交错轴渐开线锥形齿轮的接触特性

Based on the theory of gearing and the gear generating mechanism, this study investigates the contact characteristics of conical involute gear pairs with crossed axes. The meshing model with a reference rack as intermedium is established and tooth contact analysis （TCA） is performed to examine the meshing and bearing contact of the conical involute gear pairs composed of a pinion and a gear. Using the contact line of reference rack tooth surface, the path of contact is confirmed, and the calculation formula of principal direction, relative curvature, path of contact and ellipse of contact are derived. Finally, numerical examples are provided to demonstrate computational results and test gears are made for tooth-bearing tests. The conclusion verifies that the theory is applicable.     

留数计算方法的改进

本文在传统的留数计算方法的基础上，提出了三种改进的留数计算方法，并给出了应用实例。     

具有摩擦支承边界矩形薄板的局部分岔

建立了具有摩擦支承边界的矩形薄板在面内载荷作用下的动力学方程 ,利用L S方法和奇异性理论对系统进行了局部分叉研究 ,讨论了非退化情况下Z2 分叉问题 .利用数值模拟给出了开折参数局部分叉集图和分叉响应曲线及物理参数平面上的分叉响应规律 ,其结果与解析和实验研究有很好的一致性 .     

EDGE SINGULARITY OF BONDED PIEZOELECTRIC MATERIALS WITH REPEATED EIGENVALUES

ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｗｅｌｌｋｎｏｗｎｔｈａｔｓｔｒｅｓｓｓｉｎｇｕｌａｒｉｔｙｍａｙａｒｉｓｅａｔｔｈｅｉｎｔｅｒｆａｃｅｅｄｇｅｏｆｂｏｎｄｅｄｄｉｓｓｉｍｉｌａｒｍａｔｅｒｉａｌｓ.Ｄｕｅｔｏｔｈｅｉｎｔｒｉｎｓｉｃｅｌｅｃｔｒｏｅｌａｓｔｉｃｃｏｕ ｐｌｉｎｇｂｅｈａｖｉｏｒ,ｔｈｅｓｔｒｅｓｓｓｉｎｇｕｌａｒｉｔｙｗｉｌｌｌｅａｄｔｏｔｈｅｓｉｎｇｕｌａｒｂｅｈａｖｉｏｒｏｆｔｈｅｅｌｅｃｔｒｉｃｄｉｓｐｌａｃｅ ｍｅｎｔ.Ｄｉｎｇｅｔａｌ.( 1 996)ｄｅｄｕｃｅｄｔｈｅｇｅｎｅｒ…     

Stress field near an interface edge of linear hardening materials

The elastic-plastic singular stress field near an interface edge of bounded linear hardening material is substantially as same as that of bonded elastic materials whose Young's modulus and Poisson ratio are substituted by equivalent values, respectively. Further investigation by the elasto-plastic boundary element method (BEM) on the stress field near the interface edge showed that the stress field there can be divided into three regions: the domain region of the elastic-plastic singular stress field, the transitional region and the elastic region. The domain region of the elastic-plastic singular stress becomes larger with the increasing of the linear hardening coefficient. When the linear hardening coefficient decreases to a certain value, the effective stress in most of the yield zone equals approximately the yield stress. The stress distribution in the elastic region under small-scale yielding condition was also investigated. Project (No. 19972060) supported by the National Natural Science Foundation of China.     

Beyond Rational Autonomy: Levinas and the Incomparable Worth of the Student as Singular Other

This article explores the question: Why are students of worth? Educationally, an answer often involves a Kantian response: They are of worth because they are always ends and never means. This response is usually connected to a notion of autonomy interpreted as individual, rational self-determination. The article argues for a different answer. The essay begins with a recent educational example of construing worth as rational autonomy. Meira Levinson, in her book The Demands of Liberal Education (1999), argues for a version of rational autonomy which is taken in the essay as a Kantian response to the question. The essay then turns to Kant’s own understanding of intrinsic human worth as ends. Although the essay agrees in general with the notion of end, it criticizes Kant’s version of rational autonomy. Instead, it argues for a notion of worth as irreplaceable singularity. Both the critique of the Kantian answer and theessay’salternative are shaped by the philosophy of Emmanuel Levinas. Here technical notions of “the other,” proximity and singularity are brought to bear on the question of human worth. The Levinasian alternative, so the essay argues, better answers the question of student worth by highlighting the incomparability of the student as a singular other.     

关于场论中旋度的两个重要问题

本文指出了场论中旋度这一名称由来的缺陷,并作了改进,同时提出了研究奇点旋度的重要性及奇点旋度的算法。通过对几个典型物理场旋度的计算和分析,给出了利用场论理论研究一般物理场有关性质的方法。     

R~3中一类二次齐次向量场的拓扑结构

本文讨论R~3中的二次齐次向量场:Q(x)=(x_1(ax_1 bx_2 cx_3),x_2(bx_1 cx_2 ax_3),x_3(cx_1 ax_2十bx_3))=(Q_1(x),Q_2(x),Q_3(x))x=(x_1,x_2,x_3,)的拓扑结构,当它只有孤立奇点时,利用向量场W_Q(X)的相图,得到Q(X)的轨线共有12种不同的拓扑等价类.     

HCMU度量的一个存在性定理和能量积分公式

HCMU度量是紧黎曼面上带奇点的extremal Kähler度量.本文给出一个带锥奇点的非常曲率HCMU度量(non-CSC HCMU度量)的存在性定理,并讨论一般non-CSC HCMU度量的能量积分公式.     

解决格点大气环流模式极点问题的一种方法

以球面正压浅水方程显式能量守恒格式的设计为例,在不失动力学方程物理意义的情况下,给出南北极网格点上速度的表达式,以及其预报方程的差分格式.克服数学意义上的极点奇异问题,直接预报极点速度.数值试验表明,此方法简单易行,能合理描述极点速度及其变化.