火焰原子吸收光谱法直接测定蜂蜜制品中锌

本文研究了阴离子表面活性剂十二烷基磺酸钠（ＳＤＳ），阳离子表面活性剂十六烷基三甲基溴化铵（ＣＴＭＡＢ），非离子表面活性ＴｒｉｔｏｎＸ－１００，Ｔｗｅｅｎ－２０，Ｔｗｅｅｎ－８０及铬天菁Ｓ（ＣＡＳ），邻菲罗啉（Ｐｈｅｎ），８－羟基喹啉（Ｏｘｉｎｅ），盐酸羟胺，二乙基二硫代氨基甲酸钠（ＤＤＴＣ）等数种试对锌的增敏作用，初探了其增敏机理和抑制干扰的机理，选用了增敏作用最强的Ｔｒｉｔｏｎ－Ｘ－１００增敏剂     

Dynamical effects of a one-dimensional multibarrier potential of finite range

We discuss the properties of a large number N of one-dimensional (bounded) locally periodic potential barriers in a finite interval. We show that the transmission coefficient, the scattering cross section σ, and the resonances of σ depend sensitively upon the ratio of the total spacing to the total barrier width. We also show that a time dependent wave packet passing through the system of potential barriers rapidly spreads and deforms, a criterion suggested by Zaslavsky for chaotic behaviour. Computing the spectrum by imposing (large) periodic boundary conditions we find a Wigner type distribution. We investigate also the S-matrix poles; many resonances occur for certain values of the relative spacing between the barriers in the potential. Received 1st August 2001 and Received in final form 18 November 2001     

一类并行数值Schwarz格式的收敛性及比较定理

本文对［１］给出的一类求解椭圆型偏微分方程的并行数值Ｓｃｈｗａｒｚ格式作了进一步的分析，给出了一个新的收敛定理，根据该收敛定理，可以把文［１］中的主要收敛快慢进行了比较，得出了一些比较结果。     

The inverse M-matrix problem

One aspect of the inverse M-matrix problem can be posed as follows. Given a positive n × n matrix A=(a_ij) which has been scaled to have unit diagonal elements and off-diagonal elements which satisfy 0 < y ? a_ij ? x < 1, what additional element conditions will guarantee that the inverse of A exists and is an M-matrix? That is, if A^?1=B=(b_ij), then b_ii> 0 and b_ij ? 0 for i≠_j. If n=2 or x=y no further conditions are needed, but if n ? 3 and y < x, then the following is a tight sufficient condition. Define an interpolation parameter s via x²=sy+(1?s)y²; then B is an M-matrix if s^?1 ? n?2. Moreover, if all off-diagonal elements of A have the value y except for a_ij=a_jj=x when i=n?1, n and 1 ? _j ? n?2, then the condition on both necessary and sufficient for B to be an M-matrix.     

一类广义Sylvester方程的反对称最小二乘解及其最佳逼近

本文利用矩阵的奇异值分解(SVD),给出了广义Sylvester矩阵方程AX YA=C反对称解存在的充分必要条件,导出了其反对称解和反对称最小二乘解的表达式,同时在解集合中得到了对给定矩阵的最佳逼近解.     

一种校正XRF光谱基体吸收效应的新方法

根据校正XRF光谱基体吸收效应的基本理论,提出了一种用基本参数法校正基体吸收效应的新方法,该法既不需要标准,又对样品和衬底靶无特别要求,仅用一些基本的物理参数(ω,J,τ)和荧光强度的测量值便可算得样品中待分析元素的含量,方便简单。用岩石标准SY-2,SY-3和MRG-1检验该法,其结果与文献报道的值相符。     

一类多元回归模型参数的优于BLUE的估计

本文考虑多元线性回归模型i=1,2,B_i 未知在一定的条件下,得到参数的优于 BLUE 的估计。     

On spectral radii of matrices governing some numerical estimating algorithms with incomplete data

Many estimating procedures are carried out with incomplete data by means of different types of EM algorithms. They allow us to obtain maximum likelihood parameter estimates in classical inference and also estimates based on the posterior mode in Bayesian inference. This paper analyzes in detail the spectral radii of the Jacobian matrices algorithm as a possible way to evaluate convergence rates. The eigenvalues of such matrices are explicitly obtained in some cases and, in all of them, a geometric convergence rate is, at least, guaranteed near the optimum. Finally, a comparison between the leading eigenvalues of EM and direct and approximate EM-Bayes algorithms may suggest the efficiency of each case.     

指数—2非线性广义系统的解及其稳定性

本文主要给出指数－2的非线性广义系统的可解性和零解的稳定性分析．     

三价原子的非相对论能级结构

采用拉卡基函数并借助角动量耦合理论,导出了三价原子非相对论性哈密顿的矩阵元的一般表达式,完成了所有的角向积分和自旋求和计算,结果用3j、6j和9j符号表示,径向积分则表示为Slater-Condon参数.用相关结果对(n1p)2(n2p)组态的谱项结构进行了分析