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Impact of rock anisotropy on fracture development

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Progress in Natural Science:Materials International 2008年第11期18卷 1403-1408页

作者： Lianbo Zeng~(a,b,*) Jiyong Zhao~c Shengju Zhu~c Weiliang Xiong~c Yonghong He~c Jianwen Chen~c a key state laboratory of Petroleum Resource and Prospecting in china University of Petroleum,beijing 102249,china b Resources and information Faculty,china University of Petroleum,beijing 102249,china c Exploration and Development Research Institute,Changqing Oilfield Branch,Xi’an 710021,china key state laboratory of Petroleum Resource and Prospecting in china University of Petroleum Beijing 102249 China Resources and information Faculty China University of Petroleum Beijing 102249 China Exploration and Development Research Institute Changqing Oilfield Branch Xi’an 710021 China

Experiments on uniaxial and triaxial rock mechanics and rock acoustic emissions have been conducted for research on the impact of rock anisotropy on the development of the fractures of different directions by taking as an example the ultra-low-permeability sandstone reservoir in the Upper Triassic Yanchang Formation within the Ordos *** experimental results prove the existence of anisotropy of the rock mechanical property in the different directions on the plane,which is the chief reason for the production of impacts on the development of different assemblages of fractures in the geological *** rock anisotropy usually restricts the development of one assemblage of conjugate shear *** fractures in the Yanchang Formation within the Ordos Basin are mainly shear fractures that formed under two tectonic ***,here,four assemblages of shear fractures should have developed,but due to the effect of a strong rock anisotropy,in each period one assemblage of fractures chiefly ***,two assemblages of fractures are usually developed in every part at present.

关键词： Fracture Rock anisotropy Rock mechanical experiments Acoustic emission experiments

Eavesdropping in a quantum secret sharing protocol based on Grover algorithm and its solution

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Science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 491-495页

作者： HAO Liang1, LI JunLin1 & LONG GuiLu1,2 1key laboratory for Atomic and Molecular NanoSciences and Department of Physics, Tsinghua University, beijing 100084, china 2Tsinghua National laboratory for information Science and Technology, beijing 100084, china 1. key laboratory for Atomic and Molecular NanoSciences and Department of Physics Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China

A detailed analysis has showed that the quantum secret sharing protocol based on the Grover algorithm (Phys Rev A, 2003, 68: 022306) is insecure. A dishonest receiver may obtain the full information without being detected. A quantum secret-sharing protocol is presents here, which mends the security loophole of the original secret-sharing protocol, and doubles the information capacity.

关键词： quantum secret sharing Grover algorithm quantum cryptography quantum search algorithm

Modeling of Hillslope Runoff and Soil Erosion at Rainfall Events Using Cellular Automata Approach

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Pedosphere 2009年第6期19卷 711-718页

作者： MA Ting ZHOU Cheng-Hu CAI Qiang-Guo state key laboratory of Resources and Environmental information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 (China) Graduate University of the Chinese Academy of Sciences Beijing 100049 (China)

A novel quantitative cellular automata (CA) model that simulates and predicts hillslope runoff and soil erosion caused by rainfall events was developed by integrating the local interaction rules and the hillslope surface hydraulic processes. In this CA model, the hillslope surface was subdivided into a series of discrete spatial cells with the same geometric features. At each time step, water and sediment were transported between two adjacent spatial cells. The flow direction was determined by a combination of water surface slope and stochastic assignment. The amounts of interchanged water and sediment were computed using the Chezy-Manning formula and the empirical sediment transport equation. The water and sediment discharged from the open boundary cells were considered as the runoff and the sediment yields over the entire hillslope surface. Two hillslope soil erosion experiments under simulated rainfall events were carried out. Cumulative runoff and sediment yields were measured, respectively. Then, the CA model was applied to simulate the water and soil erosion for these two experiments. Analysis of simulation results indicated that the size of the spatial cell, hydraulic parameters, and the setting of time step and iteration times had a large impact on the model accuracy. The comparison of the simulated and measured data suggested that the CA model was an applicable alternate for simulating the hillslope water flow and soil erosion.

关键词： hillslope surface hydraulic parameters sediment simulation water

Study on dynamic fracture behavior of TA15ELI alloy under mode-Ⅱ loading by caustics method

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Rare Metals 2010年第4期29卷 361-365页

作者： LIU Rui,HUI Songxiao,YE Wenjun,MI Xujun,XIONG Baiqing,and YOU Zhenping state key laboratory for Fabrication & Processing of Nonferrous Metals,General Research Institute for Nonferrous Metals,beijing 100088,china state key laboratory for Fabrication & Processing of Nonferrous Metals General Research Institute for Nonferrous Metals Beijing China

The dynamic fracture behavior of TA 15ELI alloy with lath-like microstructure was studied by caustics method. Specimens with double-side pre-notch were tested under the plane-stress condition at mode-II loading with a drop hammer system. Caustics information recorded in films illustrated the histories of both crack length and stress intensity factor. The dynamic fracture toughness and crack growth velocity of TA15ELI with lath-like microstructure were determined to be 279 MPa.m1/2 and 32.6 m/s, respectively. SEM fractograph analysis showed a mixed feature of mainly plastic mode for TA 15ELI alloy in dynamic mode-II fracture. Shear localization was observed in the vicinity of the crack initiation area.

关键词： titanium alloy dynamic fracture caustics method fracture toughness crack growth

An improved exponential filter for fast nonlinear registration of brain magnetic resonance images

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Progress in Natural Science:Materials International 2009年第6期19卷 759-767页

作者： Zhiying Long a, Li Yao a,b, Kewei Chen c, Danling Peng a a state key laboratory of Cognitive Neuroscience and Learning, beijing Normal University, beijing 100875, china b School of information Science and Technology, beijing Normal University, beijing 100875, china c Banner Alzheimer Institute (BAI) & Samaritan PET Center, Phoenix, AZ, USA [a]state key laboratory of Cognitive Neuroscience and Learning Beijing Normal University Beijing 100875 China [b]School of Information Science and Technology Beijing Normal University Beijing 100875 China [c]Banner Alzheimer Institute (BAI) & Samaritan PET Center Phoenix AZ USA

A linear elastic convolution filter was derived from the eigenfunctions of the Navier-Stokes differential operator by Bro-Nielsen in order to match images with large deformations. Due to the complexity of constructing the elastic convolution filter, the algorithm’s efficiency reduces rapidly with the increase in the image’s size. In our previous work, a simple two-sided exponential filter with high efficiency was proposed to approximate an elastic filter. However, its poor smoothness may degenerate the performance. In this paper, a new exponential filter was constructed by utilizing a modified nonlinear curve fitting method to approximate the elastic filter. The new filter’s good smoothness makes its performance comparable to an elastic filter. Its simple and separable form makes the algorithm’s speed faster than the elastic filter. Furthermore, our experiments demonstrated that the new filter was suitable for both the elastic and fluid models.

关键词： Exponential filter Nonlinear Registration Magnetic resonance imaging

On an attack on RSA with small CRT-exponents

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Science china(information Sciences) 2010年第8期53卷 1511-1518页

作者： HAN LiDong 1,2 , WANG XiaoYun 3 & XU GuangWu 3,4 1 key laboratory of Cryptologic Technology and information security, Ministry of Education, Shandong University, Jinan 250100, china 2 School of Mathematics, Shandong University, Jinan 250100, china 3 Institute for Advanced Study, Tsinghua University, beijing 100084, china 4 Department of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA 1. key laboratory of Cryptologic Technology and information security Ministry of Education Shandong University Jinan 250100 China2. School of Mathematics Shandong University Jinan 250100 China3. Institute for Advanced Study Tsinghua University Beijing 100084 China4. Department of Electrical Engineering and Computer Science University of Wisconsin-Milwaukee Milwaukee WI 53201 USA

This paper concerns the RSA system with private CRT-exponents. Since Chinese remainder representation provides efficiency in computation, such system is of some practical significance. In this paper, an existing attack to small private CRT-exponents is analyzed. It is indicated that this attack makes nice use of lattice in RSA analysis, but some argument does not hold in general. Several counterexamples are constructed. Refinements and more precise statements of the attack are given.

关键词： RSA CRT cryptanalysis continued fraction lattice reduction

Identification of the Quaternary low gas-saturation reservoirs in the Sanhu area of the Qaidam Basin,china

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Petroleum Science 2011年第1期8卷 49-54页

作者： Li Xiongyan Li Hongqi Zhou Jinyu He Xu Chen Yihan Yu Hongyan state key laboratory of Petroleum Resource and Prospecting China University of PetroleumBeijing 102249China key laboratory of Earth Prospecting and information Technology China University of PetroleumBeijing 102249China Department of Computer Science and Technology China University of PetroleumBeijing 102249China Exploration and Development Institute Changqing Petroleum CompanyShaanxi 710021China

Low gas-saturation reservoirs are gas bearing intervals whose gas saturation is less than 47%. They are common in the Quaternary of the Sanhu area in the Qaidam *** to the complex genesis mechanisms and special geological characteristics,the logging curves of low gas-saturation reservoirs are characterized by ambiguity and diversity,namely without significant log response characteristics. Therefore,it is particularly difficult to identify the low gas-saturation reservoirs in the study *** addition,the traditional methods such as using the relations among lithology,electrical property,physical property and gas bearing property,as well as their threshold values,can not effectively identify low gas-saturation *** solve this problem,we adopt the decision tree,support vector machine and rough set methods to establish a predictive model of low gas-saturation reservoirs,which is capable of classifying a mass of multi-dimensional and fuzzy *** to the transparency of learning processes and the understandability of learning results,the predictive model was also revised by absorbing the actual reservoir *** applications indicate that the predictive model is effective in identifying low gas-saturation reservoirs in the study area.

关键词： Sanhu area Qaidam Basin low gas-saturation reservoir decision tree support vector machine rough set predictive model identification

A new approach toward object-based change detection

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Science china(Technological Sciences) 2010年第S1期53卷 105-110页

作者： ZHANG Guo1,2,LI Yang1 & LI ZhiJiang3 1 state key laboratory of information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University,Wuhan 430079,china 2 Satellite of Surveying and Mapping Application center,state Bureau of Surveying and Mapping,beijing 100830,china 3 School of Printing and Packaging,Wuhan University,Wuhan 430079,china Wuhan Univ State Key Lab Informat Engn Surveying Mapping & R Wuhan 430079 Peoples R China state Bur Surveying & Mapping Satellite Surveying & Mapping Applicat Ctr Beijing 100830 Peoples R China Wuhan Univ Sch Printing & Packaging Wuhan 430079 Peoples R China

Object-based change detection has been the hotspot in remote sensing image processing.A new approach toward object-based change detection is *** two different temporal images are unitedly segmented using the mean shift procedure to obtain corresponding *** change detection is implemented based on the integration of corresponding objects’ intensity and texture *** are conducted on both panchromatic images and multispectral images and the results show that the integrated measure is robust with respect to illumination changes and *** color detection is conducted to determine whether the color of the unchanged objects changes or not when dealing with multispectral *** verification work is carried out to show the accuracy of the proposed approach.

关键词： mean shift united segmentation change detection object-based intensity texture integration

Human knowledge acquisition from 3D interaction in virtual environments

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Science china(information Sciences) 2012年第7期55卷 1528-1540页

作者： CHENG Cheng,JIANG Ru & DONG XueMei beijing laboratory of Intelligent information Technology,School of Computer Science,beijing Institute of Technology,beijing 100081,china 1. beijing laboratory of Intelligent information Technology School of Computer Science Beijing Institute of Technology Beijing 100081 China

Recently,virtual environment (VE) based design and planning,which is a kind of interaction intensive computing,has shown great *** users of such systems are specialists or technicians and their 3D interactions with the system embed a great deal of knowledge and ***,how to integrate human knowledge and skills into VE is a great challenge to researchers in the human computer interaction *** paper proposes a method for acquiring user knowledge from *** main ideas and work include,abstracting the interactive process and formalizing the interactive semantics,as well as providing a semantic model of an interactive information repository,from which user interactive processes can be retrieved and all kinds of application logics can be established.A virtual assembly planning system is introduced as an example of a practical application of this *** show that the related models can well capture user knowledge and retrieve the interaction process.

关键词： human computer interaction interactive semantics virtual environment temporal logic virtual manufacturing virtual assembly