差分方程

Continuity equation and motion equation which can be applied to cone-shaped pipes are obtained and finite difference method for them is brought forward.

根据非稳定流的一维流动理论，对圆锥形管道中的瞬变流动进行了分析，推导出了适用于圆锥形管道的连续性微分方程和运动微分方程，给出了这两个方程的有限差分解法，同时对计算结果进行了相对误差的对比分析。

In calculation, the discretization of continuity equation is performed in accordance with semi-implicit Scharfetter-Gummel scheme and the electric field is solved by the current conservation instead of the Poisson's equation, so it saves plenty of time for calculation.

在计算中，对于粒子的连续性方程我们采用Scharferter和Gummel提出的有限差分方法，并用电流守恒方程代替泊松方程来求解电场，从而节省了大量的计算时间。

In Chapter 2, starting from the basic fractional ordinary differential equations,weapply a high order approximation of fractional derivative advanced by Lubich to frac-tional differential equation, construct a high numerical difference scheme to solve thefractional differential equation, present error analysis of the algorithms theoretically,and prove the consistency ,convergency and stability.

接下来的第二章中，首先从基本的分数阶常微分方程出发，对Lubich提出的一个关于分数阶导数的高阶近似，将其应用于分数阶微分方程，构造高阶数值差分格式来进行分数阶微分方程的数值求解，并在理论上给出这一算法的误差分析，证明了它的相容性，收敛性和稳定性。

Because the equation is a various coefficients second-order parabolical partial differential equation,explicit difference formats usually have high condition for stability. Implicit difference formats have good stability,but they must calculate a set of algebraic equations,which are too complex.

由于泥沙扩散方程是一个二维变系数的抛物型方程，对于多维的方程，显格式往往稳定性要求很高，而隐格式虽然稳定性较好，但它要解大型的代数方程组，工作量也非常大，为了克服这两种格式的不足，常用ADI法求解，但仍存在一些计算量偏大等不足之处，因此构造出更好的差分格式是有必要的。

Within this context, four specific areas are addressed:(1) By means of finite integration technique, a new kind of the first order partial difference equation is derived from the original disperse transmission line equation of the uniform waveguide's. As it is the kind of one dimension Dirichlet's boundary problem, it is convenient for us to solve this equation from the leapfrog scheme. Because computation is carried out in one dimension, both high calculation efficiency and precision have been obtained in this method. Meanwhile, this method provide us a different selection to simulate the transient response of waveguide with non-simplical, for examples cylinder and elliptic waveguide, and avoid solving the second order equation, or using finite difference time domain to simulate a three dimension problem, sometimes the latter precision is not satisfied with the need, or low efficiency.

在这一研究内容下，主要研究四个方面的问题：(1)在完成金属波导传输线方程时域形式的基础之上，应用有限积分技术，把波导特征模式的色散传输线方程，化简为一组新的一阶偏微分方程组，该边值问题属一维Dirichlet边值问题，从而便于用蛙跳格式求解，由于是在一维中计算，该方法具有很高计算效率和精度，从而避免了以往为得到金属波导中特征模的时域响应特性，须要求解二阶方程，或用时域有限差分方法求解三维问题的方法，对于后者来说，计算有时是不准确的，或是很耗时的例如计算诸如圆波导、椭圆波导等其它复杂形状的波导。

In calculation, the discretization of continuity equation is performed in accordance with semi-implicit Scharfetter-Gummel scheme and the electric field is solved by the current conservation instead of the Poissons equation, so it saves plenty of time for calculation.

在计算中，对于粒子的连续性方程我们采用Scharferter和Gummel提出的有限差分方法，并用电流守恒方程代替泊松方程来求解电场，从而节省了大量的计算时间。

In calculation, the discretization of continuity equation is performed in accordance with semi-implicit and the electric field is solved by the current conservation instead of the Poissons equation.

在计算过程中，对于粒子的连续性方程我们采用有限差分方法，并用电流守恒方程代替泊松方程来求解电场。

Use of the finite difference method for Volterra equation here as a variable element of the equation, As the same...

用差分方法求解沃尔泰拉方程，此处为一个变元的方程，由于该方程同时含有微分和积分，一般求解有一定的困难。

In this paper,a space fractional differential equation is considered.The equation is obtained from the advection-diffusion equation by replacing the second order derivative in space by a fractional derivative in space of order.

考虑空间分数阶微分方程(即在一个标准的扩散-对流方程中，用分数阶导数代替空间二阶导数)，给出了该分数阶微分方程的显式和隐式有限差分格式。

By introducing the parameter , construct a new kind of weighted implicit difference scheme for (1+1)-dimension nonlinear Sine-Gordon equation and the generalized nonlinear Sine-Gordon equation respectively. Give out an ADI scheme for (2+1)-dimension nonlinear Sine-Gordon equation.

通过引进参数，分别为（1+1）维的非线性Sine-Gordon方程和广义的非线性Sine-Gordon方程建立了它们的加权隐式差分格式，给出了（2+1）维的非线性Sine-Gordon方程的ADI格式。

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