边界点

The result shows that the improved Snake Model can quickly converge the concavity region and the more complex region,and has decreased the dependence of the result of segmentation to the initial value and the influence of noise point to the boundary.

结果表明，改进的Snake模型能迅速地收敛到深凹陷区域和更复杂区域，且减弱了分割结果对初值的依赖性和噪声点对边界的影响。

And also relative techniques involved, such as primary component analysis technique and convex technique, are introduced. And based on this, our method of surface reconstruction is described in detail. Still a method of border connection is brought forward. Using our method surface reconstruction can be well finished.

对所用到的主成分分析技术、聚类分析技术、凸壳技术等做了详细的介绍，并在此基础上详细阐述了自己的算法，提出了一种新的边界缝合技术，较好的解决了散乱点曲面重建问题。

The PSE in the curve coordinate systems are solved by the numerical techniques developed efficiently in this paper. A normal transform is introduced, and there are enough much grids in the region between the critical layer and the wall, where the variation of the disturbance is the quickest. The finite-difference of governing equations with fourth-order accuracy in the normal direction is utilized in full regions including points close the wall, and is very important for accurately discreting equations.

对于曲线坐标系下的抛物化稳定性方程，文中发展了求解的高效数值方法：引进法向变换，使得在临界层与壁面之间的扰动量变化最快的区域有更多的法向网格点；导出包含边界邻域在内的完全四阶精度的法向有限差分格式，这对方程精确离散至关重要；采用全局法和局部法相结合的方法及其新的迭代公式，大大加速收敛并得到更精确的特征值。

The bending of rectangular plate is divided into the generalized statically determinate bending and the generalized statically indeterminate bending based on the analysis of the completeness of calculating condition at the corner point. The former can be solved directly by the equilibrium differential equation and the boundary conditions of four edges of the plate.

在分析角点求解条件完备性的基础上将矩形板弯曲划分为广义静定问题和广义超静定问题，广义静定弯曲可以由板的平衡微分方程及四边边界条件直接求解，广义超静定弯曲可以由叠加法求解。

The thesis can be divided into five parts as follows: First, the structural characteristics of finned-pipe evaporator are analyzed. After selecting suitable microelement controller, the heat-transfer and mass-transfer processes are analyzed for every microelement under the conditions of dryness, wetness and frostiness. Based on previous equations, some parameters of frostiness are confirmed and the frost-growing model is set up under frost condition. Some hypotheses are postulated and with the help of the equation of mass-conservation, energy-conservation and momentum-conservation, the evaporation model which fits in the dynamic simulation is built, which set a solid foundation for system simulation. Second, the starting and stopping behaviors under disturbed condition are analyzed and calculated by using the dynamic concentrative parameter model, which gives some advice to better prescribe refrigeration system and set theoretic foundation for carrying out automatic control of refrigeration system. Third, the normal running process is analyzed and calculated by means of rational matching theory, which gives some advice on how to better understand the parameter change under steady state and the affection of inlet-parameter on evaporator. Fourth, the simulation software with dynamic characteristic is designed, which can be applied to calculate thernio-parameter of cryogen, air humidity and frost thickness under different initial and boundary conditions, and to carry out dynamic simulation under conditions of dryness, wetness and frostiness, at the same time, to achieve detection and simulation at any stage from starting to stopping.

本文的主要内容如下：1对翅片管蒸发器结构特点进行分析，选取适当的微元控制体，就干、湿和霜工况下对每个微元分别进行传热传质分析，基于经验关系式确定霜的有关参数，对于霜工况下的霜生长建立模型，经适当假设，运用质量守恒、能量守恒和动量守恒方程建立适合动态仿真的蒸发器数学模型，为系统仿真奠定基础； 2对蒸发在大扰动下的开、停机过程，运用动态集中参数模型进行分析和计算，为更好地描述制冷系统运行的全过程奠定基础，同时也为制冷系统实现自动控制提供一定的理论基础； 3对蒸发器正常运行过程，运用动态分布参数和参数间定量耦合的观点来分析和计算，为更好地了解稳态工况下各点参数的变化情况及各入口参数对蒸发器动态特性的影响即蒸发器性能对各参数变化的敏感性； 4编写翅片管蒸发器动态特性仿真计算程序，可以计算不同边界条件和初始条件下的制冷剂热力参数、空气温湿度和霜厚度分布场，实现对翅片管蒸发器在干、湿和霜工况下的动态仿真。

According to the matrix presentation of NURBS curve, ordinary interpolating algorithm on cubic NURBS curve is shown.

根据NURBS曲线的矩阵表示，对常用的三次NURBS曲线进行插值计算，可以了解边界条件和型值点的参数化对插值曲线的影响。

Detail are introduced as following: transfering the LS equation to difference equation, setting the initial conditions for different shape explosive at different initiation way (point, line, plane, divergent or convergent); the dealing method of different edge conditions; how to draw the curve graph in two dimensional space or surface graph in three dimensional space with the calculated data.

本文提出了在三维直角坐标系中爆轰波传播LS方程离散化方法，建立了相应的差分方程，研究了对不同形状炸药在多种起爆形式（点、线、面、散心、聚心）下初值条件的设定，以及各种边界条件的处理方法。

Interpolation functions in the point interpolation method have delta function property, which is convenient to implement essential boundary conditions.

点插值方法的插值函数具有 Delta 函数性质，可以很方便的施加本质边界条件，但在计算插值函数时矩阵易出现奇异。

The created shape functions possess the properties of the Kronecker delta function, which allows easy imposition of essential boundary conditions.

而点插值法具有精确的函数拟合性质，且形函数具有Kroneckerdelta函数的特性，使得施加本质边界条件变得简单。

However, its accuracy is not much high in interpolation. On the other hand, interpolation functions in the point interpolation method have delta function property, and it is convenient to apply the essential boundary conditions.

而点插值方法的插值函数具有Delta函数性质，可以很方便的施加本质边界条件，不利之处是在计算插值函数时矩阵易于奇异。

By the time of its fall, most of the prisoners were writers who had written against the corruptions of the government.

到它被攻陷的时候，里面多数的犯人是写了反对政府贪污文章的作家。

The most obvious variation to ovum morphological character was that the color was changed from light green to sepiaceous in embryonic development, and all the ovums were almost hatched after 96h.

在胚胎发育过程中卵的形态特征最明显的变化是颜色从淡绿到深褐色，卵在发育96h后卵基本全部孵化。