表面活性剂增敏光度法测钴

文章研究了在 Co(Ⅱ)-XO体系中,几种表面活性剂对该体系显色反应的增敏效果. 结果表明:在pH=5.7醋酸-醋酸钠的缓冲溶液中,表面活性剂十六烷基三甲基溴化铵(CTMAB)存在时,钴(Ⅱ)与二甲酚橙可形成稳定的络合物. 其最大吸收波长由570nm红移至592nm,测定的灵敏度明显提高,表观摩尔吸光系数由3.3104L·mol-1·cm-1提高至 4.9×105 L·mol-1·cm-1 . Co(Ⅱ)在每25ml 0～20μg范围内符合比尔定律. 本法可用于人发及环境水样中微量钴的测定,同时也拓宽了二甲酚橙显色剂的使用范围.     

以表面活性剂为增敏剂光度法测微量铁

亚甲基蓝是一种高灵敏度显色剂，以十二烷基苯磺酸钠为表面活性剂，铁(Ⅲ)与邻二氮菲形成络合物后，在PH=4．5时，该络合物有最大吸收蜂λ=660nm，铁含量在O～40μg范围内符合比尔定律。选用660nm作为工作波长，可选择性地测定多样品中微量铁(Ⅲ)，方法灵敏，操作简便．     

阳离子表面活性剂平衡移动增敏机理的研究

本文研究了氯化十六烷基吡啶(CPC)对铜(Ⅱ)—邻硝基苯基萤光酮(ONPF)络合物在可见分光光度法中的增敏作用的机理。这种增敏效应被认为是由于CPC和Cu(Ⅱ)—ONPF络合物间的半分子缔合作用而引起的,阐明了增敏作用与溶液中CPC各存在型态间的关系及溶液体系的盐效应。     

火焰原子吸收分析中表现活性剂对铬吸收信号的增敏作用及机理研究

通过研究火焰原子吸收分析中表面活性剂对铬吸收信号的增敏作用，建立表面活性剂的增敏作用机理模型。     

表面活性剂在分析化学中的应用简介

介绍了表面活性剂在光度分析，滴定分析，电化学分析，色谱分析，原子吸收光谱分析等领域中的应用。     

水溶性大分子化合物在光度分析中的增溶增敏作用

本文简述了大分子化合物在光度分析中的应用,从物质结构的角度探讨了大分子化合物增溶增敏作用的机理,指出了大分子化合物与低分子表面活性剂联合使用更能提高增溶增敏作用。     

表面活性剂增敏光度法测定水样中的微量铁

在HAc-NaAc缓冲溶液(pH=5)存在下,以邻二氮菲(phen)作显色剂,表面活性剂曲拉通X-100对Fe(II)与邻二氮菲的显色反应具有增敏作用,形成的Fe(II)-phen-Triton三元络合物呈红色,络合物的最大吸收波长为510 nm,表观摩尔吸光系数为1.2×105L.mol-1.cm-1,铁含量在0.5~12μg/mL范围内符合比尔定律,用于水样中微量铁的测定,回收率在97.1%~98.0%之间。     

表面活性剂在三次采油中的应用

根据石油开发过程的方式,将石油开发分成三个阶段：一次采油、二次采油和三次采油。在一次采油和二次采油后,为了进一步提高原油采收率,需要进行三次采油。三次采油主要有化学驱、气驱、热力采油驱和微生物驱。表面活性剂驱油技术是化学驱中的一种重要驱油方式,本文介绍了表面活性剂的分类、驱油机理、技术要求、注入参数和在三次采油中的应用,同时对表面活性剂在油田开发中的应用提出了几点建议。     

镉-铽-铕-强力霉素-曲通X-100体系增敏效应研究

研究了在表面活性剂TritonX-100存在下,Cd2+和Tb3+对Eu（Ⅲ）-强力霉素（DC）体系的协同荧光增敏效应。建立了Cd（Ⅱ）-Tb（Ⅲ）-Eu（Ⅲ）-DC-TritonX-100协同荧光增敏体系,并提出了一个高灵敏度测定稀土元素销的荧光分析法.     

表面活性剂在光度分析中应用的新进展

本文简略回顾了我国近五年来表面活性剂在光度分析中应用的新进展,介绍了表面活性剂在光度分析中一些新方法和新体系.通过对五种表面活性剂体系的介绍对表面活性剂在光度分析中应用的发展状况和趋势有个了解.     

表面活性剂对铬天青S-铝的显色反应的影响及应用研究

本文系统的研究了表面活性剂聚氧乙烯醚(Brij35),聚乙二醇辛基苯基醚(OP-10),十六烷基三甲基溴化铵(CTAB),十二烷基硫酸钠(SDS)单一胶束或其混合胶束对铬天青S-铝显色反应的影响,其中Brij35胶束和铬天青S-铝形成的三元配合物的摩尔吸光系数达到1.2685×105L/mol.cm,在0～2μg.10mL-1范围内符合朗伯-比尔定律。将其应用于自来水中的铝的测量,得到良好的测量结果,提高了测量的灵敏度。     

Exploring the underlying factor structure of the home literacy environment (HLE) in the English and Spanish versions of the Familia Inventory: A cautionary tale

Few research-based measures of the family literacy environment are commercially available, especially in Spanish. One exception is the Familia Inventory (Taylor, 1995). The present study investigated the 10 subscales of this instrument and the factor structure they imply, using data from a low-socioeconomic (SES), largely Hispanic population. Confirmatory factor analysis (CFA) was used to test the structure of the instrument as well as whether it is invariant across English and Spanish language versions. The scale was administered to 232 parents of preschoolers. Results of the CFA revealed that the a priori dimensions of the Familia Inventory were not supported for this sample. Follow-up analyses suggested poor fit both within and between subscales. The scale fit poorly within both English and Spanish, precluding testing of invariance across language. Supplemental analyses using exploratory factor analysis (EFA) on a subset of the items that had adequate variance suggested that a four-factor solution accounting for 53% of the variance best represented the English data and that a two-factor solution accounting for 43% of the variance best represented the Spanish data. Implications are discussed.     

要素投入对中国经济增长的影响

根据丹尼森对经济增长因素分析方法,分析改革开放以来,各要素对中国高速经济增长的贡献,得出改革开放以来,中国的经济增长主要依赖于资金的投入。通过与韩国、日本在经济高速增长时期,各要素对他们经济增长的贡献做比较,说明大部分国家经济发展的起飞阶段,其经济发展比较多地依赖资金投入和劳动力的投入,是一种普遍现象。并从产业结构方面对经济增长划分三个阶段,对中国靠高投入来支撑的高速经济增长以理论支持。     

酸可分解型非离子表面活性剂在酸性溶液中分解反应动力学的研究

非离子表面活性剂 12 80 0、14 80 0、1680 0在酸性溶液中分解成的羰基化合物是甲醛。可用乙酰丙酮比色法测定 .实验结果表明 :它们在 0 .1mol/LHCl溶液中的分解反应是准一级反应 .3小时以后 ,它们的分解率均大于 90 % .其中 ,12 80 0几乎 10 0 %分解     

Factor Analysis of Drawings: Application to college student models of the greenhouse effect

Exploratory factor analysis was used to identify models underlying drawings of the greenhouse effect made by over 200 entering university freshmen. Initial content analysis allowed deconstruction of drawings into salient features, with grouping of these features via factor analysis. A resulting 4-factor solution explains 62% of the data variance, suggesting that 4 archetype models of the greenhouse effect dominate thinking within this population. Factor scores, indicating the extent to which each student's drawing aligned with representative models, were compared to performance on conceptual understanding and attitudes measures, demographics, and non-cognitive features of drawings. Student drawings were also compared to drawings made by scientists to ascertain the extent to which models reflect more sophisticated and accurate models. Results indicate that student and scientist drawings share some similarities, most notably the presence of some features of the most sophisticated non-scientific model held among the study population. Prior knowledge, prior attitudes, gender, and non-cognitive components are also predictive of an individual student's model. This work presents a new technique for analyzing drawings, with general implications for the use of drawings in investigating student conceptions.     

基于因子分析的鄱阳湖生态经济区文化创意产业发展研究

文化创意产业是一种新兴的生态型产业,作为区域产业经济发展"乳化器",文化创意产业已成为"后危机"时代经济转型的新增长点。通过对比分析鄱阳湖内部各地区和其与周边相邻经济区创意产业竞争力,可以对鄱阳湖地区文化创意产业进行正确、合理的定位,有利于进一步促进该区域创意产业发展,真正把鄱阳湖生态经济区建设成为具有全国领先水平的、先进高效的生态产业集群区。     

高校毕业生公共就业服务联动机制探析

我国已经建立了高校毕业生公共就业服务平台,但联动机制的缺乏使得公共就业服务没有发挥应有的作用,造成高校毕业生在就业中难以获得有效的帮助.发挥高校毕业生公共就业服务的协同作用,需要构建多方参与的战略联合机制、打造服务流程的再造机制和构建公共就业服务的监督评估机制.     

因子分析方法研究渭河水质

选取不同的水质指标和样本,分别对甘肃省天水市境内渭河水质进行因子分析,给出每个样本的水质类别,并通过对结果分析比较,找出区别和联系,从而使人们在选取指标和样本时,减少盲目性和随意性,把因子分析方法更好地用于水质评价.     

A Comparison of Method Effects in Two Confirmatory Factor Models for Structurally Different Methods

It is well known that measurement error in observable variables induces bias in estimates in standard regression analysis and that structural equation models are a typical solution to this problem. Often, multiple indicator equations are subsumed as part of the structural equation model, allowing for consistent estimation of the relevant regression parameters. In many instances, however, embedding the measurement model into structural equation models is not possible because the model would not be identified. To correct for measurement error one has no other recourse than to provide the exact values of the variances of the measurement error terms of the model, although in practice such variances cannot be ascertained exactly, but only estimated from an independent study. The usual approach so far has been to treat the estimated values of error variances as if they were known exact population values in the subsequent structural equation modeling (SEM) analysis. In this article we show that fixing measurement error variance estimates as if they were true values can make the reported standard errors of the structural parameters of the model smaller than they should be. Inferences about the parameters of interest will be incorrect if the estimated nature of the variances is not taken into account. For general SEM, we derive an explicit expression that provides the terms to be added to the standard errors provided by the standard SEM software that treats the estimated variances as exact population values. Interestingly, we find there is a differential impact of the corrections to be added to the standard errors depending on which parameter of the model is estimated. The theoretical results are illustrated with simulations and also with empirical data on a typical SEM model.     

试论因素分析法在教育研究中的应用

因素分析法是比较教育学的研究方法之一。用它来鉴定和分析作用于教育内外的因素,并解释教育研究特别 是教育比较研究中的现象和问题,都是一种有效的途径。