查询词典 parabolic partial differential equation

This paper, firstly, after a deep study of image mathematical models, sets up two kinds of image models namely Laplace partial differential equation model and biharmonic equation model and then obtains the eigenvectors of image by the methods of eigenfunction expansion and boundary recurrence.

本文首先较深入地研究了图象的数学描述，提出图象的Laplace偏微分方程和双调和方程两种模型，继而采用特征函数展开法和边界递推法分别求得图象的特征矢量。

In this paper we study the method of interpolation by radial basis functions in H~k(k ≥ 1) and give some error estimates. By means of such interpolation with a special kind of radial basis function, we construct a basis in H~k(k ≥ 1). Combined with the Galerkin method, this theory can be applied to solve boundary value problems for elliptic partial differential equations (such as the third boundary value problem for Poisson equation and the corresponding problem for the biharmonic equation), and some numerical experiments are also given.

本文从求解偏微分方程的角度出发，在被逼近函数u属于一般的Sobolev空间H~k(k≥1)的情形，引入了一种径向基函数插值方法，并建立了相应的误差估计；再利用这种插值性质，从一类特殊径向基函数出发构造Sobolev空间的一组基，针对Poisson方程第三类边值问题和重调和方程类似边值问题，为用无网格算法求解偏微分方程边值问题建立了相应的理论，并通过算例来验证了这一算法。

Through the limit difference method,the partial differential equation of the semiconductor device is transformed into a difference equation,and the corresponding boundary condition is discretized with high accuracy.

采用有限差分法把器件工作的偏微分方程转化为差分方程，并将相应的边界条件转化为精度较高的离散化形式。

It is known theoretically that to the variational problem with weak constraints in cost functional J, its Euler equation can be discreted into difference format, by using matrix theory and difference method of partial differential equation we know that there exists optimal selection of weight factors in the cost functional under the condition of minimal variance between analysis field and ideal field.

从理论上可知，对于目标泛函J带有约束条件的变分问题，将其Euler方程离散成差分形式，利用矩阵理论和偏微分方程的差分方法，则目标泛函的权重因子，在分析场和理想场的最小方差意义下存在最优选取。

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。

The proposed method is sample and does not need to compute both complex partial differential equation and operator equation of Riccati.

该方法计算简单，无须计算复杂的偏微分Riccati方程或算子Riccati方程。

The pressure equation for the liquid phase is obtained as, which is a no-linear elliptic partial differential equation.

推导了喂料熔体流导率的计算公式，得出压力场的控制方程是一非线性椭圆偏微分方程。

The Laplace equation is a typical and simplest elliptic partial differential equation with wide applications.

Laplace 方程是最典型，最简单但应用广泛的椭圆型偏微分方程。

Based on the principle of variation, boundary value problem of pressure partial differential equation was transformed into the extreme value problem of fonctionelle and finite element equation of flow model was deduced for calculating the simulation result.

根据变分原理，将压力微分方程的边值问题转化为泛函的极值问题，建立了渗流模型的有限元方程。

Due to the effect of curvature of shell, the equation of motion of elastic waves in shell is much more complex than that in plate. The method of operator factorization can't be directly used to solve the equation of motion of elastic waves in shell by reducing it to the second order partial differential equations.

由于壳体曲率的影响，使得壳体的弹性波动方程比平板的运动方程复杂得多，难以直接采用算子因式分解方法，将其化成二阶偏微分方程求解。

Diabetes is a social disease that affects several million people worldwide.

糖尿病是一个社会性疾病，全世界有数百万人罹患此病。

I'll call you on Friday to see if we can reschedule our luncheon meeting at your convenience.

我星期五会给您打电话在您方便的时候我们重新安排我们的午餐约会。