R1^3中类空曲面的“欧氏”曲率椭圆与副法方向

在Minkowski空间R13中的类空曲面上,考虑曲率椭圆和副法方向的定义及其性质,采用活动标架的方法进行局部计算和整体结构的刻画,推广并改进了欧氏空间中的已有结果。

多曲率椭圆轴承对转子系统动态特性影响研究

多曲率椭圆轴承的下瓦由多个曲率不同的部分组成,具有承载能力强、稳定性高等特点,多应用于兆瓦级发电机系统中。针对描述多曲率椭圆轴承的雷诺方程具有不连续性的特点,在不连续区域使用有限体积法,在其他区域利用有限差分法,由此建立整个求解域内的差分方程。利用此数值模型得到多曲率椭圆轴承的油膜刚度和油膜阻尼随各几何参数的变化规律;针对某660 MW发电机转子系统进行优化设计,给出可行域内油膜参数的最优值以及对应的轴承几何参数,并进行数值验证,为多曲率椭圆轴承-转子系统的研究及工程设计提供理论支持。

复二维空间形式中曲率椭圆是圆的辛临界曲面

本文研究了复二维空间形式中曲率椭圆是圆的辛临界曲面.利用活动标架法,获得了这类曲面是极小曲面的结果,丰富了辛临界曲面的内容.

平面曲线曲率半径的运动学探究

以曲线和曲面为代表的几何特征在现代生活中随处可见，研究者对其在现代大型建筑设计、工业生产制造、物体运动学规律等诸多领域进行了广泛深入的探究。本文详细分析了平面曲线曲率几何学特征以及其对应的运动学规律，试图从多个角度对曲线曲率问题进行全方位的解读与探索，同时利用电脑编程求解，进一步研究了椭圆曲线在不同长短半轴比下的曲率半径变化规律。

A Public Verifiable Identity Based Signcryption in the Random Oracle Model

Since Libert and Quisquater's identity based signcryption scheme cannot provide public verifiability after research, the paper proposes a new identity based signcryption scheme. The scheme uses quadratic residue and pairings over elliptic curves to realize public verifiability. By analysis the scheme is proved to be more efficient than Libert and Quisquater's scheme. Moreover, a security proof of the original scheme is presented in the random oracle model.

Families of hyperelliptic curves with maximal slopes

For each integer g≥2, we construct a family of hyperelliptic curves of genus g whose slope reaches the upper bound obtained by Xiao.

A priori Estimates and Existence for a Class of Fully Nonlinear Elliptic Equations in Conformal Geometry

In this paper we prove the interior gradient and second derivative estimates for a class of fully nonlinear elliptic equations determined by symmetric functions of eigenvalues of the Ricci or Schouten tensors. As an application we prove the existence of solutions to the equations wb.en the manifold is locally conformally flat or the Ricci curvature is positive.