曲率不变量

We then introduce a conformal invariant quantity which is formulated in terms of the square of the length of the trace free part of the second fundamental form and the mean curvature, and prove that if this quantity is bounded above by that value of the Clifford torus then x is either a totally umbilical sphereor a conformal Clifford torus.

接著我们介绍一个由第二基本型式迹为零部份的张量长度平方与平均曲率形成的保角不变量，并证明此保角不变量的上界若为Clifford环面之值，则x不是全脐球面就是Clifford环面的保角类。

The paper deals with curvature line and curvature characteristic of developable surface based on differential invariant of developable surface and it details curvature line and curvature characteristic of cone and tangent surface .

本文通过可展曲面的微分不变量，导出可展面的曲率线与曲率特征，并以锥面和切线曲面为例阐明这些特性的几何意义。

In this paper,focusing on the symplectic manifolds,we discuss the Seiberg-Witteninvariants,some basic construction.the existence of symplectic forms,and the existenceof Riemannian metric of positive scalar curvature.

本文主要围绕辛流形，讨论其Seiberg-WItten不变量、辛流形的一些基本构造，辛形式的存在怀及其上是否存在具有正数量曲率的黎曼度量等问题而展开的。

For the axicons with 20 mm radius, 10-2 cone angle, when using incident spherical wave whose radius of curvature varius from 1200 mm to 1400 mm, the focal length increases from 200 mm to 120 mm and the lateral intensity distribution increases only 15μm.

对于半径20 mm，锥角θ=1×10－2的圆锥透镜，采用曲率半径为1200~1400 mm的球面入射波，可扩展焦深200 mm到120 mm，光强的均匀性有明显改善，横向场能量分布形状改变量不超过15 μm，完全达到应用要求。

Four main types of spatial binary links are investigated in details for kinematic synthesis both in precision-position synthesis and multi-position synthesis. In terms of the invariants of spherical curve and cylindrical curve, the mathematical models of adaptive fitting sphere and cylinder are constructed by means of the saddle-point programming.

再次，根据常见空间机构运动副组合的约束曲线与约束曲面的曲率理论，阐述了空间机构运动综合的基本要素及其不变量拟合理论与方法，研究了有限位置和多位置情况下，自适应综合方法在空间S-S、C-S、C-C和S-C四类二副杆组运动综合中的应用，实现了自适应综合方法从平面到空间的扩展。

In order to reduce the cost of matching, we used multiple scale technique. 4. We presented a novel method of searching for similar fragments of 3D curves. with this method, a hash vector is associated with each fixed-length fragments of 3D sherd. Each vector consists of low frequence component of Fourier-Like spectrum for the distance between profile curve and the centroid.

依据样条曲线的基本理论，研究了基于B样条的轮廓曲线的匹配方法，给出了由轮廓曲线不变量曲率和挠率构造的相似不变量的选取以及基于相似矩阵的匹配算法，并对该算法的时间复杂度作了估计，同时，将多尺度技术引入到物体轮廓的匹配问题中。

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。