Quasi–Stationary Regime of Ring Laser Generation

An exact solution to the equations that describe the operation of a ring laser having nonstationary parameters is obtained. An iterative formula is derived and the conditions under which a quasi–stationary solution can be used are determined. Lasers with vibrating and reversing differences of the frequencies of opposite waves are considered. In the case of a reversing shift, it is always possible to isolate a quasi–stationary regime when transient processes are completed.     

基于不同任务难度的注意缺陷多功障碍（ADHD）儿童与正常儿童的手部运动协调性差异研究

以ADHD儿童和正常儿童为被试,设计视觉-运动整合实验方法,研究基于不同任务难度的ADHD儿童与正常儿童手部运动协调性的差异. 结果表明：（1） 在简单手指序列按键实验中,ADHD儿童的准确性较正常儿童低,运动协调性较差,节奏不稳定.（2） 在复杂手指序列按键实验中,ADHD儿童的视觉-运动整合的准确性明显下降,运动协调性在准确性方面与正常儿童相比达到显著性差异,节奏变化波动大、更不稳定,结果揭示ADHD儿童从事复杂任务更为困难.     

黄土滑坡发育类型及其空间预测方法

现场调查了黄土地区的大量滑坡,按运动方式将其分成错落式滑坡、高速远程滑坡、低速缓动滑坡和滑坡泥流四种类型,并以4个典型滑坡为例,分析了各类滑坡的形成条件和运动学特征。提出了在各类运动方式下黄土滑坡的空间预测指标、影响因子和建模思想。为黄土地区的滑坡灾害空间预测提供了整体思路,为滑坡的预测理论建模提供了基础依据。     

Stability and initial postbuckling behavior of anisotropic cylindrical shells under external pressure

A solution is obtained to describe the stability and initial postbuckling behavior of cylindrical shells made of composites with one plane of symmetry. The solution is based on the Donnell-Mushtari-Vlasov nonlinear theory of anisotropic shells and Koiter’s theory of buckling and postbuckling behavior. Calculated results are presented for boron plastic shells with reinforcement of different types under external pressure. It is shown that the conventional model of a composite as an orthotropic material is erroneous for many types of reinforcement __________ Translated from Prikladnaya Mekhanika, Vol. 43, No. 3, pp. 86–103, March 2007.     

Task‐performing dynamics in irregular,biomimetic networks

Understanding self‐organized collective dynamics—especially in sparsely connected, noisy, and imperfect networks—has important implications for designing and optimizing task‐performing technological systems as well as for deciphering biological structures and functions. We note that stomatal arrays on plant leaves might provide an ideal example of task‐performance in this context. Guided by observations of stomatal networks, we examined a simple model of task‐performing, collective dynamics that included state noise, spatial rule heterogeneity, dynamic modules, and network rewiring. Our results indicate that task‐performance in such networks can actually be enhanced by various kinds of spatial and temporal irregularity. © 2007 Wiley Periodicals, Inc. Complexity 12: 14–21, 2007     

A note on pólya enumeration theory

The power group method of de Bruijn and Harary in enumeration under group action of mappings between finite sets is extended to include correlation of group actions on domain and range. By relaxing the restriction of weight functions to be constant over orbits, more specific results concerning the enumeration of orbits by weight are obtained.This paper is dedicated to Professor Dr. Ernst Ruch on the occasion of this 65th birthday     

On the equivalence of three types of blocking in non-Markovian tandem queues

Definitions of blocking types for tandem queueing systems are given where each stage consists of multiple servers. Some of them are shown to be identical with respect to service initiation epochs at each stage. Such identical relationships are proved using sample path correspondence, and are therefore valid irrespective of the arrival process and the service time distributions.     

STRONG CODING THEOREM AND ASYMPTOTIC ERROR EXPONENT OF ARBITRARILY VARYING SOURCE

ＳＴＲＯＮＧＣＯＤＩＮＧＴＨＥＯＲＥＭＡＮＤＡＳＹＭＰＴＯＴＩＣＥＲＲＯＲＥＸＰＯＮＥＮＴＯＦＡＲＢＩＴＲＡＲＩＬＹＶＡＲＹＩＮＧＳＯＵＲＣＥ符方伟，沈世镒）￥ＦｉＦａｎｇｗｅｉ；ＳｈｅｎＳｉｙｉ（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＮａｎｋａｉＵｎｉｖ．，Ｔ...     

Magnetic and electronic phase transitions and magnetoresistance effect in the Pr0.5−xLaxSr0.5MnO3 (, 0.15) system

The electronic and magnetic phase transitions of Pr_0.5−xLa_xSr_0.5MnO₃ with x=0.10 and 0.15 were investigated. The M(T) and ρ(T) curves for these samples clearly show transitions from antiferromagnetic insulator to ferromagnetic semiconductor, ferromagnetic metal and finally to paramagnetic semiconductor as the temperature is increased from 5 to 300 K. Especially, two obvious protrudent peaks in the magnetoresistance curves MR(T) for these samples were clearly observed in the relative low magnetic field, 1 T. One peak appears at around the antiferromagnet-ferromagnet transition temperature T_N (150 K) with MR≈−23%, another occurs at around the ferromagnet-paramagnet transition temperature T_C(275 K ) with MR≈−8.2%. In addition, when the magnetic field was increased, the temperature corresponding to the MR peak at T_N shifts to lower temperature while the temperature corresponding to the MR peak at T_C is fixed.     

Cubical 4-Polytopes with Few Vertices

A cubical polytope is a convex polytope all of whose facets are conbinatorial cubes. A d-polytope Pis called almost simple if, in the graph of P, each vertex of Pis d-valent of (d+ 1)-valent. It is known that, for d> 4, all but one cubical d-polytopes with up to 2^d+1vertices are almost simple, which provides a complete enumeration of all the cubical d-polytopes with up to 2^d+1vertices. We show that this result is also true for d=4.