Preparation and Properties of GaN Films on GaAs Substrates

Polycrystalline gallium nitride films with hexagonal structure were prepared by a post-nitridation technique. A strong blue photoluminescence located at 458 nm and a UV photoluminescence located at 368 nm were observed at room temperature. The 368 nm peak is PL from band-edge emission. The blue luminescence is attributed to the transition from deep donor level to the valence band.     

内爆腔X光发射机制研究

介绍了首次利用三台亚千X光能谱仪和一台针孔相机研究腔靶内爆区X光发射机制,实验结果表明内爆区X光发射主要是壁X光面发射。     

~(12)C离子与各种靶核相互作用的裂变激发函数

本工作采用金硅面垒型半导体探测器和固体径迹探测器测量了57.0—73.0MeV~(12)C ~(169)Tm,~(175)Lu,~(181)Ta,W,Re,Pt.~(197)Au,Pb和~(209)Bi裂变反应碎片角分布和裂变激发函数。由相当于全动量转移的裂变事件的碎片角分布统计理论直接确定了全熔合反应截面σ_(fu),从而获得了作为激发能函数的〈Г_f/Г_n〉实验值。与理论计算符合得到裂变位垒高度,标准偏差为2.5MeV。实验上确定的裂变位垒与非旋转液滴模型计算值相符合。用同样方法,我们还分析了已经发表了的~(12)C ~(174)Yb,~(12)C ~(198)Pt,~(16)O ~(142)Nd,~(16)O ~(170)Er,~(16)O ~(181)Ta和~(18)O ~(192)Os裂变反应激发函数,研究了裂变位垒随裂变核质量数A的变化,并且和液滴模型理论做了比较。     

X射线二极管的灵敏度标定和应用

阐述了Ｘ射线二极管铝阴极光电转换量子效率，并在单色亚千Ｘ射线光源装置上对铝阴极的灵敏度进行了绝对标定，最后介绍了采用Ｘ射线二极管探头来测量激光－等离子体相互作用中产生的亚千Ｘ射线能量。     

定比分点公式的向量形式及应用

众所周知，向量法是解决平面几何问题的重要方法，而定比分点公式是解析几何中应用非常广泛的重要公式．本文介绍定比分点公式的向量形式及其在解决平面几何问题中的应用，供大家参考。     

141Pr+波长56908 nm谱线超精细结构测量

利用共线快离子束-激光高分辨光谱学测量了141Pr+波长为56908nm谱线的超精细结构光谱，由此得到超精细相互作用常数和参与跃迁激发态、亚稳态能级的超精细能级分裂-与已有的数据比较，在实验误差范围内一致，但测量精度提高了一个数量级- 关键词： 超精细结构 快离子束-激光光谱学 磁偶极矩和电四极矩超精细作用常数     

Gravitational quasinormal modes of static Einstein-Gauss-Bonnet anti-de Sitter black holes

In this paper, we describe quasinormal modes(QNMs) for gravitational perturbations of Einstein-GaussBonnet black holes(BHs) in higher dimensional spacetimes, and derive the corresponding parameters of such black holes in three types of spacetime(flat, de Sitter(d S) and anti-de Sitter(Ad S)). Our attention is concentrated on discussing the(in)stability of Einstein-Gauss-Bonnet Ad S BHs through the temporal evolution of all types of gravitational perturbation fields(tensor, vector and scalar). It is concluded that the potential functions in vector and scalar gravitational perturbations have negative regions, which suppress quasinormal ringing. Furthermore,the influences of the Gauss-Bonnet coupling parameter α, the number of dimensions n and the angular momentum quantum number l on the Einstein-Gauss-Bonnet Ad S BHs quasinormal spectrum are analyzed. The QNM frequencies have greater oscillation and lower damping rate with the growth of α. This indicates that QNM frequencies become increasingly unstable with large α. Meanwhile, the dynamic evolutions of the perturbation field are compliant with the results of computation from the Horowitz and Hubeny method. Because the number of extra dimensions is connected with the string scale, the relationship between α and properties of Einstein-Gauss-Bonnet Ad S BHs might be beneficial for the exploitation of string theory and extra-dimensional brane worlds.     

Ag掺杂对高重复频率飞秒激光诱导Gd_2O_3-MoO_3-B_2O_3玻璃析晶的影响

将800nm高重复频率250kHz的飞秒激光分别聚焦到掺Ag和没有掺Ag的Gd2O3-MoO3-B2O3玻璃表面,研究掺Ag对飞秒激光诱导析晶的影响.对激光辐照的区域显微拉曼分析发现对于没掺Ag玻璃,诱导玻璃析晶需要的激光功率和辐照时间比掺了Ag的玻璃要大要长,这说明Ag的掺入促进了玻璃的析晶.其机理可能为飞秒激光的多光子吸收效应,导致玻璃基质中桥氧键断裂,产生非桥氧空穴和自由电子,玻璃中的Ag离子捕获电离出来的电子被还原成Ag原子,Ag原子在热动力的驱动下移动聚集形成银纳米颗粒,形成的银纳米团簇作为核促进了钼酸盐玻璃的析晶.     

现代分析技术在药物分析中的研究与应用

综述了国内外近年来共振瑞利散射法、原子吸收光谱法、磷光光谱法和质谱联用技术在药物分析中的研究与应用.从反应条件、线性范围、灵敏度等方面介绍了4类方法对不同反应体系的研究现状,展望了药物分析的发展方向.     

甲酸双氧铀的红外多光子离解

本文研究了固相甲酸双氧铀[UO_2(HCOO)_2·H_2O]在TEA CO_2激光作用下的红外多光子离解。测得其中间产物为碱式甲酸双氧铀[UO_2(OH)(HCOO)·H_2O],最终的固体产物主要是八氧化三铀[U_3O_8];并提出了该反应模型。