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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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Simultaneously achieving high energy density and responsivity in submicron BaTiO_(3) film capacitors integrated on Si

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Journal of advanced Ceramics 2024年第2期13卷 198-206页

作者： Jun Ouyang Yinxiu Xue Chuanqi Song Meiling Yuan Kun Wang Yuyao Zhao Hongbo Cheng Hanfei Zhu Chao Liu Institute of Advanced Energy Materials and Chemistry School of Chemistry and Chemical EngineeringQilu University of Technology(Shandong Academy of Sciences)Jinan 250353China Key Laboratory of Key Film Materials&Application for Equipment School of Material Sciences and EngineeringXiangtan UniversityXiangtan 411105China School of Materials Science and Engineering Shandong UniversityJinan 250061China Academic Affairs Office Civil Aviation University of ChinaTianjin 300300China China Tobacco Shandong Industrial Co. Ltd.Jinan 250014China

In the research field of energy storage dielectrics,the“responsivity”parameter,defined as the recyclable/recoverable energy density per unit electric field,has become critically important for a comprehensive evaluation of the energy storage capability of a *** this work,high recyclable energy density and responsivity,i.e.,W_(rec)=161.1 J·cm^(-3) and ξ=373.8 J·(kV·m^(2))^(-1),have been simultaneously achieved in a prototype perovskite dielectric,BaTiO_(3),which is integrated on Si at 500℃ in the form of a submicron thick *** ferroelectric film features a multi-scale polar structure consisting of ferroelectric grains with different orientations and inner-grain ferroelastic domains.A LaNiO_(3) buffer layer is used to induce a{001}textured,columnar nanograin microstructure,while an elevated deposition temperature promotes lateral growth of the nanograins(in-plane diameter increases from~10-20 nm at lower temperatures to~30 nm).These preferably oriented and periodically regulated nanograins have resulted in a small remnant polarization and a delayed polarization saturation in the film’s P-E behavior,leading to a high recyclable energy ***,an improved polarizability/dielectric constant of the BaTiO_(3) film has produced a much larger maximum polarization than those deposited at lower temperatures at the same electric field,leading to a record-breaking responsivity for this simple perovskite.

关键词： energy storage energy density responsivity BaTiO_(3) dielectric capacitor Si

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Microstructure Evolution and Mechanical Properties of a Novel High-Strength Ti2alnb Alloy Processed by Large-Strain Hot Extrusion

SSRN

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SSRN 2022年

作者： Liu, Shishuang Cao, Jingxia Zhou, Yi Hou, Chenrui Dai, Shenglong Huang, Xu Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys AECC Beijing Institute of Aeronautical Materials Beijing100095 China

The microstructure evolution and tensile behavior of a novel Ti2AlNb alloy (Ti-22Al-23Nb-1Mo-1Zr) processed by two-pass hot extrusion and two-step heat treatment were investigated. After extruding deformation in the B2 phase field, the B2 grains were refined from about 1500 μm to 50 μm through dynamic recrystallization. The microstructures subjected to solution treatment in the B2+α2 phase field and aging treatment in the B2+O phase field include B2 matrix, lamellar O, rim O and lamellar α2/O phases. The microstructure and tensile properties are sensitive to aging temperature. As the increase of the aging temperature, the content of the B2 phase and the size of the lamellar O phase increase, resulting in low strength and high ductility. The alloy aged at 800 oC has a good match of strength and ductility. It has an elongation of 6.4 % with a tensile strength as high as 1228 MPa due to the precipitation strengthening of numerous lamellar O phase and fine grain strengthening. The tensile fracture mode predominantly shows quasi-cleavage characteristics with typical cleavage facets and massive dimples, which is consistent with the good balance of tensile strength and ductility. An in-depth understanding of the relationship between microstructure and tensile properties in this study can be helpful for the engineering application of the Ti2AlNb alloy. © 2022, The Authors. All rights reserved.

关键词： Tensile strength

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Semi-supervised Open-set Recognition of Radar Active Jamming

Semi-supervised Open-set Recognition of Radar Active Jamming

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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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A Study on the Correlation Between Poles and Cuts in ππ Scattering

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Communications in Theoretical Physics 2019年第11期71卷 1309-1318页

作者： Ling-Yun Dai Xian-Wei Kang Tao Luo School of Physics and Electronics Hunan University College of Nuclear Science and Technology Beijing Normal University Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) and Institute of Modern Physics Fudan University Helmholtz Institut für Strahlen-und Kernphysik and Bethe Center for Theoretical Physics Universit?t Bonn Institute for Advanced Simulation Institut f¨ur Kernphysik and Jülich Center for Hadron Physics Forschungszentrum Jülich

In this paper we propose a dispersive method to describe two-body scattering with unitarity imposed. This approach is applied to elastic ππ scattering. The amplitudes keep single-channel unitarity and describe the experimental data well, and the low-energy amplitudes are consistent with that of chiral perturbation theory. The pole locations of the σ, f0(980), ρ(770) and f2(1270) and their couplings to ππ are obtained. A virtual state appearing in the isospin-two S-wave is confirmed. The correlations between the left(and right) hand cut and the poles are discussed. Our results show that the poles are more sensitive to the right hand cut rather than the left hand cut. The proposed method could be used to study other two-body scattering processes.

关键词： dispersion relations partial-wave analysis chiral lagrangian meson production

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Research on Modular Inverter Control technology of Dual Three-Phase Permanent Magnet Synchronous Motor

Research on Modular Inverter Control Technology of Dual Thre...

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IEEE International Conference on Power and Power and Renewable Energy (ICPRE)

作者： Changfang Wei Yiming Song Jin Wang Libing Zhou State Key Laboratory of Advanced Electromagnetic Technology Huazhong University of Science and Technology Wuhan China AECC Hunan Aviation Powerplant Research Institute Zhuzhou China

ISBN: (数字)9798350377460

ISBN: (纸本)9798350377477

Using medium-voltage DC transmission instead of traditional three-phase AC transmission can significantly reduce cable losses. However, high DC bus voltages pose challenges for voltage equalization across inverter modules. This paper proposes a topology for a modular dual three-phase permanent magnet synchronous motor (PMSM) inverter, and studies its dual closed-loop vector control and modular inverter voltage equalization control strategies. By using a series connection of inverters and three-phase decoupled PWM technology for individual control of inverter modules, a modular inverter series bus voltage equalization control strategy is established. Compared to parallel modular inverter, it can further reduce voltage fluctuations and enhance the dynamic performance of the motor. simulation has verified the performance of the motor operation based on this control strategy, demonstrating that this method can achieve effective voltage equalization.

关键词： Renewable energy sources Voltage fluctuations Fluctuations Pulse width modulation Permanent magnet motors Inverters Stability analysis Topology Voltage control Underwater vehicles

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An Method to Quantify Control Rod Worth Uncertainty Propagated from Nuclear Data

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Energy Procedia 2017年 127卷 178-186页

作者： Chen Hao Wenqi Hu Qiang Zhao Fu Li Yan Yu Yizhen Wang Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Harbin 150001 China Institute of Nuclear and New Energy Technology(INET) Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University Beijing 100084 China

One of the main issues of nuclear reactor design is the accurate calculation of control rod worth. However, in the calculation results there exists uncertainty inevitably, which is propagated from uncertainty in input parameters, computing models and calculation methods. Therefore, carrying out control rod worth uncertainty quantification is urgent but full of challenges, especially for application of a feasible method for propagating input uncertainties to control rod worth. In this paper, a new uncertainty analysis method for quantifying uncertainty of control rod worth propagated from macroscopic cross sections has been proposed. The basic idea is to use efficient sampling method to propagate nuclear data uncertainties through the function between control rod worth and all macroscopic cross sections. This is done by applying perturbation theory. Numerical results indicate that the new method proposed in this paper is an effective way to quantify uncertainty of control rod worth propagated from nuclear data.

关键词： Control rods worth Uncertainty Perturbation theory Sampling

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Research on knowledge network modelling for aero-craft system design 7

Research on knowledge network modelling for aero-craft syste...

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7th International Conference on simulation and Modeling Methodologies, Technologies and Applications, SIMULTECH 2017

作者： Zhai, Xiang Dai, Feng Qu, Huiyang Zhong, Lingling Du, Chenyong Beijing Complex Product Advanced Manufacturing Engineering Research Center Beijing Simulation Center Beijing China School of Mechanical Engineering Zhejiang University Hangzhou China State Key Laboratory of Intelligent Manufacturing System Technology Beijing Institute of Electronic System Engineering Beijing China Aviation Engineering Institute Civil Aviation Flight University of China Sichuan China Beijing ZhiYuanChuangTong IT Co Ltd Beijing China

ISBN: (纸本)9789897582653

A great amount of existing knowledge is required during the development of aero-craft system. At present, the existing knowledge organization model construct different knowledge model for different stages is difficult to adapt to the complicated product life cycle application. This study proposes a product development oriented knowledge network model focusing on expressing the knowledge demands and connecting the computer-aided system. Under the overall knowledge network model, this study describes the ontology description method of spacecraft product model, development tasks and aerospace terminology. Recommending missile aerodynamic knowledge within the design stage is presented as a case study, and the framework and the method is proved to be effective. © Copyright 2017 by SCITEPRESS - science and technology Publications, Lda. All rights reserved.

关键词： Ontology

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A quantitative microplasticity-based approach to rationalize the poor strengthening response of polycrystalline Mg alloys

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Journal of Magnesium and Alloys 2023年第5期11卷 1656-1671页

作者： X.Z.Jin W.C.Xu D.B.Shan B.Guo B.Jin M.T.Pérez-Prado National Key Laboratory for Precision Hot Processing of Metals&School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001PR China IMDEA Materials Institute C/Eric Kandel2GetafeMadrid 28906Spain Advanced Composites Simulation Lab University of Southern CaliforniaLos AngelesCA 90089U.S.A M.C.Gill Composites Center University of Southern CaliforniaLos AngelesCA 90089U.S.A

This work aims to understand the inefficiency of nanoprecipitates to strengthen a weakly textured,polycrystalline Mg-Gd-Y-Zr *** experimental micromechanical approach consisting on micropillar compression combined with analytical electron microscopy is put in place to analyze the effect of nanoprecipitation on soft and hard basal slip and twinning in individual grains with different *** study shows that,in grains that are favorably oriented for basal slip(“soft”basal slip),aging leads to extreme localization due to the ability of basal dislocations to shear the nanoparticles,resulting overall in the softening of basal ***,in grains in which the c-axis is almost perpendicular to the compression axis,prismatic slip dominates deformation in the solid solution state and nanoprecipitation favors twinning due to the concomitant lattice solute ***,in grains oriented with their c-axis making an angle of about 5-7°with respect to the compression axis,which deform mainly by“hard”basal slip,precipitation leads to the strengthening of basal systems in the absence of obvious *** work reveals that the poor hardening response of the polycrystalline alloy is related to the capability of basal dislocations to shear the nanoparticles,in the absence of Orowan looping events,and to the associated basal slip localization.

关键词： Magnesium Precipitation Basal slip Particle shearing Slip localization

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Improving hazard analysis of integrated modular avionics system based on system-theoretic process analysis 18th

Improving hazard analysis of integrated modular avionics sys...

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18th AIAA aviation technology, Integration, and Operations Conference, 2018

作者： Rong, Hao Gu, Qingfan Chen, Zhixiong Xu, Desheng China National Aeronautical Radio Electronics Research Institute Civil Aviation Department No.432 Zi Yue Road Shanghai China Science and Technology on Avionics Integration Laboratory Civil Aviation Department No.432 Zi Yue Road Shanghai China State Key Laboratory for Civil Aircraft Flight Simulation Commercial Aircraft Corporation of China Ltd. No.5188 Jin Ke Road Shanghai China

ISBN: (纸本)9781624105562

Integrated modular avionics systems bring new concepts and benefits for function integration and resource utilization in developing advanced aircraft avionics, as well as a series of challenges related to hazard analysis in components interaction and functions operation. When software applications provided independently by the subsystem developers are integrated onto the IMA hardware platform, it is very difficult for designers to understand and predict how the system will behave and what interaction hazards could occur. Although the ARP 4761-based safety analysis methods have solved a large number of safety problems on the development of civil aircraft and system designs in early times, there are some limitations when analyzing more and more complex integrated modular avionics systems in modern times. To gain a good or better understanding and a comprehensive awareness of applications interaction hazards in today’s more complex, software-intensive IMA systems, it is significant to use a method to consider these new causal factors that are not handled by the older techniques and to provide more guidance to the analyst in performing hazard analysis. System-Theoretic Process Analysis (STPA) is one of typical systemic hazard analysis methods. STPA has its foundation in a new accident causality model called STAMP (System-Theoretic Accident Model and Process). STAMP was proposed based on the cybernetics of systems theory. In STAMP, the dysfunctional interactions and requirements flaws during operation are primary types of inadequate control. The STPA-based hazard analysis method is extended in this paper to account for behavior that emerges when software applications are integrated and make functional interaction. This method will be capable of modeling the new causal factors that contribute to component interaction hazards. The paper illustrates the new method with a case that includes real-world avionics display functions, this application of the proposed method will b

关键词： Hazards

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