查询词典 calculus of finite differences

In chapter 2,all kinds of numerical methods of computational fracturemechanics are summarized,the development histories and present situation ofboundary collocation method,boundary integral method,finite difference method,boundary element method and finite element method are expounded,and theapplication of finite element method in fracture mechanics are emphaticallydiscussed.

第二章 总结了计算断裂力学中各种数值方法，论述了边界配位法、边界积分法、有限差分法、边界元法及有限元法的发展历史和现状，并着重讨论了有限元法在断裂力学中的应用。

Firstly, we give out the definitions of L-graph and partial L-subgraph, and we ob-tain some properties of partial L-subgraphs. Secondly, continuous mapping is intro-duced respectively between L-graphs and between L-cotowers, and the relationshipbetween the category L-FG of L-graphs and the category FG_L~C of L-cotowers isstudied. At last, we study the finite topological property of the category L-FG, andgive out the concrete constructions of finite product and finite coproduct.

本章首先给出了L-图和部分L-子图的概念，得到了部分L-子图的若干性质；其次，给出了L-余塔的概念，在L-图之间和L-余塔之间分别引入连续映射，研究了L-图范畴L-FG和L-余塔范畴FG_L~G之间的联系；最后，研究了L-图范畴L-FG的有限拓扑性质，给出了L-图范畴L-FG的有限积和有限余积的具体构造。

On the basis of experimental research, this thesis applies 2-dimensional non-linear finite element method to the analysis of transient temperature field on the section by means of relatively high precision triangular element of six joints. When the temperature field is analyzed, finite element reseaus are divided in space field and finite difference reseaus are divided in time field, and then the program is compiled. The computing results are in good agreement with the test data. It indicates that the program is stable and precise.

在试验研究的基础上，本文采用精度较高的三角形六结点单元对构件截面二维非线性瞬态温度场进行了有限元分析，即在空间域内采用有限元网格划分，在时间域内采用有限差分网格划分，据此编制了计算程序，计算结果与试验数据符合较好，程序稳定性好，精度满足要求。

This paper is devoted to solving linear saddle point problems, Specifically, We consider nonsymmetric systems, written as usual in block form, where the upper left block is an invertible linear operator with positive definite symmetric part. Such saddle point problems arise, for example, in certain finite element and finite difference discretizations of NavierStokes equations, Oseen equations, and mixed finite element discretization of second order convection-diffusion problems.

中文题名求解鞍点问题的迭代方法副题名外文题名论文作者冯丽红导师曹志浩教授学科专业计算数学研究领域\研究方向学位级别博士学位授予单位复旦大学学位授予日期2002 论文页码总数87页关键词鞍点问题迭代方法网格离散线性方程组馆藏号BSLW /2003 /O241 /15 论文针对鞍点问题的求解分析了一些典型的快速算法。

If there is a finite number of players and the action sets and the set of states are finite, then a stochastic game with a finite number of stages always has a Nash equilibrium.

如果随机博弈中参与者的数量有限并且每个博弈阶段可能的状态数量有限，那么一个具有有限博弈阶段的随机博弈一般都存在一个纳什均衡。

Many scholars have studied these respects and given many important results, for example, the Hupperts famous theorem, namely, a finite group G is supersolvable if and only if every maximal subgroup of G has prime index; a finite group G is nilpotent if and only if every maximal subgroup of G is normal in G; a finite group G is solvable if and only if every maximal subgroup of G is c-normal in G (See it in [70]); etc.

很多学者都在这些方面进行了研究，得到了很多重要的结果，如：著名的Huppert定理，即有限群为超可解当且仅当它的所有极大子群的指数为素数；有限群为幂零当且仅当每个极大子群都正规；有限群为可解当且仅当它的极大子群均c-正规(见[70])；等等。

The approach of computational simulation is the finite element method.The whole research is combined by the following three parts. In part one, a program on quadtree method is compiled. It can automatically generate planar structures with all-quadrangular, good quality elements in high speed, and it can create data files on information of elements and nodes, which provide the foundation for finite element analysis. In part two, a program on finite element calculation is compiled by object-oriented method, During the simulation of fracture, the displacement and stress are calculated by the program.

本文的工作可分为三大部分：第一部分编制了四叉树法程序，通过它可对平面结构进行单元离散，快速自动生成质量较好的全四边形单元，并获得离散后的单元信息和节点信息，为有限元计算打下基础；第二部分利用面向对象方法编制了有限元计算程序，在破坏模拟过程中，利用它进行位移、应力分析；第三部分对脆性材料的破坏过程进行了模拟。

In this paper,the development of non-linear analysis approach,a more detailed presentation of the finite element software ADINA and ANSYS in the reinforced concrete structure,step by step analysis of a reinforced concrete structure of the finite element analysis techniques and the use of commercial finite element analysis software for concrete the structure of the two most important components-beams and columns of the comparative study of performance analysis.

本文从非线性分析的发展入手，较为详尽的介绍了有限元软件ADINA和ANSYS在钢筋混凝土结构中的应用，逐步分析了钢筋混凝土结构的有限元分析技术，并且利用商业有限元分析软件对混凝土结构中最重要的两类构件——梁和柱的性能进行了对比研究分析。

In the first chapter , we consider the law of iterated logarithm with finite partial sum. Under certain condition ,we extend the law of iterated logarithm with finite partial sum for the Wiener process to Gaussian process ; In addition, we apply the law of iterated logarithm of Chung to the finite partial sum condition.

第一章考虑有限项部分和的重对数律，在一定条件下，将 Wiener过程下有限项部分和的重对数律推广到高斯过程中，得到高斯过程下的有限项部分和的重对数律；另外，将Chung氏重对数律进一步推广到有限项部分和的情形下。

Finite element discretization was carried out on the mathematical model to get a fully coupled finite element equation with the parameters of element nodal displacement and element nodal pore pressure as unknown variables. Finally, the transient nonlinear finite element equation in incremental form for reservoir fluid-solid coupling is obtained by means of time discretization in implicit difference scheme.

基于与微分方程等价的加权余量公式，在空间域采用有限元离散，对时间域进行隐式差分格式离散，导出了以单元节点位移和单元节点孔隙压力为未知量的储层流固耦合的非线性有限元增量方程。

You can snipe the second and third union leaders from this position.

您可以鹬第二和第三工会领袖从这一立场出发。

Aiming at the currently shortage of XML streams quality detecting, this paper proposes a new forecasting method of XML streams quality by least squares support vector machines, which is used the method of XML keys' vector matrix as windows, and vector product wavelet transform to multilevel decompose and refactor the XML streams series, that can fulfill real-time checking demand of XML quality, and ensure constraint, consist- ency and integrality. For even more adapting net load, it proposes a control strategy by weight and adaptive adjustment to ensure XML streams quality.

针对当前XML数据流质量检测存在的不足，提出构建XML键的矢量矩阵作为窗口，利用矢量积小波变换多级分解与重构XML数据流，再结合最小二乘支持向量机对XML数据流质量进行预测的一种方法，满足XML数据流质量重构时实时检测的要求，保证XML数据的约束性、一致性与完整性；为了更好的适应网络负载，采取加权与自适应窗口调整等调度策略充分保证XML数据流的质量检测。