铅蓄电池正极材料的X射线衍射分析

本文用X射线衍射法对铅蓄电池正极活性材料二氧化铅进行了结构分析。结果表明:正极的二氧化铅同时存在二种不同的晶体结构。正方晶系的β—PbO_2主要分布在电极表面,针方晶系的α—PbO_2则分布在电极内部。如果将块状电极碾磨测量,α—PbO_2与β—PbO_2的含量几乎是相等的。     

Some estimation procedures using a linear model in successive sampling

ABSTRACT

In successive sampling some recent works depict the use of super-population models where information on stable auxiliary variable over occasions has been utilized. Stability character of auxiliary variable may not sustain, if the duration between occasions is large. To cope with such situations, the present work is an attempt to develop some estimation procedures by utilizing the information on two independent auxiliary variables through a linear super-population model. Some estimators are proposed to estimate the current population mean in two occasions successive (rotation) sampling. Optimum replacement strategies are formulated and performances of the proposed estimators have been discussed. Results are interpreted through empirical studies.     

A family of estimators of population variance in two-occasion rotation patterns

Abstract

In this article, we have considered the problem of estimation of population variance on current (second) occasion in two occasion successive (rotation) sampling. A class of estimators of population variance has been proposed and its asymptotic properties have been discussed. The proposed class of estimators is compared with the sample variance estimator when there is no matching from the previous occasion and the Singh et al. (2013) estimator. Optimum replacement policy is discussed. It has been shown that the suggested estimator is more efficient than the Singh et al. (2013) estimator and a usual unbiased estimator when there is no matching. An empirical study is carried out in support of the present study.     

Use of several auxiliary variables in estimating the population mean in a two-occasion rotation pattern

ABSTRACT

This paper addresses the problem of estimation of the population mean on the current (second) occasion in two-occasion successive sampling. Utilizing the readily available information on several auxiliary variables on both occasions and the information on the study variable from the previous occasion, an estimation procedure of the population mean on the current occasion has been proposed. Theoretical properties of the proposed estimator have been investigated. Optimum replacement policy to the proposed estimator has been discussed. The proposed estimator has been compared empirically with the sample mean estimator, when there is no matching and the optimum estimator which is a linear combination of the means of the matched and unmatched portions of the sample at the current occasion. Appropriate recommendations have been made for practical applications.     

On the Use of Superpopulation Model in Estimation of Population Mean in Two-Occasion Rotation Patterns

The present work is an attempt to study the estimation of the population mean on the current occasion in two-occasion successive (rotation) sampling under a superpopulation model. Six different estimators are proposed for estimating the current population mean in two-occasion successive (rotation) sampling. Optimum replacement policies and performances of the proposed estimators have been discussed. Results are interpreted via empirical studies.     

Effective Rotation Patterns Under Non Response in Two-Occasion Successive Sampling

This article intends to develop some effective rotation patterns with the aid of attractive imputation methods when the problems of non response occur in two-occasion successive sampling. Utilizing the information on p (p ??1) auxiliary variables regression methods of imputation have been considered and subsequently multiple linear regression type estimators are proposed to estimate the current population mean in two-occasion successive sampling. Proposed estimators are compared with the estimator for same situations but in the absence of non-response. Optimum replacement strategies of the respective estimators have been discussed and results are interpreted with the help of empirical studies. Conclusions and suitable recommendations are made.     

On asymptotic non-normality of null distributions of mrpp statistics

Severe departures from normality occur frequently for null distributions of statistics associated with applications of mulLi-response permutation procedures (MRPP) for either small or large finite populations. This paper describes the commonly encountered situation associated with asymptotic non-normality for null distributions of MRPP statistics which does not depend on the underlying multivariate distribution. In addition, this paper establishes the existence of a non-degenerate underlying distribution for which the null distributions of MRPP statistics are asymptotically non-normal for essentially all size structure configurations. It is known that MRPP statistics are symmetric versions of a broader class of statistics, most of which are asymmetric. Because of the non-normality associated with null distributions of MRPP statistics, this paper includes necessary results for inferences based on the exact first three moments of anv statistic in this broader class (analogous to existing results for MRPP statistics).     

大中型企业构建物资供应管理体系的对策

物资供应管理既是一个技术过程,也是一个管理过程.构建完善的物资供应管理体系,使物资供应管理工作达到效益和效率双项目标的统一,是大中型企业的当务之急.     

中华民族的理想社会及其当代启示

中华民族的理想社会是“大同社会”、“天下为公”,追求理想社会的实践活动促进了历史的发展。中华民族传统的理想社会观念对今人有如下启示：历史告诉我们,理想是我们改造社会的巨大的精神力量,纯粹的理想主义和现实主义都是不可取的;理想社会应该物质文明与精神文明并重,应该既重视制度的作用,又重视人的作用;不应以个人主义为出发点,而应将为己与为人统一起来。     

人学探要

人学是关于人的存在、本质及其产生、运动、发展、变化规律的新兴科学。人学首先以人自身为研究对象,并将人纳入自然界和宇宙之中予以通观。人是肉体和精神的物质辩证统一体,精神的实质也是物质。人与自然界物质存在形态在根本上是一致的,人与宇宙在本质上是同一的。人生的意义和价值存在于为他人、为社会、为人类做出的贡献之中。正确的宇宙观、人生观、价值观、时空观和发展观的确立,将会使人走上真正彻底自由和解放的道路。