Cs-K混合蒸气中Cs(8D)+K(4S)碰撞能量转移

在Cs-K混合蒸气中，两步激发Cs原子到8D态，观察了Cs(8D) K(4S)→Cs(5D) K(4P)碰撞能量合并逆过程(REP，reverse energy pooling)。应用双调制技术探测K(4P)原子发射的荧光，基态K原子密度用光学吸收方法测量。得到了REP速率系数，讨论了其它过程对速率系数的影响．     

Estimation and Optimization of the Principal H-Maser Parameters

The scale along the coordinate axes in the equations of motion hitherto used for an H-maser (in relative units) is shown to depend on Q as the quality factor for an H-maser. This hinders both analysis of the operation of the H-maser and optimization of its parameters. The modified equations of motion proposed here do not have that shortcoming. We determine the atomic flux into the bulb that gives the H-maser the best metrological characteristics.     

有机化合物中碳原子化学环境的分类

进行碳－１３ＮＭＲ波谱模拟的一种常用方法为线性回归，其数学模型则由已知结构所测得的化学位来建立。显然，每一数学模型仅可用于某种相似的化学环境。因此，为了进行化学环境的分类，本文提出权重层次位图法和分子连接性指数法两种方法以进行一些参数的计算，同时采用多元分析手段，如主成分分析和聚类分析，以进行多维空间数据点的显示，所得结果比较满意，从而可为碳－１３波谱模拟中回归方程的选择提供理论依据。     

PDB-18C6对TI(Ⅰ),An(Ⅲ),Cu(Ⅱ)的吸附及从α轰击的金靶中分离~(199)TI

本文研究了用冠醚树脂二苯并-18-冠-6甲醛聚合物(简称PDB-18C6)对T1(Ⅰ),Au(Ⅲ),Cu(Ⅱ)的吸附行为。实验表明,在盐酸溶液中冠醚树脂的吸附效率顺序为Au(Ⅲ)>T1(Ⅰ)>Cu(Ⅱ)。用高氯酸和乙二醇乙醚淋洗T1(Ⅰ),Au(Ⅲ),它们的回收率一般在82-98.9％和98-100％。还在1.2m回旋加速器的外靶装置上,用25-27MeV的α粒子轰击金靶,累计束流强度为27μA·h,经处理分离后得到仅含0.50％~(200)T1的较高纯度的~(199)T1。     

Heterogeneous chain propagation in low-pressure flames

An analysis of papers on hydrogen combustion at low pressures is performed, which refines the contribution of the catalytic reactions on the reactor wall to the gas-phase part of the process. A new model for the heterogeneous loss of active reaction centers was proposed and tested experimentally to explain inconsistencies that occur in some papers. In this model, the diffusion region of chain termination is formed under standard experimental conditions in vacuum oxyhydrogen flames at a reactor gas pressure a thousand times lower than the boundary pressure postulated by the previous models as the pressure below which the diffusion region of chain termination cannot be formed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 2, pp. 10–18, March–April, 2006.     

The Role of Metastable Atoms in a Homogeneous Atmospheric Pressure Barrier Discharge in Helium

A one-dimensional fluid model for homogeneous atmospheric pressure barrier discharges in helium is presented by considering elementary processes of excitation and ionization including a metastable atom effect. Using this model we investigate the behaviours of the helium metastable atoms in discharges as well as their influence on the discharge characteristics. It is shown that the metastable atoms with a relatively high concentration during the discharge are mainly produced in the active phase of the discharge and dissolved in the off phase. It is also found that the metastable atom collisions can not only provide seed electrons for discharges but also influence the concentration of ions. A reduction of matestable atom density results in a drop in the charged particle densities and causes a qualitative change in the discharge patterns.     

低能重离子及其碰撞产生的级联原子在生物材料中的直接作用范围

用Ｍｏｎｔｅ Ｃａｒｌｏ法模拟计算了３０ｋｅＶ和２００ｋｅＶ的Ｎ＾＋与１１０ｋｅＶ的Ｆｅ＾＋在模拟细胞中的射程分布和径迹结构，并将１１０ｋｅＶＦｅ＾＋模拟计算的结果与ＲＳＢ测量的结果相比较，发现计算与测量的结果吻合较好，离子的作用范围小于１μｍ。计算和实验的结果都说明能量相当低的重离子不大可能直接作用引起麦胚深层生物效应。     

叔丁醇氧化产物的气相色谱分析

介绍了用气相色谱分析叔丁醇两步氧化制甲基丙烯酸液相产物的组成，该分析方法能够分析液相产物中的醛类，酮类和酸类化合物共计9个组分，C2－C4有机酸无记忆效应，其色谱峰不拖尾，该分析方法的相对标准偏差≤8．5％，回收率在94．5％－103．7％之间，是一种快速，准确，操作简单的分析方法。     

MECHANISM OF NON-EQUILIBRIUM SEGREGATION OF SOLUTE TO GRAIN BOUNDARIES

本文以空位-溶质原子拖曳机制为基础,并考虑了空位、溶质原子和复合体三者的反应平衡及晶界平衡偏聚的作用,得到了溶质原子的非平衡晶界偏聚动力学方程。对硼在奥氏体中等温及连续冷却时所产生的非平衡晶界偏聚现象进行了理论计算,得到了与实验较为一致的结果。     

过渡金属硫化物在高级氧化法中的研究进展

近年来,高级氧化技术(Advanced oxidation processes,AOPs)被广泛用于去除废水中的污染物,但高成本、高能耗限制了该技术的应用,开发低成本、高效、可重复利用的催化剂来降低该技术的使用成本是提高AOPs应用的有效手段。过渡金属硫化物(Transition metal sulfides,TMS)具有良好的导电性、机械稳定性和热稳定性,具有带隙可调特性的TMS可用作光催化剂。综述了TMS在AOPs中的应用,TMS可通过不饱和硫暴露金属活性位点提高Fenton法中Fe~(3+)还原为Fe~(2+)的速率,还可直接活化过硫酸盐或作光催化剂。同时介绍了TMS的改性方法,主要通过元素掺杂改性来增加活性位点,降低带隙宽度;通过TMS与金属化合物复合来提高电导率,增强催化活性;通过TMS与碳基材料复合原位生成H_2O_2,降低光生电子-空穴对的重组速率。最后,对TMS在AOPs中的发展方向进行了展望。