Knockout reaction mechanism studied by 6He projectile

Knockout reaction experiment was carried out by using the ⁶He beams at 61.2 MeV/u impinging on a CH₂ target. The α core fragments at forward angles were detected in coincidence with the recoiled protons at larger angles. From this exclusive measurement the valence nucleon knockout mechanism and the core knockout mechanism can be distinguished by the relation between the polar angles of the core fragments and the recoiled protons, respectively. It is demonstrated that the core knockout mechanism may result in some strong contamination to the real invariant mass spectrum.

     

表面分形球、柱的光散射

分形和分维是近些年才兴起的一门处理复杂事物的新方法￣［１］。本文主要研究具有表面分形的球、柱的光散射特征。我们首先利用几何光学近似研究了一种表面满足自仿射原理的分形均匀球的散射，其散射特性与分维存在一定的关系。我们还利用微扰法讨论了表面具有沟槽的分形柱的光散射的分形特征。     

一种由自由电子能带模型计算费米能级的方法

对面心立方（fcc)、体心立方（bcc)和六角密堆积（hcp)三种不同结构的晶体,在假设它们的原胞中包含8个价电子并将价电子近似为自由电子的情况下,采用“自由电子气理论”和“自由电子能带模型”,研究其根据费米球确定的费米能级EF与根据自由电子能带模型计算的平均键能Em。研究结果表明,由自由电子能带模型计算所得3种不同结构晶体（因而电子密度也不一样）的平均键能Em等于各自自由电子系统的费米能级EF。平均键能Em是我们在异质结带阶理论计算中建议的一种参考能级,研究结果在深化对平均键能Em物理实质认识的同时,提供了一种借助于自由电子能带模型计算自由电子系统费米能级EF的新方法。     

皮秒脉冲在色散缓变光纤中的孤子效应压缩

本文给出了描述皮秒脉冲在色散缓变单模光纤中孤子效应压缩过程的数学模型。通过数值求解，首次对该孤子效应压缩进行了全面的计算和分析。结果表明，与常规光纤相比，采用色散缓变程度合适的光纤压缩皮秒脉冲，不仅能显著地提高压缩后脉冲的峰值功率和脉冲压缩比，而且能有效地消除压缩后脉冲的次峰和脉座。对于确定的脉冲输入，发现，当光纤的色散缓变程度取某一最佳值时，能获得最佳的压缩效果。进一步研究表明，色散的这一最佳变     

稳态锁模产生4ps激光脉冲

首次利用ＧａＡｓ光电导开关，控制Ｎｄ：ＹＬＦ激光器腔内Ｑ值，实现稳态锁模，获得脉宽和能量稳定性极高的４ｐｓ激光脉冲。     

用YAG激光制备类金刚石薄膜及其光学折射率研究

用高功率的Ｎｄ＾３＋：ＹＡＧ脉冲激光轰击真空室内的石墨靶，形成激光等离子体雾状物质，在硅衬底上沉积形成类金刚石薄膜，用椭圆偏振光谱法测量不同衬底温度下制备的系列样品的厚度和折射率，发现随着衬底温度的升高，薄膜的厚度减小而的折射率增大，这种可以控制折射率米化的薄膜，可能为光学增透增反膜的制备提供一种新方法。     

Theoretical kinetic study on the decomposition of 1,5‐diaminotetrazole

1,5‐Daminotetrazole (DAT) is of much interest because of the practical significance and the diversity of characteristics. The study on the decomposition pathway and the kinetics of DAT has been performed based on the quantum chemistry theory. The minimum energy path (MEP) calculation has shown that NH₂N₃ and NH₂CN are the initially detected products of DAT. And the structures of reactant, products and transition state were optimized with MP2 methods using 6‐311G** basis sets, and the energies were refined using CCSD(T)/6‐311G** levels of theory. The calculated rate constants were obtained using the conventional transition‐state theory (TST) and the canonical variational transition‐state theory (CVT) methods. The calculation results indicated that the energy barrier of decomposition reaction is 47.98 kcal mol^?1 and the variational effect is small. In addition, the rate constants and the Arrhenius experience formula of DAT decomposition have been obtained between 200 and 2500 K temperature regions. The fitted three‐parameter expressions calculated using the TST and CVT methods are (TST) and (CVT). This work may provide the theoretical support for further experimental synthesis and testing. Copyright © 2015 John Wiley & Sons, Ltd.     

First-principles calculation of structural stability,lattice dynamic and thermodynamic properties of BeX (X = S,Se and Te) compounds under high pressure

The phase transitions, lattice dynamical and thermodynamic properties of BeS, BsSe and BeTe at high pressure have been investigated with the density functional theory. The calculated equilibrium structural parameters agree well with the available experimental and theoretical values. The phase transition pressures from the zinc-blende (ZB) to the nickel arsenide (NiAs) phase of these compounds are determined. The calculated phonon dispersion curves of these compounds in ZB phase at zero pressure do not show any anomaly or instability. Dynamically, the ZB phase of BeS, BeSe and BeTe is found to be stable near transition pressures P_T. Within the quasiharmonic approximation, the thermodynamic properties including the thermal expansion coefficient, heat capacity at constant volume, heat capacity at constant pressure and entropy are predicted.     

航天通用测发控软件平台设计与应用

随着我国航天器频繁发射的常态化,对航天测发控软件技术的要求也逐渐提高,主要表现在提高软件通用性、自动化程度和数据处理能力三个方面。本文在分析测发控业务需求的基础上,提出了测发控信息全过程可配置、测试数据通用化处理、测试实时判读和试验数据快速后处理的方法,构建了航天通用测发控软件平台,实现了测发控软件的型号通用化,降低了软件研制成本,减少了现场测试人员和现场测试时间,提高了飞行器测发控效率。