查询词典 curvature of curve

By means of uniting geometry with algebra, the arc length, tangent line, cotangent space and curvature of curve in four dimensional space are investigated, and the corresponding calculation formula in each cases are given.

用形数结合的观点研究了四维空间中曲线的弧长、切线、法空间和曲率问题，并给出了其计算公式。

Curve C at the spot P(x0, y0) curvature is the maximal circle of the curve C tangency at the spot P(x0, y0). Contrail curve G of the center D of curvature circle entitles evolute of curve C.

曲线C在点Px0，y0）曲率圆是与该曲线C相切于点P(x0，y0的最大圆，曲率圆的圆心D的轨迹曲线G称为曲线C的渐屈线。

In order to study the popular curve shortening flow in the plane, Gage[3] has shown in 1983 the following inequality, if k is the signed curvature of a closed convex plane curve γ with length L and enclosing area A, then one gets Gage calls it an isoperimetric inequality in [3], but he does not show that the equality holds if and only if the curve γ is a circle, while as an isoperimetric-type inequality, one should prove this kind of result.

Gage称之为等周不等式，但他没有证明其中等号成立当且仅当，γ为圆周，而作为等周型的不等式是应该证明这种结果的，本文我们利用单位速率外法向量流，通过努力证明了这种结果，从而把Gage不等式加强成更加等周的形式。

First, the relative curvature of a certain curve at its first end and the directional angle of the first port tangent vector of that curve as well as the weight factor of the interpolation curve are given, then all the other control vertexes can be gotten by using the conditions of G continuity, and a method to construct transitional curves is also introduced so that we can get the closed interpolation curve which achieves G continuity globally.

首先给定某段曲线的首端相对曲率和该段曲线的首端切矢量的方向角以及插值曲线的权因子，然后利用G2连续条件求出其余控制顶点，并给出了构造过渡曲线的方法，得到了G2连续的闭插值曲线。

A method of construct a quadratic uniform B-spline curve through data points is given.If the relative curvature of a certain curve on the first control point and the direction angle of the first port's tangent vector is given,here can get the whole curve by using the character of the port of quadratic uniform B-spline curve.

提出了一种二次均匀B样条插值曲线的构造方法，首先给定某一段曲线首点的相对曲率和该段曲线的首端切矢量的方向角，利用二次均匀B样条曲线的端点性质，求出其余各段曲线控制顶点，来生成整条插值曲线。

Geodesic curvature of the pitch curve on spherical surface was introduced as a medium,through which the pitch curve on spherical surface can be changed into equivalent planar pitch curve by numerical computation method.

以曲面上曲线的短程曲率为媒介，导出了球面节曲线伸展成平面当量节曲线的算法。

From this viewpoint, we fulfilled to control the step-size with the curvature of integral curve. The step-size is smaller in calculating these points that the value of the curvature is bigger and the step-size is bigger in calculating these points that the value of the curvature is smaller, which is rather reasonable choice and is also a creative point in this paper.

从这个想法出发，在文中实现了以积分曲线的曲率控制步长大小的作法，在曲率大的点步长小，而在曲率小的点步长大，这是非常合理的选择，也是本文的一个创新点。

The weakness of fixed step-size is that step-size is not variable regardless the curvature of each point of the integral curve change or not, which will affirmatively bring serious error in these points that the value of curvature is bigger. And, this kind of error will accumulate in calculating process.

定步长的缺点在于不管是积分曲线的各个点的曲率如何都取一样的步长，这样肯定会在曲率大的一些点带来比较严重的误差，这种误差将在每一步的计算中积累。

At the same time, the method which feed can be adjusted with curvature of curve to implement the control of interpolation error in high speed and high precision is found.

同时为了保证自由曲线插补精度要求，提出了进给速度能随曲线曲率自适应调整，实现高速高精度插补误差控制的方法。

First, a smooth curve is obtained from the data by curve fitting with the method of non-linear least squares fit. Then the tangent vector and the radius of curvature of each point on the curve can be calculated for the error evaluation. With the fitted curve, the focusing state of the aspheric lens can be obtained by the method of ray tracing.

主要过程为首先采用非线性最小二乘拟合的方法进行曲线拟合，并计算出曲线上各点的切矢量和曲率半径，分析它们的误差，最后对拟合后的曲线用光线追迹的方法得到非球面镜的聚焦情况。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。