its nanoscale structure to construct a conductive porous membrane. The whole process takes only 30 s with an ultrafast heating rate exceeding 2400°C/min and a maximum temperature over 1500°C. Upon heating the pore structures in the coal membrane evolves into micro- and mesopores with a specific surface area of over 300 m2/g. The carbonized coal-based membrane provides superior performance as a solar evaporator for water treatment, due to its interconnected porous structures, hydrophilicity, and over 85% absorption of full-band visible light. Under 1 sun solar irradiation, the membrane shows over 98.2% removal rate of salts, heavy metal ions, and volatile organic compounds (VOCs). © 2023, The Authors. All rights reserved.

关键词： Metal ions

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Hamiltonian Dynamics and Targeted Energy Transfer of a Grounded Bistable Nonlinear Energy Sink

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SSRN 2022年

作者： Li, Shuangbao Zhou, Xinxing Chen, Jianen Research Institute of Science and Technology Civil Aviation University of China Tianjin300300 China College of Science Civil Aviation University of China Tianjin300300 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

A two-degree-of-freedom nonlinear mechanical system describing a damped linear oscillator weakly coupled to a lightweight grounded bistable nonlinear energy sink is proposed to investigate the targeted energy transfer (TET) under asymmetric local nonlinear potentials. The Bogdanov-Takens bifurcations of equilibria are discussed to reflect the bistable and asymmetric characteristics of the system. Through projections of isoenergetic manifolds, the topological features of the Hamiltonian dynamics under $1:1$ internal resonance have been investigated, which induces conditions for energy localization and exchange. In the general case, the topological features of the Hamiltonian dynamics related to the nonlinear normal modes (NNMs) are classified by the Poincare map, the relations between the NNMs and the Hamiltonian dynamics have been interpreted through the frequency energy plots. The results show that introducing the asymmetric characteristics may enhance the TET and realize the complete TET. © 2022, The Authors. All rights reserved.

关键词： Degrees of freedom (mechanics)

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Disorder- and Topology-Enhanced Fully Spin-Polarized Currents in Nodal Chain Spin-Gapless Semimetals

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Physical Review Letters 2022年第9期129卷 097201-097201页

作者： Xiaodong Zhou Run-Wu Zhang Xiuxian Yang Xiao-Ping Li Wanxiang Feng Yuriy Mokrousov Yugui Yao Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) School of Physics Beijing Institute of Technology Beijing 100081 China Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems School of Physics Beijing Institute of Technology Beijing 100081 China Peter Grünberg Institut and Institute for Advanced Simulation Forschungszentrum Jülich and JARA 52425 Jülich Germany Institute of Physics Johannes Gutenberg University Mainz 55099 Mainz Germany

Recently discovered high-quality nodal chain spin-gapless semimetals MF3 (M=Pd, Mn) feature an ultraclean nodal chain in the spin up channel residing right at the Fermi level and displaying a large spin gap leading to a 100% spin polarization of transport properties. Here, we investigate both intrinsic and extrinsic contributions to anomalous and spin transport in this class of materials. The dominant intrinsic origin is found to originate entirely from the gapped nodal chains without the entanglement of any other trivial bands. The side-jump mechanism is predicted to be negligibly small, but intrinsic skew scattering enhances the intrinsic Hall and Nernst signals significantly, leading to large values of respective conductivities. Our findings open a new material platform for exploring strong anomalous and spin transport properties in magnetic topological semimetals.

关键词： Transport phenomena Topological materials

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Tetrahedral shape of Zr110 from covariant density functional theory in 3D lattice space

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Physical Review C 2024年第1期109卷 014311-014311页

作者： F. F. Xu (许方方) B. Li (李博) Z. X. Ren (任政学) P. W. Zhao (赵鹏巍) State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing 100871 China Institut für Kernphysik Institute for Advanced Simulation and Jülich Center for Hadron Physics Forschungszentrum Jülich D-52425 Jülich Germany Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics Universität Bonn D-53115 Bonn Germany

Covariant density functional theory is solved in 3D lattice space by implementing the preconditioned conjugate gradient method with a filtering function. It considerably improves the computational efficiency compared to the previous inverse Hamiltonian method (IHM). This new method is then applied to explore the tetrahedral shape of Zr110 in the full deformation space. Although the ground-state energy and deformation are consistent with the previous study, the pear-shaped isomeric state is significantly lowered in energy. The energy difference between the two states is only 0.07 MeV, indicating an interesting possible shape coexistence in Zr110. This effect is analyzed with the microscopic evolution of the single-particle levels near the Fermi surface driven by the deformation.

关键词： Nuclear density functional theory Nuclear shapes and moments Nuclear structure & decays 90 ≤ A ≤ 149

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Direct Evidence of the Relationship between Piezoelectricity and Catalytic Activity

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SSRN 2025年

作者： Gao, Wenpeng Zheng, Huashan Luo, Huajie Zhang, Haibo Jo, Wook Xie, Bing School of Power and Energy Jiangxi Key Laboratory of Green General Aviation Power Nanchang Hangkong University Nanchang330063 China Functional Materials and Acousto-optic Instruments Institute School of Instrumentation Science and Engineering Harbin Institute of Technology Harbin150080 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing100083 China School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan430074 China Ulsan44919 Korea Republic of Beijing Advanced Innovation Center for Materials Genome Engineering China State Key Laboratory of Material Processing and Die & Mould Technology China School of Materials Science and Engineering

Piezocatalysis is highly valued for its efficient energy conversion and environmental capabilities. However, the fundamental connection between piezoelectricity and piezocatalytic activity remains to be thoroughly investigated. Herein, piezoceramic thin flakes with varying levels of piezoelectricity were examined to quantitatively assess the impact of the piezoelectric coefficient (d33) on the piezocatalytic activation in energy and environment applications. The piezoceramic flake, 220 μm thick, possessing the highest piezoelectricity (d33 = 1100 pC/N), demonstrated the highest H2O2 yield (572 μM h-1) and the fastest degradation rate (k = 0.0725 min-1) of Rhodamine B (RhB), exceeding the best performance of previously reported ceramic blocks. In contrast, the same thickness flake with the lowest piezoelectricity (d33 = 150 pC/N) exhibited the weakest piezocatalytic performance. By analyzing internal carrier characteristics and simulating carrier migration pathways under an electric field, a quantitative relationship between piezoelectricity and piezocatalytic activity was established. The piezoceramic flake with higher piezoelectricity demonstrated a higher effective free carrier concentration, a larger number of transiently migrating carriers, and a shorter migration distance due to a stronger built-in electric field, resulting in enhanced piezocatalytic activity. This work clearly elucidates the relationship between piezoelectricity and piezocatalytic activity. © 2025, The Authors. All rights reserved.

关键词： Piezoelectricity

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A Data-Driven Method for Fast Calculation of Electromagnetic Radiation Field of Flexible HVDC Converter Valves

A Data-Driven Method for Fast Calculation of Electromagnetic...

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Frontiers of Power and Energy (ACFPE), Asian Conference on

作者： Haijun Tang Minhua Xie Qin Qin Shuncheng Wang Wei Bao Minghui Su State Key Laboratory of Advanced Power Transmission Technology State Grid Smart Grid Research Institute Co. Ltd. Beijing China Beijing Key Laboratory of DC Grid Technology and Simulation State Grid Smart Grid Research Institute Co. Ltd. Beijing China State Grid Shanghai Electric Power Research Institute State Grid Shanghai Municipal Electric Power Company Shanghai China Department of Electrical Engineering North China Electric Power University Baoding China

ISBN: (数字)9798350367676

ISBN: (纸本)9798350378467

In order to solve the problem of time-consuming computation of electromagnetic radiation field on specific planes of flexible HVDC converter valves, this paper proposes a fast calculation method which combines Proper Orthogonal Decomposition (POD) and Radial Basis Function Response Surface method with Linear Polynomial(RBFLP) to improve the calculation efficiency. To validate the accuracy and practicality of this method, a three-phase MMC converter valve antenna model was constructed. The excitation of the antenna model are the spectral quantities of the MMC valve currents and voltages transformed from the time domain. And the calculation results on any field plane will be predicted from the known simulation results on discrete planes from available software. The results show that the maximum absolute error in the test conditions between the reduced-order prediction data and the available software simulation data is 1.1326. And the absolute error gradually decreases as the distance increases. Therefore, this method is suitable for fast calculation of electromagnetic radiation field where efficiency is necessary more than accuracy. Since the results are needed for only a few discrete planes, the simulation of all the needed planes is avoided, especially if there are many needed planes, which is convenient and efficient.

关键词： Accuracy HVDC transmission simulation Electromagnetic radiation Predictive models Valves Software Reduced order systems Response surface methodology Time-domain analysis

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Super-directive Scattering of Optimized Multi-layered Dielectric Cylinder by Differential Evolution Algorithm 4

Super-directive Scattering of Optimized Multi-layered Dielec...

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4th IEEE International Conference on Electronic Information and Communication technology, ICEICT 2021

作者： Zhang, Yongli Chen, Wan Lv, Bo Gao, Lei Zhang, Mingyue China Academy of Civil Aviation Science and Technology Beijing China Space Environment Simulation and Research Infrastructure Harbin Institute of Technology Harbin China Key Laboratory of In-Fiber Integrated Optics of Ministry of Education College of Physics and Optoelectronic Engineering Harbin Engineering University Harbin China Harbin Medical University Harbin China Heilongjiang Xinshan Technology Co. Ltd Harbin China Key Laboratory of In-Fiber Integrated Optics of Ministry of Education College of Physics and Optoelectronic Engineering Harbin Engineering University Harbin China

ISBN: (纸本)9781665432030

Superdirective antenna can realize high channel capacity of multiple-input multiple-output system (MIMO). The optimization of superdirective scattering by a novel weighting optimizing goal and Dirac-Delta function model is proposed. Both main-lobe and side-lobe characteristics of the lobe are optimized. Compared with the traditional optimization method, which only takes the main-lobe characteristic into consideration, the directivity has improved by 50% (from 6.0 to 9.0). Meanwhile, the radius of the scattering object is only 0.1λ0, which indicates this antenna is a super-directive antenna. ©2021 IEEE

关键词： Dielectric devices

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Corrigendum to “Aeroelastic stability of labyrinth seal ring under steady and dynamic total pressure intake distortion conditions” [Mech. Syst. Signal Process. 204 (2023) 110776]

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Mechanical Systems and Signal Processing 2024年 214卷

作者： Guozheng Su Dan Sun Yu Li Guozhe Ren Zemin Yang Haoyu Yin Liaoning Key Laboratory of Advanced Measurement and Test Technology for Aviation Propulsion System Shenyang Aerospace University Shenyang 110136 China Key Laboratory of Turbomachinery Advanced Seal Technology Shenyang Shenyang Aerospace University Shenyang 110136 China

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Intrinsic mechanical behavior of MgAgSb thermoelectric material:An ab initio study

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Journal of Materiomics 2020年第1期6卷 24-32页

作者： Guodong Li Qi An Umut Aydemir Sergey I.Morozov Bo Duan Pengcheng Zhai Qingjie Zhang William A.Goddard Ⅲ Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics School of ScienceWuhan University of TechnologyWuhan430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China Department of Chemical and Materials Engineering University of Nevada RenoRenoNV89557USA Department of Chemistry Koc UniversitySariyerIstanbul34450Turkey Boron and Advanced Materials Research Center Koc UniversitySariyerIstanbul34450Turkey Department of Computer Simulation and Nanotechnology South Ural State UniversityChelyabinsk454080Russia Materials and Process Simulation Center California Institute of TechnologyPasadenaCA91125USA

α-MgAgSb based thermoelectric(TE)device attracts much attention for its commercial application because it shows an extremely high conversion efficiency of ~8.5% under a temperature difference of 225 ***,the mechanical behavior of α-MgAgSb is another serious consideration for its engineering ***,we apply density functional theory(DFT)simulations to examine the intrinsic mechanical properties of all three MgAgSb phases,including elastic properties,shear-stress-shear-strain relationships,deformation and failure mechanism under ideal shear and biaxial shear *** find that the ideal shear strength of α-MgAgSb is 3.25 GPa along the most plausible(100)<010>slip *** strength is higher than that of β-MgAgSb(0.80 GPa)and lower than that of γ-MgAgSb(3.43 GPa).The failure of α-MgAgSb arises from the stretching and breakage of MgeSb bond α-MgAgSb under pure shear load,while it arises from the softening of MgeAg bond and the breakage of AgeSb bond under biaxial shear *** suggests that the deformation mechanism changes significantly under different loading conditions.

关键词： MgAgSb thermoelectric materials Density functional theory Ideal strength Deformation mechanism

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