几何基础

The lighting calculation of light guide is a complex problem, which is always based upon the geometric optics.

导光管照明计算是一个十分复杂的问题，国内外已有的导光管照明计算多建立在几何光学的基础上。

The author put forth the H function,which is capable of measuring the distributive characteristics of a two dimension discrete point set in a square,and derives its analytical expression theoretically based on geometric probability.

作者以几何概率为理论基础，提出测度正方形区域内2维离散点集分布特征的H函数并推导其解析表达式，运用H函数设计和实现了集聚型2维离散点集结构信息提取的通用算法。

This generator interacts directly with the geometric representation through geometric interrogation only and is capable of generating meshes with controlled gradations in arbitrary domains.

因此，本文在分析和比较当今一些流行的网格自动生成方法的基础上，针对自适应有限元分析的特点，基于叉树法研制了先进的完全面向几何特征的全自动自适应网格生成器。

First, geometric theory basis of nonlinear control is introduced.

本文首先介绍了非线性控制的几何理论基础。

This paper presents a 3D complex geological entity modeling method based on line-frame model, designed to accurately express the spatial geometrical shape of every element of a complex geological entity and their mutual relationship.

提出了一种基于线框架模型的复杂地质体三维建模方法，在准确表达复杂地质体各要素空间几何形态与相互关系的基础上，实现地层交错情况下断层面、地层面模型及复杂地质体模型的准确快速构建。

These three laws form the basis of what is called geometrical optics .

这三条定律构成了所谓几何光学的基础。

Conventional X ray radiography is based on absorption contrast and assumes geometrical optics.

常规X射线成象技术是建立在吸收衬度和几何光学基础上。

Compared with traditional DEM or TIN based methods, this pure vector approach obtains not only the topological structure of drainage system in planar graph, but also the valley distribution polygon range. Depending on geometrical computation and judgment of vector line, polygon, the structured properties in drainage representation is enhanced, avoiding the case of noise disturbance in DEM based method. The core algorithm makes use of the ability of Delaunay triangulation in detecting hierarchical structure of each contour line.

中文摘要：基于Delaunay三角网模型在矢量等高线基础上通过弯曲特征分析，给出了一种地形结构特征提取及谷地树组织的方法，与传统的基于DEM或TIN数据结构提取地形特征的方法相比，该方法不仅得到了谷地系统在平面图上的拓扑结构，还获得了河谷在空间分布上的汇水范围，依托矢量线、多边形的几何关系判断，增强了谷地树组织中的结构化，避免了DEM方法中的噪音干扰，方法的核心是Delaunay三角网在单根等高线弯曲深度表达上的层次结构识别。

MM is developed from set theory and integral geometry, and is widely used in geometrical analysis and description.

MM是一门建立在集论基础之上的学科，它是几何形态分析和描述的有力工具。

Based on relative references and experimental data,these kinds of geometrical effects were analysed and discussed.

本文在分析有关文献和实验基础上，分析探讨了这几类几何效应。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。