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Science china Mathematics 2007年第11期50卷 1583-1596页

作者： Da-chuan XU~(1+) Shu-zhong ZHANG~2 1 department of Applied Mathematics,Beijing University of Technology,Beijing 100022,china 2 department of Systems engineering and engineering management,The Chinese University of Hong Kong,Shatin,Hong Kong,china 1. department of Applied Mathematics Beijing University of Technology Beijing 100022 China 2. department of Systems engineering and engineering management The Chinese University of Hong Kong Shatin Hong Kong China

In this pap.r.we consider a class of quadratic maximization *** a subclass of the problems,we show that the SDp.r.laxation ap.r.ach yields an ap.r.ximation solution with the worst-case p.r.ormance ratio at leastα=0.87856….In fact,the estimated worst-case p.r.ormance ratio is dependent on the data of the problem withαbeing a uniform lower *** light of this new bound,we show that the actual worst-case p.r.ormance ratio of the SDp.r.laxation ap.r.ach (with the triangle inequalities added) is at leastα+δ_d if every weight is strictly positive,whereδ_d>0 is a constant depending on the problem dimension and data.

关键词： quadratic maximization max-cut problem semideflnite programming relaxation ap.r.ximation algorithm p.r.ormance ratio

Ap.r.ximation algorithms for indefinite complex quadratic maximization problems

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Science china Mathematics 2010年第10期53卷 2697-2708页

作者： HUANG Yongwei1,& ZHANG Shuzhong2 1department of Electronic and Computer engineering,The Hong Kong University of Science and Technology,Kowloon,Hong Kong,china 2department of Systems engineering and engineering management,The Chinese University of Hong Kong,Shatin,Hong Kong,china 1. department of Electronic and Computer engineering The Hong Kong University of Science and Technology Kowloon Hong Kong China2. Department of Systems Engineering and Engineering Management The Chinese University of Hong Kong Shatin Hong Kong China

In this pap.r.we consider the following indefinite complex quadratic maximization problem: maximize zHQz,subject to zk ∈ C and zkm = 1,k = 1,...,n,where Q is a Hermitian matrix with trQ = 0,z ∈ Cn is the decision vector,and m *** (1/log n) ap.r.ximation algorithm is presented for such ***,we consider the above problem where the objective matrix Q is in bilinear form,in which case a 0.7118 cos mπ 2ap.r.ximation algorithm can be *** the context of quadratic optimization,various extensions and connections of the model are discussed.

关键词： indefinite Hermitian matrix randomized algorithms ap.r.ximation ratio semidefinite programming relaxation

CHArACTErISTICS OF CrITICAL STATE OF TENSILE INSTABILITY

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中国有色金属学会会刊：英文版 1996年第3期6卷 58-62页

作者： Zhou Weixian(department of Aeronautical manufacturing engineering, Northwestern polytechnical University, Xi’an 710072) NOrTHWESTErN pOLYTECH UNIV DEPT AERONAUT MFG ENGNXIAN 710072PEOPLES R CHINA

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ＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＣＲＩＴＩＣＡＬＳＴＡＴＥＯＦＴＥＮＳＩＬＥＩＮＳＴＡＢＩＬＩＴＹ￥ＺｈｏｕＷｅｉｘｉａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＡｅｒｏｎａｕｔｉｃａｌＭａｎｕｆａｃｔｕｒｉｎｇＥｎｇｉｎｅｅｒｉｎｇ，ＮｏｒｔｈｗｅｓｔｅｒｎＰ...

关键词： tensile instability critical state deformation characteristic

Dynamic behavior of polymer surface and the time dependence of contact angle

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Science china Chemistry 2005年第6期48卷 553-559页

作者： WANG Xinping1, CHEN Zhifang1 & SHEN Zhiquan2 1. Key Laboratory of Advanced Textile Materials and manufacturing Technology of Education Ministry, department of Applied Chemistry, Zhejiang Institute of Science and Technology, Hangzhou 310033, china 2. department of polymer Science and engineering, Zhejiang University, Hangzhou 310027, china 1. department of Applied Chemistry Zhejiang Institute of Science and Technology Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry 310033 Hangzhou China 2. department of polymer Science and engineering Zhejiang University 310027 Hangzhou China

Time-dependent contact angles were measured by depositing sessile drops of wa-ter on the polymer surfaces and monitoring the drop shape as a function of time. It was found that contact angles decreased sharply with contact time and the equilibrium contact angle was finally attained after a certain time. Values of starting (θ s) and equilibrium contact angles (θ e) obtained by the sessile drop method depend on polymer prop.r.ies. The Wilhelmy plate technique was used to measure advancing and receding contact angles. The variations of starting (θ s) and equilibrium contact angles (θ e), advancing (θ a) and receding contact angles (θ r) have been studied on the oxidized surface of polymers containing polybutadiene block to explore the cause of time-dependence in contact angle measurement and the meaning of θ s and θ e. The results showed the linear relationships between starting (θ s) and advancing contact angles (θ a), the equilibrium (θ e) and receding contact angles (θ r). The similar relationship was also established between the contact angle hysteresis (θ a?θ r) and differences (θ s ?θ e) in starting contact angles and equilibrium contact angles. Therefore, time-dependence in contact angle measurement was mainly attributed to the surface reconstruction when water drops were deposited on polymer surfaces. The starting contact angle was contributed by the hydrophobic component on polymer surface and the equilibrium contact angle mainly by the hydrophilic component of polymer. These results not only demonstrated the interdependency between two contact angle measurements, the sessile drop method and the Wilhelmy plate technique, but also provided the exp.r.mental evidence to explain the cause of time-dependent contact angle. This may also provide a new method to study dynamic behavior of polymer surface.

关键词： contact angle, surface dynamic behavior, polymer surface, dynamic contact angle, time-dependence.

The Design, p.r.ormance Analysis and Implementation of VCAT in Backbone Networks for Software radio System

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china Communications 2009年第1期6卷 85-91页

作者： Wang peng1, JiaDong1, Jin Depeng2 , Zeng Lieguang2 1JiangNan Institute of Computer Technology, Wuxi, Jiangsu, 214083, p. r. china 2department of Electronic engineering, Tsinghua University, Beijing, 100084, p.r. china JiangNan Institute of Computer Technology Wuxi Jiangsu 214083 China department of Electronic engineering Tsinghua University Beijing 100084 China

Software radio is a kind of promising technology in today and future’s communication systems. To share the resources of software radio systems to a large extent, we need to connect the instruments through backbone networks, such as the Multi-Service Transp.r. platform (MSTp), which is a dominating network technology that adopts both telecom and datacom traffic into existing transp.r. infrastructures — Synchronous Digital Hierarchy (SDH). Virtual concatenation (VCAT) is one of the key technologies in MSTp. Comp.r.d with traditional contiguous concatenation, VCAT reduces transmission granularities, provides more flexibility to Network management System (NMS) and as a result, improves the network efficiency greatly. In this pap.r. we introduce our design and implementation of VCAT module for a MSTp ASIC. The procedure of theoretical analysis to determine several imp.r.ant p.r.ormance related p.r.meters is also discussed in detail. The over- all design has been thoroughly simulated and verified through our self-made FpGA board, and has been successfully applied in our MSTp ASICs. We believe our work is significant for future development of software radio technology.

关键词： SrT VCAT NMS MSTp ASIC

Truncation error calculation based on richardson extrapolation for variable-step collaborative simulation

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Science china(Information Sciences) 2011年第6期54卷 1238-1250页

作者： ZHANG HeMing 1 , LIANG SiLu 2 , SONG ShiJi 1 & WANG HongWei 3 1 department of Automation, TNList, Tsinghua University, Beijing 100084, china 2 Computer and Information management Center, Tsinghua University Beijing 100084, china 3 engineering Design Centre, engineering department, Cambridge University, Cambridge CB2 1pZ, UK 1. department of Automation TNList Tsinghua University Beijing 100084 China2. Computer and Information Management Center Tsinghua University Beijing 100084 China3. Engineering Design Centre Engineering Department Cambridge University Cambridge CB2 1PZ UK

Collaborative simulation is an effective ap.r.ach to p.r.orming simulation analysis for complex systems by integrating models developed for different engineering disciplines. Collaborative simulation issues include the modeling of coupled multidisciplinary systems, and the simulation running time integration of these models that are solved p.r.llelly. Estimation of the local truncation error of coupling models is the key to solve multidisciplinary collaborative simulation problem, which is actually used to restrict the simulation step. This pap.r.presents a variable-step method based on richardson extrapolation for calculating the local truncation error to solve collaborative simulation problem of multidisciplinary coupling models. Formulas for estimating the local truncation error are derived through theoretical analysis by using integration methods and interpolation technologies, respectively. The simulation exp.r.ments are illustrated to validate the accuracy and efficiency of proposed collaborative simulation algorithm in comp.r.son with the usual combinative algorithm.

关键词： multidisciplinary systems collaborative simulation variable-step algorithm error estimation

research on rapid response Schematic Design for Flexible Transfer Line CApp-Based

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厦门大学学报（自然科学版） 2002年第S1期41卷 174-175页

作者： GAO Ju-hong 1, XU Yan-shen 2 (1. department of Industrial engineering, School of management, Tianjin University, 2. department of Mechanical engineering, School of management, Tianjin Univers ity, Tianjin 300072, china)

To meet the market requirements for Flexible Transf er Line (FTL), which consists of modular NC machining tools of high quality and co st saving, the methodologies and technologies of client-oriented FTL rapid resp onse schematic design CApp-based, one of the key techniques, are presented in t his pap.r. In order to achieve this p.r.ose, an integrated system for integrated design of CAD/CApp/FTL with box-type p.r.s is realized. In this pap.r. firstly the theory of the conceptual design of FTL based on CApp is established and the software architecture is developed. The global-domain pr oduct model is put forward to meet with data representation. After the manufactu ring feature is analyzed and decomposed for machining op.r.tions, the feature-b ased p.r. unified data model object-oriented is built. Secondly the knowledge- based CApp system data model is established. The process planning unit model is formed by work element (WE), which is tool-cell based function abstraction meth od, and has unified layers with respect to designing and manufacturing. With WEs through dynamic response and simultaneous structure in process planning, the pr inciple solution for CApp function system can be implemented. Lastly the mapping from process domain to module design domain is built. The unidirectional select ion process based on fuzzy matching technology is easily dealt with computer. Th e algorithm of decision with fuzzy synthetic evaluation method and technology is applied to estimate the feasibility of the results in local working procedure o f modular NC machine tools and make decision of designs in overall FTL, which co nsists of many different factors. The example shows that the rapid response desi gn in bidding-based FTL scheme design is realized.

关键词： CApp flexible transfer line product model rapi d response design

A NEW OrTHOTrOpIC YIELD FUNCTION DESCrIBABLE ANOMALOUS BEHAVIOr OF MATErIALS

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中国有色金属学会会刊：英文版 1994年第2期4卷 37-41页

作者： Zhou,Weixian(department of Aeronautical manufacturing engineering,Northwestern polytechnical University,Xi’an 710072) Northwestern polytechnical Univ Xi'an China

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ＡＮＥＷＯＲＴＨＯＴＲＯＰＩＣＹＩＥＬＤＦＵＮＣＴＩＯＮＤＥＳＣＲＩＢＡＢＬＥＡＮＯＭＡＬＯＵＳＢＥＨＡＶＩＯＲＯＦＭＡＴＥＲＩＡＬＳＡＮＥＷＯＲＴＨＯＴＲＯＰＩＣＹＩＥＬＤＦＵＮＣＴＩＯＮＤＥＳＣＲＩＢＡＢＬＥＡＮＯＭＡＬＯＵＳＢＥＨＡＶＩＯＲＯＦ...

关键词： orthotropy anomalous behavior non-qudratic yield function

Exp.r.mental study of dynamic mechanical prop.r.ies of reactive powder concrete under high-strain-rate impacts

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Science china(Technological Sciences) 2010年第9期53卷 2435-2449页

作者： JU Yang1,2,LIU HongBin1,SHENG GuoHua1,3 & WANG HuiJie1 1 State Key Laboratory of Coal resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of rocks and Concrete,china University of Mining and Technology,Beijing 100083,china 2 department of Mechanical and manufacturing engineering,University of Calgary,2500 University Drive,AB T2N 1N4,Canada 3 School of resources and Civil engineering,Northeastern University,Shenyang 110004,china 1. State Key Laboratory of Coal resources and Safe Mining Beijing Key Laboratory of Fracture and Damage Mechanics of Rocks and Concrete China University of Mining and Technology Beijing 100083 China2. Department of Mechanical and Manufacturing Engineering University of Calgary 2500 University Drive AB T2N 1N4 Calgary Canada3. School of Resources and Civil Engineering Northeastern University Shenyang 110004 China

The dynamic mechanical prop.r.ies of reactive powder concrete subjected to compressive impacts with high strain rates ranging from 10 to 1.1×102 s-1 were investigated by means of SHpB (split-Hopkinson-pressure-bar) tests of the cylindrical specimens with five different steel fiber volumetric *** prop.r.ies of wave stress transmission,failure,strength,and energy consumption of rpC with varied fiber volumes and impact strain rates were *** influences of impact strain rates and fiber volumes on those prop.r.ies were characterized as *** general forms of the dynamic stress-strain relationships of rpC were modeled based on the exp.r.mental *** investigations indicate that for the plain rpC the stress response is greater than the strain response,showing strong brittle *** rpC with a certain volume of fibers sustains higher strain rate impact and exhibits better deformability as comp.r.d with the plain *** a constant fiber fraction,the peak compressive strength,corresponding peak strain and the residual strain of the fiber-reinforced rpC rise by varying amounts when the impact strain rate increases,with the residual strain demonstrating the greatest *** the fiber content makes trivial contribution to improving the residual deformability of rpC when the impact strain rate is *** tests also show that the fiber content affects the peak compressive strength and the peak deformability of rpC in a different *** a constant impact strain rate and the fiber fraction less than 1.75%,the peak compressive strength rises with an increasing fiber *** peak compressive strength tends to decrease as the fiber volume exceeds 1.75%.The corresponding peak strain,however,incessantly rises with the increasing fiber *** total energy Edisp that rpC consumed during the p.r.od from the beginning of impacts to the time of residual strains elevates with the fiber volume increment as long as the fiber fraction

关键词： impact reactive powder concrete (rpC) high strain rate dynamic strength energy consumption dynamic stress-strain response