The characteristic finite difference fractional steps methods for compressible two-phase displacement problem

For compressible two-phase displacement problem, a kind of characteristic finite difference fractional steps schemes is put forward and thick and thin grids are used to form a complete set. Some techniques, such as piecewise biquadratic interpolation, of calculus of variations, multiplicative commutation rule of difference operators, decomposition of high order difference operators and prior estimates are adopted. Optimal order estimates inL ² norm are derived to determine the error in the approximate solution. Project supported by the National Scaling Program, the National Tackling Key Problems Program and the Doctorate Foundation of the State Education Commission of China.     

On similarity homogeneous locally compact spaces with intrinsic metric

In this article, we generalize partially the theorem of V. N. Berestovskii on characterization of similarity homogeneous (nonhomogeneous) Riemannian manifolds, i.e., Riemannian manifolds admitting transitive group of metric similarities other than motions to the case of locally compact similarity homogeneous (nonhomogeneous) spaces with intrinsic metric satisfying the additional assumption that the canonically conformally equivalent homogeneous space is δ-homogeneous or a space of curvature bounded below in the sense of A. D. Aleksandrov. Under the same assumptions, we prove the conjecture of V. N. Berestovskii on topological structure of such spaces.     

具有变系数的二阶中立型差分方程

研究一类具有变系数的二阶中立型时滞差分方程 △τ^2[x（t）-c（t）x（t-τ）]=p（t）x（t-σ），t≥t0〉0 的解的振动性，给出了该类方程一切有界解振动的几个充分条件．     

On 8mm Microwave Radiometric Imaging System

This paper describes structure of imaging system, imaging mechanism of microwave radiometer, and the microwave radiation image features and recognition. Results of image experiments show: on microwave radiation image, the features of metal target, water surface and road among trees, grassland and jungle become extremely obvious.     

亚波长光栅衍射效率特性设计的遗传算法优化

亚波长光栅中的衍射需要使用矢量衍射理论进行分析,其衍射效率与多个因素有关,对任意面形、任意入射条件的亚波长光栅的衍射来说,使用严格的耦合波理论进行分析计算可以得到数值解。通过分析不同参数条件下的衍射特性和衍射效率对各个参数的敏感性,获得了对衍射效率影响最大的光栅参数——槽深。用接近衍射效率曲线的抛物线作为目标函数建立了适应度函数。使用遗传算法进行优化,得到了所期望的衍射效率滤波特性,从而完成了具有防伪功能的亚波长光栅的设计。     

Deformation of a singularity of type E8 and Mordell‐Weil lattices in characteristic 2

In this paper, we study the Mordell‐Weil lattices of the family of elliptic surfaces which is arising from the E₈⁴ singularity, one of the ADE singularities in characteristic 2. And we construct a subfamily of the universal family of supersingular K 3 surfaces in characteristic 2 as an application (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

一种多传感器数据的统计融合方法

针对多个传感器对某一特性指标进行测量实验的数据融合问题,提出了统计距离意义上的不同传感器之间的融合度定义,并给出了一种可以较好地避免主观因素的关系矩阵的方法,从而得到了一种新的多传感器数据的融合算法.该算法简洁稳定,可用于提高智能仪表的测量准确度和改善智能仪表的抗干扰能力.     

Characteristic Classes for Difference Operators

We introduce and describe the characteristic class of a difference operator over the difference field (k((t)),). Here k is an algebraically closed field of characteristic zero and is the k-linear automorphism of k((t)) defined by (t)=t/(1+t). The approach is based on the characterization of simple difference operators in terms of their eigenvalues.     

Asymptotic Expansions of Large Deviations for Sums of Nonidentically Distributed Random Variables

The work is designated for obtaining asymptotic expansions and determination of structures of the remainder terms that take into consideration large deviations both in Cramer zones and Linnik power zones for the distribution function of sums of independent nonidentically distributed random variables (r.v.). In this scheme of summation of r.v., the results are obtained first by mainly using the general lemma on large deviations considering asymptotic expansions for an arbitrary r.v. with regular behaviour of its cumulants [11]. Asymptotic expansions in the Cramer zone for the distribution function of sums of identically distributed r.v. were investigated in the works [1,2]. Note that asymptotic expansions for large deviations were first obtained in the probability theory by J. Kubilius [3].