二次曲面

Its main function include "arbitrary transversal analysis","complanation of the dragonfly"s wing","second curving surface fif " and "third curving surface fit.

其主要功能包括蜻蜓翅膀任意截面数据分析，蜻蜓翅膀高度数据的平面拟合、二次曲面拟合和三次曲面拟合。

Inner point and exterior point of a quadric and its plane of the type of contact plane;2. The article gives a way by which a quadratic curve is processed by a linkage,and then a quadric can be formed by revolving the quadratic curve as a generatrix around the axis.

提出一种利用能够生成二次曲线的连杆机构作辅助装置，将生成的二次曲线作为母线绕轴线旋转而形成旋转二次曲面的方法，从理论上进行了推导，并通过实例说明了该方法的应用。

Through studying some fundamental properties of the curved surface in differential geometry , a method of linear feature extraction based on differential geometry is introduced.

通过研究微分几何理论中曲面的一些基本性质，本文介绍了一种基于微分几何的线状地物提取方法，首先在局部区域内拟合一个二次曲面函数，然后通过该函数来估算灰度曲面的梯度和曲率，设定合适的梯度和曲率阈值来检测线状地物，最后进行后处理，消除许多噪声颗粒及小块区域。

First, the algrithm classify the measurement characteristics as point, line and surface which can be classified to conicoid and free surface. Then, this algorithm establishes the parametric equation according to various features. After that this paper brings forward the characteristic parameters utilising least square method with several characteristic points. Finally high precision probe radius compensation is carried out according to the features.

该算法首先把测量特征分为点、线、面3种基本特征（其中面特征又分为二次曲面和自由曲面），然后建立各种特征的参数方程，利用测量得到的少量特征点，采用最小二乘法拟合得到被测特征的参数，最后根据被测特征参数进行高精度半径补偿。

The parametric representation of segment can be gained from quadratic patch and constrained equations with cubic patches.

利用二次曲面的参数形式，由三次曲面片可得到曲线的隐参数约束形式，从而得到曲线的参数形式。

Firstly, the quadric surface with three points which doesn't on one line is fitted, and then the tangent plane of this fitting surface is got. Meanwhile, the random tangent plane of surface patch subdivided is got also. Finally, the distance can be obtained through iteration between two tangent planes.

首先对点云数据中邻域不在同一直线的三个点进行局部二次曲面拟合，并求取该拟合曲面的切平面，同时求得细分曲面片任意一点处的切平面，最后在两个切平面上进行点对迭代运算，得到点到曲面片的最短距离。

The compensator can be used not only the conicoid but also the high-order surface.

这些透镜补偿器既可以检验二次曲面，又可以检验高次曲面。

Using numerical analysis method and GLSFA the paper researches into the plane, conicoid and three cubed anti error fitting model.

利用数值分析方法和GPS水准拟合过程分析软件对相关平面、二次曲面和三次曲面抗差推估数学模型进行对比分析研究。

The result indicates that conicoid anti error is smaller than that of plane and three cubed anti error fitting model, but the validity of the model doesn't necessarily have relationship with model steps.

结果 二次曲面抗差的结果要好于相关平面与三次曲面抗差的结果精度，并非抗差模型阶次越高有效性越高。

The constructed surface not only has the same structure to the bicubic Coons pacth, but also it can help us to obtain different surfaces by changing the values of the parameters. Furthermore, it can accurately represent torus、ellipsoid and so on.

所构造的曲面不仅具有双三次Coons曲面片的相似的结构，可以通过改变参数，得到不同的曲面片，而且还能精确地表示圆环面、球面、椭球面等二次曲面。

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。