p进制中幂的数字和

给出ｐ 进制中正整数α的数字和Ｓ（α）与αｎ 的数字和Ｓ（αｎ）之间的关系：Ｓ（αｎ）－ １αｎ－ １ ≤Ｓ（α）－ １α－ １ （α≠１）．     

图Pm＋Pn的Smarandachely邻点全色数

运用组合分析法,给出了m阶路与n阶路（m〈n）的联图的Sm arandachely邻点全色数.     

LOCAL ASYMPTOTIC PROPERTIES OF HAZARD RATE ESTIMATORS FOR TRUNCATED AND CENSORED DATA

1 IntroductionLet (X, T, Y) denote random variables where X is the variab1e of interest, called the lifetimevariab1e, with distribution function (d.f.) F; T is the random 1eft truncation time with arbitraryd.f G and Y is the random right censoring time with arbitrary d.f. H. It is assumed that Xis independent Of (T, Y), bnt T and Y may be dePendent and, Without 1oss of generality thatthey are nonnegative. In the random 1eft truncation and right censoring (LTRC) model oneobserves (Z, T…     

无限方阵的二平方和定理

证明了在有单位元的环上，任一无限方阵M都可唯一地表示为2个特殊形状无限方阵S及T的平方和．进一步讨论了当M为行列有限的无限方阵时S及T的形状．     

静电涂油机喷涂机理研究

在油液带电的静电涂油机中，接高压直流电源负极的刀形喷油梁与接地的带钢（或钢板）之间产生高压静电场，从喷油梁刃口狭缝中流出的油液直接带电，在强电场中雾化后吸附在带钢（板）表面上，实现“静电涂油”。喷油梁结构型式与直流电源输出电压是影响静电涂油的主要因素。     

一种基于医学三维数据场模糊分割的体元投射算法

论证了医学三维数据场边界过渡区域的存在性，并提出了一个修正体元投射算法。该方法先对三维数据场进行归一、整数化的预处理，并修正扩展二维图像的分割方法，使之适用于提取三维数据场边界过渡区。在此基础上将三维数据场非此即彼的分类优化为将数据场分为边界过渡区域和非边界过渡区域的模糊分割，再分别予以不同的体元投射绘制。最后给出的实验结果表明，算法既可以提高了数据场过渡区域的图像质量，又可以保证图像的绘制速度。     

A preliminary study on the teratogenesis of dexamethasone and the preventive effect of vitamin B12 on murine embryonic palatal shelf fusion in vitro

Excessive dexamethasone （Dex） administrated into pregnant mice during critical periods of palatal development can produce a high incidence of cleft palate. Its mechanisms remain unknown. Vitamin B12 has been shown to antagonize the teratogenic effects of Dex, which, however, remains controversial. In this study, we investigated the effects of Dex and vitamin B12 on murine embryonic palatal shelf fusion using organ culture of murine embryonic shelves. The explanted palatal shelves on embryonic day 14 （E14） were cultured for 24, 48, 72 or 96 h in different concentrations of Dex and/or vitamin B 12. The palatal shelves were examined histologically for the morphological alterations on the medial edge epithelium （MEE） and fusion rates among different groups. It was found that the palatal shelves were not fused at 72 h or less of culture in Dex group, while they were completely fused in the control and vitamin B 12-treated groups at 72 and 96 h, respectively. The MEE still existed and proliferated. In Dex＋vitamin B12 group the palatal shelves were fused at each time point in a similar rate to controls. These results may suggest that Dex causes teratogenesis of murine embryonic palatal shelves and vitamin B12 prevents the teratogenic effect of Dex on palatogenesis on murine embryos in vitro.     

HgTe量子阱中的量子自旋霍尔绝缘态

近来,理论研究预言量子霍尔效应,在外加磁场为0的情况下物质出现的一种全新的量子态可以在HgTe/（Hg,Cd）Te量子阱中实现。我们制造了低密度高迁移率的样品结构,在样品中我们可以通过外加栅极电压调节载流子从n型穿过绝缘区到p型。对于宽度d〈6.3nm的薄量子阱,绝缘区在低温下具有常规的难以察觉的微小电导。然而,对于厚的量子阱（d〉6.3nm）,在绝缘层中也出现接近2e2/h的剩余电导,其中e是电子电荷,h是Planck常数.剩余电导与样品宽度无关,证明这是由边缘态引起的.此外剩余电导可以被微小的外加磁场所破坏.在临界厚度d=6.3nm处发生的量子相变也与磁场诱发的绝缘-金属转变互相独立.这些观察结果为量子自旋霍尔效应提供了实验证据。     

确定一类数列中指定项值的快速算法

针对一类方幂之和构成的递增数列问题,分析了数列的数学特性,研究了求取数列中指定项值的两种快速算法,提出的算法能够以较低的计算成本求得问题的解.     

两类图的平均距离

研究圈的p-次方图以及复合图的平均距离．利用计数理论并借助于这两类图的特殊构造，得出了相应的结论．