光电过程原子能级截面大量计算的实现

在HFR方法的基础上,考虑束缚组态间的相互作用,解决了Cowan程序光电计算过程中小能量区间误差偏大及一次计算自由电子能量范围受限制的问题,确定了阈能点的计算方式,从而使大量计算成为可能。分析证明了计算结果的正确性并估计了计算精度。并对锂、钠与铯原子计算的结果与参考文献做了比较,从理论上分析了能极水平光电截面求和后的结果与轨道水平光电截面的过渡关系与差别。     

基于模糊一致矩阵法的优选炮阵地模型研究

运用基于模糊一致矩阵元素与权重关系式的排序方法,建立了一个基于模糊一致矩阵法的优选炮兵阵地的数学模型,具有较强的可操作性,利于计算机实现,可为实现炮兵作战自动化指挥提供有力支持.     

关于极端原子核的相对论自洽角动量投影壳模型计算(英文)

相对论自洽角动量投影壳模型是最近发展出来的一个自洽模型, 它对于不同核区具有稳定的参数, 能够很好地描述已知和未知具有稳定形变的各种原子核的性质。 计算了若干包括稳定核素、 极端核素和超重核素, 并把计算结果与现有的实验数据进行了比较。     

Consistent Initialization for Nonlinear Index-2 Differential–Algebraic Equation: Large Sparse Systems in MATLAB

An important component of any initial-value solver for higher-index differential–algebraic equations consists in the computation of consistent initial values. In a recent paper [5], an algorithm is proposed which is applicable to a very general class of index-2 systems. Unfortunately, the computational expense is rather high. We present a modification of this approach, which gives rise to a MATLAB implementation capable of handling systems of moderate dimension (several thousands of unknowns). The algorithm is illustrated by examples.     

基于残差平方和的线性模型选择简单方法及其相合性研究

本文研究了回归分析理论中的自变量选择的重要问题,利用线性回归模型自变量增减的残差平方和理论,获得了一种选择自变量的准则,该准则的分析表明,它计算简单,而且在一定的条件下具有强相合性.     

Differentiability of Consistency Functions for DAE Systems

In the present paper, parametric initial-value problems for differential-algebraic (DAE) systems are investigated. It is known that the initial values of DAE systems must satisfy not only the original equations in the system but also the derivatives of these equations with respect to time. Whether or not this actually imposes additional constraints on the initial values depends on the particular problem.Often the initial values are not determined uniquely, so that the resulting degrees of freedom can be used to optimize a given performance index. For this purpose, the class of so-called consistency functions is defined. These functions map a set of parameters, which include also those undetermined initial values, to consistent initial values for the DAE system. Because of frequent gradient evaluations of the performance index and the constraints with respect to these system parameters needed by many optimization procedures, we state conditions such that the consistency functions represent differentiable functions with respect to these parameters. Several examples are provided to illustrate the verification of the theoretical assumptions and their differentiability properties.The authors would like to thank the referees for helpful suggestions and comments     

Estimating a survival function with incomplete cause-of-death data

We propose a random censorship model which permits uncertainty in the cause of death assessments for a subset of the subjects in a survival experiment. A nonparametric maximum likelihood approach and a “self-consistency” approach are considered. The solution sets corresponding to both approaches are found. They are infinite and identical. Only some of the solutions are consistent; i.e., the MLEs and self-consistent estimators are not consistent in general. Two estimates are thus proposed and their asymptotic properties are studied. It is shown that both estimates are strongly consistent and converge to Gaussian processes. The covariance structures of these Gaussian processes are derived.     

On exponential rates of likelihood ratio estimators for location parameters

In this paper the exponential rates, bounds, and local exponential rates for likelihood ratio estimators are studied. Under certain regularity conditions, a family of likelihood ratio estimators is shown to be admissible in exponential rate. It is also shown that the maximum likelihood estimator is the limit of this family of estimators.     

X-ray energy levels: Deviations between experimental and theoretical values

Energy values ofK, L _II andL _III levels calculated by the relativistic self consistent field method have been used to compute the energies ofKα _{1, 2} lines. These values deviate considerably from the experimental values due to Bearden and Burr. The deviations are discussed and given an empirical fit.