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Research on Fault Ride Through Control Strategy Based on Multi Terminal Flexible DC Transmission system 1

37th Annual Conference on Power system and Automation in Chinese Universities, CUS-EPSA 2022

作者： Wang, Yunmin Yang, Zhiyong Yang, Bingyuan Wang, Chao Qu, Wenyuan Enterprise Key Laboratory of Smart Grid Simulation of Electrical Power System Inner Mongolia Electric Power Science and Research Institute Hohhot China Co Ltd. Xilin Guole Power Supply Bureau Xilinhot China Inner Mongolia University of Technology Hohhot China

ISBN: (数字)9789819914395

ISBN: (纸本)9789819914388

Under the goal of "double carbon", the power system is facing the challenge of ensuring supply and security. The new direction of power system development is to promote integration of large scale renewable energy and use long distance transmission based on the new flexible DC transmission technology. For this reason, the control strategy of multi-terminal flexible DC system and the fault ride-through coordination control strategy without communication between converter stations are studied by using hybrid DC circuit breaker (DCCB), unloading resistor and improved modular multilevel converter (MMC) control strategy. Through RTDS platform simulation experiments, the effectiveness of the fault ride through coordinated control strategy is verified, that is, when the AC transmission line has a three-phase short-circuit fault, the DC voltage fluctuation is suppressed in the range of 1.1 p.u.;In case of pole-pole short circuit fault of flexible direct system, DCCB will isolate DC fault in about 5 ms to ensure the normal and stable operation of the unfaulted line. © 2023, State Grid Electric Power.

关键词： Electric circuit breakers

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Antenna Position and Power Allocation Design for Shared Aperture Sparse Linear Array 10

Antenna Position and Power Allocation Design for Shared Aper...

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10th International Conference on Control, Automation and Information sciences, ICCAIS 2021

作者： Liu, Ruitao Wei, Wenqiang Yu, Xianxiang Lu, Qinghui Cui, Guolong Fang, Xueli Zhang, Lei University of Electronic Science and Technology of China Chengdu China Key Laboratory of Complex Aeronautical System Simulation Beijing China

ISBN: (纸本)9781665440295

This paper considers the joint design of the antenna position and power allocation in a shared aperture sparse phased array. We introduce a new optimization model relying on the minimization of the Peak Sidelobe Levels (PSL) of beampattern under the antenna position constraints, mainlobe constraints and transmit power constraints. In order to tackle the non-convex problem, we resort to a Modified Membrane Algorithm based on P systems (MMAPS) along with its each iteration executed in parallel. Finally, numerical simulations verify the effectiveness of the proposed algorithm. The results highlight that MMAPS can obtain a better beampattern in terms of the PSL in comparison with the available methods. © 2021 IEEE.

关键词： Iterative methods

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Constructing a Raman and surface-enhanced Raman scattering spectral reference library for fine-particle analysis

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Journal of Environmental sciences 2022年第8期34卷 1-13页

作者： Hui Chen Fengkui Duan Kebin He Jingjing Du Zhenli Sun Suhua Wang Key Laboratory of Resources and Environmental System Optimization of Ministry of Education College of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Guangdong Provincial Key Laboratory of Petrochemcial Pollution Processes and Control School of Environmental Science and EngineeringGuangdong University of Petrochemical TechnologyMaoming 525000 China

Fine particles associated with haze pollution threaten the health of over 400 million people in China. Owing to excellent non-destructive fingerprint recognition characteristics, Raman and surface-enhanced Raman scattering(SERS) are often used to analyze the composition of fine particles to determine their physical and chemical properties as well as reaction mechanisms. However, there is no comprehensive Raman spectral library of fine particles. Furthermore, various studies that used SERS for fine-particle composition analysis showed that the uniqueness of the SERS substrates and different excitation wavelengths can produce a different spectrum for the same fine-particle component. To overcome this limitation, we conducted SERS experiments with a portable Raman spectrometer using two common SERS substrates(silver(Ag) foil and gold nanoparticles(Au NPs)) and a 785 nm laser. Herein, we introduced three main particle component types(sulfate-nitrate-ammonium(SNA), organic material, and soot) with a total of 39 chemical substances. We scanned the solid Raman, liquid Raman, and SERS spectra of these substances and constructed a fine-particle reference library containing 105 spectra. Spectral results indicated that for soot and SNA, the differences in characteristic peaks mainly originated from the solid-liquid phase transition;Ag foil had little effect on this difference, while the Au NPs caused a significant red shift in the peak positions of polycyclic aromatic hydrocarbons. Moreover, with various characteristic peak positions in the three types of spectra, we could quickly and correctly distinguish substances. We hope that this spectral library will aid in the future identification of fine particles.

关键词： Raman Surface-enhanced Raman scattering(SERS) Spectral library Fine-particle

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DOA Estimation of Distributed mmWave Radar system via Fast Iterative Adaptive Approach 10

DOA Estimation of Distributed mmWave Radar System via Fast I...

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10th International Conference on Control, Automation and Information sciences, ICCAIS 2021

作者： Wei, Wenqiang Liu, Ruitao Yu, Xianxiang Lu, Qinghui Cui, Guolong Fang, Xueli Zhang, Lei University of Electronic Science and Technology of China Chengdu China Key Laboratory of Complex Aeronautical System Simulation Beijing China

ISBN: (纸本)9781665440295

In this paper, we propose a fast algorithm based on iterative adaptive approach to address the DOA estimation for the distributed mmWave radar system under the challenging conditions of a single snapshot and coherent sources. In order to improve angular resolution, let each transmit sensor emit the same signal in time-sharing to construct a large aperture virtual array. We first roughly derive azimuth angles with one mmWave radar using conventional beamforming. Then, resorting to iterative adaptive approach, we search for the accurate DOA estimations within a very small region based on the estimated azimuth to improve computational efficiency and angular resolution. Finally, numerical simulation results are provided to demonstrate superior performance of the proposed algorithm over some counterparts. © 2021 IEEE.

关键词： Computational efficiency

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Preparation of hollow-fiber nanofiltration membranes of high performance for effective removal of PFOA and high resistance to BSA fouling

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Journal of Environmental sciences 2022年第12期34卷 14-24页

作者： Wenjing Tang Yunyi Meng Bin Yang Dongyu He Yan Li Bojun Li Zheming Shi Changwei Zhao College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193China Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China The Fourth Construction CO.LTD of China Electronics System Engineering Tianjin 300130China State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China

Nanofiltration(NF)process has become one of the most promising technologies to remove micro-organic combined water *** a NF membrane material with efficient separation for perfluorooctanoic acid(PFOA)combined pollution is highly desired,this manuscript targets this unmet need *** this work,hydrophilic SiO_(2)nanoparticles with various contents blended with carboxylic multiwalled carbon nanotube were used to modify poly(m-phenylene isophthal amide)(SiO_(2)/CMWCNT/PMIA)hollow fiber NF *** modified membrane with 0.1 wt%SiO_(2)doping exhibits way better fouling resistance with irreversible fouling ratio decreased dramatically from 18.7%to 2.3%,and the recovery rate of water flux increases significantly from 81.2%to 97.7%.The separation experiment results had confirmed that the modified membrane could improve the rejection from 97.2%to 98.6%for perfluorooctanoic acid(PFOA)and its combined pollution with bovine serum albumin(BSA).It is clear that this reported SiO_(2)/CMWCNT/PMIA hollow fiber NF membrane potentially could be applied in water *** research also provides a theoretical basis for efficiently removal of PFOA and its combined pollution by NF membrane.

关键词： Nanofiltration SiO_(2)nanoparticles Perfluorooctanoic acid Combined pollution Water treatment

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Research on Key Technologies of Cross-domain Guidance 8

Research on Key Technologies of Cross-domain Guidance

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8th Symposium on Novel Photoelectronic Detection technology and Applications

作者： Guo, Xiaoyun Wu, Chengfeng Fang, Xueli Xu, Cheng Li, Hui Beijing Institute of Mechanical and Electrical Engineering Beijing China Beijing Institute of Mechanical and Electrical Engineering Science and Technology on Complex System Control and Intelligent Agent Cooperative Laboratory Beijing China Beijing Institute of Mechanical and Electrical Engineering Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (数字)9781510653122

ISBN: (纸本)9781510653115

Cross-domain synergy and intelligence will become important features of future warfare. Cross-domain guidance is one of the typical forms of cross-domain synergy. It can significantly improve the ability to respond quickly to random targets and time-sensitive targets and enhance the anti-jamming ability in the case of confrontation. This article introduces the concept and winning mechanism of cross-domain guidance, analyzes the research progress of cross-domain guidance at home and abroad, combs the key technologies of cross-domain guidance, summarizes the current challenges and problems in cross-domain guidance research, and proposes development suggestions. © 2022 SPIE

关键词： Optical engineering

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基于晶体塑性的辐照金属材料局部化颈缩和吕德斯带的模拟研究

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Acta Mechanica Sinica 2023年第4期39卷 132-146页

作者：付家琪刘文斌隋昊男程杨洋段慧玲 State Key Laboratory for Turbulence and Complex System Department of Mechanics and Engineering ScienceThe Beijing Innovation Center for Engineering Science and Advanced TechnologyCollege of EngineeringPeking UniversityBeijing100871China Key Laboratory of High Energy Density Physics Simulation Center for Applied Physics and Technologyand Inertial Fusion Sciences and ApplicationsCollaborative Innovation Center of Ministry of EducationPeking UniversityBeijing100871China

金属材料中,颈缩失稳通常由表面缺陷或材料不均匀性等潜在扰动引起并随着微结构的演化进一步发展.本文将构型扰动法与考虑辐照效应的晶体塑性本构关系相结合,模拟了辐照前后局部化颈缩和吕德斯带等现象.通过考虑模拟局部化变形中扰动的... 详细信息

金属材料中,颈缩失稳通常由表面缺陷或材料不均匀性等潜在扰动引起并随着微结构的演化进一步发展.本文将构型扰动法与考虑辐照效应的晶体塑性本构关系相结合,模拟了辐照前后局部化颈缩和吕德斯带等现象.通过考虑模拟局部化变形中扰动的必要性,发现了外在的几何缺陷和内禀的微结构演化在颈缩过程中的竞争关系.此外,以纯金属铜和奥氏体不锈钢为例研究了辐照硬化效应对颈缩失稳的影响.结果表明,流动应力的增加和功硬化能力的降低是均匀延伸率下降的原因,辐照效应导致的织构软化作用可以忽略.为了解释辐照后低碳钢下屈服点和吕德斯应变同时增加的现象,一种位错脱钉扎和位错与辐照缺陷的交互作用相耦合的塑性变形机制被提出并结合修正的流动方程,很好地模拟出包含屈服下降、应力平台、应变扩展和应变硬化等特征的吕德斯带现象.其中,位错与辐照缺陷的相互作用也可以解释辐照后纯金属材料中发现的扩散颈缩现象.我们的模拟结果既阐明了几何缺陷在颈缩失稳中的重要作用,也为辐照金属中常见的宏观塑性失稳现象提供了清晰的物理图像.

关键词：吕德斯带金属材料奥氏体不锈钢晶体塑性下屈服点流动应力几何缺陷均匀延伸率

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Blockchain-based UAV continuous authentication

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Aerospace Traffic and Safety 2024年第2期1卷 85-92页

作者： Yongguang Jin Fangwei Ye Qihui Wu The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsChina College of Computer Science and Technology Nanjing University of Aeronautics AstronauticsChina

With the growing utilization of unmanned aerial vehicles(UAVs),low-altitude airspace is becoming increasingly congested,posing significant challenges to Air Traffic Control(ATC).The Automatic Dependent Surveillance-Broadcast(ADS-B)system is used to report the location of ***,due to channel noise and adversarial interference,ADS-B data may be *** address this issue,a position estimation method based on Bidirectional Long Short-Term Memory Multi-Layer Perceptron(BiLSTM-MLP)was *** this method,ADS-B signal power is used to estimate the position of UAVs as a baseline *** results demonstrate that the BiLSTM-MLP based method significantly improves estimation ***,a blockchain-based dynamic reputation mechanism,aligned with the position estimation method,was *** mechanism integrates information from the third-party UAV and the location data provided by the UAV itself to dynamically update the credibility of the UAV,and thus achieves decentralized access control of UAVs in low-altitude airspace.

关键词： UAV Reputation system Blockchain BiLSTM

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Study on Diffusion and Migration Characteristics of Impurities in Secondary Side of Simplified U-Tube Steam Generator

SSRN

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SSRN 2023年

作者： Li, Meng Cheng, Kun Wen, Jiming Tian, Ruifeng Fundamental Science on Nuclear Safety Simulation Technology Laboratory Harbin Engineering University Harbin150001 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

In the operation process of nuclear power system, leakage accidents of main and auxiliary condensers are easy to occur, which leads to seawater entering the secondary loop from the condenser, and impurities such as Cl- enter the steam generator with the feed water of the secondary loop, and are enriched near the heat transfer tube. It is easy to cause wear and corrosion of steam generator heat transfer tube, which threatens the safety of nuclear power plant. In order to study the migration and diffusion process of impurity Cl- in the secondary side of steam generator, a multi-bundle three-dimensional physical model of fluid-solid coupling heat transfer in the primary and secondary loop of steam generator and heat transfer tube was established respectively. The fluid flow and heat transfer process between Ushaped tube bundles were simulated numerically to reveal the distribution law of key thermo-hydraulic parameters between Ushaped tube bundles, such as volume vapor fraction, temperature, velocity, etc. The diffusion and migration of Cl- in two-phase flow were also investigated. The influence of thermalhydraulic parameters on impurity migration, two-phase flow in the secondary side and effective diffusion coefficient of chloride ions on chloride ion concentration distribution were *** concentration of chloride ions changes with the change of effective diffusion coefficient of chloride ions. The effective diffusion coefficient of chloride ions is affected by the boiling intensity of coolant and the flow velocity of coolant. The synergistic effect of the boiling intensity of coolant and the flow velocity of coolant affects the migration and diffusion of chloride *** above phenomena may lead to impurity deposition and stress corrosion of heat transfer tubes near the surface. © 2023, The Authors. All rights reserved.

关键词： Steam generators

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Erratum to: Depth estimation using an improved stereo network (Frontiers of Information technology & Electronic Engineering, (2022), 23, 5, (777-789), 10.1631/FITEE.2000676)

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Frontiers of Information technology and Electronic Engineering 2023年 1-1页

作者： Xu, Wanpeng Zou, Ling Wu, Lingda Qi, Yue Qian, Zhaoyong Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing101416 China Peng Cheng Laboratory Shenzhen518055 China Digital Media School Beijing Film Academy Beijing100088 China

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