惰性气体离子注入铝镁尖晶石合成金属纳米颗粒的探索

实验在表面蒸镀了金属(Cu,Au)薄膜的尖晶石(MgAl2O4)样品中注入惰性气体离子(Ar,He),随后对注入样品进行了退火处理.在紫外可见光谱上观察到了由于金属纳米颗粒存在引起的较强的表面等离子体共振吸收峰,提供了材料中金属纳米颗粒形成的证据.采用这种方法在材料中引入金属纳米颗粒,发现影响金属纳米颗粒形成的因素除了退火温度外,金属薄膜厚度的影响不可忽略.

An 8.1 Ma calcite record of Asian summer monsoon evolution on the Chinese central Loess Plateau

IEECAS SKLLQG

中能重离子碰撞中同位旋分馏的同位旋效应

基于改进的同位旋相关量子分子动力学模型 ,研究了中能重离子碰撞中同位旋分馏强度(N Z) 气 (N Z) 液 随着碰撞系统中子 -质子比和碰撞参数的变化所呈现出的同位旋效应 ,得到了一些有兴趣的结果 .如在碰撞系统质量、入射能量和碰撞参数固定的条件下 ,(N Z) 气 (N Z) 液 随碰撞系统中子 -质子比的增加而增加 .对于丰中子系统而言 ,(N Z) 气 (N Z) 液 灵敏地依赖于对称势而较弱地依赖于核子 -核子碰撞截面 ;而缺中子系统 ,(N Z) 气 (N Z) 液 对于对称势和介质中核子 -核子碰撞截面都不灵敏 .对于造成这种现象的物理机制进行了分析和讨论 .一般核反应中 ,碰撞参数是各种物理观测量的灵敏函数 ,但计算结果表明同位旋分馏强度对于碰撞参数并不灵敏 ,故对于丰中子系统而言 ,同位旋分馏强度是提取对称势知识的灵敏物理观测量 .

锇的一个重同位素:~(197)Os

利用14 MeV中子轰击天然铂靶,通过~(198)Pt(n,2p)~(197)Os反应产生锇的一种同位素~(197)Os,以γ(X)谱学方法鉴别了它,同时研究了它的衰变性质。观测到了能量为41.2、50.7、196.8、199.6、223.9、233.1、250.2、342.1、403.6和406.4keV的10条新γ射线,并指定为~(197)Os的衰变。测定它的半衰期为2.8±0.6 min。

加速器自动调束系统的研究

描述了加速器自动调束系统的设计方法,介绍了加速器调束工作的现状和实现自动调束的意义,阐述了基于遗传算法进行加速器自动调束的原理和加速器自动调束系统的设计方法,给出了计算机仿真实验结果,并指出了自动调束研究的发展方向.

不同初始温度时Na_8+Na_8团簇碰撞动力学研究

采用距离相关紧束缚的分子动力学模型 ,在不同初始温度T0 =0 .0 2K、50K、10 0K、2 0 0K、30 0K、4 0 0K时 ,对Na8+Na8在质心系轰击能量为 0 .0 12 5eV/n的中心碰撞时的反应动力学进行了研究。发现团簇碰撞动力学与初始温度密切相关。在T0 <10 0K时 ,初始温度不影响反应动力学 ,而在T0 =4 0 0K时将对反应动力学有强烈影响。

Gravitational corrections to energy-levels of a hydrogen atom

The first-order perturbations of the energy levels of a hydrogen atom in central internal gravitational field are investigated. The internal gravitational field is produced by the mass of the atomic nucleus. The energy shifts are calculated for the relativistic 1S, 2S, 2P, 3S, 3P, 3D, 4S, and 4P levels with Schwarzschild metric. The calculated results show that the gravitational corrections are sensitive to the total angular momentum quantum number.

Systematic study of properties of Hs nuclei

The ground-state properties of Hs nuclei are studied in the framework of the relativistic meanfield theory. We find that the more relatively stable isotopes are located on the proton abundant side of the isotopic chain. The last stable nucleus near the proton drip line is probably the (255)Hs nucleus. The alpha-decay half-lives of Hs nuclei are predicted, and together with the evaluation of the spontaneous-fission half-lives it is shown that the nuclei, which are possibly stable against spontaneous fission are (263-274)Hs. This is in coincidence with the larger binding energies per nucleon. If (271-274)Hs can be synthesized and identified, only those nuclei from the upper Z = 118 isotopic chain, which are lighter than the nucleus (294)118, and those nuclei in the corresponding alpha-decay chain lead to Hs nuclei. The most stable unknown Hs nucleus is (268)Hs. The density-dependent delta interaction pairing is used to improve the BCS pairing correction, which results in more reasonable single-particle energy level distributions and nucleon occupation probabilities. It is shown that the properties of nuclei in the superheavy region can be described with this interaction.