基于近似熵的随机数检验方法的设计与实现

把近似熵用于密码技术中,设计一种实用的随机数检验方法.该方法可以检测随机序列发生器产生序列的随机性,也可以用于检验密码算法的安全性.通过实验,发现该方法能更全面检验序列的随机特性.     

极值Beltrami系数的Hamilton序列

考虑了Strebel点与Hamilton序列之间的关系.这个问题是Gardiner F.P.最早研究的(见[Approximation of infinite-dimensional Tcichmiiller spaces,Trans.Amer.Math.Soc.,1984,282(1):367-383]).在无限小Teichmiiller空间中,证明了范金华在[On infinitesimal Teichmüller space,Bull.Austral Math.Soc.,2008,78:293-300]中得到的使{φ_n}成为Hamilton序列的充分条件不是必要的.     

变系数反馈移位寄存器及其序列的几个性质

本文给出了一类新的密钥流生成器一变系数反馈移位寄存器,得到了该密钥流生成器序列的几个重要的密码学性质,并在文中给出了严格的数学证明。     

递推数列xn＋1=f（xn）的单调性与收敛性讨论

利用函数单调递增对递推数列xn＋1=f（xn）单调性进行讨论,在对递推数列收敛性作分析的基础上,得到使得递推数列收敛的初始迭代值的区域,讨论的方法可以用于类似问题的研究．     

Banach空间中有限族渐进伪压缩映象的迭代程序

Let E be a real Banach space and K be a nonempty closed convex and bounded subset of E. Let Ti ： K→ K, i=1, 2,... ,N, be N uniformly L-Lipschitzian, uniformly asymptotically regular with sequences {ε^（i）n} and asymptotically pseudocontractive mappings with sequences {κ^（i）n}, where {κ^（i）n} and {ε^（i）n}, i = 1, 2,... ,N, satisfy certain mild conditions. Let a sequence {xn} be generated from x1 ∈ K by zn：= （1-μn）xn＋μnT^nnxn, xn＋1 ：= λnθnx1＋ [1 - λn（1 ＋ θn）]xn ＋ λnT^nnzn for all integer n ≥ 1, where Tn = Tn（mod N）, and {λn}, {θn} and {μn} are three real sequences in [0, 1] satisfying appropriate conditions. Then ｜｜xn- Tixn｜｜→ 0 as n→∞ for each l ∈ {1, 2,..., N}. The results presented in this paper generalize and improve the corresponding results of Chidume and Zegeye, Reinermann, Rhoades and Schu.     

Dynamics of intramolecular recognition: Base-pairing in DNA/RNA near and far from equilibrium

The physics of the base-pairing interaction in DNA and RNA molecules plays a fundamental role in biology. Past experimental and theoretical research has led to a fairly complete and quantitative understanding of the equilibrium properties such as the different phases, the melting behavior, and the response to slow stretching. The non-equilibrium behavior is even richer than might be expected on the basis of thermodynamics. However, the non-equilibrium behavior is also far less understood. Here, we review different theoretical approaches to the study of base-pairing thermodynamics and kinetics, and illustrate the rich phenomenology with several examples that use these approaches.     

副猪嗜血杆菌的MLST分析及数据库建立

对副猪嗜血杆菌86个分离株的7个看家基因,包括ATP合成酶β链(atpD)、翻译起始因子IF-2(in-fB)、核糖体蛋白β亚基(rpoB)、苹果酸脱氢酶(mdh)、6-磷酸葡萄糖脱氢酶(6pgd)、3-磷酸甘油醛脱氢酶(g3pd)和延胡索酸还原酶B(frdB)进行了PCR扩增;对扩增产物进行了测序;对序列编辑、队列     

基于拟群的伪随机序列周期研究

基于拟群的非线性伪随机序列在密码学中有着重要的应用,尤其是周期长的非线性伪随机序列,但该序列的拟群目前只能通过计算机做统计实验的方法得到.笔者从理论上给出了周期增长率高的拟群的代数与组合特征以及其构造方法.     

桔全爪螨几丁质合成酶基因克隆与序列

以桔全爪螨Panonychus citri(MeGregor)为研究对象,利用RT-PCR和SMART RACE技术克隆获得其几丁质合成酶基因的全长cDNA序列(命名为PcCHS,GenBank登录号为KM242063),并利用生物信息学方法对序列进行分析。结果表明:桔全爪螨几丁质合成酶PcCHS基因的cDNA全长为4 925bp,其中5’非翻译区(5’-UTR)为155bp,3’非翻译区(3’-UTR)为345bp,开放阅读框(ORF)包含4 425bp,编码1 474个氨基酸,预测其蛋白质分子质量约为168.43kD,理论等电点为6.83。其包含EDR和QRRRW这2个几丁质合成酶基因的标签序列。ExPASy在线分析表明,PcCHS具有15个跨膜螺旋、4个糖基化位点。推导的氨基酸序列同源性分析结果表明:桔全爪螨与二斑叶螨相似度为89%,其次为西方盲走螨,相似度为55%。分子系统进化的结果也表明桔全爪螨与二斑叶螨和西方盲走螨的进化关系最近。     

Non-linear electromechanical response of 1–3 type piezocomposites

Domain switching in piezoelectric materials is caused by external loads such as electric field and stress that leads to non-linear behaviour. A study is carried out to compare the non-linear behaviour of 1–3 piezocomposites with different volume fractions and bulk piezoceramics. Experiments are conducted to measure the electrical displacement and strain on piezocomposites and bulk ceramics under high cyclic electrical loading and constant compressive prestress. A thermodynamically consistent uni-axial framework is developed to predict the nonlinear behaviour by combining the phenomenological and micromechanical techniques. Volume fractions of three distinct uni-axial variants (instead of six variants) are used as internal variables to describe the microscopic state of the material. In this model, the grain boundary effects are taken into account by introducing the back fields (electric field and stress) as non-linear kinematic hardening functions. An analytical model based on equivalent layered approach is used to calculate effective properties such as elastic, piezoelectric, and dielectric constants for different volume fractions of piezocomposites. The predicted effective properties are incorporated in the proposed uni-axial model and the dielectric hysteresis (electrical displacement versus electric field) as well as butterfly curves (strain versus electric field) are simulated. Comparison between the experiments and simulations show that this model can reproduce the characteristics of non-linear response. It is observed that the variation in fiber volume fraction and compressive stress has a significant influence on the response of the 1–3 piezocomposites.