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A NEW METHOD FOR SOLUTING TRANSIENT RESPONSE OF GENERALLY VISCOUS DAMPING MULTI-DEGREE SYSTEM

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Transactions of Nonferrous Metals Society of China 1996年第1期6卷 120-124页

作者： Zhang Huailiang bu yingyong Zhong Jue Tan Qing College of Mechanical and Electrical Engineering< Central South University oj TechnologyChangsha 410083

By means of the theory of composite-modality,the superposition principle of the vibra-tion mode of the linear system,and the analytical method of the original coordinate,a mathematical model of transient response to any stimulus for generally viscous damping multi-degree system was *** method not only solves the problem of the transient response of displacement,but also calculates the transient response of the elastic force or the elastic couple of the system.

关键词： damping multi-degree transient response

Repair of Second-Generation Recycled Fine Aggregate of Waste Concrete from Freeze-Thaw Environment by Carbonation Treatment

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Journal of Renewable Materials 2024年第1期12卷 187-201页

作者： Jie Huang Rongbin Jiang Xiaobo Sun yingyong Shuai School of building Engineering Taizhou Polytechnic CollegeTaizhou225300China

The reuse of waste recycled concrete from harsh environments has become a research hotspot in the field of *** study investigated the repair effect of carbonation treatment on second-generation recycled fine aggregate(SRFA)obtained from recycled fine aggregate concrete(RFAC)subjected to freeze-thaw(FT)*** and after carbonation,the properties of SRFA were *** second-generation recycled fine aggregate(CSRFA)at five substitution rates(0%,25%,50%,75%,100%)to replace SRFA was used to prepare carbonated second-generation recycled fine aggregate concrete(CSRFAC).The water absorption,porosity and mechanical properties of CSRFAC were tested,and its frost-resisting durability was *** results showed after carbonation treatment,the physical properties of SRFA was improved and met the requirements of II *** micro-hardness of the interfacial transition zone and attached mortar in CSRFA was 50.5%and 31.2%higher than that in SRFA,*** the increase of CSRFA replacement rate,the water absorption and porosity of CSRFAC gradually decreased,and the mechanical properties and frost resistance of CSRFAC were gradually *** treatment effectively repairs the damage of SRFA caused by FT cycles and improves its application potential.

关键词： Carbonation treatment repair freeze-thaw cycles second-generation recycled fine aggregate

THE PRELIMINARY ATTEMPT TO DEVELOP PREVENTIVE-PREDICTIVE MAINTENANCE

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Journal of Central South University 1995年第2期7卷 32-36页

作者： bu yingyong Zhang Huailiang(College of Mechanical and Electrical Engineering, Central South University of Technology, Changsha, 410083, China) College of Mechanical and Electrical Engineering Central South University of Technology Changsha China

This paper presents a conception of Preventive-Predictive Maintenance, describes a living instance which combines the technology of equipment condition supervising and failure diagnosing with the system of computer a... 详细信息

关键词： equipment management maintenance computer

A Privacy-preserving Energy Management System Based on Homomorphic Cryptosystem for IoT-enabled Active Distribution Network

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 167-178页

作者： Qian Hu Siqi bu Wencong Su Vladimir Terzija the Department of Physics Hong Kong Baptist UniversityHong KongChina the Department of Electrical and Electronic Engineering Shenzhen Research InstituteThe Hong Kong Polytechnic UniversityHong KongChina the Department of Electrical and Computer Engineering University of Michigan-DearbornDearbornMI 48128USA the School of Engineering Newcastle UniversityNewcastleUK

Active distribution network(ADN),as a typically cyber-physical system,develops with the evolution of Internet of Things(IoTs),which makes the network vulnerable to cybersecurity *** this paper,the eavesdropping attacks that lead to privacy breaches are addressed for the IoT-enabled ADN.A privacy-preserving energy management system(EMS)is proposed and empowered by secure data exchange protocols based on the homomorphic *** the information transmission among distributed generators and load customers in the EMS,private information including power usage and electricity bidding price can be effectively protected against eavesdropping *** correctness of the final solutions,e.g.,optimal market clearing price and unified power utilization ratio,can be deterministically *** simulation results demonstrate the effectiveness and the computational efficiency of the proposed homomorphically encrypted EMS.

关键词： Eavesdropping attack energy management system homomorphic cryptosystem Internet of Things(IOTs) active distribution network(ADN) privacy-preserving

Photocatalytic reduction of CO_(2) with H_(2)O into C_(2)H_(6) mediated by dual metalation strategy

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Science China Chemistry 2024年第5期67卷 1381-1383页

作者： Mei Wang Tong-bu Lu School of Materials Science and Engineering Institute for New Energy Materials&Low Carbon TechnologiesTianjin University of TechnologyTianjin 300384China

Artificial solar-energy-driven CO_(2) reduction into value-added fuels under mild conditions provides a promising strategy to mitigate energy crisis and alleviate environmental issues around the world. Among diverse products of CO_(2) reduction reaction, C_(2+) compounds are more desirable in terms of their high energy density and commercial value [1].Thus far, various photocatalysts have been constructed for CO_(2) reduction.

关键词： reduction desirable value

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深水超声波换能器设计

仪器仪表学报 2005年第z1期26卷 379-381页

作者：周知进卜英勇湖南科技大学机电工程学院湘潭411201 中南大学机电工程学院长沙410083

利用回声信号探测无声目标的原理,测量信号往返所需时间与在水中超声波声速的乘积,就可以确定目标所处的位置。根据该原理来探测海底微地形的高程数据,为此对适合于深海环境下工作的超声波换能器参数进行了理论分析与设计计算,该参数将... 详细信息

利用回声信号探测无声目标的原理,测量信号往返所需时间与在水中超声波声速的乘积,就可以确定目标所处的位置。根据该原理来探测海底微地形的高程数据,为此对适合于深海环境下工作的超声波换能器参数进行了理论分析与设计计算,该参数将为海底微地形探测系统提供技术依据。

关键词：超声波测距高程数据深海环境超声波换能器

Detection of Nonlinear Behavior Induced by Hard Limiting in Voltage Source Converters in Wind Farms Based on Higher-order Spectral Analysis

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 630-645页

作者： Zetian Zheng Shaowei Huang Qiangsheng bu Chen Shen Jun Yan State Key Laboratory of Power Systems Department of Electrical EngineeringTsinghua UniversityBeijing 100084China State Grid Jiangsu Electric Power Co. Ltd.Research InstituteNanjingChina

In recent years, sub-synchronous oscillation accidents caused by wind power integration have received extensive attention. The recorded constant-amplitude waveforms can be induced by either linear or nonlinear oscillation mechanisms. Hence, the nonlinear behavior needs to be distinguished prior to choosing the analysis method. Since the 1960s, the higher-order statistics(HOS) theory has become a powerful tool for the detection of nonlinear behavior(DNB) in production quality control wherein it has mainly been applied to mechanical condition monitoring and fault diagnosis. This study focuses on the hard limiters of the voltage source converter(VSC) control systems in the wind farms and attempts to detect the nonlinear behavior caused by bi-or uni-lateral saturation hard limiting using the HOS analysis. First, the conventional describing function is extended to obtain the detailed frequency domain information on the bi-and uni-lateral saturation hard limiting. Furthermore, the bi-and tri-spectra are introduced as the HOS, which are extended into bi-and tri-coherence spectra to eliminate the effects of the linear parts on the harmonic characteristics of hard limiting in the VSC control system, respectively. The effectiveness of the HOS in the DNB and the classification of the hard-limiting types is proven, and its detailed derivation and estimation procedure is presented. Finally, the quadratic and cubic phase coupling in the signals is illustrated, and the performance of the proposed method is evaluated and discussed.

关键词： Bi-coherence spectrum detection of nonlinear behavior hard limiting higher-order statistics tri-coherence spectrum voltage source converter wind farms.

Efficient reduction and adsorption of Cr(Ⅵ)using FeCl_(3)-modified biochar:Synergistic roles of persistent free radicals and Fe(Ⅱ)

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Journal of Environmental Sciences 2024年第3期137卷 626-638页

作者： Shujie Hu Chengshuai Liu Hongling bu Manjia Chen Ying-heng Fei National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of ScienceGuiyang 550081China School of Environment Science and Engineering Guangzhou UniversityGuangzhou 510006China College of Resources and Environment Chongqing SchoolUniversity of Chinese Academy of SciencesChongqing 400714China School of Environmental Science and Engineering Guangdong University of TechnologyGuangzhou 510006China

Transition metal iron and persistent free radicals(PFRs)both affect the redox properties of biochar,but the electron transfer relationship between them and the coupling reduction mechanism of Cr(Ⅵ)requires further *** untangle the interplay between iron and PFRs in biochar and the infuences on redox properties,FeCl_(3)-modified rice husk biochar(FBCs)was prepared and its reduction mechanism for Cr(Ⅵ)without light was *** FBCs had higher surface positive charges,oxygen-containing functional groups,and PFRs compared with pristine rice husk biochar(BC).Phenoxyl PFRs with high electrondonating capability formed in *** pronounced electron paramagnetic resonance signals showed that the PFRs preferred to form at lower Fe(Ⅲ)*** a high concentration of Fe(Ⅲ)would be reduced to Fe(Ⅱ)and consumed the formed *** kinetics and X-ray photoelectron spectroscopy analysis indicated that the FBCs effectively enhanced the Cr(Ⅵ)removal efficiency by 1.54-8.20 fold and the Cr(Ⅵ)reduction efficiency by 1.88-9.29 fold compared to those of *** quenching and competitive reductant addition experiments revealed that the higher Cr(Ⅵ)reduction performance of FBCs was mainly attributed to the formed PFRs,which could contribute to~74.0%of Cr(Ⅵ)reduction by direct or indirect electron *** PFRs on FBCs surfaces could promote the Fe(Ⅲ)/Fe(Ⅱ)cycle through single electron transfer and synergistically accelerate~52.3%of Cr(Ⅵ)*** study provides an improved understanding of the reduction mechanism of iron-modified biochar PFRs on Cr(Ⅵ)in environments.

关键词： Biochar Iron-modification Cr(Ⅵ) Electron transfer Reduction mechanism

An End-To-End Hyperbolic Deep Graph Convolutional Neural Network Framework

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 537-563页

作者： Yuchen Zhou Hongtao Huo Zhiwen Hou Lingbin bu Yifan Wang Jingyi Mao Xiaojun Lv Fanliang bu School of Information Network Security People’s Public Security University of ChinaBeijing100038China Institute of Computing Technology China Academy of Railway Sciences Corporation LimitedBeijing100081China

Graph Convolutional Neural Networks(GCNs)have been widely used in various fields due to their powerful capabilities in processing graph-structured ***,GCNs encounter significant challenges when applied to scale-free graphs with power-law distributions,resulting in substantial ***,most of the existing GCN models are shallow structures,which restricts their ability to capture dependencies among distant nodes and more refined high-order node features in scale-free graphs with hierarchical *** more broadly and precisely apply GCNs to real-world graphs exhibiting scale-free or hierarchical structures and utilize multi-level aggregation of GCNs for capturing high-level information in local representations,we propose the Hyperbolic Deep Graph Convolutional Neural Network(HDGCNN),an end-to-end deep graph representation learning framework that can map scale-free graphs from Euclidean space to hyperbolic *** HDGCNN,we define the fundamental operations of deep graph convolutional neural networks in hyperbolic ***,we introduce a hyperbolic feature transformation method based on identity mapping and a dense connection scheme based on a novel non-local message passing *** addition,we present a neighborhood aggregation method that combines initial structural featureswith hyperbolic attention *** the above methods,HDGCNN effectively leverages both the structural features and node features of graph data,enabling enhanced exploration of non-local structural features and more refined node features in scale-free or hierarchical *** results demonstrate that HDGCNN achieves remarkable performance improvements over state-ofthe-art GCNs in node classification and link prediction tasks,even when utilizing low-dimensional embedding ***,when compared to shallow hyperbolic graph convolutional neural network models,HDGCNN exhibits notable advantages and performance enhanceme

关键词： Graph neural networks hyperbolic graph convolutional neural networks deep graph convolutional neural networks message passing framework