查询词典 second boundary value problem

This thesis contributed to the comprehensive study of the Finite-Difference Time-Domain method and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies. The work includes mainly three parts: the study on the performance of PML absorbing boundary condition applied to pseudo low frequency electromagnetic problems; the validation of the FDTD method with PML absorbing boundary conditions and the corresponding computer software based on the numerical study of the electromagnetic field of an electric dipole antenna, and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies; the development of an improved alternating direction implicit finite-difference time-domain method.

在综合前人工作基础上，本文对时域有限差分法及其在开关电源辐射电磁场数值计算中的应用进行了系统的分析和研究，其核心内容包括：伪低频电磁场数值计算中PML吸收边界条件性能的研究；基于基准问题—电偶极子天线三维辐射电磁场，验证了本文构造的基于PML吸收边界条件的三维FDTD法及其计算软件，并应用于高频开关电源辐射电磁场的数值分析；提出了一种改进的交替方向隐格式时域有限差分法。

An adaptive grid scheme controlling cell area is used to generated grids in the divergent section of symmetric annular nozzle, and the generated grids are used in the flowfield calculation through the uncoupled way. The elliptic equations are used to generate grids in three dimensional regions of FDN divergent section, the source terms used in the equations employ a mathematical form which is independent of the boundary shape and of the boundary grid point distribution, the free parameters contained in the source terms are determined by the two restraint conditions, the intersection angle of transverse grid lines with boundaries and the local curvature of the transverse grid lines at the boundaries, and the interior grid distribution controlled directly by the grid point distribution assigned on the boundaries is realized, it makes the grid more clustering near the nozzle wall. For the generated grids in the whole computational regions have a good smoothness and orthogonality, the accuracy of calculation in the flowfield is ensured.

对轴对称的环形喷管采用控制网格面积的自适应网格方法对扩散段部分进行了网格生成，并通过非耦合方式应用于喷管的流场计算中；对强制偏流喷管扩散段内的三维区域采用椭圆型方程进行网格生成，方程中的源项采用了与边界形状和边界网格点分布无关的数学形式，源项内的自由参数由横向网格线与边界的交角及横向网格线在边界处的局部曲率两个约束条件来确定，实现了由边界上的网格分布直接控制内部的网格点，使壁面附近具有较密集的网格，并且在整个计算区域内的网格都具有良好的光滑性和正交性，从而保证了流场计算的准确性。

In region of columnar grain, preferred orientation growth is obvious. Obviously preferred orientation on 〈001〉 was confirmed by the antipole figure. Besides, the CSL grain boundary such as ∑3,∑5 and so on are observed. Among these kinds of boundaries, the ∑3 boundary has the highest frequency.

测试结果表明：CVDW生长组织具有三个生长区，分别是等轴晶区、混合生长晶区和柱状晶区；柱状晶区的晶粒具有显著的〈001〉择优生长；低∑CSL晶界占据较大比例，其中以∑3、∑5为主要结构，∑3的出现频率最大。

The concentration of D-phenylalanine in the external phase and the separation factorαcan be expressed as: The diffusion of boundary layer in outer aqueous phase is the controlled process while the concentration of D-phenylalanine in the external phase far less than the concentration of chiral carrier in the emulsion liquid membrane phase, then the diffusion coefficient k_e of boundary layer in outer aqueous phase can be achieved by data fitting.

外水相苯丙氨酸对映体的浓度以及分离因子α表示为：当外相对映体浓度远小于液膜相手性载体浓度时，该手性传质过程中外相边界层的扩散为控制步骤，利用数据拟合得到了外水相与液膜相界面边界层扩散的传质系数k_e。

In this paper the defect of the traditionary boundary layer methods (including the method of matched asymptotic expansions and the method of Visik-Lyusternik) is noted, from those methods we cannot construct the asymptotic expansion of boundary layer term really.

本文指出传统的边界层方法包括匹配法和Vi(？ik—Lyusternik方法的不足：不能作出边界层项的渐近展开式。提出多重尺度构造边界层项的方法，得到符合实情的结果。

In this thesis, we provide a simpler form of the axisymmetric boundary integral equation, and modify some aspects of the direct boundary integral method.

本论文给出了轴对称情形下边界积分方程的一个更简单的形式，并在若干方面改进了直接的边界积分算法。

Plate collision boundary, discrete boundary, transform faults and adjacent sea are sorted in this paper. The M8.3 Azov earthquakes, Nov.

本文划分了板块碰撞边界、离散边界、转换断层和陆缘海4种类型。

On the base of Lord Kelvin point-source solution, the integral of Bessel function, Poisson superimpose formula and boundary element method, we resolve it and obtain the boundary element basic solution.

受求解方法局限性的限制，目前经典渗流力学理论还无法精确求解复杂外边界油藏中生产井层部分射孔问题。

In Part I, the biharmonic equation are chosen, and the boundary peanlty finite method using piecewise cubic Hermite elements is used to seek their approximate solutions, in particular satisfying the derivative and periodical boundary conditions.

在第一部份里，选择使用片断三次 Hermite元素的边界惩型有限元素法来求解满足边界导数条件和边界周期条件的重调和方程式的近似解。

The theory of complex variable function for anisotropy plate combined with boundary collocation method is applied to calculation pin-loads and contact region as well as the contact stress on the hole boundary.

采用各向异性板的复变函数理论和边界配置方法，对连接件进行分区，加以限制条件，对多钉连接的复合材料层合板的钉载和板与螺栓间的接触应力和接触区域进行了计算。

We have something to do in the new stage.

在这段崭新的时期中，我们有一些要做的。

The difference between tourism decision-making under uncertainty and risky tourism decision-making is indistinctive.

其中不确定性旅游决策和风险旅游决策的界线比较模糊，两者的区分是相对的。