Thermodynamic Properties and Transport Coefficients of Nitrogen,Hydrogen and Helium Plasma Mixed with Silver Vapor

Species composites of Ag-N2,Ag-H2 and Ag-He plasmas in the temperature range of 3,000-20,000 K and at 1 atmospheric pressure were calculated by using the minimization of Gibbs free energy.Thermodynamic properties and transport coefficients of nitrogen,hydrogen and helium plasmas mixed with a variety of silver vapor were then calculated based on the equilibrium composites and collision integral data.The calculation procedure was verified by comparing the results obtained in this paper with the published transport coefficients on thc case of pure nitrogen plasma.The influences of the silver vapor concentration on composites,thermodynamic properties and transport coefficients were finally analyzed and summarized for all the three types of plasmas.Those physical properties were important for theoretical study and numerical calculation on arc plasma generated by silver-based electrodes in those gases in sealed electromagnetic relays and contacts.     

X射线荧光光谱法测定粗银中九种元素

应用波长扫描X射线荧光光谱仪对粗银中Ag、Au、Cu、Se、Te、Sb、Pb、Pd、Bi九种元素进行测定。运用空白试样系数校正法对各元素的谱线重叠进行校正,理论系数与经验系数相结合对样品基体效应进行校正,有效克服了各元素谱线的背景干扰与基体效应。精密度试验和比对试验表明:该方法分析检测值与化学法检测值相吻合;分析相对标准偏差为0.24%～13.64%,对比分析相对误差为0～13.93%;本方法简单、快速、准确。     

Atomic and electronic structure of the Si(111)-√3x√3-Ag surface reexamined using first-principles calculations

We have reexamined the atomic and electronic structures of the Si(111)-√3x√3-Ag surface using first-principles calculations within the local density functional approach. First, we found that a discrepancy among previous first-principles studies concerning the honeycombchained- triangle (HCT) model, which was believed to describe the structure of the surface, can be attributed to the difference in the structural parameters adopted in the calculations. Second,we have confirmed that the recently proposed inequivalent triangle (IET) model, where the positions of the Ag atoms are distorted a little from those in the HCT, is energetically more stable than the HCT one. We have also examined several othermodels that have distortions similar to the IET one. The results suggest that at room temperature the surface does not stay in the HCT configuration, but fluctuates between various configurations.     

PVP还原制备花朵状银纳米颗粒

以硝酸银为前驱体,聚乙烯吡咯烷酮为还原剂和保护剂,制备出了花朵状纳米银。利用紫外可见吸收光谱（UV-Vis）、扫描电子显微镜（SEM）、X射线衍射仪（XRD）及傅里叶红外光谱仪（FT-IR）等对其进行了分析表征。研究表明,制得的Ag纳米颗粒属于面心立方结构,随着反应温度的升高,Ag纳米颗粒形貌由类球形到立方体形、薄片形、花朵形转变,溶液中的Ag＋会得到PVP分子内酰胺基中N的给电子,使Ag＋获得电子而转化为Ag。     

Formation of Analcime Film under Hydrothermal Conditions

Polycrystalline analcime film was prepared from hydrogels under hydrothermal conditions. The analcime film of about 200 pm thickness built up on a porous alumina support at temperatures above 160°C, and the size and crystallinity of analcime increased with temperature. The thickness of analcime film increased with incubation time, and the growth rate at 180°C was faster than that at 160°C. The analcime film obtained was thermally stable at temperatures up to 700°C, and no structural changes were observed after treatment in nitric acid solutions below 0.01M. Analcime had an ion-sieve ability to large sized Cs⁺ ion, and Ag⁺ and Rb⁺ ions of small sizes were incorporated in analcime.     

AAO模板中AgBr的显影过程探讨

在AAO(Anodic Aluminum Oxide)模板中生长AgBr纳米线,并对其进行化学显影.显影结果表明,D-72显影液和D-76显影液显影后得到的银大部分都在模板的表面,分别呈丝状和颗粒状;而原位显影液得到的银则在孔隙中呈线状分布.文章认为,3种显影液中物质传质过程及显影剂活性的不同造成了显影银存在位置和形貌的差异,并提出用直接电子转移和间接电子转移机理解释银的形貌差异.     

电子辐射对渗透性材料上书写墨水信息记录的影响

本文介绍电子辐射对不同墨水书写信息的影响。2001年10月当发现炭疽病毒感染邮寄的信件时,美国政府开始利用电子辐射杀死邮件上的病毒,并在全国推广这项技术。可是过了一段时间发现,这项技术对某些邮寄物品是有害的。数据表明电子辐射可能对邮品上存在的时间特征有损害,尤其是邮寄通过常规船运的美术和历史资料,时间特征是非常重要的。     

墨彩山水创作之我见

墨彩是最能够体现景德镇陶瓷艺术巧夺天工、技艺精湛特点的工艺技法。这不仅要在线描上下功夫,色彩上也十分讲究,而且在题材上也要有所选择。就拿墨彩山水来说,要始终保持着用色少"墨色浓淡、雅洁宜人"的艺术效果;在构图上舍弃不必要的背景,以白衬黑使主题更为突出,更能突出景德镇瓷白如玉和造型的独特完美。