Experimental study on helium optical electron polarimetry

Optical electron polarimetry is suitable for calibration of a spin-polarized electron source, especially for measurement of polarization of spin-polarized electron beam. In this paper, a new optical electron polarimeter is described, which is based on the circularly polarized He radiation induced by the bombarding of He atoms with spin-polarized electrons. The theoretical basis of the optical electron polarimetry and the structure of the optical electron polarimeter are discussed. The measurement of polarization of spin-polarized electrons produced from a new GaAs （100） spin-polarized electron source is carried out. The result of polarization of 30.8% for our spin-polarized electron source is obtained using the He optical electron polarimeter.     

关于Pt偶同位素的i_(13/2)中子对

本文对偶Pt同位素i_(13/2)中子对作了一个较细致的系统的分析.实验数据和用不同κ、μ参数所得到的Nillson推转模型结果间的比较,给出如下重要性质:1)改善的κ、μ参数能够很好符合~(185)Au数据,对Pt同位素一般地似乎也是合适的,但尚需更多的实验与理论数据检验.2)仅仅有vi_(13/2)排列不能解释~(184)Pt中大的上弯现象,而πh_(9/2)排列应该同样也起作用.3)实验数据与理论计算之间的偏离表明,一种包括ε_2,ε_4及γ三维势能面的计算是必需的.     

Photoluminescence study on Eu-implanted GaN

The photoluminescence (PL) properties of Eu-implanted GaN thin films are studied. The experimental results show that the PL intensity is seriously affected by ion implantation conditions. The PL efficiency increases exponentially with annealing temperature increasing up to a maximum temperature of 1050℃. Moreover, the PL intensity for the sample implanted along the channelling direction is nearly twice more than that observed from the sample implanted along the random direction. The thermal quenching of PL intensity from 10K to 300K for sample annealed at 1050℃ is only 42.7%.     

电子-光子符合散射实验中受激原子态电荷云分布的研究

根据电子原子碰撞受激态退激偶极辐射的电子-光子符合实验的一般性理论，采用扭曲波近似方法，计算了电子与碱金属钠原子碰撞退激辐射光子的Stokes参数.引入取向和排列参数，用以描述受激态电荷云的分布，得到了与已有实验数据一致的结果. 关键词： 取向 排列 Stokes参数 电子-光子符合测量     

单模光纤弯曲损耗的测量与分析

从理论和实验两方面讨论了弯曲半径及工作波长对单模光纤弯曲损耗的影响，测量了1310nm和1550nm波长光作用下，弯曲损耗随弯曲半径的变化关系。结果表明：随着弯曲半径的增大，弯曲损耗系数呈下降趋势，并且伴有振荡现象出现；而且，在弯曲半径较大时，弯曲损耗变化平缓，1550nm波长较1310nm波长明显更易产生弯曲损耗，而小弯曲半径对应的弯曲损耗振荡剧烈，此时两种光波长对弯曲损耗的敏感程度交替变大。     

机加工中的振动问题

 系统在粘滞阻力的作用下,振幅随时间而减少的振动称阻尼振动。在运动速度不大时,可认为振动系统受到的粘滞阻力fr与速度v成正比,方向与速度相反,即fr=-rv。     

黄原脂棉分离-石墨炉原子吸收光谱法测定咸味食品中Pb~(2+)

利用单因素试验对黄原脂棉吸附溶液中Pb~(2+)的条件进行了实验优化,结果显示:在pH=5.0的溶液体系中,于温度20℃,振荡吸附15min,黄原脂棉对Pb~(2+)的吸附效果最佳;吸附的Pb~(2+)用6.0mL 3.0mol/L HCl,于40℃下解吸15min,可将Pb~(2+)从黄原酯棉上完全洗脱。采用石墨炉原子吸收光谱法,将该条件用于测定咸味食品中痕量Pb~(2+),结果表明:黄原脂棉能有效消除盐类基体给测定Pb~(2+)带来的干扰,方法的相对标准偏差为1.56%~2.31%(n=6);回收率为97.0%~102.7%;检出限为0.047mg/kg。本法灵敏、准确、可靠,可用于咸味食品中痕量Pb~(2+)的测定。     

Analysis of random laser scattering pulse signals with lognormal distribution

The statistical distribution of natural phenomena is of great significance in studying the laws of nature. In order to study the statistical characteristics of a random pulse signal, a random process model is proposed theoretically for better studying of the random law of measured results. Moreover, a simple random pulse signal generation and testing system is designed for studying the counting distributions of three typical objects including particles suspended in the air, standard particles, and background noise. Both normal and lognormal distribution fittings are used for analyzing the experimental results and testified by chi-square distribution fit test and correlation coefficient for comparison. In addition, the statistical laws of three typical objects and the relations between them are discussed in detail. The relation is also the non-integral dimension fractal relation of statistical distributions of different random laser scattering pulse signal groups.