差分方程

Through the numerical computation and comparison with the exact solutions of one dimensional linear convection equation and nonlinear equation, accuracy of the first order upwind scheme is analyzed in detail.

摘 要：通过对一维线性对流方程和一维非线性对流方程的数值求解，对一阶迎风差分格式的精度作了较详细的分析。

In the simplified model, the governing equation of heat conduction is discretized using implicit finite difference method, and the computational domain is discretized using cell centered scheme, and the solution of Maxwell equation is used to determine the distribution of the internal heating sources.

使用的简化模型中热传导方程的离散采用隐式差分法、区域的离散采用内节点法，并以Maxwell方程的解确定内热源分布。

Based on the theory of tidal flow and sediment motion, a 2-D depth-integrated mathematical model for the Jiaojiang Estuary is developed by using explicit scheme of finite difference on the triangle elements. The results show that the rotary currents occurring in this area can be simply and effectively simulated by the model. Meanwhile, the suspended sediment concentration simulated is in agreement with the field data.

本文根据椒江口实测水文地形资料，从平面二维水流泥沙基本方程和基本理论出发，采用三角单元有限差分法对水流泥沙方程显示求解，对椒江口潮流泥沙进行了数值模拟，模型简单实用，较好地再现了具有旋转潮波性质的椒江河口水流运动特征，含沙量场也得到了基本正确的反映。

In the first part we consider the convergence and stability of finite difference scheme for Landau-Lifshitz equation in one dimensions space and 2d radial symmetric Landau-Lifshitz equation.

在第一部分，我们研究一维Landau-Lifshitz方程非齐次边值问题和二维柱对称Landau-Lifshitz方程Neumann边值问题的有限差分格式。

Using difference method, the first-order and the second-order differential equations of fractional derivative can become the first-order ordinary differential equation, and the high precision direct integration can be used for the solution.

所论方法首先引入差分格式，将含有分数阶导数的一阶和二阶微分方程变为一阶的常微分方程，然后再用精细积分方法逐步积分进行求解。

The nonlinear dynamic equations including the initial geometric imperfections of laminated composite cylindrical shells were derived from Hamilton's philosophy. Assuming the transverse displacements to be composed of axially symmetrical part and axially asymmetrical part, the governing equations expressed as displacement forms of dynamic buckling were obtained by Galerkin method. The equations were solved by finite difference method. The effects of impact velocity, lamination angle, initial geometric imperfection on the axial dynamic buckling of laminated composite cylindrical shells were discussed.

由Hamilton原理导出包含初始几何缺陷的复合材料层合圆柱壳的非线性动力方程；将横向位移设为对称及非对称两部分，由Galerkin方法得到以位移形式表达的动力屈曲控制方程，通过有限差分方法求解；讨论了冲击速度、铺层角度、初始几何缺陷等各种因素对复合材料圆柱壳轴向冲击动力屈曲可能产生的影响。

The results of the numerical solutions for Euler equation and shallowwater equations by GAUSS schemes presented in the paper under distributedmemory parallel multiprocessor are presented.The efficient of parallelcomputation are satisfied.

利用曙光-1000型分布存储大规模并行机，对我们在交错网格下所构造求解Euler方程和浅水方程的高分辨差分格式进行了并行实现，并对并行效率进行了分析，计算结果和并行效率都比较令人满意。

This paper gives a 45 degree up-going wave equation with an absorbing layer and constructs its implicit difference scheme.

给出了附加吸收层的三维45°上行波方程，构造了该方程的一种隐式差分格式。

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。

A finite difference method is derived for the analysis of time domain electric field integral equation of thin wire-structures.

针对时域电场积分方程的矩量法求解过程的繁琐及算法的时序推进稳定性不好等问题，提出了一种有限差分法求解时域电场积分方程的方法。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐