氢化物发生微分电位溶出法测定人尿、头发及自来水中痕量锡

研究了氢化物发生微分电位溶出法测定人尿、头发及自来水中痕量锡的方法,该法能有效地消除共存离子的干扰。详细研究了锡化氢发生以及微分电位溶出法测定锡的最佳条件。方法的线性范围0－150mg.ml^-1,检出限2．5ng.ml^-1,成功地用于自来水、人尿及头发痕量锡的测定。测定发样中304．5ng.g^-1锡时,回收率为100．3％,相对标准偏差为5．1％（n=6)。     

Oxidative Dehydrogenation of Ethane to Ethylene over LiCl/MnOx/PC Catalysts

The catalytic stability of LiCl/MnO_x/PC catalyst have been investigated, the deactivation mechanism was discussed. The experimental results show that ethane conversion decreases and ethylene selectivity keeps about 90% as reaction time increases. The main deactivation reasons of LiCl/MnO_x/PC catalyst for oxidative dehydrogenation of ethane (ODHE) to ethylene are the transition of active species Mn₂O₃ to MnO species and the loss of active component Cl in catalyst. Instead of ethane with FCC tailed‐gas, the stability of LiCl/MnO_x/PC catalyst has been largely improved.     

材料交界面上连续应力分析的改进拉氏乘子法

引进材料界面的节理单元,以其刚度参数为罚参数,利用代表界面接触应力的拉氏乘子,通过迭代求解得到界面上的应力,为计算粘结在一起的不同材料交界面上的应力提供了一种非常有效的方法。     

信息系统中的可移动Agent

介绍了可移动Agent的特性,可移动Agent可在异质计算机网络中移动,它能感知网络的状态,监控系统并与其它Agent进行交互,导航模型可以让Agent适应网络的变化并自主制定导航计划,从而方便、有效、智能地完成信息检索的任务．     

RING-OPENING POLYMERIZATION OF TRIMETHYLENE CARBONATE BY CALIX[8]ARENE-NEODYMIUM*

Ring-opening polymerization of trimethylene carbonate (TMC) with a rare earth calixarene compound as catalysthas been studied for the first time. The effect of TMC/Nd (molar ratio) and polymerization conditions were investigated indetail. It was found that calix[8]arene-neodymium is a highly effective catalyst for the bulk polymerization of TMC and giveshigh molecular weight (M_v = 60,000) polymer. The optimum conditions of TMC polymerization were found to be asfollows:TMC/Nd (molar ratio) = 2,000, 80℃, 16 h. The polymers were characterized by NMR, GPC and DSC. Studying themechanism by NMR showed that the polymerization of TMC catalyzed by calix[8]arene-neodymium proceeds via a cationicmechanism.     

蚕丝辐射接枝丙烯腈

以氯化锌水溶液为溶剂 ,用钴 60γ射线引发蚕丝均相溶液接枝丙烯腈 .研究了辐射吸收剂量、剂量率、铜离子浓度、蚕丝浓度和单体浓度及“后效应”对单体转化率、接枝率、接枝效率、接枝链分子量的影响 ;研究发现初始接枝效率主要取决于 [S]丝/ ( [S]丝 +[M]单) ,接枝效率随吸收剂量增加而增加 ;铜离子的存在使接枝链分子量下降 ,而对接枝率和接枝效率影响不大 ;用IR、TGA、DTA等多种方法对接枝物进行了表征 ,表明蚕丝接枝上聚丙烯腈后 ,其热学性能有较大提高 .     

氢中杂质CO对LaNi5,LaNi4.7Al0.3,MlNi4.5Al0.5合金PCT特性的影响

研究了 3种贮氢合金 ,即LaNi5 ,LaNi4.7Al0 .3,MlNi4.5 Al0 .5 在纯氢 ( 99 999% )及含 0 0 1%CO气体杂质氢中毒化前后的PCT特性。对于LaNi5 ,毒化后不出现平台 ;对LaNi4.7Al0 .3及MlNi4.5 Al0 .5 合金 ,平台压升高 ,平台倾斜加剧 ,平台宽度缩小 ,饱和吸氢量减小。LaNi5 中加入少量Al后 ,可以提高其抗毒化能力。分析了PCT平台变短、倾斜的原因。     

Laser-phase determination methods and transfer equations for direct temporal structure measure- ments of atto- and femtosecond XUV pulses

In this paper the laser-phase determination methods and transfer equations are presented to directly reconstruct the detailed temporal structures of ultra-short extreme ultraviolet (xuv) pulses from the measured photoelectron energy spectra (PES). Each transfer equation includes one of PID (proportional-integral-differential) terms of PES. The intensity and instantaneous frequency of attosecond xuv can be retrieved from the integral term of PES. The intensity profiles of narrow bandwidth atto- and femtosecond xuvs can be rebuilt from the proportional and differential terms of PES respectively. The methods and equations may be used to improve time resolutions in measuring ultrashort pulses.     

BEPCⅡ Control System

The BEPCⅡ project is for upgrading the Beijing Electron Positron Collider to reach a higher luminosity.BEPCⅡ is designed as micro-β plus multi-bunches with double rings and has adopted cryogenic superconducting technology. The BEPCⅡ control system is a distributed system based on EPICS. In the past few years, we went through the design stage, R&D stage, development stage and the system will be installated. The BEPCⅡ machine commissioning with beam will start in October 2006. This paper describes the BEPCⅡ~control system and the progress of its development.