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1.
研究了弹性力学中一退化波方程的Riemann问题.其应力函数非凸非凹,从而使得激波条件退化.通过引入广义激波条件下的退化激波,构造性地得到了各种情形下Riemann问题的整体解.  相似文献   

2.
针对Wiener退化失效型产品寿命试验与退化试验优化问题,以Wiener过程和逆高斯分布为依据,用分位寿命渐近方差作为可靠性指标进行了分析.首先比较了退化试验与定时截尾寿命试验的试验设计变量之间关系.然后考虑实际情况,研究试验费用有限情况下,寿命试验和退化试验分别达到渐近方差最小时的最优试验方案设计,发现退化试验的效率高于寿命试验.研究为小子样条件下长寿命产品可靠性试验设计提供了依据.  相似文献   

3.
本文利用比较原理以及一种特殊变换研究了一类非线性退化方程的混合问题,得到了这类复杂问题解的渐进性质。  相似文献   

4.
邓聚成 《数学季刊》1990,5(4):86-94
本文讨论非散度型的退化扩散问题(1) 主部是呈散度型的退化扩散问题已得到了广泛的研究(如见仁[1]),对于非散度型的退化抛物型方程,已有的工作甚少。[2]研究了φ(u)=u时的问题(1),得出其弱解的存在性,局部性,并讨论了唯一性。  相似文献   

5.
一类退化半导体方程弱解存在性的研究   总被引:2,自引:0,他引:2  
文章研究了当■(s)=sm(m>1),b(s)=s2和初值为u0,v0∈L 2(Ω)时一类退化半导体方程弱解的存在性.文章首先将原问题正则化,然后对正则化问题在L 2(Ω)空间上做出了有界估计,最后利用收敛性得到了问题的结论.  相似文献   

6.
胡学刚  穆春来 《数学学报》2008,51(2):291-298
研究一类在非均匀介质中带可变系数和吸收项的非线性退化抛物方程Cauchy问题解的局部性质和渐近行为,得到了解有局部性的条件.同时,证明了解的渐近性质,发现了有限时刻的熄灭现象.这些结果改进和推广了相关问题的最新成果.  相似文献   

7.
张海  蒋威 《大学数学》2008,24(2):54-57
讨论了退化中立型微分方程的周期解问题,给出了周期解存在性的条件和二维退化中立型微分方程周期解存在的代数判据,并且举例说明了其应用.  相似文献   

8.
此文研究一类在Radon测度给定下二阶退化拟线性椭圆型方程,通过引入逼近子问题列并求解、先验估计和收敛性研究,证明了该方程广义解在带权Sobolev空间的存在性。  相似文献   

9.
提出一类广义指派问题,这类问题研究的是m个人执行n项任务,每个人执行的任务数、执行每项任务的人数以及总的指派人项数均有限制,要求最优指派.对这类广义指派问题建立了数学模型,并找到一种转换方法,将这类问题转换为平衡指派问题,从而用传统方法,如匈牙利法求解.最后用一个箅例来说明这种转换方法的简便和有效性.  相似文献   

10.
非自治退化抛物-双曲型方程可以描述许多自然现象.主要研究这类方程的柯西问题,建立了动力学公式,在对流函数、扩散函数适当光滑性的基础上,证明了该问题动力学解的存在唯一性.  相似文献   

11.
基于对广义系统、泛导、泛对称、泛箱原理、泛系相对性提出了新的分析模式与新的相对数学化的简化强化的定义 ,发展了泛系方法论与泛系相对论的框架与理法 ,具体内容涉及 :相对普适的数学化的泛系 ,2 0 0类对偶 ,对偶转化 ,泛对称转化 ,泛系辩证 ,八畴方法 ,泛系数学方法 ,广义量化 ,逼近转化原则 ,泛等价定理 ,供求分析 ,思维实验 ,广义灰色系统 ,等等·  相似文献   

12.
Results of single transverse compression testing of PPTA and PIPD fibers, using a novel test device, are presented and discussed. In the tests, short lengths of single fibers are compressed between two parallel, stiff platens. The fiber elastic deformation is analyzed as a Hertzian contact problem. The inelastic deformation is analyzed by elastic-plastic FE simulation and by laser-scanning confocal microscopy of the compressed fibers ex post facto. The results obtained are compared to those in the literature and to the theoretical predictions of PPTA fiber transverse elasticity based on PPTA crystal elasticity.Presented at the 11th International Conference on Mechanics of Composite Materials (Riga, June 11–15, 2000).3TEX, Inc. 109, MacKenan Drive, Cary, North Carolina 27511, USA. Published in Mekhanika Kompozitnykh Materialov, Vol. 36, No. 4, pp. 533–544, March–April, 2000.  相似文献   

13.
Suohai Fan   《Discrete Mathematics》2009,309(17):5411-5419
Symmetry of graphs has been extensively studied over the past fifty years by using automorphisms of graphs and group theory which have played and still play an important role for graph theory, and promising and interesting results have been obtained, see for examples, [L.W. Beineke, R.J. Wilson, Topics in Algebraic Graph Theory, Cambridge University Press, London, 2004; N. Biggs, Algebraic Graph Theory, Cambridge University Press, London, 1993; C. Godsil, C. Royle, Algebraic graph theory, Springer-Verlag, London, 2001; G. Hahn, G. Sabidussi, Graph Symmetry: Algebraic Methods and Application, in: NATO ASI Series C, vol. 497, Kluwer Academic Publishers, Dordrecht, 1997]. We introduced generalized symmetry of graphs and investigated it by using endomorphisms of graphs and semigroup theory. In this paper, we will survey some results we have achieved in recent years. The paper consists of the following sections.
1. Introduction
2. End-regular graphs
3. End-transitive graphs
4. Unretractive graphs
5. Graphs and their endomorphism monoids.
Keywords: Graph; Endomorphism; Monoid; Generalized symmetry; End-regular; End-transitive; Unretractive  相似文献   

14.
How much information does a small number of moments carry about the unknown distribution function? Is it possible to explicitly obtain from these moments some useful information, e.g., about the support, the modality, the general shape, or the tails of a distribution, without going into a detailed numerical solution of the moment problem? In this, previous and subsequent papers, clear and easy to implement answers will be given to some questions of this type. First, the question of how to distinguish between the main-mass interval and the tail regions, in the case we know only a number of moments of the target distribution function, will be addressed. The answer to this question is based on a version of the Chebyshev–Stieltjes–Markov inequality, which provides us with upper and lower, moment-based, bounds for the target distribution. Then, exploiting existing asymptotic results in the main-mass region, an explicit, moment-based approximation of the target probability density function is provided. Although the latter cannot be considered, in general, as a satisfactory solution, it can always serve as an initial approximation in any iterative scheme for the numerical solution of the moment problem. Numerical results illustrating all the theoretical statements are also presented.  相似文献   

15.
本文利用差方法对自反MD设计SCMD(4mp,p,1)的存在性给出了构造性证明,这里p为奇素数,m为正整数.  相似文献   

16.
17.
Using the predicate language for ordered fields a class of problems referred to aslinear problems is defined. This class contains, for example, all systems of linear equations and inequalities, all linear programming problems, all integer programming problems with bounded variables, all linear complementarity problems, the testing of whether sets that are defined by linear inequalities are semilattices, all satisfiability problems in sentenial logic, the rank-computation of matrices, the computation of row-reduced echelon forms of matrices, and all quadratic programming problems with bounded variables. A single, one, algorithm, to which we refer as theUniversal Linear Machine, is described. It solves any instance of any linear problem. The Universal Linear Machine runs in two phases. Given a linear problem, in the first phase a Compiler running on a Turing Machine generates alinear algorithm for the problem. Then, given an instance of the linear problem, in the second phase the linear algorithm solves the particular instance of the linear problem. The linear algorithm is finite, deterministic, loopless and executes only the five ordered field operations — additions, multiplications, subtractions, divisions and comparisons. Conversely, we show that for each linear algorithm there is a linear problem which the linear algorithm solves uniquely. Finally, it is shown that with a linear algorithm for a linear problem, one can solve certain parametric instances of the linear problem.Research was supported in part by the National Science Foundation Grant DMS 92-07409, by the Department of Energy Grant DE-FG03-87-ER-25028, by the United States—Israel Binational Science Foundation Grant 90-00434 and by ONR Grant N00014-92-J1142.Corresponding author.  相似文献   

18.
19.
Sun Yongsheng, professor of mathematics, was born on January 22, 1929, in Wanghaisi Village, Cang County, Hebei Province, China. He died of lung cancer at 23 hour 15 minutes,March 22, 2006 in Beijing.  相似文献   

20.
The PlatoCAVE, the MiniCAVE, and the C2 are immersive stereoscopic projectionbased virtual reality environments oriented toward group interactions. As such they are particularly suited to collaborative efforts in data analysis and visual data mining. In this article, we provide an overview of virtual reality in general, including immersive projection technology, and the use of stereoscopic displays for data visualization. We discuss design considerations for the construction of these immersive environments including one-wall versus four-wall implementations, augmented reality, stereoscopic placement, head tracking, the use of LCD devices, polarized light stereo, voice control, and image synchronization.  相似文献   

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