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Steady-state stability assessment of AC-busbar Plug-in Electric Vehicle Charging Station with Photovoltaic

Journal of Modern Power Systems and Clean Energy 2020年第5期8卷 884-894页

作者： Rui Wang Qiuye Sun Dehao Qin Yushuai Li Xiangke Li Peng Wang IEEE College of Information Science and Engineering Northeastern UniversityShenyang 110819China School of Electrical and Electronic Engineering Nanyang Technological University639798Singapore Department of Electrical and Computer Engineering University of DenverDenver80208 ColoradoUSA Northwestern Polytechnical University Xi’an710072China

Although the deployment of alternating current(AC)-busbar plug-in electric vehicle(PEV)charging station with photovoltaic(PV)is a promising alternative,the interaction among subsystems always causes the instability problem.Meanwhile,the conventional generalized Nyquist criterion(GNC)is complex,and it is not suitable for the design of the AC system.Therefore,this paper proposes a modified infinityone-norm(MION)stability criterion based on the impedance method to assess the stability of the foresaid charging station.Firstly,the typical structure and operation modes of the charging station are studied.Furthermore,each subsystem impedance matrix is built by small-signal method,and the MION stability criterion based on impedance method is proposed to assess the charging station stability.Compared with the previous simplified stability criteria based on the norm,the proposed criterion has lower conservatism.Furthermore,the design regulation for the controller parameters is provided,and the stability recovery way is provided by connecting the doubly-fed line and energy storage equipment,which are selected based on intermediate variable,i.e.,short-circuit ratio(SCR).Finally,the effectiveness and conservatism of the proposed stability criterion are validated through simulation and experimental results.

关键词： Impedance-norm plug-in electric vehicle(PEV) charging station photovoltaic(PV) stability assessment

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Formation Mechanism and stability assessment of the Colluvial Deposit Slope in Zuoyituo

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Journal of China University of Geosciences 2004年第4期15卷 395-400页

作者： JianWenxing ZhangYihu YinHongmei FacultyofEngineering ChinaUniversityofGeosciencesWuhan430074China

The basic features of the colluvial deposit slope in Zuoyituo such as geological conditions, dimensions, slip surfaces and groundwater conditions are described concisely in this paper. The formation mechanism of the slope is discussed. It is considered that the formation of the colluvial deposit slope in Zuoyituo has undergone accumulation, slip, load, deformation and failure. The effects of rainfall on slope stability are categorized systematically based on existing methodology, and ways to determine the effects quantitatively are presented. The remained slip force method is improved by the addition of quantitative relations to the existing formulae and programs. The parameters of the colluvial deposit slope are determined through experimentation and the method of back-analysis. The safety factors of the slope are calculated with the improved remained slip force method and the Sarma method. The results show that rainfall and water level in the Yangtze River have a significant effect on the stability of the colluvial deposit slope in Zuoyituo. The hazards caused by the instability of the slope are assessed, and prevention methods are put forward.

关键词： Zuoyituo colluvial deposit slope formation mechanism improved remained slip force method back-analysis stability assessment prevention method.

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Smart and fast reinforcement design for anti-dip bedding rock slopes

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第11期15卷 2943-2953页

作者： Yun Zheng Congxin Chen Fei Meng Xiaodong Fu Wei Yuan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China School of Civil Engineering and Architecture Wuhan University of TechnologyWuhan430070China Key Laboratory of Roads and Railway Engineering Safety Control of Ministry of Education Shijiazhuang Tiedao UniversityShijiazhuang050043China

Rock slopes are usually reinforced by a number of rock bolts due to the high efficiency and low price.However,where should the rock bolts be installed is still a troublesome issue.For anti-dip bedding rock slopes(ABRSs),the installation position of rock bolts is a controlling factor that determines the reinforcement effect.In this work,a theoretical method is firstly proposed for assessing the stability of ABRSs reinforced by rock bolts using a limit equilibrium model.A comparison of theoretical calculations and numerical results was conducted to test the correctness of the theoretical method.Based on the stability assessment of ABRSs,we introduce adaptive moment estimation method(Adam)to optimize the installation location of rock bolts.Using Adam optimizer,the optimal layout of rock bolts with the maximum factor of safety can be determined,and the factor of safety of the slope increases by about 25%using the same amount of rock bolts but with different installation locations.The proposed method enables the fast stability analysis and supporting design for reinforced ABRSs,which paves the way to smart supporting design of slopes.

关键词： Rock slopes Toppling failure Rock bolts stability assessment Smart analysis

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Bleeder entry evaluation using condition mapping and numerical modeling

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International Journal of Mining Science and Technology 2021年第1期31卷 137-143页

作者： Ted M.Klemetti Mark A.Van Dyke Gabriel S.Esterhuizen National Institute for Occupational Safety and Health Pittsburgh Mining Research DivisionPittsburghPA 15236USA

One of the most common critical areas of longwall mining in terms of ground stability are the gateroad and bleeder entries.These critical entries provide much-needed safe access for miners and allow for adequate ventilation required for dilution of hazardous airborne contaminants and must remain open during mining of a multi-panel district.This paper is focused on the stability of the longwall entries subjected to a single abutment load such as bleeders,first tailgate,and last headgate.First tailgate and last headgate are also referred to as blind headgate and tailgate.A study of a longwall district through conditions mapping,support evaluations,and numerical modeling was conducted and evaluated by researchers from the National Institute for Occupational Safety and Health(NIOSH).The condition mapping and support evaluations were performed on entries that spanned the previous five years of mining and relied on a diverse selection of supports to maintain the functionality of the entry.Numerical modeling was also conducted to evaluate various support types with further investigation and comparison to the condition mapping.The study demonstrated the importance of the abutment load decay versus distance from the gob edge,the potential for a reduction in material handling related injuries,as well as optimal usage of secondary and standing support.

关键词： stability assessment Bleeder entry Abutment loading Condition mapping Longwall Ground control

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Estimation of unloading relaxation depth of Baihetan Arch Dam foundation using long-short term memory network

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Water Science and Engineering 2021年第2期14卷 149-158页

作者： Ming-jie He Hao Li Jian-rong Xu Huan-ling Wang Wei-ya Xu Shi-zhuang Chen Powerchina Huadong Engineering Corporation Limited Hangzhou 311122China Research Institute of Geotechnical Engineering Hohai UniversityNanjing 210098China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China

The unloading relaxation caused by excavation for construction of high arch dams is an important factor influencing the foundation’s integrity and strength.To evaluate the degree of unloading relaxation,the long-short term memory(LSTM)network was used to estimate the depth of unloading relaxation zones on the left bank foundation of the Baihetan Arch Dam.Principal component analysis indicates that rock charac-teristics,the structural plane,the protection layer,lithology,and time are the main factors.The LSTM network results demonstrate the unloading relaxation characteristics of the left bank,and the relationships with the factors were also analyzed.The structural plane has the most significant influence on the distribution of unloading relaxation zones.Compared with massive basalt,the columnar jointed basalt experiences a more significant unloading relaxation phenomenon with a clear time effect,with the average unloading relaxation period being 50 d.The protection layer can effectively reduce the unloading relaxation depth by approximately 20%.

关键词： Columnar jointed basalt Unloading relaxation Long-short term memory(LSTM)network Principal component analysis stability assessment Baihetan Arch Dam

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Preliminary establishment of a spinal stability scoring system for multiple myeloma

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World Journal of Clinical Cases 2021年第30期9卷 9023-9037页

作者： Xing-Chen Yao Xiang-Jun Shi Zi-Yu Xu Jie Tan Yan-Zhe Wei Lei Qi Zi-Hao Zhou Xin-Ru Du Department of Orthopedic Beijing Chaoyang HospitalBeijing 100020China Department of Hematology Beijing Chaoyang HospitalBeijing 100020China

BACKGROUND Multiple myeloma is an incurable malignant plasma cell disorder that represents the most common primary malignant bone tumor.It commonly involves bone metastasis in multiple vertebral bodies,and the Spinal Instability Neoplastic Score scoring system may not be fully applicable to multiple myeloma(MM)patients.AIM To evaluate the spinal stability of patients with MM spinal involvement to guide their clinical treatment.METHODS By using the Delphi method,we collected and extracted information through a series of questionnaires and improved it via feedback.We also preliminarily established a spinal stability scoring system for multiple myeloma.RESULTS Fifteen clinicians completed a second round of questionnaires and compared their answers with those of the first round of questionnaires to identify significant comments or changes that required group discussions.As a result,no further feedback was used to improve the scoring system.After integrating the information from the expert consultation questionnaire,we established the initial scoring system for MM spine stability and used the scoring system to assess a series of representative clinical cases.The MM spinal stability scoring system was created by calculating the scores of the six separate components:location,pain,number of segments,physiological curvature,comorbidities,and neurological function.The minimum value was"0",and the maximum value was"24".A score of"0-10"indicated"spine stability",a score of"11-17"indicated"potential instability",and a score of"18-24"indicated"spine instability".Patients with a score of"11-24"need an intervention such as surgery.CONCLUSION The initial establishment of the MM spine stability scoring system provides a vital theoretical basis for the evaluation of spine stability in individuals with MM.

关键词： Multiple myeloma stability assessment Spine Spinal instability neoplastic score Patient-specific modeling

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