查询词典 boundary

However, the second associated Legendre function is too complicated to compute, so a simple and practical ellipsoidal harmonic series expansion is introduced, and the series solution and integral solution of the Dirichlet boundary value problem and the Neumann boundary value problem under ellipsoidal boundary are given.

鉴于展开式中第二类缔合勒让德函数的计算较为复杂，接着引入一种形式简单、实用的椭球谐级数展开，介绍了椭球界面下Dirichlet边值问题和Neumann边值问题的级数解和积分解。

FENG Kang, YU De-hao and some other scholars of our country are the first ones to create the natural boundary element method, and they have successfully studied the natural boundary reduction method for the boundary value problems of harmonic equation and biharmonic equation.

我国学者冯康、余德浩等首创自然边界元法，并已成功地研究了调和方程及双调和方程边值问题的自然边界归化方法。

In the numerical simulation, the Blasius equation of boundary layer based on the Chebyshev interpolation points was solved by using of the Runge utta method with variable step. On the basis of the coordinate transformation of the boundary condition, the Chebyshev spectral method was applied to solve the hydrodynamic stability equation of boundary layer.

在数值模拟中，采用变步长的Runge Kutta方法，求解基于Chebyshev插值点的边界层Blasius方程，然后对边界条件进行坐标变换，使Chebyshev谱方法适用于边界层稳定性方程的求解。

By analyzing the characteristics of the boundary pixels to formulate a boundary pixel extraction operator, the operator need only calculate up to 4 pixels neighborhood pixels, is efficient, fast, he can direct the use of binary images are extracted as the boundary pixel, are single-pixel wide border.

通过分析边界象素的特征，归纳出一个边界象素提取算子，该算子最多只需要计算象素的4邻域象素，运算量小，速度快，运用他能直接提取出二值图象的边界象素，得到单象素宽的边界。

Based on image statistical characteristic, the algorithm can search automatically the boundary start-point using Sobel operator and special template operation, then according to the connection status of every boundary point in its 8-connection neighbor field, seek automatically the search direction, form the whole data collection of a target boundary outline.

该算法依据目标图象特征，在二值图象中利用Sobel算子和特定的模板操作，自适应搜索边界起点；然后，按照每个边界点在其8邻域内的连通情况，自动寻找搜索方向，形成了完整目标边界轮廓数据集。

Subsequently, an intuitionistic definition of Complex boundary is given with Simplex boundary and then a capture method of it is offered too, thereby auto-capture of Complex boundary is achieved.

随后，本文利用单形边界给出了复形边界的直观性定义，提供了具体应用中复形边界的获取方法，从而可以对复形的边界进行自动获取。

Then the boundary element integral equation of interior and exterior form is deduced in detail, also the form with corner coefficient. The significance for numerical calculation and principle of the singular integral is analyzed, and a non-isoparametric transformation method is presented to calculate weak singular integral and Cauchy integral, the method presented provides us a very simple way to computer the two kinds of singular integral of Helmholtz boundary integral equation, and it is easy to program in computer. After the difficulty of the calculation for multi-frequency of Helmholtz boundary element is explained, a method named SECHIEF (Series Expansion Combined Helmholtz Integral Equation Formulation), which is focused on the computational efficiency, is presented.

对结构声辐射的边界积分方程的内部形式与外部形式进行了详细的推导，给出了角点系数的计算方法与边界积分方程的形式，在此基础上，分析了奇异积分产生的原理及其对数值计算的重要性，提出了一种计算奇异积分的非等参(来源：Ae8a8BC论文网www.abclunwen.com)单元的变换方法，该方法给Helmholtz 声学边界积分方程中的弱奇异积分与Cauchy 奇异积分的计算以及编程提供了极大便利。

Spectral element methods for partial differencial equation is introduced in this study from viewpoint of the collocation approximation of Chebyshev polynomial. Wave Equation and its space discretization are deduced. Two time integral methods, central difference method and implicit Newmark method, are introduced, and their stability and applicability are also discussed in some details. The significance of absorbing boundary conditions in spectral element methods for Aeroacoustics is explained, and Clayton-Engquist-Majda absorbing boundary conditions is emphasized and introduced, then the discrete scheme of this boundary conditions is deduced and applied to spectral element methods for wave equation.

本文从Chebyshev多项式逼近理论出发，详细介绍了谱元方法求解偏微分方程的过程；推导了流体中的声波动方程并在空间上对其进行了谱元离散；详细讨论了两种时间积分方法──中心差分法和Newmark方法，分析了它们的稳定性条件，并从理论上对比了两种方法的优缺点和适用范围；将吸收边界条件推广应用于谱元方法求解气动声学问题中，重点介绍了Clayton-Engquist-Majda吸收边界条件的原理和公式，推导了该吸收边界条件的变分形式，并将其引入波动方程的离散形式中。

The phase of optical wave can be recovered by the intensity transport equation under the paraxial approximation For the optical system with diffraction limit, it is difficult to get the boundary radical slope of phase and sample in the circular domain boundary when using the intensity transport equation to recover the phase, consequently, we reviewed an algorithm mentioned in the reference ［4］, namely, the equation, computation domain and boundary condition are changed, then the phase is reconstructed by the multigrid method and corrected at last Moreover, the experiment system is set to testify the algorithm, and the recovered phase from the intensity data detected by CCD is compared with the result from phase retrieval algorithm, it is found that the phase reconstruction error can reach 017 λ in the case of non-uniform intensity distribution, as a result, the method is suitable for the phase recovery with low wavefront sensing accuracy.

在傍轴近似条件下，可以利用光强传播方程对畸变波前进行相位恢复。对于衍射受限的光学系统，很难获得相位的边界径向斜率值作为边界条件，此外，要获得精确的圆域边界采样值也并非易事。为了克服上述困难，进一步研究了相位恢复改进方法，即改变了方程的表示形式、计算区域和边界条件，并用多重网格法进行求解获得重构相位，最后再将其修正。为了验证算法的精确性，搭建了实验系统对算法进行实验验证，将由CCD探测的光强分布进行计算得到的相位分布与相位恢复算法的结果进行比较，证明在光强分布非均匀的情况下，该方法恢复的相位均方根误差能够达到017 λ，可以适用于波前传感精度要求不是很高的相位恢复。标签自适应光学相位恢复相位修正光强传播方程 adaptive optics phase retrieval phase correction intensity transport equation

Through discussing further the reflective and refractive coefficients of line boundary, the features of line boundary are as follows: the attenuation of high frequency band (especially in band of line trap) of transient components generated by fault through line boundary is obvious, whereas the low frequency band (1~10kHz) components are hardly influenced. Moreover, the transient components below 100kHz should be adopted in purpose of outstanding the line boundary and weakening the transmission influence of transmission line.

通过对线路边界的透、反射系数的进一步分析发现：暂态信号的高频段穿越线路边界时将大为衰减，而低频段(1~10kHz)几乎不衰减；为弱化线路的传输影响而突出线路边界的作用，宜选用100kHz以下的信号分量。

This is not an ordinary box, which is used as a background picture of the dialog box, very pretty.

详细说明：这可不是一个一般的对话框，它是用图片作为背景的对话框，非常好看。

Conceal me what I am,and be my aid for such disguise as haply shall become the form of my intent.

遮掩我的身份，帮助我，我的面具将成为我的目的。