平面曲线

Though the analysis of the convexity of the front surface, this paper gained some terse and practical results.We can control the shape of developable surface through adjusting corresponding plane curves.

本文通过对上述两种可展B样条曲面进行保凸分析，得到了一些简洁，适用的结论：只要调整相应平面曲线，就能控制可展面的形状。

A plane curve everywhere equidistant from a given fixed point, the center.

圆，圆形从定点等距离到任一点的平面曲线

A helicoidal surface in Minkowski 3-space is defined as the orbit of a plane curve under a screw motion.

三维Minkowski空间中的螺旋面是一条平面曲线经由螺旋运动所生成的曲面。

In the paper, on the basis of aggregation of previous studies, the development of optical technology and development trends at home and abroad are introduced, the principle of Fresnel lens is summarized. In accordance with its principle, circle equidistant steps Fresnel lens design is described. And on this basis, based on Fresnel design, also based on a continuous upward spiral of the plane curve concept, incidence surface and the backlight is set up to greet Archimedes - Fresnel lens design formula and the Second parabolic type Fresnel lens design formula, and on this basis, the advantages and disadvantages of the three designs is discussed.

本文在充分了解非球面光学技术在国内外的发展状况和趋势的基础上，同时从菲涅尔透镜的光学原理出发，并根据它的工作原理推导了圆环等距菲涅尔透镜的设计步骤，并在此基础上依据菲涅尔的设计思想，同时依据平面曲线的连续又呈螺旋的构思，推导出了迎光面和背光面阿基米德型菲涅尔透镜的设计公式和二次抛物面型菲涅尔透镜的设计公式，并在此基础上讨论了这三种设计各自的优缺点。

The question of searching characteristic points or straight lines on moving rigid body is decomposed into two relatively independent sub-questions. The first one is to evaluate the characteristic of points and straight lines on moving rigid body, whose mathematics model is a kind of special non-differential max-mini optimal problem with inequality constraints. By the method of Saddle-point Programming and maximum entropy, the problem can be transformed as a differential optimal problem with single objective. The second oner is to search approximative character points or straight lines on moving rigid body within design space, whose mathematic model is nonlinear and non-differential problem with multiple constraints.

本文将在运动刚体上寻找特征点或直线的优化问题分解为两个相对独立的子问题，一是对运动刚体上点或直线的特征性评定，其实质是平面曲线的圆度或直线度的评定问题，优化模型是以最大误差为最小作为优化目标的约束不可微的优化问题，本文采用鞍点规划和极大熵方法，将其转化为单目标可微优化模型；二是在设计空间内，寻找运动刚体上特征性评定指标最小的近似特征点或直线，其优化模型是非线性、多约束的不可微优化问题，本文提出用遗传算法和BFGS局部搜索法相结合来求解。

Consider a plane curve with parametric equation.

设平面曲线的参数方程为，则曲率为

We shall give some computational results to illustrate the properties of the weighted curvature flow when ω is a nonnegative piecewise smooth weight function.

紧接著，我们将探讨当加权函数是一非全平滑的函数时，该加权的曲度流程对於平面曲线的作用。同时，我们将尝试透过电脑模拟该加权曲度流程对於影像的变化。

The shape classification and recognition of planar curve plays an important role in computer vision.

在计算机视觉中，平面曲线的形状分类和识别具有重要的意义。

Please tell me what the plane curve means.

请告诉我这条平面曲线是什么意思。

This is a plane curve .

这是一条平面曲线。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了