查询词典 second boundary condition

The research achievement are acquired as follows: 1From mathematical models for inverse scattering in two dimensional homogenous media including Dirichlet, Neumann, Robin,all kinds of probable mixed boundaries and cracks, direct and inverse scattering are discussed, and ill-posed integral equation and indicator function method are formulated for the diverse of boundary identification. It is shown that the kernel of the integral equation characters the boundary of scatterer, which is determined by solving it by virtual of regularity method, meanwhile, some numerical tests are given.

本研究取得了如下研究成果： 1）在二维均匀介质逆散射各种边界识别的数学模型（包括Dirichlet，Neumann，Robin，各种可能的混合边界问题，裂纹问题）下，分别考虑了正散射问题和逆散射问题，推导了上述各种边界识别的不适定积分方程以及指示函数方法，由于积分方程的核充分表征了散射物的边界，由此说明只要利用正则化方法求解该积分方程，就可以确定散射物的边界，并给出了一些数值实验。

A boundary integral formulation describing constant-αforce-free field with finite energycontent in the semi-infinite space above the sun was proposed(Yan,1995), this formulationcontains boundary field and its normal gradient under integral sign.

颜毅华1995年在太阳物理杂志上发表一文，就太阳磁场提出了一个具有有限能量的线性无力场模型，并对磁场给出了一个边界积分表示公式，该公式用边界上的已知磁场值和未知的磁场法向导数值来确定空间任意点的磁场值。

Firstly, by using the vector integral theory and boundary conditions of the electromagnetic filed, the boundary problem of two electromagnetic fields in the upper half space and lower half space is transformed into two vector integral equations just related to the topography interface, i.e.

提出了一种用边界元法计算频率域人工源三维地形电磁场的数值模拟方法。

It has been solved to deal with the boundary when using interpolation function method to evaluate boundary value problem.

解决了插值函数法的边界（以及求解区域内不同介质间分界线）处理问题，其结果已得到实际计算的验证。

Special attention should be paid when we apply the decomposition method to two-point boundary value problems, it is necessary to solve a algebraic system;It should be noted that a modification of inverse operator should be made when dealing with singular boundary value problems;Laplace transform and Pade approximants can be coupled to enhance the efficiency of the decomposition method.

比如，在求解两点边值问题时就需要特别注意，这时需要采用待定系数法，最后会涉及到系数方程组的求解；在处理奇异边值问题时需要重新定义逆运算；不少研究人员还把分解方法与Laplace变换和Padé逼近相结合来进一步提高分解方法的精度。

In the present work,the existence and uniqueness results aboutperiodic boundary value problems for different kinds of the nonlin-ear periodically perturbed nonconservative systems are establishedthrough the discretization technique,under suitable assumptions,by using global inverse function theorem and result about the ex-istence and uniqueness of periodic solution for nonhomogeneouslyfirst order linear periodic boundary value problem.

本文的第一章概述了在讨论原问题解的存在唯一性过程中以及构造和分析相关的数值求解方法时将要用到的全局反函数定理、有关矩阵特征值的若干重要引理、线性常微分方程非齐次周期问题解的存在唯一性定理和单参数影射方法及有关结论，并简单回顾了已有的证明非线性微分方程周期边值问题解的存在唯一性的方法，其中包括谱理论、最大最小化形式方法、摄动技术和全局反函数理论方法，最后，介绍了两类数值求解非线性微分方程问题的方法。

Then, the methods used for elastic mixed boundary problems, and the inverse integral transformation method may be employed to solve viscoelastic mixed boundary problems in time domain.

结合在求解粘弹性边值问题中的应用，对各类方法的特点进行了评述，并指出存在的问题及发展新的数值方法的研究重点。

The present method is applied to two-dimensional potential problems and the corresponding discrete equations are derived. Because the shape functions so-obtained possess the Kronecker delta property, the essential boundary conditions can be enforced as the FEM; furthermore, the Heaviside step function is used as the test function, there is no domain integral, and only a regular boundary integral is involved.

因为滑动Kriging插值方法构造的形函数满足Kronecker函数性质，所以本文建立的改进的无网格局部Petrov-Galerkin法可以像有限元法一样直接施加边界条件；由于采用Heaviside分段函数作为局部弱形式的权函数，因此在计算刚度矩阵时只涉及边界积分，而没有区域积分。

By coupling the moving least squares approximation with a modified functional, the Hybrid Boundary Node Method is a boundary-only, truly meshless method.

中文摘要：杂交边界点方法是一种纯边界类型的无网格方法，它将修正泛函和移动最小二乘近似结合。

Then, the boundary points are extracted. By using Shu's theorems the sum of Legendre polynomial of the boundary points is calculated.

首先使用Yang-离散格林公式将二值图像矩计算中区域内求和转换为沿区域边界求和；然后提取该图像的边界点；再利用Shu提出的公式计算出边界点的Legendre多项式的叠加值。

Aquatic or marsh-growing fern allies; known to have existed since the Cenozoic; sometimes included in Lycopodiales.

生活于水中或湿地的蕨类；从新生代生存至今；有时归于石松目之中。

The engine was uprated from a 90hp Franklin to a 125hp Lycoming.

改良过的引擎是从90hp到125hp莱康明富兰克林。