ICP-AES氢化物发生法测定生物样品中的痕量硒

本文研究了ICP-AES氢化物发生法测定生物样品中痕量硒的方法。对氢化物发生条件和样品消化过程进行了选择,并使之达最佳化。方法检出限达0.09ng/ml。     

机械抽样在林业伐区蓄积量调查中的应用

本文叙述了过去林业伐区木材蓄积量调查的一般概况。在学生生产实习中采用了机械抽样方法进行木材蓄积量调查，结果表明，该方法缩短调查时间，降低生产成本，效果较好     

Bartlett's formulae—Closed forms and recurrent equations

We show that the entries of the asymptotic covariance matrix of the sample autocovariances and autocorrelations of a stationary process can be expressed in terms of the square of its spectral density. This leads to closed form expressions and fast computational algorithms.This research has been partly supported by contract No. MM 440/94 with the Bulgarian Ministry of Science and Education and by the Division of Quality Technology and Statistics, Luleå University, Sweden.     

位置刻度分布族中参数的两步置信区间

寻找一些分布中的参数的具有预先给定宽度和预先给定覆盖概率的置信区间是令人感兴趣的，对于位置刻度分布族中位置参数和刻度参数，这种类型的置信区间的存在性问题已在文献中被解决，本文利用两步抽样，具体地构造出这样的固定宽度置信区间，此外，对于Cauchy分布，第一阶段的最优抽样量和一些统计量的分位点也被计算出，所得到的结果具有应用价值。     

广义非参数回归的B样本贝叶斯估计

本文主要研究广义非参数模型B样条Bayes估计 .将回归函数按照B样条基展开 ,我们不具体选择节点的个数 ,而是节点个数取均匀的无信息先验 ,样条函数系数取正态先验 ,用B样条函数的后验均值估计回归函数 .并给出了回归函数B样条Bayes估计的MCMC的模拟计算方法 .通过对Logistic非参数回归的模拟研究 ,表明B样条Bayes估计得到了很好的估计效果     

固体进样石墨炉原子吸收法直接测定饲料中钴

研究了各种实验条件,建立了一种快速准确分析饲料中痕量元素的方法,适合于常规环境监测分析。特征质量7×10~(-12)g/1%吸收,回收率94～102%,相对标准偏差4.0～8.0%。     

On the equivalence of three types of blocking in non-Markovian tandem queues

Definitions of blocking types for tandem queueing systems are given where each stage consists of multiple servers. Some of them are shown to be identical with respect to service initiation epochs at each stage. Such identical relationships are proved using sample path correspondence, and are therefore valid irrespective of the arrival process and the service time distributions.     

On Sequential Fixed-Size Confidence Regions for the Mean Vector

In order to construct a fixed-size confidence region for the mean vector of an unknown distribution functionF, a new purely sequential sampling strategy is proposed first. For this new procedure, under some regularity conditions onF, the coverage probability is shown (Theorem 2.1) to be at least (1−α)−Bα²d²+o(d²) asd→0, where (1−α) is the preassigned level of confidence,Bis an appropriate functional ofF, and 2dis the preassigned diameter of the proposed spherical confidence region for the mean vector ofF. An accelerated version of the stopping rule is also provided with the analogous second-order characteristics (Theorem 3.1). In the special case of ap-dimensional normal random variable, analogous purely sequential and accelerated sequential procedures as well as a three-stage procedure are briefly introduced together with their asymptotic second-order characteristics.     

高陡山区岩体移动分析的Fuzzy数学模型

本文利用 Fuzzy数学理论 ,针对高陡山区地下房柱法采矿所引起的岩体移动变形问题 ,建立了具体的数学模型和预测分析方法 .通过对工程实例的计算分析 ,表明本文所建立的数学模型和分析方法适用于工程实际