ON THE GENERATION OF LASER-INDUCED PLASMA ACOUSTIC WAVES

In this paper, the transition of laser plasma waves into laser plasma acoustic waves has been discussed first, and it is suggested that the weak limitation of laser-induced-plasma shock wave is an acoustic wave. Based on this idea, a definition of laser plasma acoustic wave is given, and this kind of acoustic waves for some materials has been obtained experimentally.     

滑线变阻器的传感作用

传感器能将所感受到的物理量(如力、热、光、声等)转换成便于测量的量(一般是电学量)．其工作过程是通过对某一物理量敏感的元件将感受到的信号按一定规律转换成便于利用的信号，经相应的仪器进行处理，就可以达到自动控制等目的．如常用的光电传感器、热电传感     

K-MoO3/γ-Al2O3催化剂表面物种状态、组成和性能

应用XPS、XRD、ESR 和TPR技术分析了KCl助剂含量变化对MoO_3/γ-Al_2O_3催化剂表面物种状态、组成及其硫化还原性能的影响. K/Mo比小于0.8时, 钾离子完全和钼作用, 形成钾钼作用物种, 催化剂硫化后发生K~+表面富集, Cl~-游离并流失; K/Mo比0.8时, 钾钼作用达到饱和; K/Mo比大于0.8时, 多余的K~+和Cl~-结合以体相KCl形式存在. 钾钼作用减弱了Mo(Ⅵ)和载体之间的作用, 部分抑制了Mo(Ⅵ)的硫化还原. 钾钼作用物种硫化后可能产生CO合成醇的活性中心.     

稀土助剂对Zr—Mn—K催化剂上甲醇,异丁醇合成的影响

在Ｚｒ－Ｍｎ－Ｋ催化剂中添加稀土氧化物助剂Ｐｒ６Ｏ１１，Ｓｍ２Ｏ３可以显著提高合成气合成甲醇，异丁醇的活性，特别是异丁醇的时空产率在４００℃，１０ＭＰａ，５０００＾－１的反应条件下，由原来的５．９分别增加到１１．５，９．８ｍｌ／ｈ．ｌｃａｔ。     

Synthesis,Crystal Structure and Fluorescent Properties of a 4-Fold Interpenetrating Zn(Ⅱ) Polymer

A new coordination polymer [Zn(isop)(bps)]n 1(H2isop=benzene-1,3-dicer-boxylic acid,bps=4,4'-dipyridyl sulfide) has been prepared and structurally characterized by X-ray diffraction method.It crystallizes in monoclinic,space group P21/n with a=12.1936(11),b=10.7720(9),c=13.0685(11),V=1709.0(3)3,C18H12N2O4SZn,Mr=417.76,Z=4,Dc=1.624g/cm3,S=1.046,F(000)=848,the final R=0.0305 and wR=0.0858 for 3085 independent reflections with Rint=0.0147.Single-crystal X-ray diffraction analyses reveal that 1 is a 4-fold interpenetrating diamondoid network.The zinc(Ⅱ) atom is coordinated by two nitrogen atoms of two bps and two carboxylate oxygen atoms of isop ligands,resulting in a tetrahedral geometry.     

基于平均质量的悬浮颗粒物的质量密度算法

基于米氏(Mie)散射理论得到了粒子计数器测量球形颗粒物质量密度的计算公式。考虑非球形颗粒,从颗粒群粒度分布概念出发,提出了统计意义上的平均质量概念,推导了非球形颗粒物质量密度的理论公式。运用理论公式证明了粒子计数器测量非球形颗粒物质量密度计算公式的合理性,进而给出了基于平均质量的悬浮颗粒物的质量密度算法,该算法只需对两个系数进行标定。实验表明,该算法的质量密度计算值与实际值十分吻合,两者拟合直线的斜率为0.9713,相关系数为0.9998。该算法为实现粒子计数器在线测量悬浮颗粒物的质量密度提供了一种可行途径。     

A model for aerosol mass concentration using an optical particle counter

A model for measuring aerosol mass concentration by an optical particle counter is presented using the conception of the average mass. In this model, to understand the meaning of the pulse height distribution of particles which is used to inverse mass concentration, the relationship among intensity distribution in the optical sensing volume, particle shape, and the pulse height distribution is discussed. To solve the instability of the equivalent factor, a novel two-step calibration method is proposed. The experimental results demonstrate that mass concentrations calculated by the model are in good agreement with those measured by a norm-referenced instrument. For samples of soot and air, the slopes of fitting lines of data points are 0.9582 and 0.9220, and the correlation coefficients are 0.9991 and 0.9965, respectively.     

激光荧光法测定天然水中痕量铀

一、引言近几年来,由于核电站的增建和运行,一些国家的核武器试验,农业上磷酸盐化肥的增产和使用,使自然环境中特别是大气和水中的铀含量有增大的趋势。由于铀的化学毒性及放射性对人体的危害,使人们对它的存在日益关心。环境中铀含量的测定已成为环保分析中的一个重要项目。此外,由于水文地球化学的研究和发展,通过测定天然水中铀含量可以进行