鲁米诺化学发光熄灭法测定铈的研究

目前,铈的测定方法报道较多［１,２］,但其化学发光分析法却未见文献报道。在适宜条件下,铈对鲁米诺－过氧化氢－铬（Ⅲ）体系存在熄灭效应,熄灭程度与浓度呈良好的线性关系,以此建立了铈的流动注射化学发光分析法。该法线性范围为１．０×１０－６～１．０×１０－４ｍｏｌ／Ｌ,相关系数大于０．９９８０,检出限为３×１０－７ｍｏｌ／Ｌ铈,用于合成样品分析,结果满意。１　实验部分１．１　试剂１．０×１０－４ｇ／ｍＬ铬（Ⅲ）标准溶液：用Ｃｒ－Ｃｌ３·６Ｈ２Ｏ（Ａ．Ｒ．）配制;５×１０－４ｍｏｌ／Ｌ鲁米诺溶液：称取８…     

化学修饰电极—石墨炉原子吸收光谱法联用测定水体及其悬浮物中铬（…

本文以Ｎａｆｉｏｎ化学修饰电极，聚乙烯吡啶（ＰＶＰ）化学修饰电极分别在ｐＨ４．０的溶液中预富集Ｃｒ（Ⅲ），Ｃｒ（Ⅵ），以石墨炉原子吸收法测定，Ｃｒ（Ⅲ）测定的线性范围为５～４０ｎｇ／ｍｌ，检出限为２．５ｎｇ／ｍｌ。十次平行测定含１０ｎｇ／ｍｌＣｒ（Ⅲ）的溶液，相对标准偏差为５．０％，Ｃｒ（Ⅵ）在ｐＨ４的盐酸介质中，测定的线性范围为１～２５ｎｇ／ｍｌ检出限为０．４ｎｇ／ｍｌ，十次平行测定含１０displa     

硝酸钠和亚硝酸钠溶液中氯化物的分析

介绍了用莫尔法分析硝酸钠和亚硝酸钠溶液中氯化物的影响因素，溶液中的Ｆｅ，ＣＯ＾２－３，ＮＨ＾＋４等物质参加反应，影响测定结果，酸度的变化（ＰＨ偏离６．５～１０．５）也会导致副反应发生，采用佛尔哈德法可以克服上述缺点，通过加标回收率和重复性测定试验，确证佛尔哈德法准确度高，相对偏差在０．６６％～１．２８％，重复性也好。     

电沉积光亮锡锌合金的研究

推荐了一种电沉淀光亮锡锌合金新工艺。其溶液组成及操作条件：Ｎａ３Ｃ６Ｈ５Ｏ７．２Ｈ２Ｏ８０～１００，ＮＨ４ＡＣ４５～５５，ＥＤＴＡ２５～３５，ＳｎＣｌ２．２Ｈ４Ｏ４～５０，ＺｎＣｌ２６０～８０ｇ／Ｌ，稳定剂ＷＤＺ－１８０～１００，光亮剂ＷＤＺ－２５０～８０ｍｌ／Ｌ，ｐＨ＝５～６，５～３５℃，１～３．５Ａ／ｄｍ＾２，在上述条件下，可获得锌含量１％～３０％光亮锡锌合金沉积层。     

碘光谱法测定非离子表面活性剂的临界胶束浓度

考察了碘光谱法测定非离子表面活性剂在水溶液中的临界胶束浓度（ｃｍｃ）的影响因素。欲得正确结果，须将碘－胶束溶液（不同浓度）放置，待碘的分配达到平衡（例如２４ｈ）后再进行测定，这样测得ＴｒｉｔｏｎＸ－１００、ＴｒｉｔｏｎＸ－３０５和单分散的纯化合物Ｃ１２Ｈ２５Ｏ（Ｃ２Ｈ４Ｏ）６Ｈ的ｃｍｃ分别为２．４×１０－４、３．５×１０－４和８．４×１０－５ｍｏｌ·ｄｍ－３，与文献中用表面张力法测得的结果一致。若按Ｒｏｓｓ和Ｏｌｉｖｅｒ将预先配好的溶液稀释后１小时内测定的方法，则所得结果偏低。只要测定时碘－胶束溶液已达平衡，则碘浓度在４～１２ｍｇ／１００ｍｌ范围内对ｃｍｃ的测定结果无明显的影响。文献中提到的碘浓度对ｃｍｃ测定值的影响可能是由于碘的分配未达平衡所致。     

纳米级铜粉的制备

研究了以ＣｕＳＯ４·５Ｈ２Ｏ 和ＮａＨ２ＰＯ２ 为主要原料制备纳米铜粉的初步工艺：２ ５６０ ｍＬｃ（ＣｕＳＯ４） ＝ ０ ．０７１５ ｍｏｌ／Ｌ的溶液（ 用ＮＨ３·Ｈ２Ｏ将其ｐＨ 值调到５ ．０ ,含ＯＰ分散剂４ ｍＬ） 与２４０ ｍＬｃ（ＮａＨ２ＰＯ２） ＝ １ ．０３２０ ｍｏｌ／Ｌ的溶液反应,溶液反应前的温度为５５ ～６６ ℃,ＮａＨ２ＰＯ２ 溶液的加入速率为８０ ｍＬ／ｍｉｎ ,搅拌强度为１２０ ｒ／ｍｉｎ 。用该工艺制备的纳米铜粉收率在９０ ％ 以上。ＸＲＤ 检测结果表明产物为单质铜;ＴＥＭ 检测结果表明这种铜粉的粒径为３０ ～５０ ｎｍ 。     

流动注射分析法测定食盐中的碘酸盐

本文采用流动注射分析法测定了食盐中的碘酸盐含量，最佳操作条件为０．１５％碘化钾－１．５％磷酸－０．１％淀粉溶液，水为载液，线性范围０．４～１００ｍｇ／ｋｇ，检测限为０．４ｍｇ／ｋｇ连续１１次测定含碘量为１８．９２ｍｇ／ｋｇ食盐样品，变异系数２．２８４％，回收率９９．８％～１００．３％。     

高稳定性多羟甲基三聚氰胺初缩体的合成

采用甲醚化使多羟甲基三聚氰胺初缩体溶液的稳定性达到满意效果。研究了反应物的浓度、介质ｐＨ、温度及反应时间对合成的影响，测定了初缩体的红外光谱。最佳合成条件为：三聚氰胺（ｍｏｌ）∶甲醛（ｍｏｌ）∶甲醇（ｍｏｌ）＝１∶（３．５～６）∶（４～７）；羟甲基化ｐＨ＝７５～９，温度７０～９０℃，时间０５～１５ｈ；醚化缩合反应ｐＨ＝４～７，温度５０～７０℃，时间０５～２ｈ。     

合成橡胶产品检测相关标准选萃（五）

合成橡胶产品检测相关标准选萃（五）兰化公司研究院王琪４．４．２丁二烯橡胶溶液色度测定定义：丁二烯橡胶溶液色度，以铂－钴标准比色溶液的颜色表征丁二烯橡胶苯乙烯溶液颜色的深浅程度。方法提要：在试验条件下，将５％丁二烯橡胶苯乙烯溶液的颜色与铂－钴标准比色溶...     

含铈固体超强酸SO42-/ZrO2-Ce2O3的制备及对环己醇催化脱水制环己烯的研究

在２５ ℃下,将０－５ ｍｏｌ／Ｌ的氨水滴加到不同配比的二氯氧锆和硝酸铈（ Ⅲ） 的混合溶液中,经过滤、洗涤,制备了不同质量分数的三氧化二铈和二氧化锆的混合物,再经０－５ ｍｏｌ／Ｌ的稀硫酸浸渍１ ｈ、过滤、１００ ℃干燥１ ｈ,最后分别在５５０、６５０ 和７００ ℃焙烧４ ｈ 制得了一系列的含铈固体超强酸ＳＯ４２－／ＺｒＯ２Ｃｅ２Ｏ３ 。发现加入质量分数为０－５％ ～２％ 的三氧化二铈可使其对环己醇脱水活性显著提高,过高的酸强度不利于环己烯的生成,其中以５５０ ℃时焙烧制得的固体超强酸ＳＯ４２－／ＺｒＯ２Ｃｅ２Ｏ３［ ｗ（Ｃｅ２Ｏ３）＝ １－５％ ］ 的催化活性及环己烯的选择性最好,在１４０ ℃下,环己醇的转化率为９５－３ ％ ,环己烯的选择性高达１００％ 。并分别用正己烷和吡啶做探针分子对其进行了差动热分析研究,结果表明加入质量分数为０－５％ ～２％ 的三氧化二铈使ＳＯ４２－／ＺｒＯ２Ｃｅ２Ｏ３ 超强酸酸强度和酸总量得到不同程度的提高。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。