Stable Ergodicity and Frame Flows

In this note we show that all diffeomorphisms close enough to the time-one map of the frame flow on certain negatively curved manifolds are ergodic. As a simple corollary we deduce that the frame flows are ergodic for all compact manifolds with curvature pinched sufficiently close to –1, thus providing results in the case of manifolds of dimension 7 or 8 which were missing from the results of Brin and Karcher.     

Stress concentration and effective stiffness of aligned fiber reinforced composite with anisotropic constituents

The paper addresses the problem of calculation of the local stress field and effective elastic properties of a unidirectional fiber reinforced composite with anisotropic constituents. For this aim, the representative unit cell approach has been utilized. The micro geometry of the composite is modeled by a periodic structure with a unit cell containing multiple circular fibers. The number of fibers is sufficient to account for the micro structure statistics of composite. A new method based on the multipole expansion technique is developed to obtain the exact series solution for the micro stress field. The method combines the principle of superposition, technique of complex potentials and some new results in the theory of special functions. A proper choice of potentials and new results for their series expansions allow one to reduce the boundary-value problem for the multiple-connected domain to an ordinary, well-posed set of linear algebraic equations. This reduction provides high numerical efficiency of the developed method. Exact expressions for the components of the effective stiffness tensor have been obtained by analytical averaging of the strain and stress fields.     

Geometry of an Accelerated Rotating Disk

We analyze the geometry of a rotating disk with a tangential acceleration in the framework of the theory of Special Relativity, using the kinematic linear differential system that verifies the relative position vector of time-like curves in a Fermi reference. A numerical integration of these equations for a generic initial value problem is made up and the results are compared with those obtained in other works.     

Asymptotic Expansions of Posterior Distributions in Nonregular Cases

We study the asymptotic behaviour of the posterior distributions for a one-parameter family of discontinuous densities. It is shown that a suitably centered and normalized posterior converges almost surely to an exponential limit in the total variation norm. Further, asymptotic expansions for the density, distribution function, moments and quantiles of the posterior are also obtained. It is to be noted that, in view of the results of Ghosh et al. (1994, Statistical Decision Theory and Related Topics V, 183-199, Springer, New York) and Ghosal et al. (1995, Ann. Statist., 23, 2145-2152), the nonregular cases considered here are essentially the only ones for which the posterior distributions converge. The results obtained here are also supported by a simulation experiment.     

Banach空间上的框架与Riesz基

本文讨论Banach空间上框架、无冗框架与Riesz基之间的关系及它们的稳定性．     

THE PRACTICE OF ACRYLIC SIROSPUN YARN ON THE SEMI WORSTED SPINNING FRAME

The technique of sirospun process is applied on a modified semi-worsted balloonless spinningframe to investigate the effect of spindle-speed,yarn-twist and strand-spacing on yarn properties.Yarn breaking strength,breaking extension,evenness and imperfection are examined on the basisof CCD experimental design.Yarn hairiness is particularly concerned,being found that all spinningparameters tested have significant effects on hairiness and that the minimum number of hairs oc-curs at the strand-spacing of 14.4 mm.Compared to conventional single spun yarn,experimentshave revealed the greatest advantage of using sirospun process is that all sirospun yarns have muchless hairiness.A new sirospun yarn fault,so called“loop”,has also been examined.The most likely cause forthis yarn fault is the strand-tension unbalance between the two strands when low tension spinningis applied.Further analysis and some initial tests have been carried out in the hope of overcomingthis loop fault which is an important obstacle to the application of balloonless spinning.     

悬臂框架结构设计方案的分析比较

通过一个设计实例，介绍了工程设计中悬臂框架结构常用的处理措施；计算表明，在悬臂端设置端柱的方法是切实可行而有效的。     

钢-混凝土连续组合梁桥的理论分析和试验研究

根据完全剪力连接的连续组合梁桥的构造特点及各部分受力机理,做出合理假设,提出分层平面框架计算模型该计算模型用于沈阳市东西快速干道工程某段连续组合梁桥,计算值与静载试验实测值非常接近,证明了本计算模型用于钢-混凝土连续组合梁桥正确实用的.     

高功率微波高斯馈源口面场分析

 用波导本征模展开方法对用于高功率微波发射系统的方角锥高斯馈源口面场进行分析，提出结合馈源远场辐射特性和避免高功率击穿折衷选定相应的高斯模注腰半径，进而确定多个波导模幅值，从而为运用模匹配或耦合波理论设计高斯馈源提供依据。