乌鲁木齐市商业中心的等级体系及合理布局的探讨

本文利用85年5—6月间对乌鲁木齐市主要商业区及部分中、小商业区的实地调查资料,对乌市商业中心等级系统进行了定性和定量的分级分类,将全市商业中心划分为五个等级,八组商业中心,对已形成的商业中心分布现状进行了初步探讨,并对今后商业网点的合理布局提出了建议。     

Structure and mechanical properties of Al/AlN multilayer with different AlN layer thickness

Nanometer scale Al/AlN multilayers have been prepared by dc magnetron sputtering technique with a columnar target. A set of Al/AlN multilayers with the Al layer thickness of 2.9 nm and the AlN layer thickness variation from 1.13 to 6.81 nm were determined. Low angle X-ray diffraction (LAXRD) was used to analyze the layered structure of multilayers. The phase structure of the coatings was investigated with grazing angle XRD (GAXRD). Mechanical properties of these multilayers were thoroughly studied using a nanoindentation and ball-on-disk micro-tribometer. It was found that the multilayer hardness and reduced modulus showed no strong dependence on the AlN layer thickness. Al2.9 nm/AlN1.13 nm multilayer had more excellent tribological properties than single layers and other proportion multilayers with a lowest friction coefficient of 0.15. And the tribological properties of all the multilayers are superior to the AlN single layer.     

具功能反应的三种群捕食者——食饵系统数学模型稳定性的研究

[1]中提出了具有功能反应的三种群捕食者——食饵系统的两种模型(Ⅰ)、(Ⅱ),并给出了局部渐近稳定的条件。本文研究了另外两种模型(Ⅲ)和(Ⅳ)的局部渐近稳定的条件。     

掺铒光纤放大器中上转换过程的影响

掺杂浓度的提高影响了掺铒光纤放大器(EDFA)的性能,对经典Giles模型提出了新的要求。首先研究了高掺杂下铒离子距离较小引起的上转换过程的机理,通过优化速率方程模型分析了上转换过程对EDFA的影响,得出了在泵浦光和信号光远远大于ASE光的假设下泵浦光和信号光沿光纤长度变化的近似表达式,并将该近似分析解与解析解进行了比较。仿真结果表明上转换过程会降低随光纤传输的信号光和泵浦光,影响EDFA的放大性能,并得出了当掺铒浓度大于2.95×1025m-3时,上转换过程的影响不能忽略的结论。     

A generalization of biorthogonal systems based on Drazin inverse

In this paper, the transformations of generating systems of Euclidean space are examined in connection with the Drazin inverse of their Gram matrices and the notion of biorthogonal systems is generalized. The results obtained in this paper can be considered as the extension of some recent results concerning Moore-Penrose biorthogonal systems and reflexiveg-inverse systems in Euclidean spaces.     

Ψ(2S)粒子及粲夸克偶素物理实验研究——2001年度国家自然科学奖获奖项目介绍

文章介绍2001年度国家自然科学奖二等奖获奖成果，在北京正负电子对撞机上采集了Ψ（2S）粒子大数据样本，开展了粲偶素物理的广泛研究：完成了6个粲偶素涉及质量，宽度和衰变化支比等大批重要参数的首次测量或高精度测量；通过对Ψ（2S）和J／Ψ强衰变性质的比较研究，观察到一系列反常现象，挑战现有理论图像。该项研究成果对量子色动力学的检验与发展具有重要意义，为我国粲偶素物理实验研究的继续发展并保持先进水平奠定坚实基础。     

Convergence Rate of The Trust Region Method for Nonlinear Equations Under Local Error Bound Condition

In this paper, we present the new trust region method for nonlinear equations with the trust region converging to zero. The new method preserves the global convergence of the traditional trust region methods in which the trust region radius will be larger than a positive constant. We study the convergence rate of the new method under the local error bound condition which is weaker than the nonsingularity. An example given by Y.X. Yuan shows that the convergence rate can not be quadratic. Finally, some numerical results are given. This work is supported by Chinese NSFC grants 10401023 and 10371076, Research Grants for Young Teachers of Shanghai Jiao Tong University, and E-Institute of Computational Sciences of Shanghai Universities. An erratum to this article is available at .     

An inverse radiative transfer problem of simultaneously estimating profiles of temperature and radiative parameters from boundary intensity and temperature measurements

A parallel-plane space filled with absorbing, emitting, isotropically scattering, gray medium is studied in this paper. The boundary intensity and boundary temperature profiles are calculated for the inverse analysis. For the simultaneous estimation of temperature, absorption and scattering coefficient profiles in the medium, the sum of residuals of boundary intensity and temperature after being weighted by a balance factor is minimized through using a Newton-type iteration algorithm and the least-squares method. To avoid over-updating for the parameters, the relative updating magnitude during the iteration process is constrained not to be >0.5. It is shown that the boundary intensity measurement alone is not enough to estimate simultaneously the temperature (source) and the radiative properties (both absorption and scattering coefficients) when the measurement data contain sensitive random errors. The boundary temperature measurement can serve as a necessary supplementation to the boundary intensity to make this kind of inverse radiative transfer problem resolvable. It was shown that a compensation relationship between absorption and scattering coefficients makes it difficult to fix them accurately. Parabolic profiles for the three parameters are used to validate the estimation method. When the optical thickness approaches 4.0, the results for the radiative properties are not acceptable, although the result for temperature profile is reasonable. This means the method needs further improvements.     

二阶Volterra系统对平稳正态激励的统计响应的表示定理的数学证明

1974年,Neal根据Kac和Siegert的思想,给出了一个在电子工程、海洋工程、建筑工程、航空工程、自动控制的随机振动中有重要应用的二阶Volterra非线性系统对平稳正态输入的统计响应的表示定理.1984年,Naess对此定理又给出了一个数学证明.经过研究后发现,他们对定理条件的叙述都是模糊的,而且其数学证明都是有问题的.本文重新讨论了这个表示定理,给出了明确的定理条件及严格的数学证明,为它的广泛应用奠定了理论基础.