Variable-Coefficient Hyperbola Function Method and Its Application to (2+1)-Dimensional Variable-Coefficient Broer-Kaup System

Based on a new intermediate transformation, a variable-coefficient hyperbola function method is proposed.Being concise and straightforward, it is applied to the (2 1)-dimensional variable-coefficient Broer Kaup system. As a result, several new families of exact soliton-like solutions are obtained, besides the travelling wave. When imposing some conditions on them, the new exact solitary wave solutions of the (2 1)-dimensional Broer-Kaup system are given. The method can be applied to other variable-coefficient nonlinear evolution equations in mathematical physics.     

Relativistic Navier-Stokes equations in the Meixner-Prigogine scheme

Viscous effects are included in the relativistic Meixner-Prigogine scheme (see: A. Sandoval-Villalbazo, L.S. García-Colín, Physica A 234 (1996) 358). A relativistic generalization of the Navier-Stokes equations is obtained within this framework. The system obtained is analyzed and compared with related work.     

用力敏传感器测液体表面张力系数的误差分析

分析了采用力敏传感器测量液体表面张力系数实验误差的主要来源，给出了计算公式和测量结果，并提出了改进建议．     

Probabilistic properties of neuron spiking time-series obtained in vivo

Probabilistic properties of spiking time-series obtained in vivo from singular neurons belonging to Red Nucleus of brain are analyzed for two groups of rats: genetically defined rat model of depression (Flinders Sensitive Rat Line - FSL) and a control (healthy) group. The FSL group shows a distribution of interspike intervals with a much longer tail than that found for normal rats. The former distribution (for the FSL group) indicates a power-law with exponent α = - 1±0.1. A simple thermodynamic (noise) model is elaborated to explain obtained results. Received 13 May 2001 and Received in final form 20 September 2001     

Advanced adiabatic approximation for momentum distributions of ejected electrons in slow atomic collisions

The problem of determination of momentum distributions of ejected electrons in slow atomic collisions is studied within the impact-parameter method by using a dynamic adiabatic basis which takes into account the correct boundary conditions. An expression is obtained which relates the momentum distribution of the ejected electrons with a coherent sum of the delocalized dynamic adiabatic eigenstates (elementary wavepackets). The form of the momentum distribution exactly coincides with the form of the total wavepacket in configuration space. General formulas are applied to a model problem of electron detachment in the process in which the electron-atom interactions are described by the zero-range potentials. In the example considered, the momentum distribution of ejected electrons, in the center-of-mass frame, exhibits a maximum located in the scattering plane on the circle of radius (in atomic units), where v is the relative collision velocity and is the impact parameter. Received: 5 October 1998     

基于灰色系统的模糊综合评判在产险公司偿付能力评价中的应用

本文将灰色系统中的灰关联分析理论和模糊数学中模糊综合评判法引入保险公司偿付能力的综合评价排序中。通过案例分析，对2005年我国八家主要财产保险公司（以下简称产险公司）的偿付能力作了判断比较，给出了综合排序。     

部分线性变系数模型中估计的渐进正态性

作为部分线性模型与变系数模型的推广,部分线性变系数模型是一类应用非常广泛的模型,本文基于Profile最小二乘方法给出了模型中参数分量与非参数分量的估计,并在异方差情形下证明了这些估计的渐进正态性.     

Parabolic conjugacy in general linear groups

Let q be a power of a prime and n a positive integer. Let P(q) be a parabolic subgroup of the finite general linear group GL _n (q). We show that the number of P(q)-conjugacy classes in GL _n (q) is, as a function of q, a polynomial in q with integer coefficients. This answers a question of Alperin in (Commun. Algebra 34(3): 889–891, 2006)     

最优数学模型筛选法确定流量系数的经验公式

应用简单的最小二乘回归分析原理对多个数学模型进行分析,得到了水利工程中有坎宽顶堰流量系数的经验公式,并对其精度进行了讨论.对指导实际工程意义重大.     

单纯形上Bernstein多项式的一些性质

设Ｂ_m（ｆ，·）为函数ｆ在ｄ维单纯形σ上的ｎ阶Ｂｅｒｎｓｔｅｉｎ多项式，本文对ｆ∈Ｃ^ｒ（σ）及ｆ∈Ｃ^r+2（σ）给出了ｆ的各阶编导数用Ｂ_n（ｆ，·）相应偏导数逼近的误差估计．同时也考虑了整系数Ｂｅｒｎｓｔｅｉｎ多项式的Ｌ_p模估计