查询词典 Poisson

In order to test and verify validity of analytical methods and codes, we solve the Poisson equations and the Helmholtz equations that have analytical solutions with complex geometry using spectral element methods.

作为验证分析方法的正确性和代码的有效性，本文使用谱元方法求解了有精确解的简单区域和复杂区域的 Poisson方程和 HellnholtZ方程。

The paper aimed at resolving the question of side value of Laplace equation and Poisson equation in plane angular domain by using integral equation of the solution of mathematic physics equation.

旨在利用数学物理方程解的积分公式，去解决平面角形区域内Laplace方程和Poisson方程的边值问题，而其关键在于构造相应域内的格林函数。

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。

The response variable is fitted with Poisson and negative binomial distributions,and the coefficient is estimated with IGLS.

分布函数采用Poisson分布和负二项分布，参数估计为迭代广义最小二乘法。

The relationship between the negative binomial distribution and the time-dependent Poisson distribution was further discussed.

并进一步阐明了负二项分布与时依Poisson分布的关系。

In this paper, we expand the eigenvalue of Poisson equation using nonconforrn-ing Q1rot element. The principal term of error we get is not negative. In general, the approximate eigenvalue is the upper bound, but the approximate eigenvalue may be the lower bound when the principal term is zero.

本论文对Poisson方程的特征值采用方形旋转双线性非协调元Q_1~(rot元进行展开，得出的误差主项大于或等于零，因此在一般情况下近似特征值是上界，但当主项等于零时近似特征值可能是下界。

In this paper, a Green quasi-function is firstly set up by using the basic solution of Poisson's equation.

利用Poisson方程的基本解构造一个准格林函数，这个函数满足Poisson方程的齐次边界条件。

And based on the theory of Poisson point process, a calculation model of synthetic risk rate is given.

提出了防洪风险分析中一个Poisson标值点过程模型，并运用Poisson点过程理论，给出了综合风险率的计算模型。

The major implementations of the developed model include: Pseudo-spectral and finite-difference schemes are employed to approximate the spatial-differential operators in the horizontal and vertical directions, respectively. A second-order Runge-Kutta method is adopted to integrate in time for the velocity field and the free-surface elevation. The solenoidal condition of the velocity field is satisfied by solving the transformed pressure Poisson equation. A modified secant method is used to accelerate the iterative solution of the non-separable Poisson equation.

模式的主要数值方法包括：分别以拟频谱法以及二阶有限差分法近似控制方程与边界条件中的水平与垂直导数；以二阶Runge-Kutta法进行非稳态的自由液面位移与流场速度的时间积分；利用改良式割线叠代法求解计算区间中不可分离的压力Poisson方程式，以满足不可压缩流条件。

We addressed the solutions of the collision-less plasma Vlasov-Poisson system, involving Vlasov equation coupled with Poison equation, in quasi-neutral limit. The two asymptotic-preserving particle-in-cell methods were developed and applied to a model of one-dimensional, periodic perturbation plasma.

针对准中性无碰撞等离子体的Vlasov方程及与其相耦合的求解电势的Poisson方程所组成的Vlasov-Poisson系统，提出了两种渐近保持PIC算法，并将其运用到一维周期性波动等离子体模型上。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。