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Experimental analysis of the mechanism of high-order polygonal wear of wheels of a high-speed train

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2017年第8期18卷 579-592页

作者： Yue WU Xing DU He-ji ZHANG ze-feng wen Xue-song JIN State Key Laboratory of Traction Power Southwest Jiaotong University Chengdu 610031 China

This paper presents a detailed investigation, via field experiment, into the mechanism of high-order polygonal wear of wheels of a new type of high-speed train. The investigation was carried out during the performance acceptance test of the train and its initial commercial operation. The investigation covered the performance acceptance test of 150 000 km and the commercial operation of about 150 000 km. In the performance acceptance test of the first stage of about 70 000 km, at 200-250 km/h with full loading and sometimes overloading by 30%, the serious polygonal wear of 23-order took place on all the wheels of the train, and was measured and analyzed in detail. All the potygonized wheels were re-profiled because the polygonal wear had caused strong vibration and damage to the train parts. After re-profiling, the vibration of the train and track and the wear status of the wheels were measured and analyzed at different test mileages according to the polygonal wear situation of the wheels. The measured vibration of the train includes the accelerations at different positions of a motor car and a trail car. The vibration modes of the key parts of the bogies of the two cars were calculated. Meanwhile, the track resonant frequencies were investigated at the site. The purpose of the above tests and analysis is try to find the frequency of work mode matching the passing frequency of the high-order wheel polygon. The present investigation shows that one of the working models causes the formation and development of the high-order wheel polygonal wear. The growth of this wear was effectively reduced through the frequent changing of the running speed of the train operating on the way back and forth every day.

关键词： High-speed train Wheel High-order polygonal wear Field test Model analysis System resonance frequency

Development and validation of a model for predicting wheel wear in high-speed trains

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2017年第8期18卷 603-616页

作者： Gong-quan TAO Xing DU He-ji ZHANG ze-feng wen Xue-song JIN Da-bin CUI State Key Laboratory of Traction Power Southwest Jiaotong University Chengdu 610031 China Department of Mechanical Engineering Emei Campus of Southwest Jiaotong University Emei 614202 China

In this paper, we present a comprehensive model for the prediction of the evolution of high-speed train wheel profiles due to wear. The model consists of four modules： a multi-body model implemented with the commercial multi-body software SIMPACK to evaluate the dynamic response of the vehicle and track; a local contact model based on Hertzian theory and a novel method, named FaStrip （Sichani et al., 2016）, to calculate the normal and tangential forces, respectively; a wear model proposed by the University of Sheffield （known as the USFD wear function） to estimate the amount of material removed and its distribution along the wheel profile; and a smoothing and updating strategy. A simulation of the wheel wear of the high-speed train CRH3 in service on the Wuhan-Guangzhou railway line was performed. A virtual railway line based on the statistics of the line was used to represent the entire real track. The model was validated using the wheel wear data of the CRH3 operating on the Wuhan- Guangzhou line, monitored by the authors＇ research group. The results of the predictions and measurements were in good agreement.

关键词： High-speed train Wheel profile Wheel/Rail contact Wheel wear prediction

Recent advances in bioinspired vision systems with curved imaging structures

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Rare Metals 2024年第4期43卷 1407-1434页

作者： ze-Ping He Xun Han wen-Qiang Wu Zhang-Sheng Xu Cao-feng Pan CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing100083China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing100049China ZJU-Hangzhou Global Scientific and Technological Innovation Center School of Micro-Nano ElectronicsZhejiang UniversityHangzhou311200China Institute of Microscale Optoelectronics Shenzhen UniversityShenzhen518060China

Limited by the planar imaging structure,the commercial camera needs to introduce additional optical elements to compensate for the curved focal plane to match the planar image *** results in a complex and bulky *** contrast,biological eyes possess a simple and compact structure due to their curved imaging structure that can directly match with the curved focal *** by the structures and functions of biological eyes,curved vision systems not only improve the image quality,but also offer a variety of advanced ***,we review the recent advances in bioinspired vision systems with curved imaging ***,we focus on their applications in implementing different functions of biological eyes,as well as the emerging curved neuromorphic imaging systems that incorporate bioinspired optical and neuromorphic processing *** addition,the challenges and opportunities of bioinspired curved imaging systems are also discussed.

关键词： Bioinspired Curved vision system Compound eye Chambered eye Neuromorphic

Sensing properties and mechanisms of LaF_(3)-Co_(3)O_(4) nanorods for low-concentration methanol detection

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Rare Metals 2024年第5期43卷 2193-2204页

作者： Xiao-Xi He Hong-feng Chai Yi-wen Zhou Ke-Wei Liu ze-Xin Yu Chao Zhang College of Mechanical Engineering Yangzhou UniversityYangzhou225127China Institutefor Manufacturing Technologies of Ceramic Components and Composites(IMTCCC) University of Stuttgart70569 StuttgartGermany

Methanol is one of the characteristic gases that distinguish between healthy individuals and lung cancer(LC)lesions in exhaled human *** concentration in exhaled breath is generally below one part per million(1×10^(-6)).The second-phase composite is widely regarded as one of the methods to improve the gas-sensing perfor-mance of metal oxide semiconductor(MOS)*** this study,LaF_(3)-Co_(3)O_(4) was synthesized by a simple hydrothermal method to enhance its low-concentration methanol gas-sensing performance.5 at%LaF_(3)-Co_(3)O_(4) nanorods exhibited excellent methanol detection performance,including a wider linear detection concentration range(0.2×10^(-6)~5×10^(-6)),a response value exceeding 4.0 for 1×10^(-6)methanol at 275°C and 75%relative humidity(RH),long-term stability(maximum deviation within 15%over 2 weeks),and excellent *** mechanism of performance enhancement was studied using various techniques,and density functional *** special spinel structure of Co_(3)O_(4),the high ionic migration of F-in LaF_(3),the larger specific surface area of 5 at%LaF_(3)-Co_(3)O_(4) nanorods,and the generated crystal defects all explain the excellentmethanol gas-sensing *** work provides a novel route to prepare MOS composite materials for low-concentration methanol gas detection.

关键词： Gas sensor LaF_(3) Co_(3)O_(4) Methanol Lung cancer

Synergy between CSST galaxy survey and gravitational-wave observation: Inferring the Hubble constant from dark standard sirens

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 7-19页

作者： Ji-Yu Song Ling-feng Wang Yichao Li ze-Wei Zhao Jing-Fei Zhang wen Zhao Xin Zhang Key Laboratory of Cosmology and Astrophysics(Liaoning)&College of Sciences Northeastern UniversityShenyang 110819China CAS Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaChinese Academy of SciencesHefei 230026China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityShenyang 110819China Key Laboratory of Data Analytics and Optimization for Smart Industry(Ministry of Education) Northeastern Universty Shenyang 110819China

Gravitational waves(GWs) from compact binary coalescences encode the absolute luminosity distances of GW sources. Once the redshifts of GW sources are known, one can use the distance-redshift relation to constrain cosmological parameters. One way to obtain the redshifts is to localize GW sources by GW observations and then use galaxy catalogs to determine redshifts from a statistical analysis of redshift information of the potential host galaxies, commonly referred to as the dark siren method. The third-generation(3G) GW detectors are planned to work in the 2030s and will observe numerous compact binary *** these GW events as dark sirens requires high-quality galaxy catalogs from future sky survey projects. The China Space Station Telescope(CSST) will be launched in 2024 and will observe billions of galaxies within a 17500 deg^(2) survey area with redshift up to z ~ 4, providing photometric and spectroscopic galaxy catalogs. In this work, we simulate the CSST galaxy catalogs and the 5-year GW data from the 3G GW detectors and combine them to infer the Hubble constant(H_(0)). Our results show that the measurement precision of H0could reach the sub-percent level, meeting the standard of precision cosmology. We conclude that the synergy between CSST and the 3G GW detectors is of great significance in measuring the Hubble constant.

关键词： CSST galaxy survey galaxy catalogs gravitational waves dark sirens the Hubble constant

Investigation of Maxima Assumptions in Modelling Tropical Cyclone- Induced Hazards in the South China Sea

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China Ocean Engineering 2024年第3期38卷 491-504页

作者： wen ze-guo WANG Fu-ming WAN Jing YANG Fan School of Civil Engineering Sun Yat-sen University&Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Guangdong Academy of Safety Science and Technology Guangzhou 510060China Guangdong Key Laboratory of Oceanic Civil Engineering Guangzhou 510275China Advanced Energy Science and Technology Guangdong Laboratory(Yangjiang Offshore Wind Energy Laboratory) Yangjiang 529500China

The present study aims to examine the suitability of two commonly used assumptions that simplify modelling metoceanconditions for designing offshore wind turbines in the South China Sea (SCS). The first assumption assumes thatjoint N-year extreme wind and wave events can be independently estimated and subsequently combined. The secondone assumes peak wind and waves can be modelled as occurring simultaneously during a tropical cyclone (TC) *** better understand the potential TC activity, a set of 10000 years synthetic TC events are generated. The wind fieldmodel and the Mike 21 spectral wave model are employed to model the TC-induced hazards. Subsequently, theeffect of the assumptions is evaluated by analyzing the peak structural response of both monopile and semisubmersibleoffshore wind turbines during TC events. The results demonstrate that the examined assumptions are generally *** assessing the implications of these assumptions, valuable insights are obtained, which can inform andimprove the modelling of TC-induced hazards in the SCS region.

关键词： tropical cyclone numerical wave modelling hazards offshore wind turbines structural response

沥青混凝土砂浆层软化对车辆行驶安全性和轨道动力特性的影响（英文）

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2015年第12期16卷 976-986页

作者： Jian HAN Guo-tang ZHAO Xin-biao XIAO ze-feng wen Qing-hua GUAN Xue-song JIN State Key Laboratory of Traction Power Southwest Jiaotong University China Railway Corporation

目的：对于高速铁路，老化和雨水冲刷浸泡将导致无砟轨道水泥沥青砂浆（CA砂浆）软化现象。CA砂浆的软化严重影响轨道动力特性，甚至危害高速列车行车安全。通过仿真计算，系统地调查CA砂浆软化对高速列车行车安全以及轨道动力特性的影... 详细信息

目的：对于高速铁路，老化和雨水冲刷浸泡将导致无砟轨道水泥沥青砂浆（CA砂浆）软化现象。CA砂浆的软化严重影响轨道动力特性，甚至危害高速列车行车安全。通过仿真计算，系统地调查CA砂浆软化对高速列车行车安全以及轨道动力特性的影响。创新点：系统地对比CA砂浆软化对车辆．轨道动力学特性和轨道层间破坏的影响，为工程实际提供参考。方法：1．通过建立三维车辆．轨道耦合动力学模型以及CA砂浆软化模型，分析CA砂浆软化对行车安全以及轨道动力特性的影响（图2）；2．通过轨道．路基非线性有限差分耦合模型，分析CA砂浆软化对轨道层间破坏的影响（图3）。结论：通过车辆运行安全性分析、轨道位移限值分析以及轨道层问失效分析，得出以下结论：***砂浆软化系数达到10～100时，轨道层间剪切失效开始快速发展；***砂浆软化系数不能超过1000，当CA砂浆软化系数超过该值时，高速列车将面临脱轨危险。

关键词：高速铁路 CA砂浆软化车辆.轨道耦合动力学运行安全性轨道破坏

Intelligent Predetermination of Generator Tripping Scheme: Knowledge Fusion-based Deep Reinforcement Learning Framework

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 66-75页

作者： Lingkang zeng Wei Yao ze Hu Hang Shuai Zhouping Li Jinyu wen Shijie Cheng State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronics EngineeringHuazhong University of Science and TechnologyWuhan 430074China Dispatching and Control Center Central China Branch of State Grid Corporation of ChinaWuhan 430077China. Department of Electrical Engineering and Computer Science University of TennesseeKnoxvilleTN 37996USA

Generator tripping scheme(GTS)is the most commonly used scheme to prevent power systems from losing safety and ***,GTS is composed of offline predetermination and real-time scenario ***,it is extremely time-consuming and labor-intensive for manual predetermination for a large-scale modern power *** improve efficiency of predetermination,this paper proposes a framework of knowledge fusion-based deep reinforcement learning(KF-DRL)for intelligent predetermination of ***,the Markov Decision Process(MDP)for GTS problem is formulated based on transient instability ***,linear action space is developed to reduce dimensionality of action space for multiple controllable ***,KF-DRL leverages domain knowledge about GTS to mask invalid actions during the decision-making *** can enhance the efficiency and learning ***,the graph convolutional network(GCN)is introduced to the policy network for enhanced learning *** simulation results obtained on New England power system demonstrate superiority of the proposed KF-DRL framework for GTS over the purely data-driven DRL method.

关键词： Deep reinforcement learning generator tripping scheme graph convolutional network invalid action masking knowledgefusion

Preface to the special topic on metals and their compounds for lithium ion/metal batteries

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Tungsten 2024年第1期6卷 162-163页

作者： Ying-ze Song wen-Long Cai Gao-Ran Li State Key Laboratory of Environment-Friendly Energy Materials Southwest University of Science and TechnologyMianyang 621010China College of Materials Science and Engineering Sichuan UniversityChengdu 610064China School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China

The fast development of electronics and electric devices has inspired the practical application of lithium ion/metal *** this line,the metals and their compounds as electrode materials as well as the corresponding mechanism for energy storage have gained extensive international *** as-organized special topic focuses on W,Mo,Co,Zr,Hf,Re,Ta,Nb,V-based metals and their compounds for lithium ion/metal *** special topic involves four reviews and four research papers totally,providing the latest advances of transition metals and their related compounds for rechargeable lithium ion/metal batteries.

关键词： lithium metals gained