速度向量总是与曲线相切的。
So, the velocity vector is going to be always tangent to the curve.
它是与等值面相切的，对不对？
一条与曲面相切的直线。
我们做过若干次了，沿着圆，向量场与圆相切。
If you remember what we did several times, well, along the circle that vector field now is tangent to the circle.
它看上去并不是十分地相切，因为它穿过了曲面。
So, it doesn't look very tangent because it crosses the surface.
最终得到的角色的相切空间的法线贴图。
这条线和这个圆相切。
但实际上，这是不对的，因为这个圆与这个坐标轴相切。
But, actually, that is not true because here the circle is tangent to the axis.
另一种方法是，函数值不变的方向是,是与等值面相切的方向。
The other way to think about it, the direction in which the value doesn't change is a direction that's tangent to the level surface.
本文还给出了曲线与其特征多边形各边相切的条件。
The condition in which the curves contact with each edge of characteristic polygon is also given.
描述了一种与给定多边形相切的有理样条曲线的算法。
An algorithm for constructing rational spline closed curve which is tangent to the given polygon is described.
如果相切宇宙出现，它将极不稳定，自持不会超过几个星期。
If a Tangent Universe occurs, it will be highly unstable, sustaining itself for no longer than several weeks.
特别地，有一种简单的情况，是不用计算的，当向量场与曲面相切，没有通量。
In particular, an easy case where you know you can get away without computing anything is, of course, if your vector field is tangent to the surface because then you know that there is no flux.
对较小的单相负荷可采用由微型接触器构成的双电源单相切换开关。
For comparatively smaller single-phase load, the duplicate supply single-phase transfer switch made of miniature contactors can be selected.
由切应力互等定理可知，在截面边缘上各点处切应力方向必与圆周相切。
Based on shearing stress Theorem, we know that the shearing stress direction of all the spots on the edge of circular cross-section should be tangent to the circle.
相切是由曲面边界的最初两个控制点控制的（假设这些点在一条线上）。
Tangency is controlled by the first two control points from a surface boundary, assuming that these points lie in one line.
这是一个向量场，其中旋转轨道是，以z轴为圆心的圆周，并且这个向量场与每个圆相切。
That is a vector field in which the trajectories are going to be circles centered in the z-axis and our vector field is just going to be tangent to each of these circles.
该装置在电源母线切换过程中自动选择快速切换、同相切换及残余电压切换方式。
The system automatically selects from either the Fast, In Phase or Residual Voltage method for power supply…
如果两个等高线相切，说明它们的切线相同，也就是说他们的法向量应该平行，我再在这里画个图。
If the two level curves are tangent to each other that means they have the same tangent line. That means that the normal vectors should be parallel. Let me maybe draw a picture here.
介绍了以AT 89s52单片机为核心的金相切割机控制系统原理和软硬件设计方法。
In this paper, we introduce the principle of metallographical cutter control system and the design method of software and hardware based on the AT89S52 singal-chip microcomputer.
其二为一种修整的线接触，展成的等螺距齿面与理论轨迹曲面沿某一空间曲线近似相切。
The new tooth surface can be prolonged by the normal profile of the internal toroidal surface, or replaced by an equal pitch helical surface.
例如，在某些情况下，如果已知向量场与曲线相切，或者内积是一个常数等等，那么结果将会很简单。
And, in some cases, for example, if you know that the vector field is tangent to the curve or if a dot product is constant or things like that then that might actually give you a very easy answer.
利用拉格朗日乘子法求解二次曲线和二次曲面之间的最小距离，给出了曲线与曲面相切的条件。
With the Lagrange multiplier method, the minimum distance of the center of a circle and a quadric surface was provided and the tangency condition of curve and surface was given.
解决了由直线和圆弧构成的平面轮廓精确重构问题，满足轮廓各段之间位置连续以及相切条件。
Accurate reconstruction of planar contour mixed with straight lines and arcs is achieved with position or tangent continuity.
密封圈的横截面呈＂V＂字形，构成＂V＂字形的两个侧边条之间的内槽由两个半径不等的圆弧相切而成。
The sealing ring cross section is V-shaped, and inner groove between two side edges composed the V-shaped is formed by tangency of two arcs with different radiuses.
绿色螺旋线由内部每一个正方形和四分之一圆相切线构成，而红色的螺旋线是黄金螺旋线，它是对数螺旋线的一种特殊类型。
The green spiral is made from quarter-circles tangent to the interior of each square, while the red spiral is a Golden spiral, a special type of logarithmic spiral.
绿色螺旋线由内部每一个正方形和四分之一圆相切线构成，而红色的螺旋线是黄金螺旋线，它是对数螺旋线的一种特殊类型。
The green spiral is made from quarter-circles tangent to the interior of each square, while the red spiral is a Golden spiral, a special type of logarithmic spiral.
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