查询词典 difference boundary value problem

The main problems researched in the dissertation and achievements are as follows: The dissertation explains the science background and the theoretical and actual meaning of the task. The progress and the problems of the flow imaging technique are briefly explained. The advantages of electrical capacitance tomography are discussed. The paper discusses the formation and operating principle of ECT, and builds up the definite mathematical model by detail theoretical analyse, and establishes the Finite Element Model of the system by changing the finite boundary value problem of ECT into equivalence variation problem according to variation principle. On the basis of the FEM of the system, the paper builds the finite element model of the capacitance sensitivity field distribution and programs its finite element simulation software and proves the validity of the FEM of the ECT from different aspects. With the FEM and the qualitative analyse of the effect of each structural parameter of the capacitance transducer on its capability, this paper optimizes the structural parameters of the capacitance transducer, and obviously improves its capability. The compare of the simulated result with the static experimental result shows that the error of them is less than 0.9%.

其主要研究内容包括：阐述课题研究的学术背景及其理论与实际意义，概括总结出流动层析成像技术的发展现状和存在的问题，指出电容层析成像技术的优点；讨论电容层析成像系统的组成及工作原理，进行详尽的理论分析，以变分原理为基础，将ECT的有限元边值问题转换为等价的变分问题，从而建立系统的有限元模型；在系统有限元模型的基础上，建立敏感场的数学模型，编制有限元的仿真软件，并从不同角度证明电容层析成像系统有限元模型的正确性；利用有限元模型，定性地分析电容传感器各结构参数对其性能的影响，并对传感器结构参数进行优化设计，使其性能得到明显的改善。8电极ECT系统的仿真和静态实验结果的比较表明，它们之间的相对误差小于0。

The method ofsolution for linear discrete Hilbert boundary value problem on the unit circleis illustrated and it is proved that,in case of the index〓,the solutionsof the discrete Hilbert problems are stongly convergent to the solution of theoriginal problem.

我们给出了单位圆上线性离散Hilbert边值问题的解法，并且证明了当问题的指标k=0时离散Hilbert边值问题的解强收敛于原Hilbert边值问题的解。

The key problem of the reaction chromatography is the initial-boundary value problem for hyperbolic conservation laws systems.

反应色谱的核心问题是双曲守恒律的初边值问题。

Based on the Maxwell\'s equations, the boundary value problem, variation problem, interpolation function and stiffness matrix in two-dimensional magnetotelluric are derived.

从麦克斯韦方程组出发，推导出二维大地电磁测深的边值问题、变分问题、有限单元法的插值函数以及单元刚度矩阵。

Firstly, the eigenvalue problem of a class of second order elliptic equation with critical potential and indefinite weights is considered. Then, using critical point theory, Trudinger-Moser inequality and the properties of the first eigenvalue, we prove the existence of a nontrivial solution for a class of nonlinear elliptic with critical potentialand indefinite weights in R~2. Secondly, we prove the existence of nontrivial solutions for a class of subcritical and critical elliptic systems with indefinite part in R~2 byusing a generalized linking theorem, Trudinger-Moser inequality and concentration-compactness principle.5. The existence of at least three weak solutions for discrete boundary value problem is established by using a three critical point theorem introduced by Ricceri.

首先，讨论了R~2中一类带不定权且含临界位势的二阶椭圆型方程的特征值问题，并借此特征值问题的第一特征值性质，利用山路引理及Trudinger-Moser不等式，证明了R~2中一类带不定权且含临界位势的非线性椭圆型方程非平凡解的存在性；其次，利用广义环绕定理，Trudinger-Moser不等式及集中列紧原理，得到了R~2上一类具有强不定部分的半线性椭圆型方程组在非线性项分别为次临界增长和临界增长情形下非平凡解的存在性。

At the beginning of fourth chapter, the article transforms the solving problem of partial differential equation for the American put price into a standard initial and boundary value problem of Parabolic Type by making some transformations.

在第四章，对美式看跌期权价格所满足的偏微分方程定解问题通过作一系列变换，使之转化为一个标准的抛物型初、边值问题，接着又通过傅里叶变换，把抛物型初、边值问题转换为一个关于时间变量的常微分方程初值问题，然后再分别利用改进的欧拉法和有限元法对其进行了求解。

Based on Pontryagin maximum principle,the lunar soft landing problem is transformed into a two-point boundary value problem in mathematics.

首先，从庞德里亚金极大值原理出发，将有限推力作用下月球软着陆问题转化为数学上的两点边值问题；在考虑边界条件及横截条件的前提下，将该两点边值问题转化为针对共轭变量初值和末时刻的优化问题；然后应用非线性规划方法求解所形成的参数优化问题。

Firstly the dimensionless planar motion model of SGKW was established;then the optimal control problem of shortest time coplanar hit orbit was transformed into two-point boundary value problem by means of Pontryagin maximum principle .

首先建立了SGKW的无量纲化平面运动模型，然后利用庞特里亚金极大值原理将时间最短共面打击轨道的最优控制问题转化为两点边值问题。

According to the requirement of a minimum-fuel-consumption, a method of coplanar hit orbit optimization design for SGKW was studied. The dimensionless planar motion model of SGKW was founded, and the optimal control problem of minimum-fuel-consumption coplanar hit orbit was derived into two-point-boundary-value problem according to Pontryagin maximum principle.

针对燃料最省要求，研究了SGKW共面打击轨道优化设计方法，建立了SGKW的无量纲化平面运动模型，利用庞特里亚金极大值原理将燃料最省共面打击轨道的最优控制问题转化为两点边值问题。

This article investigates the two-point boundary value problem to a coupled system of nonlinear fractional differential equations. By applying growth conditions on the nonlinear terms, we obtain an existence result of solutions. Our analysis relies on the Schauder fixed-point theorem and the reduction of the considered problem to the equivalent coupled system of integral equations.

本文讨论非线性分数阶微分方程耦合系统的两点边值问题，应用Green函数，将其转化为等价的积分方程耦合系统，并设非线性项在无穷远处有增长条件，应用Schauder不动点定理证明解而非限于正解的存在性。

Chimborazo and Cotopaxi, took me by the hand.

越过琴博腊索山和科托帕克西山。

This car is in a good condition.

这辆车的状况很好。