用正电子研究CuCl2在NaY上的扩散

用正电子湮没谱学研究了机械混合CuCl₂与NaY中CuCl₂在NaY沸石中的扩散.分别测量了不同质量比的CuCl₂-NaY(0～0.03)沸石分子筛经140℃烘烤1h;CuCl₂-NaY(0～0.05)经450℃烘烤4h;CuCl₂-NaY(0.01)经不同温度烘烤1h以及经300℃下烘烤烘不同时间后的正电子寿命谱.所有谱中都出现了5(或4)个寿命分量,其第3,4,5寿命分量分别与β笼、超笼及沸石微粒界面空间的大小和数量相关.实验表明,正电子湮没谱学可敏感地探测出少量CuCl₂在NaY沸石中的扩散变化.而对于只含少量氯化铜(0.01)的情况,虽经高温长时间烘烤,但仍有相当数量的氯化铜存在于NaY外表面.     

用正电子湮没谱学研究氯化稀土在NaY沸石上的分散

用正电子湮没谱学研究氯化富铈稀土与NaY沸石机械混合形成的稀土NaY沸石(RE-NaY)中,氯化稀土在NaY中的分散．分别测量不同质量比的RE-NaY(1％-20％)经500℃烘烤1h,RE-NaY(5％)经过不同温度烘烤1h,以及RE-NaY(5％)经500℃烘烤不同时间后的正电子寿命谱．所有寿命谱都出现了5个寿命分量,其中第3,4,5寿命分别与β笼、超笼及沸石微粒界面空洞的大小和数量相关．实验表明了正电子湮没谱学能敏感地表征氯化稀土在NaY中的分散．     

使用化学参考物质计算和阐明元素的标准化学放射本能

Exergy is the amount of work obtainable when some matter is brought to a state of thermodynamic equilibrium with the common components of the natural surroundings by means of reversible processes, involving interaction only with the above mentioned components of nature. This paper presents standard chemical exergy values for 85 elements. Reference species in the atmosphere (air), dissolved in the hydrosphere (oceans), and contained in the lithosphere (minerals) are used for these calculations. Standard chemical exergy values of elements were calculated from tabulated values obtained for standard conditions (an ambient temperature of 298.15 K and an atmospheric pressure of 0.1 MPa). Very low concentrations of elements in the atmosphere and oceans and the abundance of elements in the Earth's crust are no longer used in determining reference states for chemical elements. Liquid and gas mixtures generally are not useful as reference states. As a result of the work in this paper, a table of the chemical exergy values of many elements in the periodic table under standard conditions was tabulated.     

生命元素图谱与化学元素周期表

旨在用化学语言表面与生命有关的问题。讨论了微量元素与生物体作用的规律性,人体生命元素平衡谱的构成,人与环境间精细的动态的物质交换平衡以及“天人合一”的哲学思想,指出生命元素在元素周期表中昂首翘尾的“近似动物体形”分布潜示生命的存在,提出不仅要注重有机营养平衡,更要注重无机营养平衡的观点。     

化学位移估算研究ATP构象随溶液pH值的变化

利用Johnson和Bovey的理论和方法计算了不同扭曲角χ(O4′－C1′－N9－C4)的ATP(5′-三磷酸腺苷)分子中糖环质子H1′和H2′由于环流效应引起的化学位移.H1′的化学位移与扭曲角χ有较强的依赖关系,反映了ATP在溶液中细微的构象变化.将计算结果与实验结果比较,证明在本文讨论的pH值范围(1～10)内,Mg2＋加入后,ATP的扭曲角χ在230～360°范围内变化.随溶液的pH值减小,ATP分子的构象由trans 构象通过-gauche构象转变为cis构象. 从而证明在酸性条件下, ATP倾向于以cis构象存在,而在碱性条件下trans构象更为稳定,从另一方面支持了在酸性条件下N1参与配位而在碱性条件下N7参与配位的结论.在讨论中也考虑了由pH变化所引起的环流强度的变化.     

Nanocrystals Assembled by the Chemical Reaction of the Dispersion Solvent

The development of methods to pattern nanocrystals with different sizes and shapes remains a challenge. In this study, we demonstrate a unique class of bottom‐up approaches to assemble nanocrystals into patterns. Our approach for patterning nanocrystals focuses on the utilization and control of the chemical reaction of solvents surrounding nanocrystals. The photopolymerization of solvent molecules through a photomask creates time‐dependent concentration gradients of the solvents. Dispersed nanocrystals such as silver nanowires (AgNWs) migrate and are gradually organized and integrated into the polymerizing films based on the concentration gradients. The AgNW‐embedded film properties are determined by the organized AgNW structures and include light transmission and electrical conductivity. Overall, the demonstrated method is very simple, widely applicable to various nanocrystals and solvents, and can thus contribute to the development of a new class of nanocrystal patterning methods.     

Chemical Modifications on Human Hair Studied by Means of Contact Angle Determination

Wetting properties of a solid surface can change as a consequence of chemical treatment. There is a relationship between the molecular structure of a surface and the macroscopic properties of this surface such as wetting and adhesion. Information on the surface energy of a solid was obtained by calculating polar and dispersion force contributions by means of contact angle determination. The superficial modification undergone by human hair treatments with or without hydrogen peroxide at alkaline pH was studied by means of wetting force measurements. The wetting increase in treated human hair fibers was analyzed following the Hüttinger method using contact angle data, taking into account the acid-base and dispersion components of the total wetting adhesion work. The hydrogen peroxide treatment at alkaline pH leads to a partial removal of hydrocarbon chains and to the formation of ionic groups (cysteic acid residues) on the outer scale cell surface. The latter phenomenon was observed by means of an increase in the acid-base adhesion work versus water wetting liquid at alkaline pH. Copyright 2001 Academic Press.     

纳米结构表面浸润性质的分子动力学研究

采用分子动力学方法研究了氩纳米液滴在铂金属及其模型固体表面的浸润现象,获得了液滴在平滑表面和三角纳米结构阵列表面的接触角和展布特性.研究表明,液滴与壁面的势能作用较强时,液滴与纳米结构表面为均匀浸润,但是由于迟滞效应,接触角受表面纳米结构的影响不明显;势能作用较弱时,纳米结构间隙中存在类似蒸汽的低密度相,液滴与纳米结构表面为非均匀浸润,接触角受纳米结构的影响而增大;表面纳米结构可以使表面具有超疏水性.     

锕系后元素的化学性质

人类进入 2 1世纪 ,科学已经非常发达 ,技术也已经非常先进 ,但许多最基本的问题仍然没有找到答案。比如 ,元素是如何形成的 ?宇宙是怎样开始的 ?大脑是如何工作的 ?生命是如何起源的 ?从某种意义上说 ,这些谜底都与元素本身有一定的关联。　　现在的周期表中的元素已经扩展到 1 1 6号 (其间的 1 1 3和 1 1 5号尚未合成成功 ) ,其中有2 3种人造元素。除Ｔｃ、Ｐｍ外 ,从 93号元素 (Ｎｐ)到 1 0 3号元素 (Ｌｒ)共 1 1种称为“锕系的超铀元素”(Ｔｒａｎｓａｃｔｉｎｉｄｅｅｌｅｍｅｎｔｓ) ;另外 1 1种称为“锕系后元素”(Ｔｒａｎｓｕｒａ…     

Numerical Simulation of Pressure-Swirl Spray Dispersion by Using Eulerian-Lagrangian Method

To gain a general understanding of atomization and sheet breakup processes, the interaction of pressure-swirl hollow-cone sprays and a quiescent medium was investigated computationally. The spray characteristics of Iso-octane (n-C₈H₁₈) with high pressure-swirl injector in the ambient conditions are modeled. The Linearized Instability Sheet Atomization (LISA) model has been used to describe the primary breakup processes of the spray. Sauter Mean Diameter, sheet thickness and exit velocity were computed as the results of primary breakup. Disintegration of large drops is simulated using Taylor analogy breakup (TAB) model in which the Rosin-Rammler distribution is used. Evaporation and collision models are deactivated in this study. The model considers the transient behavior of the pre-spray and steady-state behavior of the main spray for three various injection pressures and liquid mass flow rates. Qualitative and quantitative comparisons between the simulated and experimentally measured results were made. The numerical simulations can successfully demonstrate the spray characteristics, such as spray tip penetration, drop sizes and overall spray structure.     

元素周期表实物展窗:元素化学性质的形象化展示

以展示元素单质、化合物和矿物样品为形式制作的元素周期表实物展窗能够形象化地展示各种元素的化学特性。元素周期表实物展窗将实物样品展示度与样品背后的化学内涵相结合,可以展示元素和化学学科的风貌。     

低浓度甲醛对多肽和蛋白化学修饰的质谱研究

采用基质辅助激光解析电离飞行时间质谱( MALDI-TOF MS)和纳升电喷雾四极杆飞行时间串联质谱( Nano-ESI -QTOF MS)技术,以标准肽段和流感病毒基质蛋白酶切肽段为模型,研究了甲醛对蛋白质和多肽主链的修饰作用。采用与实际病毒灭活过程一致的实验条件(4℃,0.025%(V/V)福尔马林(37%(w/w)甲醛溶液)处理72 h),进行甲醛与多肽的化学反应。结果表明,在实验条件下,甲醛能与标准肽段N端的氨基反应生成羟甲基加合物,再发生缩合反应生成亚胺,形成+12 Da的产物。此外,甲醛还能与标准肽段中的精氨酸、赖氨酸的侧链发生反应,生成+12 Da的反应产物。对流感病毒基质蛋白的酶切肽段与甲醛的反应的质谱分析结果显示,多数的肽段都生成了+24 Da的产物,质量的增加来源于肽段N端氨基(+12 Da)和C端精氨酸或赖氨酸的侧链(+12 Da)的贡献。此外,还观察到有一个漏切位点的肽段生成了+36 Da的产物。本研究结果表明,在实验条件下,低浓度甲醛主要与肽段和蛋白的N 端氨基,以及精氨酸和赖氨酸侧链发生反应。本研究为分析低浓度甲醛与蛋白质的反应产物提供了有效的质谱分析方法和解谱依据。     

电子能谱线形分析研究碳物种的化学状态

利用ＸＰＳ的ＣＩｓ携上峰,Ｘ射线激发供歇线形,ＸＰＳ价带谱以及俄歇电子能谱的ＣＫＬＬ线形研究了几处碳材料的化学状态和电子结构。研究结果表明：ＸＰＳ的携上效应可以鉴别不同结构的碳材料。ＸＡＥＳＲ 化学位移和线形也可以有效地研究中不同的碳材料的成像方式。ＸＰＳ的价带谱电子结构的一种有效方法,对碳材料的研究也很有效。ＡＥＳ的ＣＫＬＬ俄歇线形非常适合金属碳化物的鉴别。     

Determination of Chlorpromazine in Aqueous Solutions as Studied by Photoacoustic Spectroscopy Using a Carbon-Black Detector

Abstract

A simple, fast and reproducible method for determination of chlorpromazine (CLP) is presented. Calibration curves are prepared for the 6.0 mol.dm^?3 solutions of 1.0×10^?6 to 1.0×10^?4 CLP which are oxidized with equivalent volumes of standard Ce⁺⁴ solutions to a highly coloured (λmax⁼⁵²⁵ nm.) semiquinone cation radical. Conventional photometric and photoacoustic techniques using carbon-black detection (CBD) gave consistent results and are used to calculate the CLP content of tablets and ampuls with a good precision, and an overall accuracy of 1.9% and ～3% respectively.     

微量元素在人体内的化学行为

从配位化学的角度，论述了微量元素在人体生命过程中的化学行为。     

火焰原子吸收光谱法测定水仙桃中六种元素的含量

为给水仙桃中微量元素的检测提供科学方法,采用浓硝酸微波消解法处理样品,利用火焰原子吸收光谱法对水仙桃中Ca、Mg、Fe、Cu、、Mn、Zn 6种元素的含量进行了测定。结果表明,水仙桃中含有丰富的人体必需常量和微量元素,Ca、Mg、Fe、Cu、Zn、Mn的质量分数分别为2658.685、1823.331、205.051、8.662、11.165、4.205μg.g1。方法的加样回收率为96.0%～102.0%。该法操作简单、结果准确,是水仙桃中微量元素检测的理想方法。     

电感耦合等离子体质谱法测定工业纯铁中13种元素

工业纯铁样品用盐酸、硝酸、氢氟酸微波消解,消解液用水定容至100.0mL,采用电感耦合等离子体质谱法测定上述溶液中硼、镁、钙、钛、铬、镍、铜、锆、铌、锡、锑、铅、铋等13种元素的含量。采用内标法定量,13种元素的线性范围均为0.000 10%~0.015 00%,检出限(3s)为0.24~0.66μg·L^-1。用标准加入法做方法的回收试验,测得回收率为84.0%~106%。方法应用于纯铁标准样品(GBW 01401b、GBW 01402g、SRM 2167、YSBC 11247-2007)的分析,测定值与认定值相符,测定值的相对标准偏差(n=6)为0.80%~9.6%。     

在定量分析实验中使用未知试样

本文阐述在定量分析实验中全面使用未知试样的教学方法。此方法的实施有助于调动学生的学习积极性、提高分析化学实验基本操作技能和培养学生独立分析和解决问题的能力。     

An Enthalpic Analysis on the Aggregation of Colloidal Particles Studied by Microcalorimetry

There are different theories concerning the stability of colloidal suspensions. Most of them arise from the well-known DLVO theory which relates colloidal stability to intermolecular forces between particles. Experimental corroboration of these theories has been obtained mainly by using different optical techniques that analyze changes in the optical properties of the solution while particles aggregate. However, no attention has been paid to studying the aggregation process thermodynamically. This is why we have focussed on studying the heat released during the agglutination of polystyrene particles. The enthalpy change in this aggregation process was detected by using a highly sensitive and modern technique called isothermal titration calorimetry. In addition, some results about repeptization, that is, reversibility in the aggregation process, are also shown. Copyright 2001 Academic Press.