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Chinese Annals of mathematics,Series B 2000年第4期21卷 499-510页

作者： LIUZHAOLI LIFUYI departmentofmathematics ShandongUniversityJinan250100China. departmentofmathematics ShanxiUniversityTaiyuan030006China.

Using variational method, the authors get an existence result for positive solutions of a superlinear elliptic boundary value problem without assuming the P.S. condition. To prove the results in this paper, the author... 详细信息

关键词： Superlinear elliptic BVP Positive solution Variational method Gradient flow

Planar cubic hybrid hyperbolic polynomial curve and its shape classification

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Progress in Natural Science:Materials International 2004年第1期14卷 42-47页

作者： WANG Guozhao 1,2. * and YANG Qinmin 1,2. (1. Institute of Computer Graphics and Image Processing, 2. department of mathematics, Zhejiang university, Hangzhou 31002., China) Zhejiang Univ Inst Comp Graph & Image Proc Hangzhou 310027 Peoples R China Zhejiang Univ Dept Math Hangzhou 310027 Peoples R China

The planar cubic hybrid hyperbolic polynomial curves and cubic H Bézier curves are presented. The conditions leading to inflection points and singularities (cusps and loops) are investigated and the shape of these curves is classified. The conclusions enable us to detect inflection points and singularities and get an idea of how to preserve the fair shape when designing such curves.

关键词： hybrid hyperbolic polynomial curve H-Bézier curve shape classification inflection points singularities

Existence of inner functions on classical domain

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Chinese Science Bulletin 1997年第1期42卷 84-85页

作者： LIU Taishun and ZHANG Wenjun1 department of mathematics, university of Science and Technology of China, Hefei 2.002., China 2. department of mathematics Henan university, Kaifeng 475001, China

IN function of one complex variable, the inner function on the unit disc plays an important role in the theory of H^p functions. In the mid-1960s, W. Rudin and A. Vitushkin independently raised the question of whether there exist nonconstant inner functions on the unit ball B_n. Then quickly amassed considerable evidence indicated that such functions would be so pathological that they could not exist. Lately Rudin posed the conjecture on the nonexistence

关键词： In Existence of inner functions on classical domain

Schwarz-Pick estimates for positive real part holomorphic functions on unit ball and polydisc

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Science China mathematics 2010年第4期53卷 1017-1024页

作者： LIU Yang 1,& CHEN ZhiHua 2.1 department of mathematics,Zhejiang Normal university,Jinhua 32.004,China 2.department of mathematics,Tongji university,Shanghai 2.0092.China 1. department of mathematics Zhejiang Normal University Jinhua 321004 China2. Department of Mathematics Tongji University Shanghai 200092 China

We give higher order derivatives Schwarz-Pick estimates for all positive real part holomorphic functions on Bn and D n,and generalize early work on Schwarz-Pick estimate of higher order derivatives for holomorphic fun... 详细信息

关键词： Schwarz-Pick estimate holomorphic function Taylor expansion

p-th moment exponential stability of stochastic differential equations with impulse effect

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Science China(Information Sciences) 2011年第8期54卷 1702-1711页

作者： SHEN LiJuan 1,2.& SUN JiTao 11 department of mathematics, Tongji university,Shanghai 2.0092.China 2.department of mathematics,Luoyang Normal university, Luoyang 47102.,China 1. department of mathematics Tongji University Shanghai 200092 China2. Department of Mathematics Luoyang Normal University Luoyang 471022 China

The p-th moment exponential stability of stochastic differential equations with impulse effect is *** employing the method of vector Lyapunov functions,some sufficient conditions for the p-th moment exponential stability are *** addition,the usual restriction of the growth rate of Lyapunov function is replaced by the condition of the drift and diffusion coefficients to study the p-th moment exponential *** examples are also discussed to illustrate the effectiremess of the results obtained.

关键词： stochastic differential equations impulse p-th moment exponential stability vector Lyapunov functions

Howe duality in Dunkl superspace

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Science China mathematics 2010年第12期53卷 3153-3162页

作者： REN GuangBin 1,2.1 department of mathematics, university of Science and Technology of China, Hefei 2.002., China 2.department of mathematics, university of Aveiro, Aveiro 3810-193, Portugal 1. department of mathematics University of Science and Technology of China Hefei 230026 China2. Department of Mathematics University of Aveiro Aveiro 3810-193 Portugal

In the framework of superspace in Clifford analysis for the Dunkl version, the Fischer decomposition is established for solutions of the Dunkl super Dirac operators. The result is general without restrictions on multiplicity functions or on super dimensions. The Fischer decomposition provides a module for the Howe dual pair G × osp(1|2. on the space of spinor valued polynomials with G the Coxeter group, while the generators of the Lie superspace reveal the naturality of the Fischer decomposition.

关键词： Dunkl operators superspace Fischer decomposition Dirac operator

Integrated Control Strategy for CVT Powertrains with Consideration of Vehicle Drivability

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Chinese Journal of Mechanical Engineering 2012年第3期25卷 515-523页

作者： SUN Dongye LUO Yong QIN datong State Key Laboratory of Mechanical Transmission Chongqing UniversityChongqing 400044China

During shift,power flow is not interrupted in powertrains equipped with continuously variable transmission（CVT）.When hard acceleration is commanded,engine speed will flare and corresponding torque will be consumed,which leads to a drop in vehicle drive torque and also the vehicle *** is the reason why CVT vehicles have poor drivability during hard acceleration *** method such as torque compensation doesn＇t always work due to the limited backup torque of *** to this,means to evaluate the drivability of CVT vehicles are studied,affect factors of drivability are analyzed in *** acceleration process of CVT vehicle is studied by theoretical analysis,based on which engine torque and ratio change rate of CVT are identified as two key control parameters that decide the drivability of CVT vehicles during hard acceleration ***,a control strategy based on restricting the change rate of CVT ratio together with torque compensation is proposed,and two different algorithms to establish the limitation of ratio change rate are *** two algorithms are simulated and compared with each other,results indicate that drop of vehicle acceleration is eliminated evidently by limit the change rate of CVT ratio,but small ratio change rate also results in a longer time to finish the accelerate process,an algorithm to decide a proper ratio change rate is needed in order to tune these different *** order to get better control effects,a new fuzzy logic based algorithm is proposed to decide a proper ratio change rate during kick down conditions,simulation and experiment results indicate that,the amount of vehicle acceleration decrease is reduced from about 1 m/s2.to almost 0,in the mean time the accelerate process only delayed for about 0.3 *** proposed control strategy and algorithm can effectively tune the characteristics of CVT equipped vehicle during kick down conditions.

关键词： vehicles continuously variable transmission control strategy drivability

A complex variable meshless method for fracture problems

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Science China(Physics,Mechanics & Astronomy) 2006年第1期49卷 46-59页

作者： CHENG Yumin1 & LI Jiuhong2.1. Shanghai Institute of Applied mathematics and Mechanics, Shanghai university, Shanghai 2.0072. China 2. {2. of Building Engineering, Xi’an university of Technology, Xi’an 710048, China Shanghai Institute of Applied mathematics Mechanics Shanghai University Shanghai 200072 China department of Building Engineering Xi’an University of Technology Xi’an 710048 China

Based on the moving least-square (MLS) approximation, the complex variable moving least-square approximation (CVMLS) is discussed in this paper. The complex variable moving least-square approximation cannot form ill-conditioned equations, and has greater precision and computational efficiency. Using the analytical solution near the tip of a crack, the trial functions in the complex variable moving least-square approxi- mation are extended, and the corresponding approximation function is obtained. And from the minimum potential energy principle, a complex variable meshless method for fracture problems is presented, and the formulae of the complex variable meshless method are obtained. The complex variable meshless method in this paper has greater precision and computational efficiency than the conventional meshless method. Some examples are given.

关键词： moving least-square approximation, complex variable moving least-square approximation, meshless method, complex variable meshless method, fracture.

The realization and structure of complete Lie algebras whose nilpotent radicals are Heisenberg algebras

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Chinese Science Bulletin 1998年第5期43卷 383-385页

作者： JIANG Cuibo 1 and MENG Daoji 2.1.department of mathematics,Yantai Teachers university, Yantai 2.402., China 2.department of mathematics,Nankai university,Tianjin 300071, China. department of mathematics Yantai Teachers University Yantai China department of mathematics Nankai University Tianjin China

The realization and structure of complete Lie algebras whose nilpotent radicals are Heisenberg algebras over the complex field C are given.

关键词： complete Lie algebra Heisenberg algebra nilpotent radical.

Dimension and measure theoretic entropy of a subshift in symbolic space

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Chinese Science Bulletin 1997年第14期42卷 1193-1196页

作者： CHEN Ercai and XIONG Jincheng1. department of Astronomy, Nanjing university, Nangjing 2.0093, China 2. {2., South China Normal university, Guangzhou 510631, China department of Astronomy Nanjing University Nangjing China department of mathematics South China Normal University Guangzhou China

1 Definitions and resultsWITH the development of the theory of dynamical systems and fractal geometry, one provedthat symbolic dynamics is a powerful tool to study chaos and fractals. It is useful to study thefractal characteristics of symbolic dynamics. In the present note we shall point out the relationbetween the dimension and measure theoretic entropy of any subshift in symbolic space. Weprove here that the Bowen’s formula for Hausdorff dimension holds without Markov struc-ture. A variational principle for dimension is obtained.

关键词： symbolic space subshift measure theoretic entropy dimension.