碰撞能量对He-N2的散射截面的影响

用密耦近似方法计算了He和N2体系的微分截面和总截面及转动激发分波截面,得出微分截面及总截面随入射能量变化的规律.     

武定恐龙化石的显微拉曼光谱研究

本文首次利用激光显微拉曼光谱、原子光谱和偏光显微镜等方法 ,对云南武定的恐龙化石进行了分析研究。实验发现 ,恐龙化石表面和截面的拉曼光谱 ,均为典型的方解石 (CaCO3 )晶体的拉曼谱 ,并未发现有其他成分的拉曼谱。原子发射光谱的分析结果表明 ,恐龙化石中的主要元素有Ca(>10 % ) ,其次是Si(5 0 % )和P(4 0 % ) ,还有Fe(1 0 % )等 ,但未发现铱、钍等稀有元素。由恐龙化石截面在偏光显微镜下的图像可以知道 ,恐龙化石表面层的成分主要是方解石晶体 ;内部的主要成分为方解石 (CaCO3 )晶体 ,此外还有纤维状一水二氧化硅 (分子式SiO2 ·nH2 O ,属非晶态 )等成分。激光拉曼光谱能快速无损地准确检测出恐龙化石的主要成分是方解石 (CaCO3 ) ,拉曼光谱对恐龙化石的分析结果与原子光谱、偏光显微镜的分析结果是一致的     

Synthesis, structure and optical properties of Eu/TiO2 nanocrystals at room temperature

The nanocrystal samples of titanium dioxide doped with europium ion (Eu³⁺/TiO₂ nanocrystal) are synthesized by the sol-gel method with hydrothermal treatment. The Eu³⁺ contents (molar ratio) in the samples are 0, 0.5%, 1%, 2%, 3% and 4%. The X-ray diffraction, UV-Vis spectroscopy data and scanning electron microscope image show that crystallite size is reduced by the doping of Eu³⁺ into TiO₂. Comparing the Raman spectra of TiO₂ with Eu³⁺/TiO₂ (molar ratio Eu³⁺/TiO₂=1%, 2% and 4%) nanocrystals at different annealing temperatures indicates that the anatase-to-rutile phase transformation temperatures of Eu³⁺/TiO₂ nanocrystals are higher than that of TiO₂. This is due to the formation of Eu-O-Ti bonds on the surface of the TiO₂ crystallite, as characterized by the X-ray photoelectron spectroscopy. The photoluminescence spectra of TiO₂ in Eu³⁺/TiO₂ nanocrystals are interpreted by the surface self-trapped and defect-trapped exciton relaxation. The photoluminescence of Eu³⁺ in Eu³⁺/TiO₂ nanocrystals has the strongest emission intensity at 2% of Eu³⁺ concentration.     

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介绍了在神光Ⅱ装置上开展的长脉冲2ns三倍频激光与黑腔靶相互作用的实验。报道了采用PIN探测器阵列测量大角度受激Raman散射（SRS）角分布和采用激光卡计对背向SRS光能量积分测量的实验结果。相同实验条件下激光辐照缝靶产生的SRS光能量要强于激光与全腔靶作用产生的SRS光，小腔靶的SRS光能量要强于标准腔靶。对比长脉冲2ns及短脉冲1ns激光打靶实验结果可以看出：由于激光功率密度的下降，长脉冲激光打靶时SRS散射光能量要弱于短脉冲激光打靶。长脉冲2ns激光与标准腔靶相互作用时，等离子体堵腔比较严重。     

一些特殊图类乘积的离散度

连通图的离散度是用s(G)来表示的,s(G)=max{ω(G-S)-|S|:ω(G-S)>1,SV(G)}.给出了两个完全图乘积的和一个完全图与路的乘积的离散度.还给出了两个完全图乘积的坚韧度.     

Spectroscopic and X-ray diffraction study of high Tc epitaxial YBCO thin films obtained by pulsed laser deposition

We report spectroscopic characterization of epitaxial YBCO thin films grown on LaAlO₃ by pulsed laser deposition. Raman spectroscopy and spectroscopic ellipsometry were used for film characterization and the results were correlated with X-ray diffraction measurements. The mentioned techniques allowed us to analyze crystallographic, micro-structural, and morphological properties of YBCO thin films. We also demonstrated that relatively low resolution Raman spectroscopy and spectroscopic ellipsometry are reliable techniques for a rapid and non-destructive characterization of epitaxial YBCO thin films.     

Synthesis and Raman analysis of 1D-ZnO nanostructure via vapor phase growth

1D-nanostructural zinc oxide (ZnO) with different shapes have been synthesized on p-type Si(1 0 0) and glass substrates via vapor phase growth by heating pure zinc powder at temperatures between 480 and 570 °C. The different ZnO nanostructures depend on the substrates and the growth temperatures. Scanning electron microscopy and X-ray diffraction revealed that a well-aligned nanowires array, which are vertical to the substrate of Si(1 0 0) with 18 sides on their heads, but six sides on their stems, has been formed at 480 °C. Raman study on the ZnO nanostructures shows that the coupling strength between electron and phonon determined by the ratio of the second- to the first-order Raman scattering cross-sections declines with decreasing diameter of the nanowires. However, a little changes of the coupling strength in terms of the width of the nanobelts have been observed.     

海洋激光雷达测量海中悬移质

研制了一套采用倍频YAG激光器的小型海洋激光雷达，用于测量海中悬移质浓度，2000年8月28日至9月5日，该系统安装于“东方红Ⅱ”号右舷下甲板，在渤海海区进行海中悬移质浓度现场测量，通过对18个站位的海洋激光雷达数据分析，获得的表层悬移质浓度与同步测量的海中悬移质浓度结果吻合较好。     

单壁碳纳米管的SERS研究

本文通过改进实验方法,将单壁碳纳米管的乙醇溶液与金胶混合并制作成固体薄膜,使单壁碳纳米管夹裹在金纳米粒子之间,保证了吸附的紧密性,获得了高质量的单壁碳纳米管SERS光谱。不但观测到文献中报道的径向呼吸振动模(RBM)和C-C正切拉伸模(GM)的增强,还在1100-1500cm-1区域观测到一组新峰,其峰形完整并有相当的强度。这些峰在现有的文献中几乎没有报导。文章对这组新峰的出现进行了初步的分析。     

生物分子拉曼散射测定过程中荧光背景的抑制

拉曼共焦技术、表面拉曼增强技术以及降低入射激光强度的方法，被运用于SOD、DNA等生物分子拉曼散身实验中，以抑制其荧光背景，改善光谱质量。