古墓出土猫眼宝石的分析鉴定

采用电子探针显微分析仪(EPMA)和RM-1000型显微激光拉曼仪(LRS)测定了古墓出土、具有猫眼效应的宝石戒面的矿物成分以及其中所含有元素,为确定此宝石为金绿猫眼提供了有力地佐证.     

AFM电化学阳极氧化制备二氧化钛纳米线

当材料的微观尺度进入纳米量级后，由于量子效应，材料常常会显现出特殊的性能。因此近年来制备量子点、量子线，以及具有量子效应的量子器件受到深入的研究。一些新的纳米尺度加工技术如原子力显微镜(AFM)微细加工技术受到研究者的重视。     

乙醇对合成醇用Cu-Co-Fe催化剂的修饰效应

乙醇对合成醇用Ｃｕ┐Ｃｏ┐Ｆｅ催化剂的修饰效应徐杰王向宇杜宝石（郑州大学化学系，郑州４５００５２）辛勤李灿（中国科学院大连化学物理研究所，大连１１６０２３）关键词铜，钴，铁，合成醇，乙醇，修饰作用分类号Ｏ６４３／Ｏ６４７自７０年代以来，已对多种ＣＯ加...     

宝石样品的扫描电镜研究

用扫描电镜对马来西亚天然玉石、玻璃样品的表面微观形貌和结构进行观察研究，研究结果为宝石真伪及宝石类型与价值的昨别提供了简便，快速，可靠的无损检测方法及有效信息。     

茶多酚锗的合成及测试

茶多酚锗的合成及测试卢玉振＊张长庚（贵州大学化学系贵阳５５００２５）关键词茶多酚，茶多酚锗，合成，ＬＤ５０１９９６－０３－２６收稿，１９９６－０７－０２修回自从发现一些滋补性药用植物如人参、枸杞子等都含有微量锗以来，有机锗化合物的生化效应研究促进了有...     

纳米材料的特性及其在电催化中的应用

综述了纳米材料的表面效应，体积效应和Ｋｕｂｏ效应，并介绍了其在电催化反应听一些应用。     

以氢原子的电负性为标准烷基的诱导效应是吸电子

在有机化学中,烷基的诱导效应是一个经常遇到而又十分重要的问题。那么烷基的诱导效应究竟如何呢?对此,人们往往易于接受传统的观点,认为烷基是供电子基。但随着科学技术的发展和实验水平的提高,对烷基诱导效应的认识正逐步加深。近年来,通过一些实验数据,如核磁共振谱中伯、仲、叔三种类型烷烃     

介电限域效应对SnO_2纳米微粒光学特性的影响

半导体纳米微粒作为一种新兴材料，在声、光、电、磁、热及催化等方面显示出全新的异于体相材料和分子或原子的特性，在理论和实验上已引起。们极大的兴趣I‘，’］．当纳米微粒的尺寸接近或小于激于玻尔半径时，表现出明显的量子尺寸效应，其表现光学能隙变大，一些半导体粒子如CdS，Cdse等纳米微粒的量予尺寸效应已经被人们利用有效质量近似模型做了定性解释。八但是，由于纳米微粒尺寸小，具有相对大的表面积，因而粒子周围的介质可以强烈地影响它们的光学性质【’，‘1．我们采用胶体化学方法，对SnO。阶电常数为13）半导体纳米微粒…     

泛素化核小体复合物的结构机制研究进展

核小体组蛋白(H2A、H2B、H3、H4)的泛素化修饰介导了一系列效应蛋白与核小体发生特异性的相互作用,并调控细胞的表观遗传.近年来得益于一些新的化学方法与生物方法的发展,如蛋白质化学修饰等样品获取技术以及冷冻电子显微镜等结构观测技术,一些泛素化核小体与效应蛋白的复合物结构得以被解析,揭示了泛素调控染色质表观遗传过程的分子机制.本文对近期报道的六种泛素化核小体与效应蛋白的复合物进行了归纳,对比分析了泛素化核小体对效应蛋白的特异性识别与活化机制,并总结了组蛋白上的关键相互作用位点.     

等离子体引发聚合的机理初探

等离子体引发聚合与常规自由基聚合存在许多不同之处。本文从等离子体引发聚合物一些现象,如较强的溶剂效应、极高的单体选择性、主成超高分子量聚合物等方面,系统介绍了等离子体引发聚合的机理研究成果,并提出了自己的看法。     

Der Wittelsbacher und der Hope‐Diamant

Diamonds are formed from carbon at high pressures and high temperatures in the inner part of the earth. Doping with very small amounts of boron leads to diamonds with blue colour. Two of the most famous historical blue diamonds, the Wittelsbach and Hope Diamond, were found in the Indian Kollur mine. The latter was brought to Europe by the French gem merchant Tavernier. Today it is displayed in the Smithsonian Institute. The Wittelsbach Diamond was for a long time in the possession of the House Wittelsbach until it was secretly sold in Antwerp in 1951. In 2008, it was purchased by auction by the jeweller Graff who recut the gem. In 2011, it was sold to an unknown buyer. As the Wittelsbach and the Hope diamond share origin and colour, it was assumed for a long time that both are pieces from a larger crystal. By optical investigation it was now shown that they have indeed some similar optical properties, but differ strikingly in other ones. Hence, they cannot originate from the same crystal.     

有机溶剂化效应对多元配合物显色反应作用的研究 Ⅰ.有机溶剂对 M-CAS-CTMAB 体系显色反应微环境影响之初探

本文研究了有机溶剂加入后,表面活性剂增敏型体系微环境的变化。用核磁共振方法确定了有机溶剂分子与CTMAB胶束分子的作用部位。通过CTMAB溶液电导率测定及c.m.c值的测定,发现有机溶剂加入确实形成了一种新胶束。还研究了有机溶剂对显色反应速度的影响。并考察了体系微环境变化与相应显色液吸光度值的关系。我们的实验初步表明,有机溶剂的存在,改变了原有的CTMAB胶束,是增敏作用的重要因素,因而改变了发生显色反应的微环境。     

Fast navy 2R as indicator for EDTA titrations and its application for determination of mercury in some pharmaceutical preparations

Summary Solochrome Fast Navy 2R was used as an indicator for EDTA titrations after screening the red hue present at the working p_H with Acid Green G. It shows a reversible colour change with calcium, cadmium, lead, magnesium, manganese, nickel, and zinc, and an irreversible colour change with copper, cobalt, thorium, and bismuth, and no colour change with mercury. Ferrous, ferric, and ceric ions destroy the indicator. The fact that the dye does not show any colour change with mercury was made use of for its back determination in pure solutions and some organic pharmaceutical products after disintegration with perchloricnitric acid mixture.     

Effects of auxiliary complex-forming agents on the rate of metallochromic indicator colour change

The rates of colour change reactions of metallochromic indicators such as XO, PAN, PAC and TAC at the equivalence point were measured in the chelatometric titration of copper, nickel, zinc or cobalt. Hexamine buffer has strong disturbing effects on the rate of colour change of the copper or nickel XO chelate. The effects of various auxiliary complex-forming agents were also examined. Bathophenanthroline, 2,2'-bipyridyl, 8-hydroxyquinoline, TPTZ, ethylenediamine, iminodiacetic acid, acetylacetone, 1,10-phenanthroline and glycine improve the colour change of the XO and PAN chelates of copper. Some titration methods for copper or nickel with XO or PAN as indicator are proposed.     

Evaluation of colour changes of indicators: the supercolor program

SUPERCOLOR is a microcomputer program for the computation of chromaticity parameters from spectrophotometric data. The program is written in BASIC for the HP-200 computer series and it allows the characterization of indicator colour transitions in the standard CIE chromaticity systems. The numerical results for up to 12 indicators can be compared in the same plot for each chromatic system, so that colour changes are easily compared. The pK_a values, pH transition ranges, pH of maximum colour change, SCD values and optimum indicator concentration for visual titrations can be calculated, as well as the colour coordinates.SUPERCOLOR also provides subroutines for computation of screened indicators and simulation of the colour changes of these indicators or other indicator/inert dyes mixtures. The results for some common indicators are presented.     

Photochromic reverse mode polymer dispersed liquid crystals

Control of light intensity and colour are two of the major features required in the realization of smart windows. We designed a bi‐functional polymer dispersed liquid crystal (PDLC) film in order to satisfy such requirements, i.e. it is able both to modulate the optical transmission, if an external electric field is applied, and to change colour if exposed to sunlight. A monomer/liquid crystal mixture was doped with a small amount of photochromic material and homeotropically aligned by means of rough surfaces. A transparent and pale pink coloured film was achieved after photopolymerization. Such a film changes colour upon exposure for some seconds to sunlight or ultraviolet radiation in a persistent but reversible manner. In addition, the film appears transparent without the application of an electric field (OFF state) and becomes opaque on application of a driving voltage of about 75?V (ON state), and thus the film operates in reverse mode with respect to conventional PDLCs.     

Thermochromism of polypropylene gels

It is found that polypropylene gels in some solvents of benzene-derivatives show a striking change of colour. The colour changes from blue to yellow as the temperature rises from the melting point of the solvent to around 70–80 °C. The apparent characteristic of the phenomenon resembles the thermochromism of cholesteric liquid crystals although polypropylene itself is colourless and has no asymmetric carbons in the molecules. Polypropylene flakes swelled in these solvents also show similar thermochromism.     

Photochromic reverse mode polymer dispersed liquid crystals

Control of light intensity and colour are two of the major features required in the realization of smart windows. We designed a bi-functional polymer dispersed liquid crystal (PDLC) film in order to satisfy such requirements, i.e. it is able both to modulate the optical transmission, if an external electric field is applied, and to change colour if exposed to sunlight. A monomer/liquid crystal mixture was doped with a small amount of photochromic material and homeotropically aligned by means of rough surfaces. A transparent and pale pink coloured film was achieved after photopolymerization. Such a film changes colour upon exposure for some seconds to sunlight or ultraviolet radiation in a persistent but reversible manner. In addition, the film appears transparent without the application of an electric field (OFF state) and becomes opaque on application of a driving voltage of about 75 V (ON state), and thus the film operates in reverse mode with respect to conventional PDLCs.     

Colour specification of pyridine-2-aldehyde and 6-methylpyridine-2-aldehyde p-nitrophenylhydrazones as indicators for pH determination

The physicochemical properties, chromaticity co-ordinates and chromatic parameters for pyridine-2-aldehyde p-nitrophenylhydrazone and 6-methylpyridine-2-aldehyde p-nitrophenylhydrazone (proposed as new indicators for calorimetric pH measurements) are reported. The sensitivity and rapidity of colour change have been evaluated in terms of specific colour discrimination (SCD), pH of maximum colour change and half band-width of change of SCD (in terms of pH). The chromatic separations calculated from the co-ordinates obtained by the CIE 1976 recommendations (CIELUV or CIELAB) and the LABHNU 1977 colour space are compared and correlated with the standard deviation of colour matching.     

A comparative study of some hydroxyanthraquinones as acid-base indicators

Alizarin, Alizarin S, quinizarin and quinalizarin have been compared as acid-base indicators with Bromocresol Green and Methyl Orange as reference indicators. The chromaticity co-ordinates, complementary chromaticity co-ordinates, pK(a) values, transition pH-range, pH of maximum colour change, optimum concentration for titrations and the quality of colour change were determined. The results show all four to be good indicators with a colour change quality similar to that of Bromocresol Green.