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Mechanical responses of multi-layered ground due to shallow tunneling with arbitrary ground surface load

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Frontiers of Structural and Civil Engineering 2023年第5期17卷 745-762页

作者： Xuefei HONG Dingli ZHANG zhenyu sun Key Laboratory for Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China

An analytical model based on complex variable theory is proposed to investigate ground responses due to shallow tunneling in multi-layered ground with an arbitrary ground surface *** ground layers are assumed to be linear-elastic with full-stick contact between *** solve the proposed multi-boundary problem,a series of analytic functions is introduced to accurately express the stresses and displacements contributed by different *** on the principle of linear-elastic superposition,the multi-boundary problem is converted into a superposition of multiple single-boundary *** conformal mappings of different boundaries are independent of each other,which allows the stress and displacement fields to be obtained by the sum of components from each *** analytical results are validated based on numerical and in situ monitoring *** present model is superior to the classical model for analyzing ground responses of shallow tunneling in multi-layered ground;thus,it can be used with assurance to estimate the ground movement and surface building safety of shallow tunnel constructions beneath surface ***,the solution for the ground stress distribution can be used to estimate the safety of a single-layer composite ground.

关键词： analytical model mechanical response multi-layered ground shallow tunneling ground surface load complex variable solution

Green solvent-based approaches for synthesis of nanomaterials

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Science China Chemistry 2010年第2期53卷 372-382页

作者： LIU ZhiMin sun zhenyu Beijing National Laboratory for Molecular Sciences Center for Molecular ScienceInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

The use of green solvents (including supercritical fluids and ionic liquids) in the synthesis of nanomaterials is highlighted. The methods described can not only reduce or eliminate the use or generation of substances hazardous to health and the environment, but can also be used to efficiently prepare nanomaterials with high performances. The unique characteristics of green solvents are responsible for the green features and unusual advantages of these approaches.

关键词： green solvent supercritical fluid ionic liquid nanomaterial synthesis

Cadmium-based metal-organic frameworks for high-performance electrochemical CO_(2) reduction to CO over wide potential range

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Chinese Journal of Chemical Engineering 2022年第3期35卷 143-151页

作者： Xin Li Song Hong Leiduan Hao zhenyu sun State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China College of Materials Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China

Electrochemical CO_(2)reduction(ECR)powered by renewable energy sources provides a sustainable avenue to producing carbon-neutral fuels and *** design and development of high performance,cost-effective,and stable catalysts for ECR remain a focus of intense ***,we report a novel electrocatalyst,two-dimensional cadmium-based 1,4-benzenedicarboxylate metal-organic frameworks(Cd-BDC MOFs)which can effectively convert CO_(2)to CO with a faradaic efficiency(FE)of more than80.0%over the voltage range between-0.9 and-1.1 V(versus reversible hydrogen electrode,***)in 0.1 mol·L^(-1) CO_(2)-saturated KHCO_(3)solution with an H-type cell,reaching up to 88.9%at-1.0 V(***).The performance outperforms commercial CdO and many other MOF-based materials demonstrated in prior *** catalytic property can be readily tuned by manipulating synthesis conditions as well as electrolyte ***,high CO FEs exceeding 90.0%can be attained on the Cd-BDC electrode at potentials ranging from-0.16 to-1.06 V(***)in 0.5 mol·L^(-1) KHCO_(3)solution by using a gas diffusion electrode cell *** maximum CO FE approaches~97.6%at-0.26 V(***)and the CO partial geometric current density is as high as about 108.1 mA·cm^(-2) at-1.1 V(***).This work offers an efficient,low cost,and alternative electrocatalyst for CO_(2)transformation.

关键词： Electrochemical carbon dioxide reduction Carbon monoxide Cadmium Metal-organic framework Electrocatalysis

Scientific problems and research proposals for Sichuan–Tibet railway tunnel construction

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Underground Space 2022年第3期7卷 419-439页

作者： Dingli Zhang zhenyu sun Qian Fang Sichuan–Tibet Railway Research Institute Beijing Jiaotong UniversityBeijing 100044China Key Laboratory for Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China

The Sichuan–Tibet railway construction has received significant attention from both China and *** new section from Ya’an to Nyingchi is about 1018.6 km long,including 69 tunnels with a total length of 841.7 *** longest tunnel(Yigong tunnel)is 42.4 km *** successful construction of the Sichuan–Tibet railway depends largely on tunnel *** to the complex conditions,tunnel construction for the Sichuan–Tibet railway poses great challenges to the research *** paper aims to illustrate the necessity of interdisciplinary and joint research to solve problems associated with tunnel construction that will be encountered in the immediate future and facilitate the communication and exchange of ideas between *** this end,based on a systematic analysis of the available data related to Sichuan–Tibet railway tunnels,six major aspects of the geology,environment,and engineering conditions are ***,based on the engineering responses from the Sichuan–Tibet railway tunnels,potential technical problems and risk characteristics are predicted and ***,six key scientific issues are identified and discussed based on a coupled multi-layer analysis of essential tunnel engineering ***,research directions,technical ideas,and research methods that should be carried out for this project are proposed.

关键词： Sichuan–Tibet railway tunnels Key scientific problems Complex stress environment Deformation mechanism of surrounding rock Dynamic response

多间隔信息融合的母线保护电流互感器断线再开放策略

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电力自动化设备 2024年第5期44卷 151-157页

作者：陈琦陈福锋唐治国薛明军刘凯祥王胜孙震宇国电南京自动化股份有限公司江苏南京210003 南京国电南自电网自动化有限公司江苏南京211153

对于电流互感器(CT)断线后发生金属性故障的情景,现有母线保护采取的闭锁差动保护动作方式将会引发多个变电站停电。此外,当母线区内发生高阻接地故障时,现有母线保护判据可能会将其误判为CT断线故障,不利于电力系统的安全稳定运行。针... 详细信息

对于电流互感器(CT)断线后发生金属性故障的情景,现有母线保护采取的闭锁差动保护动作方式将会引发多个变电站停电。此外,当母线区内发生高阻接地故障时,现有母线保护判据可能会将其误判为CT断线故障,不利于电力系统的安全稳定运行。针对这一问题,提出了一种母线保护CT断线再开放策略,该策略基于断线间隔与非断线间隔的零序电流变化量对负荷波动和故障进行区分,并基于非断线间隔的差流有效值和间隔失灵保护信息对区内外故障进行判别。实时数字仿真系统仿真结果验证了所提CT断线识别判据和再开放策略的正确性。

关键词：电流互感器断线多间隔信息融合短路故障电流互感器闭锁策略母线保护

Intelligent decision support platform of new energy vehicles

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Journal of Systems Engineering and Electronics 2022年第4期33卷 785-791页

作者： WANG Zhenpo sun zhenyu LIU Peng WANG Shuo ZHANG Zhaosheng Collaborative Innovation Center for Electric Vehicles&National Engineering Laboratory for Electric Vehicles Beijing Institute of TechnologyBeijing 100081China Chongqing Innovation Center Beijing Institute of TechnologyChongqing 401135China

New energy vehicles(NEVs) are gaining wider acceptance as the transportation sector is developing more environmentally friendly and sustainable technology. To solve problems of complex application scenarios and multi-sources heterogenous data for new energy vehicles and weak platform scalability,the framework of an intelligent decision support platform is proposed in this paper. The principle of software and hardware system is introduced. Hadoop is adopted as the software system architecture of the platform. Master-standby redundancy and dual-line redundancy ensure the reliability of the hardware system. In addition, the applications on the intelligent decision support platform in usage patterns recognition, energy consumption, battery state of health and battery safety analysis are also described.

关键词： new energy vehicle(NEV) intelligent decision support platform software system data platform application

Comparison of typhoon-induced near-inertial oscillations in shear flow in the northern South China Sea

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Acta Oceanologica Sinica 2015年第11期34卷 38-45页

作者： sun zhenyu HU Jianyu ZHENG Quanan GAN Jianping State Key Laboratory of Marine Environmental Science Xiamen University Department of Atmospheric and Oceanic Science University of Maryland College Park Department of Mathematics and Division of Environment Hong Kong University of Science and Technology

With moorings equipped with Acoustic Doppler Current Profilers （ADCP） in the northern South China Sea （SCS） in 2008 and 2009, we observed three near-inertial oscillation （NIO） events coded 2008a, 2009a and 2009b induced by passages of typhoons or tropical storms. This study compares characteristics of the three NIO events. Event 2008a was the strongest one among the three, and had the longest sustaining period （15 d）, while events 2009a and 2009b sustained for only 4 and 8 d, respectively. The three events were distinguished by vertical energy distribution and phase propagation. As for the frequency shift of the NIO, event 2008a had a peak frequency lower than the local Coriolis frequency （red-shift）, while events 2009a and 2009b showed blue-shift. The behavior of individual NIO event is jointly decided by the typhoon disturbance and the background ocean condition. Especially the background flow plays an important role by effects of advection and modulation. The results in this study provide observational evidence of variational NIO response to background flow field. As indicated by the distribution of vorticity and effective Coriolis frequency derived from numerical modeling, the large amplitude and elongated sustaining period of event 2008a were attributed to the waveguide effect of the background shear flow. This effect redistributed the NIO energy after the typhoon passage, absorbed incident waves and trapped energy in the area of the negative vorticity. While the background flow during events 2009a and 2009b did not have such effects due to the near-zero vorticity in the mooring area.

关键词： near-inertial oscillation typhoon northern South China Sea

Analytical solutions for deep tunnels in strain-softening rocks modeled by different elastic strain definitions with the unified strength theory

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Science China(Technological Sciences) 2022年第10期65卷 2503-2519页

作者： sun zhenyu ZHANG DingLi FANG Qian DUI GuanSuo CHU ZhaoFei Key Laboratory for Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China School of Civil Engineering Wuhan UniversityWuhan 430072China

This paper presents the analytical solutions for the responses of tunnels excavated in rock masses exhibiting strain-softening behavior. Since previous analyses give little consideration to the effect of the intermediate principal stress on the strain-softening rock behavior, the unified strength theory was introduced to analyze the tunnel response. Four cases of different definitions of the elastic strain in the softening and residual regions, used in the existing solutions, were considered. The tunnel displacements,stresses, radii of the softening and residual zones and critical stresses were deduced. The proposed solutions were verified by comparing with numerical simulations, model tests and existing solutions. Furthermore, the solutions of the four cases were compared with each other to investigate the influence of the elastic strain expressions on the tunnel responses. The results showed that the intermediate principal stress coefficient b has a significant effect on the tunnel displacements, stress fields, and plastic radii. Parametric studies were performed to analyze the influences of the softening and residual dilatancy coefficients,softening modulus and residual strength on the tunnel responses. The parametric analysis indicated that the existing models should be carefully evaluated in the analysis of tunnels constructed through average-quality rocks;the proposed solutions outperformed the existing models in solving the mentioned problem.

关键词： analytical solution elastic strain definition unified strength theory strain-softening intermediate principal stress model test

Sectional characteristics of temperature, salinity and density off the central Zhejiang coast in the spring of 2016

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Acta Oceanologica Sinica 2019年第4期38卷 175-182页

作者： Longqi Yang Zhaozhang Chen zhenyu sun Jianyu Hu State Key Laboratory of Marine Environmental Science College of Ocean and Earth SciencesXiamen University

In this study, the sectional characteristics of temperature, salinity and density off the central Zhejiang coast were analyzed using three sections of observational data in the spring of 2016. The results are as follows:(1) a cold water patch was observed in the middle layer of sections from 10 to 25 m, and a weak upwelling was observed at the upper layer near the central Zhejiang coast;(2) several thermoclines, inverted thermoclines, and haloclines were observed in the survey area;(3) the Taiwan Warm Current Water(TWCW) climbing from the slope towards the survey area affected the thermocline, making it thinner and intensified; however, the TWCW was not strong enough to break through the thermocline to reach the sea surface.

关键词： temperature salinity Taiwan Warm Current Water central Zhejiang coast