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Preface to the Special Issue on Geo-Disasters

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Journal of Earth Science 2021年第5期32卷 1053-1055页

作者： chong xu Xiwei xu Yu Huang National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China Key Laboratory of Compound and Chained Natural Hazards Dynamics(Under Construction) Ministry of Emergency Management of ChinaBeijing 100085China College of Civil Engineering Tongji UniversityShanghai 200092China

Exploring the mechanism of natural disasters and fighting against natural disasters are the eternal themes for human survival and ***-disasters are one kind of natural hazards,including landslides,debris flows,earthquakes,liquefactions,which can result in serious causalities and economic ***,geo-disaster prevention and reduction has been a grand research topic for many decades and a large number of achievements have been made in detection,monitoring,early warning and risk assessment of geo-disasters(Vilímek et al.,2020;Ritchie and Roser,2019;xu et al.,2016;xu,2015;Huang et al.,2014).However,the climate change caused by global warming and effects of human activities,geo-disasters occur from time to time and the risk remains high,which brings new challenges to scientific and technological experts in this field all over the world(xu and xu,2021;McGlade et al.,2019;Xiong and Huang,2019;Keller et al.,2015;Huang and Cheng,2013).

关键词： disaster debris warming

Restoration of outer segments of foveal photoreceptors after resolution of malignant hypertensive retinopathy

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International Journal of Ophthalmology(English edition) 2012年第6期5卷 776-778页

作者： Xiao-Qiang Liu Xin-rui Gao Ding xu chong xu Li-Ning Cao Fang Wang Department of Ophthalmology Shanghai Tenth People's Hospital Tongji University School of Medicine

Dear Sir,I am Dr. Xiao-Qiang Liu, from the Department of Ophthalmology, Shanghai Tenth People’s Hospital,Tongji University School of Medicine, Shanghai, China. I write to report a case of malignant hypertensive retin... 详细信息

关键词： line Restoration of outer segments of foveal photoreceptors after resolution of malignant hypertensive retinopathy OS

A Double Varying-coefficient Modeling Approach for Analyzing Longitudinal Observations

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Acta Mathematicae Applicatae Sinica 2019年第3期35卷 671-688页

作者： Qun-fang xu rui LI School of Business Ningbo UniversityNingbo 315211China School of Statistics and Information Shanghai University of International Business and EconomicsShanghai 201620China Key Laboratory of Advanced Theory and Application in Statistics and Data Science East China Normal UniversityMinistry of EducationShanghai 200062China

The identification of within-subject dependence is important for constructing efficient estimation in longitudinal data *** this paper,we proposed a flexible way to study this dependence by using nonparametric regression ***,we considered the estimation of varying coefficient longitudinal data model with non-stationary varying coefficient autoregressive error process over observational time *** on spline approximation and local polynomial techniques,we proposed a two-stage nonparametric estimation for unknown functional coefficients and didn’t not drop any observations in a hybrid least square loss ***,we showed that the estimated coefficient functions are asymptotically normal and derived the asymptotic biases and variances *** Carlo studies and two real applications were conducted for illustrating the performance of our proposed methods.

关键词： autoregressive process double varying coefficient irregular time quantum locally linear

A Semi-Looped-Functional for Stability Analysis of Sampled-Data Systems

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IEEE/CAA Journal of Automatica Sinica 2023年第5期10卷 1332-1335页

作者： Zhaoliang Sheng chong Lin Shengyuan xu the Institute of Complexity Science Shandong Key Laboratory of Industrial Control Technologythe School of AutomationQingdao UniversityQingdao 266071 the School of Automation Nanjing University of Science and TechnologyNanjing 210094China

Dear Editor, In recent decades, owing to the significance of sampled-data control way on reducing the burden of communication transmission and improving the control capability of networked control systems, the researc... 详细信息

关键词： network communication Functional

High-speed photographic observation of collapse of two cavitation bubbles

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Science China(Technological Sciences) 2016年第11期59卷 1707-1716页

作者： LUO Jing xu WeiLin LI rui State Key Laboratory of Hydraulics Mountain River Engineering Sichuan University

Cavitation as a hydrodynamic phenomenon exists widely in water conservancy, shipbuilding, chemical and many other *** cavitation bubble dynamic studies mainly focused on single cavitation bubbles and their interaction with the wall. This paper studies the interaction between two cavitation bubbles under conditions with or without a wall. The results show that if the inception of two cavitation bubbles is not synchronized, the cavitation bubble of early inception collapse backwards the cavitation bubble of later inception; if the inception of two cavitation bubbles is synchronized, the two bubbles collapse towards each other; if a wall exists nearby, no matter whether the line connecting the centers of the two cavitation bubbles is vertical or parallel to the wall, the two cavitation bubbles collapse towards each other and then gradually merge, and the merged collapse body quickly moves to the wall. It is suggested that, as the number of cavitation bubbles increases, the cavitation erosion effect is not simply increased proportionally. Instead, mutual inhibitory effect may be demonstrated.

关键词： cavitation bubble high-speed photography shock wave micro-jet

Interaction among controlling factors for landslides triggered by the 2008 Wenchuan, China Mw 7.9 earthquake

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Frontiers of Earth Science 2016年第2期10卷 264-273页

作者： Lingling SHEN chong xu Lianyou LIU Key Laboratory of Environment Change and Natural Disaster MOE State Key Laboratory of Earth Surface Processes and Resource Ecology Academy of Disaster Reduction and Emergency Management Beijing Normal University Beijing 100875 China Key Laboratory of Active Tectonics and Volcano Institute of Geology China Earthquake Administration Beijing 100029 China

The 12 May 2008 Mw 7.9 Wenchuan, China earthquake triggered about 200,000 landslides, which were controlled by a number of factors. This study examines five factors： slope angle, slope aspect, lithology, peak ground acceleration （PGA）, and fault side （relative position on the seismogenic fault, i.e., hanging wall or footwall）, to determine how these factors control the co-seismic land- slide occurrence and whether one or more factors, acting alone or in concert, are involved in promoting or suppressing landslides. We performed a multi-factor statistical analysis using data from the 2008 Wenchuan earthquake. The results show that in the areas characterized by steep topography or where strong ground shaking occurred during the earthquake, there is a closer relation- ship between slope aspect and landslide number density （LND） than other areas. The relationship between lithology and LND values depends on PGA. In turn, the relationship between LND values and PGA is also influenced by lithology. In addition, the controlling effect of lithology on co-seismic landslides on the hanging wall of the seismogenic fault is greater than that on the footwall. Examining interactions among these factors can improve understanding of the mechanisms of co-seismic landslide occurrence.

关键词： Wenchuan earthquake co-seismic landslides,interaction among controlling factors statistical analysis

A Modified Cellular Automaton Model for the Quantitative Prediction of Equiaxed and Columnar Dendritic Growth

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Journal of Materials Science & Technology 2014年第12期30卷 1311-1320页

作者： rui Chen Qingyan xu Baicheng Liu Key Laboratory for Advanced Materials Processing Technology School of Materials Science and Engineering Tsinghua University

Since the characteristic of dendrite is an important factor determining the performance of castings, a twodimensional cellular automaton model with decentered square algorithm is developed for quantitatively predicting the dendritic growth during solidification process. The growth kinetics of solid/liquid interface are determined by the local equilibrium composition and local actual liquid composition, and the calculation of the solid fraction increment is based on these two compositions to avoid the solution of growth velocity. In order to validate the developed model, quantitative simulations of steady-state dendritic features over a range of undercooling was performed and the results exhibited good agreement with the predictions of LGK（Liptone Glicksman-Kurz） model. Meanwhile, it is demonstrated that the proposed model can be applied to simulate multiple equiaxed dendritic growth, as well as columnar dendritic growth with or without equiaxed grain formation in directional solidification of AleC u alloys. It has been shown that the model is able to simulate the growth process of multi-dendrites with various preferential orientations and can reproduce a wide range of complex dendritic growth phenomena such as nucleation, coarsening of dendrite arms, side branching in dendritic morphologies, competitive growth as well as the interaction among surrounding dendrites.

关键词： Cellular automaton Dendritic growth Crystallographic orientation Aluminum alloys

Geometry-based distributed arc-consistency method formultiagent planning and scheduling

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Science China(Technological Sciences) 2019年第1期62卷 133-143页

作者： xu rui LI ZhaoYu CUI PingYuan Institute of Deep Space Exploration Technology School of Aerospace Engineering Beijing Institute of Technology Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information Technology

This research focuses on building a distributed algorithm for planning and scheduling multiple agents to help people deal with events beyond their cognitive capacity, such as car assembly, factory management, spacecraft constellation, etc. We address not only the efficiency of the algorithm but also communication and the individual privacy. As to reason over the problems with multiple agents which are distributed but interconnected, a formal account of the Action-centric Multiagent Simple Temporal Problem(AMSTP) is put forward using the representation of geometries. The key technique we build on is a novel distributed arc-consistency algorithm centered by the geometric method called GDAC, which pays attention to how an agent's local subproblem affects other agents' subproblems. The GDAC is based on geometries taking the action rather than the timepoint as a variable, which can deal with continuous intervals and decrease the number of variables. Comprehensive experiments are run and the proposed technique outperforms the competitor and shows considerable merit compared to the centralized algorithm.

关键词： arc consistency multiple agents planning and scheduling

Development and verification of large deformation model considering stiffness deterioration and shear dilation effect in FLAC^(3D)

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International Journal of Mining Science and Technology 2018年第6期28卷 959-967页

作者： Wang ruijie Li chong xu Jinhai Pan Lijin School of Mines China University of Mining and Technology Key Laboratory of Deep Coal Resource Mining (CUMT) Ministry of Education State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology

The existing constitutive models of rock with strain softening cannot successfully reflect the damageinduced anisotropy and nonlinearity of the post-peak failure behavior under progressive loading. In order to better reflect the nonlinear stress-strain behavior of rock, especially for the post-peak failure behavior,with expected stiffness degradation and large deformation, a modified constitutive model of rock considering stiffness degradation and dilatation behavior at large deformation was proposed in this study. This study analyzes and discusses various attenuation parameters in the proposed nonlinear plastic constitutive model using FLAC^(3D) software. The excavation-induced stress in rocks was calculated by FLAC^(3D) using the Mohr-Coulomb model, conventional strain model, and the proposed modified model. The obtained results of these models were analyzed and compared with field data. This study shows that the simulated results using the proposed new constitutive model matched much more closely with the measured field data, with an average error less than 5%. This new model can successfully reflect the damage-induced stiffness degradation at large deformation, and can provide a theoretical basis for stability design and evaluation of underground excavation.

关键词： Stiffness degradation Dilatancy behavior Nonlinearity Post-peak failure behavior Deep soft rock roadway FLAC^3D