遗传算法用于变量筛选

利用遗传算法的优越搜索寻优特性,结合有序Gram-Schmidt正文化及PLS算法可得到预报能力较强的模型,即PRESS(预报残差平方和)值较低的模型.该法可用于处理构效关系及人发微量元素与性别关系问题,并与正交递归选择法及逐步回归正向选择法进行比较,结果良好.     

Recurrence and return times of the Sierpinski carpet

We compute the limit distribution of the recurrence and of the normalizedk th return times to small sets of the Sierpinski carpet with respect to a natural measure defined on it. It is proved that this dynamical system follows the Poisson law, as one could have expected for such schemes. We study different sequences which converge in finite distribution to the Poisson point process. This limit in law is very interesting in ergodic theory, and it seems to appear for chaotic dynamical systems such as the one we study.     

Spurious Structures in Recurrence Plots Induced by Embedding

In this paper we show that delay embedding produces spurious structures in a recurrence plot (RP) that are not present in the real attractor. We analyze typical sets of simulated data, such as white noise and data from the chaotic R?ssler system to show the relevance of this effect. In the second part of the paper we show that the second order Rényi entropy and the correlation dimension are dynamical invariants that can be estimated from Recurrence Plots with arbitrary embedding dimension and delay.     

一族二阶导数计值迭代方法的收敛性

从带一个参数的三阶迭代族(其中包括Halley迭代,Chebyshev迭代和超Halley迭代)出发,推出避免二阶导数计算的带两个参数的迭代族.在Newton-antorovich型的假设条件下,通过用一个递推关系证明了此迭代族的三阶收敛性,并给出了非线性算子方程解的存在惟一性定理.     

双无限环境中马氏链的状态分类

在引进一系列与随机环境中的马氏链相关的概率特性函数,我们可以得到这些函数之间的一系列关系。     

食管癌术后吻合口复发因素和防治

探讨食管癌根治术后吻合口复发的因素,根据复发类型采取不同的治疗手段,以期降低其复发率.以21例食管癌根治术病理切缘阴性而在术后3～33个月内发现吻合口复发患者的临床资料进行回顾性分析.分别比较不同的临床分期、病理类型、手术方式、术后辅助放疗后的复发率,统计学分析用卡方检验.食管癌术后吻合口复发与肿瘤的恶性程度高、期别晚及手术范围不足等因素相关.术后纵隔区放射治疗未见改善吻合口复发的发生率.复发后适宜地采取手术或放射治疗,可以使少部分病人获益.     

新环形库仑势的束缚连续跃迁矩阵元

利用新环形库仑势的归一化的束缚态径向波函数和按“k/2π标度”归一化的散射态径向波函数,本文给出了新环形库仑势的任意幂次的束缚连续跃迁矩阵元的通项表达式.为了简化高幂次的束缚连续跃迁矩阵元的计算,我们还推导出了不同幂次的束缚连续跃迁矩阵元之间所满足的递推关系,并提出了计算径向波函数微商的矩阵元的计算办法.本文结果可广泛的用于原子与分子的散射问题特别是环形分子的散射问题之中.     

光脉冲传输模拟的快速数值差分递推算法及其应用研究

利用零邻域的马克劳林展开对归一化非线性薛定谔方程的频域差分形式进行分析，得出一个能够同时考虑光学媒质的色散作用以及非线性克尔作用的时域快速数值差分递推公式.选取若干算例，将运用该公式的数值计算结果与已知的解析结果和传统分步傅里叶方法所得的计算结果做了相应的比较，结果表明这种快速数值差分递推公式不但拥有相当快的计算速度，也有很高的计算精度，而且在物理上符合光脉冲在光学媒质中传输时色散和非线性作用同时施加影响的客观实际，这说明它是研究非线性光学媒质中光脉冲传输的一种科学、合理而快速有效的数值计算方法. 关键词： 快速数值差分递推公式 零邻域马克劳林展开 非线性薛定谔方程 光脉冲传输     

HIGHER ORDER MULTIVARIABLE NORLUND EULER-BERNOULLI POLYNOMIALS

The definitions of higher order multivariable Norlund Euler polynomials and Norlund Bernoulli polynomials are presented and some of their important properties are expounded. Some identities involving recurrence sequences and higher order multivariable Norlund Euler-Bernoulli polynomials are established.     

Recurrence spectra of He atoms in strong external fields

1 Introduction The photo-absorption phenomenon of high Rydberg atoms in strong external fields has attracted much attention in recent years. The semiclassical closed-orbit theory[1,2] developed by Du and Delos has been extensively used to explain this phenomenon. This theory has successfully calculated and interpreted the photo-absorption spectra of H- in various external fields[3,4] and has been applied to describe the photo-excitation, wave packet dynamics of some atoms and molecules such…