Asymptotic Distribution of a Kind of Dirichlet Distribution

The Dirichlet distribution that we are concerned with in this paper is very special, in which all parameters are different from each other. We prove that the asymptotic distribution of this kind of Dirichlet distributions is a normal distribution by using the central limit theorem and Slutsky theorem.     

有限级亚纯函数的不变原理

研究有限级亚纯函数的统计性质,证明了有限级亚纯函数的几乎必然不变原理,如中心极限定理、重对数定律和泛函中心极限定理等统计定律是几乎必然不变原理的推论.     

以“现金池”打造“利润中心”

当前,“现金为王（Cashis King）”的理念在企业财务管理中受到空前的重视,人们在总结历次经营失败的教训时,发现了一个共同的规律：无论何种诱因导致经营失败,最终都必然地显现为资金链断裂和现金流枯竭。现金流成为企业经营、投资、融资活动的综合体现,商业银行也把如何协助客户构建健康的现金流,     

海水入侵数值模拟的特征块中心差分法

本文研究二维海水入侵数值模拟的有限差分法．对关于压力的流动方程本文采用块中心差分法,对关于含盐浓度方程的对流扩散方程采用基于完全二次矩形插值的特征差分法,运用先验估计的理论和技巧得到了最佳阶L~2误差估计的结果．     

第十一届北京高中数学知识应用竞赛决赛试题

<正>1.(满分20分)北京市出租车计价是如下规定的:行程在3公里以内10元;大于等于3公里,每公里2元;总里程大于等于15公里的部分加收50%.每半公里计一次价,不足半公里按半公里计,例如,当行驶路程x(公里)满足12≤x<12.5时,按12.5公里计价;当12.5≤x<13时,按13公里计价.途中时速低于12公里(称为等候)时.每累计2.5分钟加收1元,不足2.5分钟不计,例     

Design and Fabrication of Ni/Ti Multilayer for Neutron Supermirror

In the applications of neutron guides and focusing devices, by using the Ni/Ti multilayer supermirrors （SM）, the neutron flux is significantly enhanced, because the critical reflective angle of supermirrors increases m times compared to the one of natural bulk Ni. We design and fabricate the Ni/Ti multilayer supermirrors by considering the effect of the interfacial imperfection, such as interface roughness and diffusion, and by using the direct current magnetron sputtering technology. The reflective performances of these supermirrors are measured on a V14 neutron beam line at the Berlin Neutron Scattering Centre （BENSC）, Germany. The measurement data suggest that the critical angles of the supermirrors are 1.5 and 2.2 times that of bulk Ni, respectively.     

A Novel Hollow-Core Holey Fibre with Random Hole Distributions in the Cladding

We provide a novel hollow-core holey fibre that owns a random distribution of air holes in the cladding. Our experiments demonstrate that many of the features previously attributed to photonic crystal fibres with perfect arrangement of air holes, in particular, photonic bandgap guidance, can also be obtained in the fibre. Additionally, this fibre exhibits a second guided mode with both the two-lobe patterns, and each pattern is in different colour.     

Half-Lives of Spherical Proton Emitters

The distorted-wave Born approximation （DWBA） method is used to calculate the half-lives of spherical proton emitters. The calculated results are in agreement with the experimental data, The sensitivity of the half-lives to the depth of central potential V0 is investigated by using the DWBA method. The half-lives of spherical proton emitters are insensitive to the detail of their nuclear potential.     

n-李代数的中心扩张

对n-李代数的中心扩张问题进行了研究,提出了Heisenberg n-李代数的概念,并对任意一个线性空间V,给出了构造Heisenberg n-李代数H(V)的一种方法且研究了一类特殊类型Heisenberberg n-李代数的导子代数的结构.     

分子束外延生长的n型Al掺杂ZnS1-xTex深中心研究

应用电容-电压、光致荧光和深能级瞬态谱技术研究了分子束外延生长的n型Al掺杂ZnS_1-xTe_x外延层深中心.Al掺杂ZnS_0.977Te_0.023的光致荧光强度明显低于不掺杂的ZnS_0.977Te_0.023，这表明一部分Al原子形成非辐射深中心.Al掺杂ZnS_1-xTe_x(x=0，0.017，0.04和0.046)的深能级瞬态傅里叶 关键词：