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Practical studies on rockfall simulation by DDA

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Journal of Rock Mechanics and Geotechnical Engineering 2011年第1期3卷 57-63页

作者： Hiroyuki Matsuyama Satoshi Nishiyama yuzo ohnishi West Nippon Expressway Co. Ltd. School of Civil Engineering Kyoto University Kyoto University

In this paper,simulations of real rockfall by discontinuous deformation analysis (DDA) are *** the simulations,the energy losses of rockfall are categorized into three types,*** loss by friction,the loss by collision,and the loss by *** of the energy loss using absolute parameters is conducted by the DDA ***,in order to verify the applicability and validity of the proposed DDA,field tests on rockfall and corresponding simulations of rockfall tests by DDA are *** simulated results of rockfall velocity and rockfall jumping height agree well with those obtained from the field ***,the new technique properly considers the energy-absorption ability of slope based on vegetation condition and shape of the rockfall,and provides a new method for the assessment and preventive design of rockfall.

关键词： discontinuous deformation analysis (DDA) rockfall numerical simulations field experiment cut slope highway

DEVELOPMENT OF THE 3D UNDERGROUND SPACE INFORMATION MANAGEMENT SYSTEM(USIMS) FOR THE MAINTENACE AND HEALTH ASSESSMENT OF TUNNELS Paper No.191

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DEVELOPMENT OF THE 3D UNDERGROUND SPACE INFORMATION MANAGEME...

Some Investigations on Early Organization of Karst System

ISRM-Sponsored International Symposium on Rock Mechanics:"Rock Characterisation,Modelling and Engineering Design Methods"(SINOROCK2009)

作者： Meiji Ryu Takumi Nakai Tomofumi Koyama Satoshi Nishiyama yuzo ohnishi Earthtech Toyo Co.Ltd. Department of Urban and Environmental Engineering Kyoto University

Due to the economical,political and social changes in Japan,the construction industry has to shift the focus from building new infrastructures to maintaining existing *** life of the infrastructures will be extended by regular maintenance considerably and this is especially true for tunnels and other underground ***,for the construction,maintenance and reinforcement of the tunnels,the new concept called asset management has been also introduced and paid *** of the key issues for asset management for tunnels is how to define,monitor and assess the performance of the *** is also important to register geological and construction related data and store them for the future use such as the maintenance and repair/reinforcement of the tunnels. At each stages(construction,maintenance and repair/reinforcement),large amount of data are gathered that should be stored and retrieved for the later *** newly developed three-dimensional Underground Space Information Management System (USIMS) enables to store and integrate all types of information related to the construction,inspection,maintenance and reinforcement systematically with a 3-D virtual world. In this study,for the purpose of the tunnel maintenance and health assessment of the tunnels,the comprehensive tunnel database was constructed using USIMS based on the geological data at the tunnel site,construction data,regular inspection records and photos,and etc.,which were stored as a hard copy and/or digital *** updating this tunnel database,time evolution of the tunnel status such as deformation,clacks *** be presented with clear 3D vision. The USIMS can help to optimize the process of regular inspections and maintenance and can be of great help to identify causes for accelerated *** USIMS can be a valuable asset management *** make a good inspection and maintenance program it is important to identify how fast and with what spread deterioration

关键词： Underground Space Information Management System(USIMS) tunnel regular inspection maintenance asset management 3-D vision

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Journal of Earth Science 1999年第4期18卷 314-321页

作者： Yu Qingchun(Geofront Laboratory, Department of Civil Engineering, Kyoto University, Kyoto 606-8501, Japan)Shen Jifang Wan Junwei(Department of Hydrogeology and Environmental Engineering, China University of Geosciences,Wuhan 430074, China)ohnishi yuzo(Geo Geofront Laboratory Department of Civil EngineeringKyoto UniversityKyoto 606-8501Japan Department of Hydrogeology and Environmental Engineering China University of GeosciencesWuhan 430074China

Some investigations on the early organization of karst system are carried out through modeling the dissolution evolution processes of stochastic fracture networks in carbonate rock. It is assumed that water flow in fracture network is laminar, and the dissolution rate process can be described with an empirical equation, The results suggest that a karst system is a self-organization system. It can spontaneously create higher hierarchical level out of a relative homogeneous structure through amplifying the microscopic heterogeneity of initial flow field. Under given boundary conditions, a karst system with initial fracture network of varied hierarchical levels is likely to have stronger tendency to lead to a typical karst system featuring conduit passages than a system with initial network of unique hierarchical level. Through merging local flow systems, a karst system concentrates the limited flow into a few pathways to promote the formation of higher hierarchical level.

关键词： karst system self-organization hierarchical structure hierarchical level

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岩体非连续裂隙网络三维面状渗流模型

岩石力学与工程学报 2005年第4期24卷 662-668页

作者：于青春刘丰收大西有三中国地质大学水资源与环境学院北京100083 黄河水利委员会河南郑州450003 京都大学土木工程系

模拟了一个野外实际入渗试验的岩体裂隙网络及其中的渗流。通过逆方法建立岩体三维裂隙网络模型,其指导原则是使模型能够再现野外通过露头和钻孔所观察到的裂隙现象。逆方法由于可以对模拟和实测裂隙进行相同条件统计抽样,因此避免了实... 详细信息

模拟了一个野外实际入渗试验的岩体裂隙网络及其中的渗流。通过逆方法建立岩体三维裂隙网络模型,其指导原则是使模型能够再现野外通过露头和钻孔所观察到的裂隙现象。逆方法由于可以对模拟和实测裂隙进行相同条件统计抽样,因此避免了实测数据统计分析中复杂的误差矫正。裂隙面状渗流分析采用了任意多边形有限差分法。讨论了通过模型校正确定裂隙导水系数的方法,进行了随机模型重复实现,验证了模型的稳定性。

关键词：岩石力学非连续裂隙网络渗流逆方法模型校正

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裂隙岩体一般块体理论初步

水文地质工程地质 2005年第6期32卷 42-48页

作者：于青春陈德基薛果夫大西有三中国地质大学水资源与环境学院北京100083 长江水利委员会三峡勘测研究院宜昌443003 京都大学土木工程系

本文在前人工作的基础上提出了一种通用方法解决任意大小裂隙、任意形状工程岩体的岩石块体识别及稳定性计算问题。在这一方法中裂隙既可以是实测裂隙也可以是通过随机模拟方法生成的随机裂隙,工程岩体可以是任意由多面体组合成的形状,... 详细信息

本文在前人工作的基础上提出了一种通用方法解决任意大小裂隙、任意形状工程岩体的岩石块体识别及稳定性计算问题。在这一方法中裂隙既可以是实测裂隙也可以是通过随机模拟方法生成的随机裂隙,工程岩体可以是任意由多面体组合成的形状,如复杂边坡或地下洞室,而且岩体和裂隙面可以是非均质的。这一通用过程被称为一般块体理论。它克服了关键块体理论(或楔形体法)中存在的弱点:即把裂隙假设为无限大的不连续面,因此无法预测岩石块体的数量和位置,而且一般只能识别出简单形状的凸形体。它在块体识别的同时将复杂的块体分解为几个简单的凸形块体,从而使复杂块体的几何描述、体积及重力计算、力学分析、可视化表示等一系列问题大大简化。在对一公路边坡的裂隙进行了详细观测之后,利用本文的方法进行了块体识别和稳定性分析,对本文的研究进行初步的验证。

关键词：裂隙岩体一般块体理论块体识别

Effects of uniaxial compressive strain on the electronic- transport properties of zigzag carbon nanotubes

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Nano Research 2016年第5期9卷 1267-1275页

作者： Masato ohnishi Ken Suzuki Hideo Miura Fracture and Reliability Research Institute Graduate School of Engineering Tohoku University Sendai 980-8579 Japan

Recently, substantial attention has been paid to the strain sensitivity of the carbon nanotubes＇（CNTs＇） electronic properties. In this study, the relationships between the geometric structures and electronic states of zigzag CNTs under uniaxial compressive strain were investigated. We found that different factors dominate the electronic states of zigzag CNTs depending on the strain regions： the initial stage of the strain loading, which lasts until column-buckling deformation begins, and the strain regions corresponding to column- and shell-buckling deformations. Because shell-buckling deformation significantly increases the re-orbital angle, the angle between the π orbital axis vectors of adjacent atoms, strong localization of the density of states （LDOS） occurs in the buckled area. We also analyzed the current able to pass through deformed CNTs using a tight-binding-based Green＇s function approach and determined that the current can be significantly suppressed by applying uniaxial compressive strain. Our method of predicting the electronic state of a deformed CNT based on the π-orbital angle is expected to be useful for predicting the electronic properties of CNT-based electronic devices and sensors.

关键词： carbon nanotube strain buckling deformation Green's function method electronic-transport property

Role of gut microbiota and Toll-like receptors in nonalcoholic fatty liver disease

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World Journal of Gastroenterology 2014年第23期20卷 7381-7391页

作者： Kouichi Miura Hirohide ohnishi Department of Gastroenterology Akita University Graduate School of MedicineAkita 010-8543Japan

Emerging data have shown a close association between compositional changes in gut microbiota and the development of nonalcoholic fatty liver disease(NAFLD).The change in gut microbiota may alter nutritional absorption and *** addition,gut microbiota are a source of Toll-like receptor(TLR)ligands,and their compositional change can also increase the amount of TLR ligands delivered to the *** ligands can stimulate liver cells to produce proinflammatory ***,the gut-liver axis has attracted much interest,particularly regarding the pathogenesis of *** abundance of the major gut microbiota,including Firmicutes and Bacteroidetes,has been considered a potential underlying mechanism of obesity and NAFLD,but the role of these microbiota in NAFLD remains *** reports have demonstrated that certain gut microbiota are associated with the development of obesity and *** instance,a decrease in Akkermansia muciniphila causes a thinner intestinal mucus layer and promotes gut permeability,which allows the leakage of bacterial *** to increase Akkermansia muciniphila improve the metabolic parameters in obesity and *** children,the levels of Escherichia were significantly increased in nonalcoholic steatohepatitis(NASH)compared with those in obese *** can produce ethanol,which promotes gut ***,normalization of gut microbiota using probiotics or prebiotics is a promising treatment option for *** addition,TLR signaling in the liver is activated,and its downstream molecules,such as proinflammatory cytokines,are increased in *** data,TLR2,TLR4,TLR5,and TLR9 have been shown to be associated with the pathogenesis of ***,gut microbiota and TLRs are targets for NAFLD treatment.

关键词： Nonalcoholic fatty liver disease Nonalcoholic steatohepatitis Gut microbiota Toll-like receptor Probiotics Prebiotics

Special focus on advances in disturbance/uncertainty estimation and attenuation techniques with applications

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Science China(Information Sciences) 2018年第7期61卷 180-181页

作者： Shihua LI Lei GUO Kouhei ohnishi Southeast University Beihang University Keio University

Disturbances and uncertainties exist in most engineering systems and always result in adverse effects on the control performances of closed-loop *** design and analysis of nonlinear control systems under disturbances is an active research topic in control systems *** advanced disturbance/uncertainty estimation and attenuation(DUEA)techniques have been developed to deal with systems in the presence of various disturbances and parametric uncertainties,e.g.,stochastic control,

关键词： Special focus on advances in disturbance/uncertainty estimation and attenuation techniques with applications

Long-Range Surface Plasmon Polaritons Guided by a Thin Metal Stripe

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Chinese Physics Letters 2007年第6期24卷 1626-1628页

作者：饶轶刘仿黄翊东 DAl ohnishi 彭江得 State Key Laboratory of Integrated Optoelectronics Department of Electronic Engineering Tsinghua University Beijing 100084 Optical Device Research and Development Centre ROHM 21 Mizosaki-Cho Saiin Ukyo-Ku Kyoto 615-8585 Japan

A long-range surface plasmon polariton （LRSPP） waveguide consisting of a 15nm thick gold stripe embedded in a homogeneous polymer BCB is reported. LRSPPs are excited by TM-mode input light successfully using an end-fire method. By scanning the output coupling fibre, the near field of the LRSPP is measured. The propagation loss of as low as 2.34 dB/mm is demonstrated.

关键词： GAP WAVE-GUIDES RESONANCE FILMS WAVELENGTHS