聚芴类半导体光谱稳定性

有机半导体的物理和化学性质直接影响其光电器件的性能, 这为物理化学提出了新的研究内容与挑战. 其中, 聚芴类蓝光二极管的光谱稳定性及低能发射带(LEEB)的起源问题是国际上近十年的热点问题之一. 本文系统概述了低能发射带的现象、表征方法以及可能的形成机理, 包括链间作用导致的激基缔合物发射、器件制备或降解过程形成的芴酮缺陷发射、芴酮聚集态发射以及聚芴端羟基界面氧化导致的绿光发射. 本文综述各种物理掺杂和界面调控改善聚芴类二极管蓝光稳定性的策略, 着重论述非平面基团的空间位阻、分子构象与链的拓扑结构以及引入抗氧化受阻胺光稳定剂来提高其光谱稳定性策略.     

低能电子在固体中散射理论及Monte Carlo模拟计算方法

本文应用较严格的理论描述低能电子在固体中散射的过程,提出了对该过程进行直接模拟的计算方法:经作者改进的Pendry分波法模型计算电子与原子间的弹性散射;非弹性散射既考虑壳层电子、导带电子贡献,也计入等离子激发的影响;电子散射及二次电子级联过程用Monte Carlo方法严格模拟,对不同能量低能电子作用下,Cu的二次电子产额、能谱曲线及背散射系数作了计算,所得结果与Kashikawa等的实验事实一致。     

用低能电子衍射研究氢在Si(100)表面吸附引起的相变

描述了用低能电子衍射(LEED)研究不同温度下在Si(100)-c(8×8)表面吸氢引起的一系列相变过程。实验发现:在液氮温度下,在Si(100)-c(8×8)表面连续吸氢将引起表面经Si(100)-(4×1)-H向(2×1)-H最终向(1×1)-H转变;而在从700℃到室温间的不同温度下饱和吸氢,实验中观察到:Si(100)-c(8×8)表面将先转变至Si(100)-c(4×4)-H,然后至(2×1)-最终至(1×1)-H。     

Pre-formation Probability of ^5He Cluster in Pre-equilibrium Mechanism

The possibility of ^5He cluster emission has been affirmed theoretically. In order to describe the emission probability of SHe cluster, the pre-formation probability of ^5He cluster in pre-equilibrium emission process is needed to be established. In terms of Iwamoto-Harada model, the theoretical formula of pre-formation probability of ^5He cluster including lp shell nucleon in pre-equilibrium mechanism has been established and calculated. In the case of low incident energies, the configuration of [1, m] for ^5He cluster is the dominant part in the nuclear reaction. The calculated results indicate that pre-formation probability of configuration [1, m] for the unstable SHe duster is much smaller than those of d, t, ^3He, and ^4He, i.e. the light stable composite particles, which are consisted of only ls shell nucleons. However, it is propitious to the emission of ^5He from the point of view on threshold energies, since the binding energies of ^5He are generally lower than that of 3He in compound nucleus. The corresponding model formula has been given in this paper for described pre-formation probability of ^5He cluster in pre-equilibrium mechanism.     

The Effective Degree of Freedom of Low Energy QCD

The adiabatic effective baryon-baryou interactions and dibaryon candidates are studied systematically with three constituent quark models based on different effective degrees of freedom:Glozman-Riska-Brown Goldstone boson exchange model based on constituent quark and Goldstone boson coupling;Fujiwara model based on constituent quark gluon coupling and Nijmegen one-boson exchange;QDCSM based on constituent quark and gluon coupling with quark delocalization and color screening.We find that the three models predicted the similar effective baryon-baryon interactions for roughly two thirds among the 64 states consisted of octet and decuplet baryons.The differences among three models and their separate characteristics are also studied.     

BESⅡ上光子探测效率的研究

利用J/ψ→ρπ衰变道,对BESⅡ上BSC对于光子的探测效率做了细致的研究.结果表明在从探测器光子能量阈值直到BES上可产生的最大光子能量范围内,用目前的Monte Carlo可以在1%—3%的精度下模拟光子的探测效率.并且对Monte Carlo在探测效率上与数据的差别进行了详细研究.同时用质心系能量s=3.770GeV处的e+e–→γe+e–数据检验了高能区MonteCarlo和数据的探测效率都达到100%,并且在1%精度下是一致的     

兰州重离子加速器

 兰州重离子加速器是由注入器(SFC)和主加速器(SSC)组成的加速系统。离子源产生的重离子束,由注入器预加速,经前束流线传输并匹配到主加速器,在主加速器内加速到最高能量后引出,经后束流线传输到实验终端。 加速后的各种离子束,主要用于重离子核物理研究,例如,用于重离子核反应机制、核结构以及新核素的合成等。另外,重离子束对许多非核科技领域的研究,例如,对材料科学、原子物理学、辐射生物学、辐射医学等领域的研究,已展现出日益广阔的前景。