变分法

We must seek two main approximation method s of solution, the variation method and perturbation theory

我们必须寻求两个主要的近似解法、变分法和微扰法。

In classical calculus of variations, functional minimum problem is often transformed into boundary-value problem of differential equations.

已有的求解方法中，无论是变分法，还是直接法，求解过程都必须离线进行。

This minimum is computed with the calculus of variations and the gradient descent method, which provide a system of evolution equations solved with the well-known level set method.

能量泛函的极小值由变分法求解，利用梯度下降法和水平集方法推倒演化方程。

The performance function and constraint equation in calculus of variations were constructed by analyzing input and output equations of the system containing parameters to be estimated. The traditional parameter estimation problem could be transformed to that of least squares estimation.

通过分析包含待估参数的系统输入输出方程，构造变分法中的性能范函和约束方程，将传统的参数估计问题化为带约束条件的最小二乘估计问题；利用拉格朗日乘子法，分析参数估计方程，得到参数的最优估计。

So the effect and the efficiency of the shape optimization are guaranteed. If using sensitivity analysis which is based on the calculus of variations in the shape optimization, the sensitivity analysis can be a relatively independent module. The efficiency of computing the design velocity field and the quality of mesh will be improved by using Herrmann method.

在形状优化过程中，采用基于变分法的敏度分析，可以使敏度分析成为单独模块，在进行设计速度场求解时采用Herrmann法，使速度场求解的效率和优化过程的质量得到保证。

The aim of this paper is to study the existence of solution and multiply results for quasilinear elliptic system in bounded domain and the whole space, semilinear elliptic equation in two dimension space, second order nonlinear difference equation by variational methods. The main results are listed in the following:1. An abstract compactness theorem is proved, and then, under weak Boccardo and De.

本文主要利用变分法，分别研究了有界区域和全空间上拟线性椭圆型方程组、二维空间上半线性椭圆型方程和二阶非线性差分方程问题的解与多重解的存在性，具体内容如下： 1。

The non-relativistic energies and wave functions were determined by Rayleigh-Ritz method. The relativistic effects, including the correction to kinetic energy, the electron-electron contact term, and the orbit-orbit interaction, Darwin term, and mass-polarization effect on the energies were calculated by using first-order perturbation theory. In order to obtain a more accurate result for the larger Z system, the quantum-electrodynamics correction should be included. This correction to energy can be evaluated for the valence electron by using a hydrogenic formula with an effective nuclear charge, Z. The ionization potential, the excitation energies and the fine structure split-tings for a lithium-like ion with higher nuclear charge (Z=26) were calculated.

非相对论能量用Rayleigh-Ritz变分法确定，包括动能修正、电子—电子接触项、轨道—轨道相互作用项以及Darwin项的相对论修正和质量极化项由全实加关联波函数的一阶微扰给出，量子电动力学修正由有效核电荷方法和类氢公式计算；给出了较高核电荷(Z=26)类锂体系1s^2nl组态的电离能、激发能和1s^2np组态的精细结构劈裂。

Finally, For the first time, the Ritz variational based mode matching method using new basis functions is proposed to deal with a discontinuity region. The general process to construct the linear equation group is developed, and the equation group's rank is only half of that of the cascading treatment. Thus the efficiency can be increased.

还首次采用新型基函数并利用里兹变分法和模式匹配法提出了构造处理一段不连续性问题的线性方程组的一般理论，方程阶数可比常规的级联处理方法降低一倍，可提高计算效率。

The exchange energy for the electron transfer process at large internuclear distance may be calculated using either perturbation or variational method.

中文摘要与电子传递相关的远程交换能可用微扰法或变分法计算。

This subject combines the basic principle of the calculus of variation and and reply and change basic theories of the function according to fracture mechanics, use mechanics, mathematics knowledge to set up corresponding mathematical model, derive out a series of mechanics and mathematics theory formula, work out procedure carry on number value calculate, to include edge crackle round stress intensity factor of component go on, ask, solve.

本课题结合变分法的基本原理并根据断裂力学和复变函数的基本理论，运用力学、数学知识建立相应的数学模型，推导出一系列的力学及数学理论公式，编制程序进行数值计算，对含边缘裂纹圆形构件的应力强度因子进行求解。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。