Measurement of Mg Content in Zn1-xMgxO Films by Electron Probe Microanalysis

Zn1-xMgxO films are grown on A-sapphire substrates by molecular beam epitaxy, and Mg content in the Zn1-xMgxO films is measured by electron probe microanalysis （EPMA） when the acceleration voltage, the emission current, and the magnification are set to be 1 k V, 30 μA and 1000, respectively. The dead time is controlled within 17%-20% during the measurement with the receive angle of characteristic x-ray of 45°. The Mg content of the ZnMgO film is calculated by the low energy calibration and the ZAF calibration. By comparing the measurement result with the theoretical analysis and the EPMA result with the inductively coupled plasma （ICP）, one can obtain that the measured value of Mg content of the samples is in good agreement with the theoretical analysis no matter whether the phase separation exists or not, and the correctness of ICP and EPMA is valid when Mg content in the samples is less than 0.5.     

22Na放射源慢正电子束流插入装置的研制

北京慢正电子强束流是利用北京正负电子对撞机电子直线加速器电子打靶产生的高强度低能单色正电子束流. 为了提高强束流的机时利用效率和节省强束流用于新建实验站的调试机时, 设计了一套基于²²Na放射源的慢正电子束流装置插入到强束流输运线上. ²²Na放射源慢正电子束流插入装置主要包括²²Na放射源及慢化体、E×B能量选择器、多级静电加速管、磁场输运系统、真空系统、高压绝缘和辐射防护措施等.     

Suppression and Acceleration Effects of Measurements on A-type Atomic Decay in Anisotropic Photonic Crystals

The measurement-induced suppression and acceleration effects on A-type atomic decay in three-dimensional anisotropic photonic crystals are investigated. We consider the two cases, only one or both of the two atomic resonant frequencies being near the band edge of a photonic crystal. Due to the deformation of the electromagnetic density of states, the repeated projection onto the excited state can lead to decay suppression or acceleration effect already at rather low repetition rates. Such measurement-induced effects are dependent on the frequency of measurements and the relative position of the atomic upper level from the band edge of photonic crystals. The behaviors of instant and effective decay rates are studied in detail, which are different from the case of isotropic photonic crystals.     

斜激波与有扰界面相互作用的数值模拟

本工作应用多流体体积分数模型，采用高分辨率PPM格式数值模拟斜激波加速有扰界面过程。侧重对比不同扰动振幅无量纲数条件下，激波加速导致快／慢界面演化的差别，并从斜压项分布差别的角度，分析涡量沉积的规律。对应不同扰动振幅无量纲数，发现了一些涡量在界面沉积及界面演化的有趣的现象。定义扰动振幅无量纲数a／L。口为扰动振幅，L是界面长度。计算的3个扰动振幅无量纲数分别为0．0，0．052，0．104。对应不同时间序列60，120，180，240，300μs，计算给出了分别对应扰动振幅无量纲数为0．0，0．052，0．104的密度、涡量、斜压项等值线图。     

4MV静电加速器调试中出现的问题

介绍了静电加速器的结构以及调试中出现的离子源不放电、控制系统失灵和加速管破裂等技术问题，分析了出现这些问题的原因以及解决办法，调试出了流强为100μA、能量在3MeV以上的稳定质子流。The structure of electrostatic accelerator and some technical problems arising in development, including the RF ion source doesn＇ t produce discharge, the controlling system is out of order and the accelerating tube cracks et al. , are introduced; the reasons and the solving means of these problems are analyzed; a stable proton beam with 100 μA and 3 MeV is obtained.     

激光等离子体中多光子非线性Compton散射的光子加速

利用相对论性电子与光子非弹性碰撞模型，研究了激光等离子体中发生多光子非线性Gompton散射时，由于尾波场的作用而引起的散射光子频率的变化。结果表明，光子可以从激光场中获得能量，在光子总数减少的情况下，光子频率增大，光子获得加速。     

Na原子能量自囚禁的加速效应

采用高分辨激光光谱方法，在较高温度条件下，实验观察到Na原子能量自囚禁加剧特征。出现原子加速的光谱行为；并导致零速度原子碰撞转移到高激发态的速度减少。从原子内能碰撞转移的角度，分析了原子速度分布变异的机理。     

匀加速穆斯堡尔谱仪系统及穆斯堡尔谱的精确测量

描述穆斯堡尔谱仪系统原理、结构、驱动机制，对探测器的选择与14．4keV能量窗口的甄别、放射源匀加速运动、驱动波形与同步问题进行了分析，指出谱仪使用和调整时应注意的问题，并就其对穆斯堡尔谱精确测量的影响进行了探讨。     

匀加速穆谱系统及穆斯堡尔谱的精确测量

描述穆斯堡尔谱仪系统原理、结构、驱动机制 ,对探测器的选择与 14.4 ke V能量窗口的甄别、放射源匀加速运动、驱动波形与同步问题进行了分析 ,指出谱仪使用和调整时应注意的问题 ,并就其对穆斯堡尔谱精确测量的影响进行了探讨 .