褪色光度法测定氰化物

根据ＣＮ－ 对５－（４－磺酸基苯偶氮）－８－氨基喹啉（ＳＰＡＱ）－Ｎｉ２＋ －ＣＴＭＡＢ体系的干扰褪色作用，建立了一种测定氰化物的新方法。该方法比传统方法操作简便，不需要萃取。体系λｍ ａｘ＝ ６００ｎｍ ，ε＝ ６．８８×１０４ Ｌ·ｍ ｏｌ－ １·ｃｍ － １。ＣＮ－ 含量在０～５ μｇ／２５ｍ Ｌ内符合比尔定律。方法用于环境水样中氰化物的测定。     

新显色剂二甲氧基羟基苯基荧光酮双波长分光光度同时测定铝和铁的研究

研究了新显色剂二甲氧基羟基苯基荧光酮（ＤＭＨ－ＰＦ）双波长分光光度同时测定铝和铁的新方法。在氨性介质中,氟化钠及Ｔｒｉｔｏｎ Ｘ－１００ 存在下,铝、铁与试剂分别形成红色和紫色配合物,最大吸收波长分别为５４７ ｎｍ 和５７８ ｎｍ 。选定铝的测定波长对为５４７～６１５．５ ｎｍ ,铁的测定波长为６１０ ｎｍ ,表观摩尔吸收系数ε５４７Ａｌ ＝ １．６７×１０５ Ｌ·ｍ ｏｌ－ １ ·ｃｍ － １,ε６１０Ｆｅ ＝ ８．３０×１０４ Ｌ·ｍ ｏｌ－ １·ｃｍ － １,０～３ μｇ Ａｌ３＋ ／２５ｍ Ｌ和０～６ μｇ Ｆｅ３＋ ／２５ｍ Ｌ范围内符合比耳定律。应用于工业硅中铝和铁的同时测定,获得满意结果。     

钯(Ⅱ)与对碘偶氮氯膦显色反应的研究

钯（Ⅱ）与对碘偶氮氯膦在硝酸介质中形成组成比为１：２的蓝色配合物,其最大吸收波长位于６４０ｎｍ,表观摩尔吸光系数ε＝３．３×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１,钯的质量浓度在０．０￣１．０ｍｇ／Ｌ范围内符合比尔定律。应用于废钯催化剂回收液中铯含量的测定,结果满意。     

对碘偶氮氯膦-高碘酸钾-钌(Ⅲ)的褪色反应用于痕量钌的催化分光光度法测定

在Ｈ２ＳＯ４ 介质中对碘偶氮氯膦与高碘酸钾的褪色反应只有在痕量钌（Ⅲ）的存在下才能定量进行。本文研究了该褪色反应的最佳条件及用于痕量钌的测定方法, 其检出限为０．０２ μｇ·１０ ｍ Ｌ－ １, 钌含量在０．０２～０．３０ μｇ·１０ ｍ Ｌ－ １范围内符合比尔定律。该方法用于贵金属精矿中钌含量的测定, 获得满意结果。     

非催化动力学光度法测定铬的研究

研究了在ＨＣｌ介质中，Ｃｒ（Ⅵ）氧化碘离子显色反应的动力学条件，建立了测定Ｃｒ（Ⅵ）的非催化动力学分析法。方法的灵敏度７．２７×１０－７ｇ·Ｌ－１，检测限５．３３×１０－６ｇ·Ｌ－１，测定范围２×１０－５～３×１０－４ｇ·Ｌ－１。用于测定标钢中的铬，测定值与标准值基本一致     

用卡尔曼滤波-分光光度法测定无机铬的形态

利用Ｋａｌｍａｎ滤波技术和二溴苯基荧光酮－溴化十六烷基三甲基铵－Ｃ_２Ｈ_５ＯＨ分光光度测定体系,同时对Ｃｒ（Ⅲ）和Ｃｒ（Ⅳ）进行测定。Ｃｒ（Ⅲ）的表观摩尔吸光系数为１．９６ × １０~５ Ｌ· ｍｏｌ~（－１）·ｃｍ~（－１）,线性范围为０～ ４．０ ｘ１０－６ｍｏｌ／Ｌ;Ｃｒ（Ⅵ）的表观摩尔吸光系数为４．１６ ×１０~５Ｌ· ｍｏｌ~（－１）· ｃｍ~（－１）,线性范围为０～５．２×１０~（－１）ｍｏｌ／Ｌ。     

IO~－_3－I~－_－结晶紫－阿拉伯胶体系分光光度法测定生物样品中的碘

在硫酸介质中，在过量碘化钾及阿拉伯胶存在下，ＩＯ－３氧化Ｉ－生成Ｉ－３，Ｉ－３再与结晶紫形成离子缔合物，缔合物的最大吸收波长为５５２ｎｍ，表观摩尔吸光系数ε５５２＝５．３８×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，ＩＯ－３量在０～１２μｇ／２５ｍＬ范围内服从比耳定律．用于生物样品中碘的测定，结果满意     

分光光度法研究血清蛋白质与钍试剂Ⅰ的作用

钍试剂Ⅰ是测定无机离子的显色剂,在ｐＨ ３．８ 的Ｂｒｉｔｔｏｎ－Ｒｏｂｉｎｓｏｎ缓冲溶液中,该试剂能与血清蛋白质形成复合物,λｍ ａｘ为５３５ ｎｍ ,比试剂本身红移约５５ ｎｍ ,表观摩尔吸光系数为３．５６ ×１０５ Ｌ·ｍ ｏｌ－ １·ｃｍ － １（ＢＳＡ）,测定蛋白质的线性范围,为２０～１６０ ｍ ｇ／Ｌ。用于人血清样品总蛋白的测定,ＲＳＤ为１．０５ ％ （ｎ＝ ４）,回收率约为１００ ％ 。方法基本无干扰。     

7-(1-苯偶氮)-8-羟基喹啉-5-磺酸-曲拉通X-100双波长分光光度法测定微量铟

研究了７－（１－苯偶氮）－８－羟基喹啉－５－磺酸与铟的显色反应及分析应用,在曲拉通Ｘ－１００存在下,于ｐＨ４．５的ＮａＡｃ－ＨＡｃ缓冲介质中,铟与题示试剂形成组成比为１∶３的黄色配合物,最大吸收波长为４４０ｎｍ,表观摩尔吸光系数为３．８６×１０４Ｌ·ｍｏｌ－１·ｃｍ－１,同时在５５０ｎｍ呈现负峰,用双峰双波长法测定铟的表观摩尔吸光系数为７．３３×１０４Ｌ·ｍｏｌ－１·ｃｍ－１,灵敏度为单波长法的１．９倍,线性范围为０～０．６ｍｇ／Ｌ,该法用于硫硒化锌基陶瓷颜料及镀膜玻璃中铟的测定,结果满意。     

人工神经网络分光光度法同时测定钼和铬

在钼，铬－二溴邻硝基苯基荧光酮－ＣＴＭＡＢ显色体系中，应用三层ＡＮＮ－ＢＰ网络解析钼和铬的吸收光谱，不经分离分光光度法同时测定钼和铬。钼和铬的表观摩尔吸光系数分别为ε５４５＝ ６．４８×１０４Ｌ·ｍ ｏｌ－ １·ｃｍ － １，ε５４７＝ １．５４×１０４Ｌ·ｍ ｏｌ－ １·ｃｍ － １。对合成样品和合金钢中钼和铬进行了同时测定，结果满意。使用改进的ＢＰ算法，避免了神经网络学习过程中可能产生的麻痹现象。提出了目标向量的简单变换方法及便于网络参数选择的收敛评价函数。     

从物质本原到干水:水的概念的发展史

在古代哲学中,水被视为一种物质本原。17世纪化学学科形成后,水被定义成一种化学元素。18世纪的化学革命中,水被发现是氢氧化合物。19世纪原子分子论的创立,使水的概念得到微观表征。至20世纪,重水的发现和干水的发明使水的概念有了新的发展。总之,水的概念的发展史,反映了化学思想的发展和科学技术的进步,对化学研究和化学教育均有重要的启示。     

多金属氧酸盐催化的水氧化研究进展

氢气以其清洁无污染、燃烧值高等优点成为未来最具潜力的可再生能源之一,而清洁生产氢气的最佳选择之一即为裂解水. 利用太阳能模拟光合作用实现水的全分解产生氢气和氧气是目前最为理想的能源转化方式,并且已经引起了众多研究者的关注. 水分解的半反应之一--水氧化反应由于其过程复杂,一直是制约水分解的瓶颈. 所以寻找高效、稳定的水氧化催化剂便成为了突破该瓶颈的关键. 多金属氧酸盐是一类以前过渡金属氧簇为基本单元形成的多金属氧簇化合物. 由于多金属氧酸盐在物理、化学性质方面具有无法比拟的特性,使得其在催化、药物、纳米科技和材料科学等方面已被广泛地应用. 多金属氧酸盐的全无机配体可很好地抵御水氧化反应的强氧化性环境,故将其作为水氧化催化剂越来越引起研究者们的注意,并且已有多种多金属氧酸盐被设计为水氧化催化剂. 本文详细介绍了各种不同过渡金属取代的多金属氧酸盐水氧化催化剂的研究进展.     

A model study on the mechanism and kinetics for the dissociation of water anion

Quantum chemical computations using both density functional theory (B3LYP functional) and wavefunction (MP2 and CCSD(T)) methods, with the 6-311++G(3df,2p) and aug-cc-pVnZ (n = D,T,Q) basis sets, in conjunction with a polarizable continuum model (PCM) method for treating structures in solution, were carried out to look again at a series of small negatively charged water species [(H₂O)_n]^•–. For each size n of [(H₂O)_n]^•– in aqueous solution with n = 2, 3, and 4, two distinct structural motifs can be identified: a classical water radical anion formed by hydrogen bonds and a molecular pincer in which the excess electron is directly interacting with H atoms. In aqueous solution, both motifs have comparable energy content and likely coexist and compete for the ground state. Some water anion isomers can dissociate when interaction with a water molecule, [(H₂O)_n]^•– + H₂O → H^•(H₂O)_m + OH^–(H₂O)_n–m, through successive hydrogen transfers with moderate energy barriers. This reaction can also be regarded as a water-splitting process in which the H transfers involved take place mainly within a water trimer, whereas other water molecules tend to stabilize transition structures through microsolvation rather than direct participation. Calculated absolute rate constants for the reversed reaction H^•(H₂O)₂ + OH^–(H₂O)₂ → [(H₂O)₄]^•־ + H₂O with both H and D isotopes agree well with the experimentally evaluated counterpart and lend a kinetic support for the involvement of a tetramer unit.     

电解离子水及其生成器

本文介绍了电解离子水的制备原理和应用。原水经电解后，阳极室生成酸性离子水，阴极室生成碱性离子水。酸性离子水具有杀菌消毒作用，碱性离子水具有保健作用。同时，简要介绍了离子水生成器的研究进展。     

Determination of freezable water content of beef semimembranous muscle DSC study

The freezable water contents of samples obtained from previously chilled semimembranous muscle of middle-aged beef carcasses after a 24 h cooling period a room at in 5±1C were determined by differential scanning calorimetry (DSC) at –5, –10, –15, –20, –30, –40, –50 and –65C. This was accomplished by freezing the samples at the above-mentioned temperatures, followed by thawing to 35C, and measuring the melting peaks of freezable water. The areas of these peaks were determined by using the peak integration method programs through a computer linked to the DSC, and they were then used to determine the latent heat of melting (H _m) in kJ kg^–1 at each freezing temperature. The resultant latent heat of melting per sample was divided by the latent heat for pure water to determine the amount of freezable water present in these samples. This amount of freezable water was divided by the total water content of the meat sample to determine the percentage of freezable water in the sample. The percentage of freezable water was subtracted from 100 to determine the percentage of bound water present in the sample.     

Determination of differences in free and bound water contents of beef muscle by DSC under various freezing conditions

The differences in bound water content of beef semimembranous muscle samples obtained from previously chilled (24 h at +4°C) middle-aged beef carcasses were determined by the use of DSC. Initially, samples obtained from fresh, unprocessed meat were frozen at –40, –50 or –65°C to determine their melting peaks for freezable water (free water) content with the use of DSC. The samples were then subjected to an environment with an ambient temperature of –30, –35, –40 or –45°C, with no air circulation, or with an air circulation speed of 2 m s^–1, until a thermal core temperature of –18°C was attained; this was followed by thawing the samples until a thermal core temperature of 0°C was reached. This process was followed by subjecting the samples to the ambient temperatures mentioned above, to accomplish complete freezing and thawing of the samples, with DSC, and thereby determination of the freezable water contents, which were then used to determine the peaks of melting. The calculated peak areas were divided by the latent heat of melting for pure water, to determine the freezable water contents of the samples. The percentage freezable water content of each sample was determined by dividing its freezable water content by its total water content; and the bound water content of each sample was determined by subtracting the percentage free water content from the total. In view of the fact that the free water content of a sample is completely in the frozen phase at temperatures of –40°C and below, the calculations of free and bound water contents of the samples were based on the averages of values obtained at three different temperatures.     

Analysis of Fischer-Tropsch by-product waters by gas chromatography

This paper describes a quantitative technique for the determination of organic constituents in Fischer-Tropsch by-product waters. Temperature-programmed gas chromatography on derivatized bonded polar capillary columns provides the required separation that permits reliable quantitation of individual compounds. A preliminary combined gas chromatographic–mass spectrometric survey to identify the components present in Fischer-Tropsch by-product waters is presented. The elution order of 58 identified components is tabulated. Components identified in a typical Fischer-Tropsch by-product water include C₁–C₉ linear and branched alcohols, C₃? C₈ ketones, C₂? C₆ carboxylic acids, and C₂? C₄ linear aldehydes.     

Interaction of water with the regenerated cellulose membrane studied by DSC

One to three endothermal peaks atributted to melting of bulk and interfacial water were observed by DSC in the regenerated cellulose — water system. The profiles of thermal effects depend on water content, time of conditioning, film pretreatment and the conditions applied during the preceding freezing-thawing cycles. The occurrence might be deduced of melting-crystallisation processes. A large amount of non-freezable strongly bounded water was also detected. Although cellulose absorbs water quickly after immersion, the structural changes consisting on ordering of polymer fraction occur during further conditioning due to increase in strength of water binding. Using the membranes in the separation module at 90°C causes weakening of these bonds. Differences between interaction of particular cellulose films with water can be detected during the first, the second and the third heating. This revised version was published online in July 2006 with corrections to the Cover Date.     

Water sorption and permeation in chitosan films: Relation between gas permeability and relative humidity

The water sorption of chitosan has been studied at 20 °C. Water transport is governed by a Fickian process for relative humidities lower than 0.4, and in that range of partial pressures, the diffusion coefficient is concentration‐dependent. At a higher activity, anomalous diffusion is observed. The sorption isotherm is well described by the Guggenheim‐Anderson‐de Boer (GAB) model, and the clustering phenomenon observed at high relative pressures can be studied with the parameters of this model. The water permeability coefficient greatly increases with the relative pressure, and the water plasticization effect leads to a loss of the gas barrier properties under wet conditions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 3114–3127, 2001