曲线的曲率

According to the boundary curve features of the object, all kinds of boundaries sign patterns of the object are setup and used to train the second RBFNN, so as to tangent points, inflection points with low curvature and boundary types.

根据工件边缘曲线的特征，建立了各种边缘的曲率符号模型，用该模型训练第二个RBFNN，从而识别具有低曲率的切点和拐点及边缘曲线的类型。

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。

When the point moves along the plane curve, the trace curve of the point is called the evolute of the curve, denoted by, and is called the involute of the curve.

当点沿曲线移动时，相应的曲率中心的轨迹曲线称为曲线的渐屈线，而曲线称为曲线的渐伸线。

A systematic study on computing the integral curvature line on NURBS surface is presented. Discrete normal is used to simplify calculation of the second fundamental form of the surface, resulting in accelerating the Euler iteration process in solving the differential equation of curvature line. Discrete points on the curvature line are then obtained and approximated by an explicitly presented B-spline curve on the NURBS surface using singular mixed interpolation and capable of controlling the error within a given tolerance.

对NURBS曲面的曲率线的积分进行了系统的公式推导，并利用NURBS曲面的离散法向量有效地简化了曲面第二基本量的计算，加速了Euler法迭代求解曲率线微分方程的过程；在求得曲率线上的离散点集以后，应用奇异混合插值技术，在可控精度内把曲率线用显式直接表示为位于NURBS曲面上的B样条曲线。

We decompose curvature signal with wavelet at first and then use its low frequency coefficients as new smooth curvature signal, which is used to construct a G^2 continuous piecewise rational cubic Bezier curve with (Geometric Hermite Interpolation, GHI) GHI method subsequently.

针对在逆向工程的实践中常见的轮廓线的光顺问题，给出了一种先对曲率图进行小波分解，提取其低频部分作为新的曲率图，并利用几何Hermite插值方法，生成G^2连续的分段三次有理Bézier曲线，从而重建出光顺的产品轮廓曲线的新方法。

Based on the characteristics of transaction curve and parallel line,the calculation formulas of boundary line parameters and length are derived,providing theoretical support for higher grade highway design,and determination,as well as practical formula for calculation,also providing mathematics model for dealing with linear data which are obtained through road survey.

本文从讨论缓和曲线边线的性质着手，对缓和曲线的曲线长度与对应的曲率半径变化规律作了分析比较，证明了缓和曲线的平行线不再具备缓和曲线的性质，如果把边线仍当作缓和曲线处理则会引起路线宽窄的变化。

Through the new research methods, this thesis has made the following contributions in this field: 1. For the first time the curvature radii and relative angles of a planar continuous curve at discrete points are chosen as local parameters to represent the curve, which reflect clearly the local geometrical characteristics of the curve and are easy to be dealt with.

借助于新的研究方法，本文在这一领域作出如下贡献：（1）首次提出用曲线上离散点处曲率半径和相对转角作为局部参数表示平面连续曲线，直观地反映曲线各个局部的几何特征，且便于曲线的修改和变换，并通过机构运动分析，快速求出机构轨迹的这两个局部参数。

In fact, we can get the optimal tangents just by solving a system of linear equations with tridiagonal coefficient matrix. Then we can construct interpolating curves with continuous curvature locally just with end points, tangents and curvatures.

整条曲线可以通过构造插值端点、端切向以及端曲率的曲线得到；通过对型值点处的曲率进行低通滤波处理并对型值点进行相应调整，可以得到平面点列的一种自动光顺算法。

The camber near the switch point changes rather slowly, while it changesrapidly at certain distance range from switch rail.

建议尖轨轨头非工作边的刨切曲线采用缓和曲线和圆曲线的组合线型，在尖轨理论尖端至圆曲线之间，为一曲率渐变的缓和曲线，在尖轨尖端附近矢度变化较慢，而在距尖轨一定范围时，矢度变化较快。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。