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Damage and progressive failure of concrete structures using non-local peridynamic modeling

Science China(Technological Sciences) 2011年第3期54卷 591-596页

作者： HUANG Dan1,2, ZHANG Qing1,2 & QIAO PiZhong1,3.1 State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering, Hohai university, Nanjing 210098, China 2 department of engineering Mechanics, Hohai university, Nanjing 210098, China 3.department of Civil and Environmental engineering, Washington State university, Pullman, WA 99164-2910, USA State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering Hohai University Nanjing China department of engineering Mechanics Hohai University Nanjing China department of Civil and Environmental engineering Washington State University Pullman USA

Peridynamics (PD), a recently developed theory of solid mechanics, which employs a non-local model of force interaction and makes use of integral formulation rather than the spatial partial differential equations used in the classical continuum mechanics theory, has shown effectiveness and promise in solving discontinuous problems at both macro and micro scales. In this paper, the peridynamics theory is used to analyze damage and progressive failure of concrete structures. A non-local peridynamic model for a rectangular concrete plate is developed, and a central pairwise force function is introduced to describe the interior interactions between particles within some definite distance. Damage initiation, evolution and crack propagation in the concrete model subject to in-plane uni-axial tension, in-plane uni-axial compression and out-of-plane impact load are investigated respectively. The numerical results show that discontinuities appear and grow spontaneously as part of the solution to the peridynamic equations of motion, and no special failure criteria or re-meshing techniques are required, which proves the potential of peridynamic modeling as a promising technique for analyzing the progressive failure of concrete materials and structures.

关键词： concrete damage progressive failure peridynamic model discontinuities

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Guided wave propagation in multilayered piezoelectric structures

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Science China(Physics,Mechanics & Astronomy) 2009年第7期52卷 1094-1104页

作者： GUO YongQiang1, CHEN WeiQiu2,3.& ZHANG YongLiang4 1 Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, and School of Civil engineering and Mechanics, Lanzhou university, Lanzhou 73.000, China 2 Key Laboratory of Soft Soils and Geoenvironmental engineering, Ministry of Education, and{3. of Civil engineering, Zhejiang university, Hangzhou 3.0058, China 3.3. of engineering Mechanics, Zhejiang university, Hangzhou 3.0027, China 4 School of Civil engineering, Lanzhou Jiaotong university, Lanzhou 73.070, China Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education and School of Civil Engineering and Mechanics Lanzhou University Lanzhou China Key Laboratory of Soft Soils and Geoenvironmental engineering Ministry of Education and Department of Civil Engineering Zhejiang University Hangzhou China department of engineering Mechanics Zhejiang University Hangzhou China School of Civil engineering Lanzhou Jiaotong University Lanzhou China

A general formulation of the method of the reverberation-ray matrix (MRRM) based on the state space formalism and plane wave expansion technique is presented for the analysis of guided waves in multilayered piezoelectric structures. Each layer of the structure is made of an arbitrarily anisotropic piezoelectric material. Since the state equation of each layer is derived from the three-dimensional theory of linear piezoelectricity, all wave modes are included in the formulation. Within the framework of the MRRM, the phase relation is properly established by excluding exponentially growing functions, while the scattering relation is also appropriately set up by avoiding matrix inversion operation. Consequently, the present MRRM is unconditionally numerically stable and free from computational limitations to the total number of layers, the thickness of individual layers, and the frequency range. Numerical examples are given to illustrate the good performance of the proposed formulation for the analysis of the dispersion characteristic of waves in layered piezoelectric structures.

关键词： multilayered piezoelectric structures the method of reverberation-ray matrix guided waves dispersion characteristic

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A new method for adaptive color image filtering

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Chinese Science Bulletin 2000年第13期45卷 1230-1235页

作者： JIANG Gangyi, YU Mei & YU Bokang1. department, of Information & Electronic engineering, Hang/hou university of Commerce, Hangzhou 3.003., China 2. department, of Electronic engineering, Hangzhou institute of Electronics engineering, Hangzhou 3.003., China 3. State Key Laboratory on Machine Perception, Peking university, Beijing 100871, China Correspondence should be addressed to Yu Mei department of Information & Electronic engineering Hangzhou University of Commerce Hangzhou China State Key Laboratory on Machine Perception Peking University Beijing China department of Electronic engineering Hangzhou Institute of Electronics Engineering Hangzhou China

An adaptive color image filter (ACIF) is proposed in this note. Through analyzing noise corruption of color image, efficient locally adaptive filters are chosen for image enhancement. The proposed adaptive color image filter combines advantages of both nonlinear vector filters and linear filters, it attenuates noise and preserves edges and details very well. Experimental results show that the proposed filter performs better than vector median filter, directional-distance filter, directional-magnitude vector filter, adaptive nearest-neighbor filter, and α-trimmed mean filter.

关键词： color image noise analysis locally adaptive filters adaptive color image filter (ACIF).

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An improved approach to the efficient construction of and search operations in motion graphs

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Science China(Information Sciences) 2012年第5期55卷 1042-1051页

作者： GAO Yan 1,CHEN ZhiHua 2,CHEN MinGang 3.& SHEN Yang 3.1 Software engineering Institute,East China Normal university,Shanghai 200062,China 2 department of Computer Science and engineering,East China university of Science and Technology,Shanghai 20023.,China 3.department of Computer Science and engineering,Shanghai Jiao Tong university,Shanghai 200240,China Software engineering Institute East China Normal University Shanghai China department of Computer Science and engineering East China University of Science and Technology Shanghai China department of Computer Science and engineering Shanghai Jiao Tong University Shanghai China

Motion graphs have been widely used as an effective technique in the synthesis of human *** synthesize well-formed motions,motion graphs require smooth transitions and good ***,the time and costs grow quadratically as the graph size *** this paper,we present a method to set up a hierarchical structure,called a structure *** coarse level of this graph models different motion categories and their transitions,and the fine level mainly captures different motion *** interpolation space method is used to improve the graph connectivity at the fine *** structure guides the establishment of a faster and more realistic graphical *** the building process,this structure also helps with searching the motion graph,by performing a traverse search and placing the findings into a direct look-up table or local search ***,when there is no direct link between the different motions,a navigation map is introduced to conduct an appropriate search path via a series of transition motion *** experimental results indicate that our approach could lower the computation time in construction and searching,while simultaneously providing a richer variety of motion styles.

关键词： motion graph structure table registration curve motion interpolation

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New method for computing unstable equilibrium points of power systems with induction motors

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Science China(Technological Sciences) 2010年第4期53卷 881-885页

作者： CHEN Lei,XU Fei & MIN Yong State Key Lab of Power Systems,department of electrical engineering,Tsinghua{3.,Beijing 100084,China State Key Lab of Power Systems Department of Electrical Engineering Tsinghua University Beijing China

The computation of the unstable equilibrium point(UEP) is a key step involved in stability region estimation of nonlinear dynamic systems.A new continuation-based method to compute the UEPs of a power system with induction motors is *** mechanical torques of motors are changed to form a parameterized equation *** the solution curve of the equation set is traced by the continuation method from the stable equilibrium point to a *** direction of mechanical torque change is varied to get multiple *** obtained UEPs are mostly *** fast assessment of induction motor stability is studied by approximating the stable manifolds of the *** method is tested in several systems and satisfactory results are obtained.

关键词： power system stability transient voltage stability unstable equilibrium point(UEP) stability boundary induction motor

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Solving the input data in error correc-tion of optical fabrication by finite Fourier coefficient algorithm

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Science China(Technological Sciences) 2006年第1期49卷 50-60页

作者： CHENG Haobo1,2, SUN Guozheng3.& FENG Zhijing2 1. department of Optical engineering, Beijing Institute of Technology, Beijing 100081, China 2. department of Precision Instruments and Mechanology, Tsinghua{3., Beijing 100084, China 3. China North Industries Group Corporation, Beijing 100089, China department of Optical engineering Beijing Institute of Technology Beijing China department of Precision Instruments and Mechanology Tsinghua University Beijing China China North Industries Group Corporation Beijing China

A free-form lens (FFL) is a special surface that is difficult to be fabricated. FFL are usually fabricated by computer-controlled optical surfacing (CCOS) technique. During CCOS, the material removal amount is determined by the unit removal function (URF) convoluting with the input data――the dwell time. When the removal amount and the URF are known, how to solve the input data involves the special algorithm――deconvolution. Usually, the input data are solved by virtue of low pass filter or iterative methods. However, an approximation solution would destroy the machining stability nec-essary to perform precisely CCOS. In this paper, to solve the input data, a new method that is based on the finite Fourier coefficient is put forward. It can give a continuous and accurate solution for fabricating choice. Several parameters are simulated, which influ-ence the process of CCOS, and evaluating on the effect of the method is also carried out. Experimental results verify that this method is suitable for guiding the manufacturing of high precision FFL.

关键词： optical fabrication, computer controlled optical surfacing, free-form lens, finite Fourier coefficient, error correction.

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Improved performance of GaN-based light-emitting diodes by using short-period superlattice structures

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Progress in Natural Science:Materials International 2010年第1期20卷 70-75页

作者： Yi-jung LIU~1,Chien-chang HUANG~1,Tai-you CHEN~1,Chi-shiang HSU~1,Shiou-ying CHENG~2, Kun-wei LIN~3.Jian-kai LIOU~1,Wen-chau LIU~1 1.Institute of Microelectronics,department of electrical engineering,National Cheng-Kung{3., Tainan 70101,Taiwan,China 2.department of Electronic engineering,Nation Ilan{3.,I-Lan 26041,Taiwan,China 3.department and Graduate Institute of Computer Science and Information engineering, Chaoyang{3. of Technology,Taichung 413.9,Taiwan,China Institute of Microelectronics Department of Electrical Engineering National Cheng-Kung University Tainan 70101 Taiwan China department of Electronic engineering Nation Ilan University I-Lan 26041 Taiwan China department and Graduate Institute of Computer Science and Information engineering Chaoyang University of Technology Taichung 41349 Taiwan China

An InGaN/GaN multiple-quantum-well（MQW）light-emitting diode（LED）with a ten-period i（undoped）-InGaN/p（Mg doped）-GaN（2.5 nm/5.0 nm）superlattice（SL）structure,was *** SL structure that can be regarded as a confinement layer of holes to enhance the hole injection efficiency is inserted between MQW and p-GaN *** studied LED device exhibits better current spreading performance and an improved quality,compared with a conventional one without SL *** to the reduced contact resistance as well as more uniformity of carriers injection,the operation voltage at 20 mA is decreased from 3.3. to 3.14 V.A remarkably reduced reverse-biased leakage current(10-7-10-9A)and higher endurance of the reverse current pulse are *** measured output power and external quantum efficiency（EQE）of the studied LED are 13.6 mW and 24.8%,respectively. In addition,significant enhancement of 25.4%in output power as well as increment of 5%in EQE for the studied devices is observed, as the studied devices show superior current spreading ability and reduction in dislocations offered by the SL structure.

关键词： GaN superlattice(SL) current spreading hole confinement electrostatic discharge(ESD)

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A Method for Head-shoulder Segmentation and Human Facial Feature Positioning

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通信学报 1998年第5期 29-34页

作者： Hu Tianjian Cai Dejun department of electrical and Information engineering (Huazhong{3. of Science and Technology, Wuhan 43.074)

ＡＭｅｔｈｏｄｆｏｒＨｅａｄｓｈｏｕｌｄｅｒＳｅｇｍｅｎｔａｔｉｏｎａｎｄＨｕｍａｎＦａｃｉａｌＦｅａｔｕｒｅＰｏｓｉｔｉｏｎｉｎｇＨｕＴｉａｎｊｉａｎＣａｉＤｅｊｕｎＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｉｃａｌａ... 详细信息

ＡＭｅｔｈｏｄｆｏｒＨｅａｄｓｈｏｕｌｄｅｒＳｅｇｍｅｎｔａｔｉｏｎａｎｄＨｕｍａｎＦａｃｉａｌＦｅａｔｕｒｅＰｏｓｉｔｉｏｎｉｎｇＨｕＴｉａｎｊｉａｎＣａｉＤｅｊｕｎＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｉｃａｌａｎｄＩｎｆｏｒｍａｔｉｏｎＥｎｇｉ...

关键词： model based image coding head shoulder segmentation facial feature extraction model adaptation edge detection.

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Spatially discontinuous ionization phenomenon in inhomogeneous soil

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Science China(Technological Sciences) 2010年第4期53卷 918-921页

作者： ZHANG BaoPing,HE JinLiang & ZENG Rong State Key Lab of Power Systems,department of electrical engineering,Tsinghua{3.,Beijing 100084,China State Key Lab of Power Systems Department of Electrical Engineering Tsinghua University Beijing China

By using X-ray film imaging technology,a phenomenon of discontinuous ionization was observed in the inhomogeneous soil around the grounding electrode on which a surge voltage was applied.A simplified two-phase solid-gas model was built to study the electric field distribution in the soil to explain the discontinuous ionization *** showed the differences of the dielectric properties,the shapes and sizes of soil particles can cause discontinuous ionization in the soil.

关键词： discontinuous ionization inhomogeneous soil X-ray film porous medium electric field distribution

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HYDRIDING INFLUENCE OF INDIUM ON Pd-In ALLOYS

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中国有色金属学会会刊：英文版 1996年第3期6卷 63-67页

作者： Chen Yanglin(department of Materials Science and engineering, Zhejiang university, Hangzhou 3.0027) department of Materials Science and engineering Zhejiang University Hangzhou 310027 China

ＨＹＤＲＩＤＩＮＧＩＮＦＬＵＥＮＣＥＯＦＩＮＤＩＵＭＯＮＰｄ－ＩｎＡＬＬＯＹＳ￥ＣｈｅｎＹａｎｇｌｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ，ＺｈｅｊｉａｎｇＵｎｉｖｅ... 详细信息

ＨＹＤＲＩＤＩＮＧＩＮＦＬＵＥＮＣＥＯＦＩＮＤＩＵＭＯＮＰｄ－ＩｎＡＬＬＯＹＳ￥ＣｈｅｎＹａｎｇｌｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ，ＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ，Ｈａｎｇｚｈｏｕ３１０...

关键词： hydriding valence electrons lattice dilatation Fermi energy

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