Wave Propagation along Axes of Symmetry in Linearly Elastic Media with Initial Stress

The proofs of the Fedorov–Stippes and Fedorov's theorems, which hold for linearly elastic homogeneous bodies in natural configurations, remain valid for any linearly elastic medium with initial stress provided that Hooke's tensor be replaced by a suitable elasticity tensor.     

Numerical simulation of the trajectory of a light ray propagating through an optic system with non-centered spherical diopters and broken optic axis

The present paper is devoted to the elaboration of a strategy for the design of some practical focusing devices for the radiation emitted by a high-power laser used in thermal treatment processes. Usually, technological solutions employ spherical mirrors. Because spherical mirrors introduce a certain astigmatism, it is necessary to get an energetically efficient configuration which reduces as much as possible the astigmatic difference, thus concentrating the laser radiation energy which is distributed within the area between the sagital and meridional foci.     

双折射调谐器设计的等色图原理

提出双折射调谐器设计的等色图方法，给出原理。分析表明当晶片光轴处在以折射光线为轴线、顶角为４５°的圆锥面上时，双折射调谐器具有最快的波长调谐速率；当光轴位于过折射光线并与入射面成４５°或１３５°的平面内时，调谐器抑制非所需波长的能力最强。由此给出光轴相对晶片表面的两个优化取向，对石英晶片它们分别为１８．７１２°和５９．９２２°。文中还给出了三块晶片组合的调谐器的设计例子，对其调谐特性进行了简要的讨论。     

On the approximation of a smooth surface with a triangulated mesh

We approximate the normals and the area of a smooth surface with the normals and the area of a triangulated mesh whose vertices belong to the smooth surface. Both approximations only depend on the triangulated mesh (which is supposed to be known), on an upper bound on the smooth surface's curvature, on an upper bound on its reach (which is linked to the local feature size) and on an upper bound on the Hausdorff distance between both surfaces.

We show in particular that the upper bound on the error of the normals is better when triangles are right-angled (even if there are small angles). We do not need every angle to be quite large. We just need each triangle of the triangulated mesh to contain at least one angle whose sinus is large enough.     

统一后的德国与欧洲一体化

德国的统一及再次强大使其精英们试图以欧洲为依托实现其梦想.于是德国通过更新了的"法德发动机"及灵活的策略使欧洲一体化取得了巨大的进展,也使自己获得了巨大的实惠.面向新世纪,德国必将更加积极的推动欧洲一体化.     

分光计的调整──望远镜光轴与望远镜（或载物台）旋转轴严格垂直

本文详细描述如何调节分光计以使望远镜光轴与其旋转轴严格垂直。     

关于有理数集的稠密性

分析了关于有理数集的稠密性的几种不同提法,澄清了对这一概念的错误认识,使对高等数学教材中关于有理数集的稠密性有全面正确的理解.     

阶乘分位制

通过逐次对数轴进行一级，二级，…，ｎ级划分，引入阶乘分位单位，进而建立起阶乘分位制。用阶乘分位制记数，使实数与数轴上的点在一种新的体制下建立起一一对应的关系。它的优点在于能在数轴上清楚地分辨出有理数与无理数所对应的点，从而为识别有理数与无理数开辟一条新的途径。     

分子轨道图形理论中对称轴定理的明确和扩展——Ⅱ.分子轨道构造定理

本文扩展了由唐敖庆、江元生教授等人确立的对称轴定理,给出了具有C_n轴对称性共轭分子π分子轨道的构造定理和明确的解析表达式。     

直线感应加速器中聚束磁场的数值计算方法

为了准确模拟出直线感应加速器中聚束磁场的值,首先利用单积分法计算出理想情况下的聚束磁场的值,再进一步用磁路分析的方法考虑直线感应加速器的加速腔中匀场环对聚束磁场的影响,然后推导出一组偏离角度与磁场分量相关的公式。将最终得到的聚束磁场分量与直线感应加速器模型结合起来,采用粒子模拟的方法来模拟电子束在加速段中的输运过程,并对结果加以分析。