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Improving low-voltage ride-through capability of a multimegawatt DFIG based wind turbine under grid faults

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Protection and Control of Modern Power Systems 2020年第1期5卷 390-402页

作者： Mohamed Nadour Ahmed Essadki Tamou Nasser Research center of Engineering and Health science and technologies(STIS) High Normal School of Technical Education(ENSET)Mohammed V UniversityRabatMorocco Research center of Engineering and Health science and technologies Higher National School of Computer Science and Systems Analysis(ENSIAS)Mohammed V UniversityRabatMorocco

Large integration of doubly-fed induction generator(DFIG)based wind turbines(WTs)into power networks can have significant consequences for power system operation and the quality of the energy supplied due to their excessive sensitivity towards grid *** voltage dips,the resulting overcurrent and overvoltage in the rotor circuit and the DC link of a DFIG,could lead to the activation of the protection system and WT *** potentially results in sudden loss of several tens/hundreds of MWs of energy,and consequently intensifying the severity of the *** paper aims to combine the use of a crowbar protection circuit and a robust backstepping control strategy that takes into consideration of the dynamics of the magnetic flux,to improve DFIG’s Low-Voltage Ride Through capability and fulfill the latest grid code *** the power electronic interfaces are protected,the WTs also provide large reactive power during the fault to assist system voltage *** results using Matlab/Simulink demonstrate the effectiveness of the proposed strategy in terms of dynamic response and robustness against parametric variations.

关键词： Wind turbine DFIG Grid faults Crowbar protection Backstepping control Low-voltage ride through

Theoretical research and experimental validation of quasi-static load spectra on bogie frame structures of high-speed trains

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Acta Mechanica Sinica 2014年第6期30卷 901-909页

作者： Ning Zhu Shou-Guang Sun Qiang Li Hua Zou Engineering Research center of Structure reliability and Operation Measurement Technology of Rail Guided Vehicles Ministry of EducationBeijing Jiaotong University

One of the major problems in structural fatigue life analysis is establishing structural load spectra under actual operating *** study conducts theoretical research and experimental validation of quasi-static load spectra on bogie frame structures of high-speed *** quasistatic load series that corresponds to quasi-static deformation modes are identified according to the structural form and bearing conditions of high-speed train bogie ***,a force-measuring frame is designed and manufactured based on the quasi-static load *** load decoupling model of the quasi-static load series is then established via calibration ***-static load–time histories,together with online tests and decoupling analysis,are obtained for the intermediate range of the Beijing—Shanghai dedicated passenger *** damage consistency calibration of the quasi-static discrete load spectra is performed according to a damage consistency criterion and a genetic *** calibrated damage that corresponds with the quasi-static discrete load spectra satisfies the safety requirements of bogie frames.

关键词： Load spectra Quasi-static Bogie frame Calibration High-speed train

Architecture Design and Interface Engineering of Self-assembly VS_(4)/rGO Heterostructures for Ultrathin Absorbent

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Nano-Micro Letters 2022年第4期14卷 222-237页

作者： Qi Li Xuan Zhao Zheng Zhang Xiaochen Xun Bin Zhao Liangxu Xu Zhuo Kang Qingliang Liao Yue Zhang Academy for Advanced Interdisciplinary science and Technology Beijing Advanced Innovation Center for Materials Genome EngineeringBeijing Key Laboratory for Advanced Energy Materials and TechnologiesSchool of Materials Science and EngineeringUniversity of Science

The employment of microwave absorbents is highly desirable to address the increasing threats of electromagnetic ***,developing ultrathin absorbent is acknowledged as a linchpin in the design of lightweight and flexible electronic devices,but there are remaining unprecedented ***,the self-assembly VS_(4)/rGO heterostructure is constructed to be engineered as ultrathin microwave absorbent through the strategies of architecture design and interface *** microarchitecture and heterointerface of VS_(4)/rGO heterostructure can be regulated by the generation of VS_(4) nanorods anchored on rGO,which can effectively modulate the impedance matching and attenuation *** maximum reflection loss of 2VS_(4)/rGO40 heterostructure can reach−43.5 dB at 14 GHz with the impedance matching and attenuation constant approaching 0.98 and 187,*** effective absorption bandwidth of 4.8 GHz can be achieved with an ultrathin thickness of 1.4 *** far-reaching comprehension of the heterointerface on microwave absorption performance is explicitly unveiled by experimental results and theoretical *** and heterointerface synergistically inspire multi-dimensional advantages to enhance dipole polarization,interfacial polarization,and multiple reflections and scatterings of ***,the strategies of architecture design and interface engineering pave the way for achieving ultrathin and enhanced microwave absorption materials.

关键词： Architecture design Interface Self-assembly Microwave absorption

Bayesian estimation of a power law process with incomplete data

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Journal of Systems Engineering and Electronics 2021年第1期32卷 243-251页

作者： HU Junming HUANG Hongzhong LI Yanfeng School of Mechanical and Electrical Engineering University of Electronic Science and Technology of ChinaChengdu 611731China School of Transportation and Automotive Engineering Xihua UniversityChengdu 610039China center for System reliability and Safety University of Electronic Science and Technology of ChinaChengdu 611731China

Due to the simplicity and flexibility of the power law process,it is widely used to model the failures of repairable *** statistical inference on the parameters of the power law process has been well developed,numerous studies largely depend on complete failure data.A few methods on incomplete data are reported to process such data,but they are limited to their specific cases,especially to that where missing data occur at the early stage of the *** framework to handle generic scenarios is *** overcome this problem,from the point of view of order statistics,the statistical inference of the power law process with incomplete data is established in this *** theoretical derivation is carried out and the case studies demonstrate and verify the proposed *** statistics offer an alternative to the statistical inference of the power law process with incomplete data as they can reformulate current studies on the left censored failure data and interval censored data in a unified *** results show that the proposed method has more flexibility and more applicability.

关键词： incomplete data power law process Bayesian inference order statistics repairable system

A novel diffusion model considering curvature radius at the bonding interface in a titanium/steel explosive clad plate

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International Journal of Minerals,Metallurgy and Materials 2015年第9期22卷 956-965页

作者： Hai-tao Jiang Qiang Kang Xiao-qian Yan National Engineering Research center for Advanced Rolling Technology University of Science and Technology Beijing China Railway Materials technologies Company Limited

This article introduces an element diffusion behavior model for a titanium/steel explosive clad plate characterized by a typical curved interface during the heat-treatment process. A series of heat-treatment experiments were conducted in the temperature range from 750℃ to 950℃, and the effects of heat-treatment parameters on the microstructural evolution and diffusion behavior were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and electron-probe microanalysis. Carbon atoms within the steel matrix were observed to diffuse toward the titanium matrix and to aggregate at the bonding interface at 850℃ or lower; in contrast, when the temperature exceeded 850℃, the mutual diffusion of Ti and Fe occurred, along with the diffusion of C atoms, resulting in the for- marion of Ti-Fe intermetallics （Fe2Ti/FeTi）. The diffusion distances of C, Ti, and Fe atoms increased with increasing heating temperature and/or holding time. On the basis of this diffusion behavior, a novel diffusion model was proposed. This model considers the effects of various factors, including the curvature radius of the curved interface, the diffusion coefficient, the heating temperature, and the holding rime. The experimental results show good agreement with the calculated values. The proposed model could clearly provide a general prediction of the elements＇ diffusion at both straight and curved interfaces.

关键词： explosive bonding metal cladding diffusion models interfaces heat treatment

Insights into friction behavior of textured amorphous carbon and lubricant composite system: Dependence on the lubricant viscosity and textured shape

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Progress in Natural science:Materials International 2023年第5期33卷 616-624页

作者： Jiaqing Ding Naizhou Du Xubing Wei Xiaowei Li Zan Chen Shiqi Lu Haolin Zhang Cunao Feng Kai Chen Jianghao Qiao Dekun Zhang Kwang-Ryeol Lee School of Materials science and Physics China University of Mining and Technology Key Laboratory of Marine Materials and Related technologies Zhejiang Key Laboratory of Marine Materials and Protective Technologies Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Computational science center Korea Institute of Science and Technology

Combining textured amorphous carbon(a-C) film with lubricant achieves ultra-low friction to improve the mechanical component’s service life. However, the coupling influence of lubricant viscosity and textured shape on friction behavior and interfacial transformation are still unclear. In this work, the evolution of friction performance with Poly-alpha-olefin viscosities and its dependence on textured shapes were investigated by reactive molecular dynamics simulation. Results reveal that as the textured shape is fixed, increasing the lubricant viscosity causes friction coefficient to decline first and then increase, due to the hydrodynamic lubrication and regional aggregation of lubricant. While under same lubricant condition, rectangular textured systems exhibit lower friction coefficient than circular textured ones, attributing to the formation of stable lubricant film without serious aggregation.

关键词： Amorphous carbon Surface texture Lubricant Reactive molecular dynamics

Overview of in-situ oxygen production technologies for lunar resources

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 233-255页

作者： Youpeng Xu Sheng Pang Liangwei Cong Guoyu Qian Dong Wang Laishi Li Yusheng Wu Zhi Wang College of Materials science and Engineering Shenyang University of TechnologyShenyang 110870China CAS Key Laboratory of Green Process and Engineering National Engineering Research Center for Green Recycling of Strategic Metal ResourcesInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial ***,crucial for supporting human life on the Moon,can be extracted from lunar regolith,which is highly rich in oxygen and contains polymetallic *** oxygen and metal extraction can be achieved using existing metallurgical ***,the ample reserves of water ice on the Moon offer another means for oxygen *** paper offers a detailed overview of the leading technologies for achieving oxygen production on the Moon,drawing from an analysis of lunar resources and environmental *** delves into the principles,processes,advantages,and drawbacks of water-ice electrolysis,two-step oxygen production from lunar regolith,and one-step oxygen production from lunar *** two-step methods involve hydrogen reduction,carbothermal reduction,and hydrometallurgy,while the one-step methods encompass fluorination/chlorination,high-temperature decomposition,molten salt electrolysis,and molten regolith electrolysis(MOE).Following a thorough comparison of raw materials,equipment,technology,and economic viability,MOE is identified as the most promising approach for future in-situ oxygen production on the *** the corrosion characteristics of molten lunar regolith at high temperatures,along with the Moon's low-gravity environment,the development of inexpensive and stable inert anodes and electrolysis devices that can easily collect oxygen is critical for promoting MOE technology on the *** review significantly contributes to our understanding of in-situ oxygen production technologies on the Moon and supports upcoming lunar exploration initiatives.

关键词： lunar resources in-situ oxygen production space metallurgy molten lunar regolith electrolysis

Epigenetics in the modern era of crop improvements

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science China Life sciences 2025年

作者： Yan Xue Xiaofeng Cao Xiangsong Chen Xian Deng Xingwang Deng Yong Ding Aiwu Dong Chengguo Duan Xiaofeng Fang Lei Gong Zhizhong Gong Xiaofeng Gu Chongsheng He Hang He Shengbo He Xinjian He Yan He Yuehui He Guifang Jia Danhua Jiang Jianjun Jiang Jinsheng Lai Zhaobo Lang Chenlong Li Qing Li Xingwang Li Bao Liu Bing Liu Xiao Luo Yijun Qi Weiqiang Qian Guodong Ren Qingxin Song Xianwei Song Zhixi Tian Jiawei Wang Yuan Wang Liang Wu Zhe Wu Rui Xia Jun Xiao Lin Xu Zhengyi Xu Wenhao Yan Hongchun Yang Jixian Zhai Yijing Zhang Yusheng Zhao Xuehua Zhong Daoxiu Zhou Ming Zhou Yue Zhou Bo Zhu Jiankang Zhu Qikun Liu College of Life sciences Institute of Life Science and Green Development Hebei University Biotechnology Research Institute Chinese Academy of Agricultural Sciences College of Biology Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation Hunan Engineering and Technology Research Center of Hybrid Rapeseed Hunan University Institute of Advanced Agricultural sciences School of Advanced Agricultural Sciences Peking University State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources Guangdong Laboratory for Lingnan Modern Agriculture South China Agricultural University National Institute of Biological sciences Key Laboratory of Seed Innovation Institute of Genetics and Developmental Biology Chinese Academy of Sciences School of Advanced Agricultural sciences Peking-Tsinghua Center for Life Sciences Peking University Synthetic and Functional Biomolecules center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry and Molecular Engineering Peking University Key Laboratory of Seed Innovation State Key Laboratory of Plant Genomics and National Center for Plant Gene Research Institute of Genetics and Developmental Biology Chinese Academy of Sciences State Key Laboratory of Wheat Improvement Peking University Institute of Advanced Agricultural Sciences Shandong Laboratory of Advanced Agricultural Sciences in Weifang State Key Laboratory of Crop Stress Adaptation and Improvement School of Life Sciences Henan University State Key Laboratory of Maize Bio-breeding National Maize Improvement Center Department of Plant Genetics and Breeding China Agricultural University Frontiers science center for Molecular Design Breeding China Agricultural University center for Crop Functional Genomics and Molecular Breeding China Agricultural University Sanya Institute of China Agricultural University Hainan Yazhou Bay Seed Laboratory Institute of Advan

Epigenetic mechanisms are integral to plant growth, development, and adaptation to environmental stimuli. Over the past two decades,our comprehension of these complex regulatory processes has expanded remarkably, producing a substantial body of knowledge on both locus-specific mechanisms and genome-wide regulatory patterns. Studies initially grounded in the model plant Arabidopsis have been broadened to encompass a diverse array of crop species, revealing the multifaceted roles of epigenetics in physiological and agronomic traits. With recent technological advancements, epigenetic regulations at the single-cell level and at the large-scale population level are emerging as new focuses. This review offers an in-depth synthesis of the diverse epigenetic regulations, detailing the catalytic machinery and regulatory functions. It delves into the intricate interplay among various epigenetic elements and their collective influence on the modulation of crop traits. Furthermore, it examines recent breakthroughs in technologies for epigenetic modifications and their integration into strategies for crop improvement. The review underscores the transformative potential of epigenetic strategies in bolstering crop performance, advocating for the development of efficient tools to fully exploit the agricultural benefits of epigenetic insights.

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Deep learning-driven interval uncertainty propagation for aeronautical structures

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Chinese Journal of Aeronautics 2024年第12期37卷 71-86页

作者： Yan SHI Michael BEER Institute for Risk and reliability Leibniz Universitat HannoverHannover 30167Germany Department of Civil and Environmental Engineering University of LiverpoolLiverpool L693BXUnited Kingdom International Joint Research center for Resilient Infrastructure&International Joint Research center for Engineering reliability and Stochastic Mechanics Tongji UniversityShanghai 200092China

Interval Uncertainty Propagation(IUP)holds significant importance in quantifying uncertainties in structural outputs when confronted with interval input *** the aviation field,the precise determination of probability models for input parameters of aeronautical structures entails substantial costs in both time and *** an alternative,the use of interval variables to describe input parameter uncertainty becomes a pragmatic *** complex task of solving the IUP for aeronautical structures,particularly in scenarios marked by pronounced nonlinearity and multiple outputs,necessitates innovative *** study introduces an efficient deep learning-driven approach to address the challenges associated with *** proposed approach combines the Deep Neural Network(DNN)with intelligent optimization algorithms for dealing with the IUP in aeronautical *** inventive extremal value-oriented weighting technique is presented,assigning varying weights to different training samples within the loss function,thereby enhancing the computational accuracy of the DNN in predicting extremal values of structural ***,an adaptive framework is established to strategically balance the global exploration and local exploitation capabilities of the DNN,resulting in a predictive model that is both robust and *** illustrate the effectiveness of the developed approach,various applications are explored,including a high-dimensional numerical example and two aeronautical *** obtained results highlight the high computational accuracy and efficiency achieved by the proposed approach,showcasing its potential for addressing complex IUP challenges in aeronautical engineering.

关键词： Uncertainty propagation Interval variable Deep learning Optimization algorithm Aeronautical structure