A characterization of spaces of constant curvature by minimum covering radius of triangles

In this paper, we prove that if in a Riemannian manifold, the minimum covering radius of a point triple of small diameter depends only on the geodesic distances between the points, then the manifold must be of constant curvature. This implies that if in a complete connected Riemannian manifold, the volume of the intersection of three small geodesic balls of equal radii depends only on the distances between the centers and the radius, then it is one of the simply connected spaces of constant curvature. This generalizes an earlier result of the first author and D. Kunszenti-Kovács (2010).     

Theoretical analysis on capillary adhesion of microsized plates with a substrate

The stiction of a thin plate induced by the capillary force has attracted much attention in the broad range of applications. A novel method is presented to calculate the capillary adhesion problem of the plate through analytical method. The expressions of the surface energy, the strain energy and the total potential energy of the plate-substrate system have been analyzed and delineated. By means of continuum mechanics and the principle of minimum potential energy, the governing equation of the plate with an arbitrary shape and the corresponding transversality boundary condition due to the moving bound have been derived. Then the critical adhesion radius of the circular plate has been solved according to the supplementary transversality condition. Thus the deflections of the plates are analytically calculated with different critical adhesion radii. The results may be beneficial to the engineering application and the micro/nanomeasurement.     

On the spectral radius of a nonnegative centrosymmetric matrix

In this paper, we discuss the spectral radius of nonnegative centrosymmetric matrices. By using the centrosymmetric structure, we establish some estimations of the spectral radius.     

图与其补图谱半径之间关系的注记

给出在一般情形和某些限制条件下图及其补图的谱半径的和与积的上界，改进了文［１］的结果。     

基于遗传算法的静态Ad-hoc拓扑结构控制

将遗传算法引入到了静态Ad—hoc无线网络的拓扑结构控制中，突破了网络中所有节点辐射半径都相同的固有思路，通过调节各无线节点的辐射半径，在相邻节点对之间形成有向路径，从而达到节省节点能源消耗和网络拓扑结构优化的目的，并取得了较好的实验结果。     

A Novel Fiber Taper for Efficient Optical Interconnection

１ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｅｒｃｏｎｎｅｃｔｉｏｎｓｏｆｏｐｔｉｃａｌｗａｖｅｇｕｉｄｅｃｏｍｐｏｎｅｎｔｓｗｉｔｈｄｉｆｅｒｅｎｔｍｏｄａｌｓｐｏｔｓｉｚｅｓ，ｐａｒｔｉｃｕｌａｒｌｙｆｏｒｔｈｅｃｏｎｎｅｃｔｉｏｎｏｆ（１）ｌａｓｅｒｓｏｕ...     

最佳的潜艇搜索模型

对直线式逃跑的潜艇被捕获的必然性进行了证明,并为驱逐舰给出了一个最佳的搜索模型.     

Effects of Density-Dependent Bag Constant and Strange Star Rotation

With the emphasis on the effects of the density-dependent bag constant and the rotation of strange star the limiting mass of strange star is calculated. The obtained results show that the limiting mass and the corresponding radius of strange star increase as the rotation frequency increases, and tend to be lowered when the density-dependent bag constant is considered.     

电子束参量对轫致辐射照射量角分布的影响

本文研究了电子束半径,发射度及能量等参量对闪光X射线照射量在1m处角分布的影响。求得了使中心照射量最大,束半径与发射度之间应满足的拟合关系,表明了电子束能量越高,发射度越小,那么中心照射量就越大,照射量的空间分布就越理想。对电子细束入射位置和入射方向使用了解析法和随机抽样法求出,两种方法的数值计算所得的照射量分布符合得比较好。