查询词典 boundary point

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。

By using the theorem on cone expansion and compression and a fixed point theorem on cone,this paper is concerned with the existence of positive solutions for some boundary value problem of singular nonliear semipositive second-order three-point boundary value problem,which improve many known results.

运用锥拉伸与压缩不动点定理研究非线性奇异半正二阶三点边值问题正解的存在性，推广了一些已知的结果。

In chapter 4, we first discussed the existence of multiple positive solutions of the second order nonsingular Dirichlet boundary value problem for impulsive differential equations by using the fixed point index theorem in cones . Next, we presented some new existence results for singular boundary value problems for second order impulsive differential equations by using fixed point theorem in cones and Leray-Schauder nonlinear alternative theorem.

第四章我们首先利用锥不动点定理讨论了非奇异二阶脉冲微分方程狄利克莱边值问题多个正解的存在性；其次我们用锥不动点定理和Leray-Schauder型非线性抉择定理，讨论了奇异二阶脉冲微分方程狄利克莱边值问题一个及多个正解的存在性。

Based on Pontryagin maximum principle, the lunar soft landing problem is transformed into a two-point boundary value problem in mathematics. In consideration of the bound condition and transversality condition, the resulted two-point boundary value problem is converted into a parameter optimization problem aiming at the initial values of conjugate variables and the terminal time, then it is solved by the nonlinear programming.

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。

The surface of conventional engineering part is composed of simple analytical surfaces and four-boundary ruled surface primarily. Therefore a point cloud segmentation method based on those feature surfaces is proposed. Several algorithms to identify the simple analytical surface feature are investigated and discussed. The theory of fitting scattered point to B－Spline and Bézier surfaces is introduced and a fitting method based on four boundary and point set is also discussed. Moreover, anew method to recover the fix-radius rolling ball blend is proposed and discussed in detail.

常规工程零件的外表面中包含了大量的特征曲面，如简单解析曲面和四边直纹面，因此，本文提出基于特征曲面的的点云分割方法，研究几种识别简单解析曲面的算法；研究由点云拟合B－Spline和Bézier曲线的理论基础，总结曲面拟合的几种方法，提出一种反求定半径滚球圆角的方法。

The CNE-AR model coefficients are invariant to translation, rotation, scale and choice of the starting point in tracing a boundary, in which both linear and nonlinear features of the shape boundary are taken into account, and the intrinsic characteristics of the shape boundary are further depicted.

CNE-AR模型系数具有平移、旋转、比例和轮廓跟踪起始点选择不变性，兼顾了图形轮廓中的线性与非线性特征，深刻反映了图形轮廓的本质特性。

Coordinate sequence method is made up of the instruct information of polygon boundary x, y coordinate. It is the easiest polygon vector encoding method. The file structure of this method is easy, but because of the polygon boundary has stored two times, it will produce data redundancy, moreover, short of neighbor threshold information; Tree index encoding method make all the boundary points digitizing, store the coordinate sequence, connect the point index to boundary line, and then connect the line index to other polygons, so as to the tree index structure has came into being. It eliminates neighbor polygons boundary data redundancy problems; Topology structure encoding method is a method which by setting up a complete topology relationship structure, resolve the neighbor threshold and island information process problem. However, it makes arithmetic more complicated and makes database bigger.

坐标序列法是由多边形边界的x，y坐标对集合及说明信息组成，是最简单的一种多边形矢量编码法，文件结构简单，但多边形边界被存储两次产生数据冗余，而且缺少邻域信息；树状索引编码法是将所有边界点进行数字化，顺序存储坐标对，由点索引与边界线号相联系，以线索引与各多边形相联系，形成树状索引结构，消除了相邻多边形边界数据冗余问题；拓扑结构编码法是通过建立一个完整的拓扑关系结构，彻底解决邻域和岛状信息处理问题的方法，但增加了算法的复杂性和数据库的大小。

A simplified model was proposed to simulate material microstructure according that metal solidification is a Monte Carlo process. First, use the point of"putting randomly, growing uniformly"to generate grain boundary, then recognize grain boundary trifurcate points, eliminate bad trifurcate points, and distinguish the connections among these points, thus obtain straight grain boundary picture.

根据金属凝固过程是—Monte Carlo过程，建立了金属材料显微组织的简化Monte Carlo方法，采用&随机投放，等速生长&的方法形成矩齿形晶界图，并通过逐点判断法识别出晶界三重点，剔除奇异三重点，并识别出晶界及晶界间相邻关系，从而获得晶界结构的直线近似形态图，为细观组织短裂纹的数值模拟作好准备。

With that point in mind we review here some advances in the classical boundary layer, multilayer boundary layer, interacting boundary layer and diffusion parabolized NS equations theories and corresponding algorithms and applications.

以此为线索，简要评述经典边界层、多层边界层、干扰边界层、扩散抛物化 NS方程诸理论、相应算法和应用的若干研究进展；诸理论之间以及他们与实验的关系；简化湍流计算的一点注释以及物理分析和数值模拟相结合的一些问题。

M-point boundary value problem; momotone iterative; equation system; impulsive differential-integro equation; three-point boundary value problem; positive solution; Fixed point; Cone

基础科学，数学，数学分析m点边值问题；单调迭代；方程组；脉冲微积分方程；三点边值问题；正解；不动点；锥

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。