查询词典 parametric curve

The basic idea is as follows: with the help of the related results of differential geometry, the problem of interpolating curve on a parametric surface is converted to a similar one on its parametric plane.

基本思想是借助于微分几何的有关结论，曲面上曲线的插值问题被转化为其参数平面上类似的曲线插值问题。

Combined with the design objects of the section and tendon curve in a prestressed concrete continual girder bridge, the establishment of parametric model and the redact of parametric drawing program are discussed. And the implementation of the three kinds of parameter-driven: variation-driven, table-driven and dimension-driven is put forward.

结合预应力连续梁桥中梁体截面和钢束曲线等设计对象的具体特点，讨论了参数化模型的建立和参数化绘图程序的编制方法，并提出了变量驱动、表驱动、尺寸驱动这三种参数驱动方式的具体实现。

In order to assurance the maching accuracy and surface quality of steam turbine blades,based on typical CAD/CAM software Pro/Engineer 2.0,the flow diagram of parametric modeling and maching of turbine blades is drawn;The 3-D entity model of Steam Turbine Blade is upbuilt by parametric modeling method,and the fit-method with NURBS is extracted to smooth the curve surface,and the matrix expression of NURBS is deduced to make the surface more accurate;Then based on it's CAD model,the maching technology process...

为保证汽轮机叶片的加工精度和表面质量，以典型的CAD/CAM软件Pro /Engineer Widefire2.0中文版为基础，绘制了汽轮机叶片参数化设计加工的流程图；用参数化建模方法建立了叶片的三维实体模型，提出用NURBS曲线拟合方法进行光顺处理，并推导出NURBS的矩阵表达式便于截面型线的拟合，进而使叶片的造型更加精确；在CAD模型的基础上，分析了叶片的加工工艺流程，并用软件的CAM功能对叶片进行数控加工仿真，生成了NC代码。

Algebraic curve is commonly used in CAGD. Traditional curve interpolation is in various forms of spline fuction. Although better result can be obtained by spline curve, the former two of elliptic, hyperbolic and parabolic shapes can not be represented by spline curve. An exploring research in this aspect is made in this thesis.

代数曲线是CAGD中经常用到的曲线，以往的曲线插值基本上是采用样条函数的形式，采用这种形式虽然能够获得很好的效果，但样条函数所能表达的形状都是抛物线型，对椭圆型与双曲线型曲线的表示是无能为力的。

In the term of unloading and opposite side loading, let the stress-strain curve have the same form of skeleton curve, the curve uses the last unloading point as its starting point, and uses soil's ultimate stress level as its asymptote. Then the hysteretic curve is constructed.

在卸载和反向加载时，采用与骨架曲线相同的函数形式，并以前一次卸载开始点作为起点，以土体的极限应力水平作为渐近线，构造出土体动力本构模型的滞回曲线。

A novel design scheme for digital optical switch with high extinction ratio by employing S curve waveguide at the end of the Y branch ii proposed. Higher extinction ratio then that of the device without S curve waveguide is obtained by applying certain synchronous voltage to tie Y branch and the curve electrode of tie S curve waveguide.

文章提出一种关于非对称电极低串扰数字光开关的新型设计方案，在Y分叉后端引入S弯曲波导，通过在Y分叉处的非对称电极和弯曲波导的弯曲电极处施加一定的同步电压，实现了比没有S弯曲的开关更低的串扰。

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。

Carried out generalized Mises yield criterion , yield curve on the n flat face was circle curve, and different elected parameters correspond to external angular point circumcircle、 internal angular point circumcircle and incircle of Mohr-Coulomb unequiangular hexagon. According to unequiangular hexagon, circle yield curve which had the same area as hexagon can be found, and corresponding yield criterionwas equilateral circle yield curve.

3广义米赛斯准则在π平面上的屈服曲线为圆曲线，选择的参数不同对应有莫尔—库仑不等角六边形的外角点外接圆，内角点外接圆和内切圆，对于不等角六边形，还可以找到一个面积和六边形相等的圆屈服曲线，对应的屈服准则为等面圆屈服曲线。

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。

The properties of the new method are that (1) the equations that the quartic Bézier curve has to satisfy for being C 2 continuous are strictly row diagonally dominant;(2) the discontinuous points of the curve are at the given data points;(3) the curve is locally adjustable;(4) if the given data points are convex, the constructed quartic Bézier curve is convex.

用样条函数方法构造插值样条曲线曲面，曲线曲面的精度和形状是由给定的数据点和端点条件唯一确定的。在有些情况下，例如，对文献 [7～ 9]中的数据点集，由样条函数方法构造的C2 插值曲线是不可接受的，但由于没有额外自由度，无法调整曲线的形状。

In the days of sailing vessels the crew were afraid they would be becalmed on the ocean.

在使用帆船的时代，船员们担心他们会因为无风而无法在海洋上航行。

As long as foreign donors pay the PA's salary bill, few expect a new intifada.

只要外国继续为巴权力机构的薪水买单，希望发动新暴动的人便寥寥无几。