曲率线

The abc are to get the generic "default parameters" for use in the comparison program CONTRAST which aligns protein sequenes based on their 3D-structure, to confirm the efficiency of the differential -geometric representation of protein backbone by comparing 3 different algorithms of the curvatures and tortions, and tO find apropriate gap penalty function.

中国科学院上海生物化学研究所，上海 200031摘要：继前面的工作把测试蛋白从三族扩大到十一族，寻求联配参数的普适"缺省值"；比较不同的主链曲率和挠率的计算方法，进一步确认主链的折线线分几何刻划方法的有效性；寻找有效的可变缺失突变惩罚函数的形式。

For better meshing performance ,included angle between directions of relative velocity and contact line,and induced normal curvature were selected as optimization objects.

为提高TI蜗杆承载能力、获得良好的蜗杆传动啮合性能，以接触线方向和相对速度方向的夹角、诱导法曲率为优化目标。

Then the influence of the different Coanda surface shapes including the circle, elliptical and logarithmic spiral TE geometries on the performance of the circulation control airfoil were investigated.

在此基础上研究了具有圆、椭圆和对数螺线形式柯恩达表面的环量控制翼型性能的变化，初步探讨了射流层附壁与高曲率表面特征参数的关联。

Direct difference is sensitive to noisy data, so a threshold limitation is given, which can not only filter the result from noisy data but also pick edge points up according men's desire. On the other hand, artificial intelligence is used for segmentation in reverse engineering. Because the essence of segmentation is clustering similar characteristics and self-organizing feature mapping is one function of neural network, SOFM network is used for segmentation in the thesis, coordinates and normal of data points is took as the characteristics vector.

第二种方法，基于双向角度微分的边点提取法，针对三维正交模型采用基于截面线的方式组织数据，此方法比基于曲率半径方法更简洁，不用进行曲面拟合，大大提高了计算速度；计算过程中由数据点的直接差分逼近微分，但直接差分对数据误差敏感，为此，本文提出了阈值过滤的方法，一方面过滤了数据误差在计算结果中引起的噪音，另一方面可以按照设计意图控制边点的提取；来决定是否提取光滑交接的边点。

The kinematic analysis of a planar cam mechanism can be realiaed by the method that the higher pair is substitute for lower pair, and then it is equivalent to a planar linkage. The main point by the way is how to calculate the radius of curvative of planar cam profile.

对于平面凸轮机构的运动分析可以用高副低代的方法将其转化成平面连杆机构来进行，而高副低代后关键的问题是如何在书籍平面凸轮廓线的基础上求解凸轮的曲率半径。

The techniques for obtaining initial tracing points and tracing intersection branches are the most important issues in surface intersection algorithm. This paper reviews the plane vector field method which is exploited to get initial tracing points,and gives the relation between normal curvature and tracing direction.

平面向量场与曲率分析在曲面求交中的应用宁涛，马德昌，王亚平，唐荣锡（北京航空航天大学制造工程系北京100083）摘要在曲面求交算法中，初始跟踪点的确定和交线分支的跟踪是最关键的两个问题。

In this paper, the following topics are covered:(1) Study of the geometry of the raceways.(2) Analyses of the principal curvature of the raceways are also accomplished. In addition, the modification of the raceway is put forward.(3) The contact forces and the reducer efficiency are evaluated.

研究包含以下内容：（1）滚道几何形状的研究；（2）完成了对滚道曲率的分析，进一步提出了对滚道的修形；（3）对接触应力的评估；（4）研究了陶瓷滚珠在密珠摆线减速器中的工作性能。

In order to improve the control performance, when the image distortion is too large resulting from camera obliquity, these parameters are transformed from image coordinate to robot coordinate through projective transformation, while parameters such as position and curvature are not necessarily provided.

为改善控制性能，当由于摄像机倾角较大而引起的图像畸变较大时，利用射影变换把参考轨线参数从图像坐标系映射到机器人坐标系，而无须提供位置、曲率等参数。

The real borehole axis is not an ideal straight line, but a helical line with arbitrary curvature, so the contact problem between the down-hole string and the borehole face is a kind of arbitrary contact nonlinear mechanics problem, which can not be solved by the common methods from material mechanics and structural mechanics.

实际的井眼轴线不是理想的直线，而是一条任意曲率的空间螺旋线，因此井下管柱和井壁的接触问题是一种随机接触的非线性力学问题，用一般的材料力学和结构力学方法是不能解决这类问题的。

For easier comparison a modified Dean number was proposed, which took into account the curvature of the spherical line cut out by the helical element from the tubular housing.

为了更简易的比较，本文提出了 Dean 数，用来考虑管路外壳上的螺旋物切出的球形线的曲率。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。