Li同位素的结构和性质

锂同位素的结构性质，特别是滴线核 ~(11)Li的异常特性，目前微观机制并不很清楚。本文系统地研究了锂同位素基态和低位态的性质，包括基态结合能、能谱、电磁矩和电磁跃迁性质、及β衰变性质，发现~6Li核基态的四极矩敏感地依赖于相互作用力中的张量力分量，~6Li、~7Li和~8Li核的第一激发态电磁跃迁几率增大，呈现集体性，可能是由集团结构所致，对远离核~9Li的某些态需要考虑sd-shell组态侵入的影响。在~(6-9)Li核性质系统研究的基础上，发现滴线核~(11)Li核的结构性质仍可在壳模型框架内得到解释，平均场效应是引起其奇异性质的微观起因，对于~(10)Li核的性质仍需进一步探讨。对锂同位素引进平均场的同位旋依赖项尚需近一步研究。在3

Li蒸气电荷交换负He离子源的设计与调试

本论文分别从离子源的历史发展，负He离子的产生机理，设计思想及调试运行等方面描述了锂蒸气电荷交换负He离子源。该离子源可以引出1μA以上的He~-离子流，可连续稳定运行十二小时以上。本文研究了其性能，获得了束流强度随蒸气温度、引出电压的变化规律，并对蒸气靶靶厚、电荷交换截面、转化率进行了简单的估算。当引出电压为18KV，蒸气温度500 ℃时，靶厚为8.5 * 10~(13)cm~(-2)，交换截面为1.0 * 10~(-16)cm~2， 转化率为0.86%。最大负He离子流强为1.37℃A.该源配置在2 * 2MeV串列静电加速器上，可在核物理实验和离子束分析提供良好的He负离子流和负H离子流。本文还提出了一些改进完善意见和设想

Influence of iron promoter on catalytic properties of Rh-Mn-Li/SiO2 for CO hydrogenation

The effect of iron promoter on the catalytic properties of Rh-Mn-Li/SiO2 catalyst in the synthesis Of C-2 oxygenates from syngas was investigated by means of the following techniques: CO hydrogenation reaction, temperature-programmed reduction (TPR), temperature-programmed desorption and reaction of adsorbed CO (CO-TPD and TPSR) and pulse adsorption of CO. The results showed that the addition of iron promoter could improve the activity of the catalysts. Unexpectedly, the yield of C-2 oxygenates increased greatly from 331.6 up to 457.5 g/(kg h) when 0.05% Fe was added into Rh-Mn-Li/SiO2 catalyst, while no change in the selectivity to C-2 oxygenates was observed. However, the activity and selectivity Of C-2 oxygenates were greatly decreased if the Fe amount exceeded 1.0%. The existence of a little iron decreased the reducibility of Rh precursor, while the reduction of Fe component itself became easier. CO uptake decreased with increasing the quantity of Fe addition. This phenomenon was further confirmed by CO-TPD results. The CO-TPD and TPSR results showed that only the strongly adsorbed CO could be hydrogenated, while the weakly adsorbed CO was desorbed. We propose that Fe is highly dispersed and in close contact with Rh and Mn; such arrangements were responsible for the high yield Of C-2 oxygenates. (C) 2002 Elsevier Science B.V. All rights reserved.

Mg-Li-RE系合金研究进展

在简要介绍高强轻质Mg-Li合金发展历史的基础上,对Mg-Li合金中含稀土(RE)的Mg-Li-RE系合金的研究情况进行总结。重点介绍Mg-Li-RE三元合金以及含RE的Mg-Li其他系合金的研究进展,叙述了RE对Mg-Li合金结构、性能的影响,指出目前存在的问题,提出下一步工作重点和今后的发展方向。