Fe-V-N稀合金中空位复合体特性的研究(Ⅱ)

本文利用离散变分法,集团模型和三维数值弛豫技术,研究了Fe-V-N稀合金中V-N-空位复合体的几何构型,正电子湮没特性和电子结构。根据正电子湮没寿命实验的结果和总能量极小原理,确定了V和N在V-N-空位复合体中的最佳占据位置。分析了V-N-空位复合体的成键特性和电荷转移情况。 关键词：     

金属氢研究新进展

简要介绍了金属氢的研究意义和应用前景 ,详细评述了有关的高压实验方法和最近的研究成果及进展 ,特别是固体氢的相图、结构和相变 .近十多年来 ,随着超高压技术的发展 ,已能在金刚石对顶砧 (DAC)上产生30 0GPa的静态压力 ,并可进行高压原位实验研究 .对固体氢进行了高压拉曼、同步辐射X射线、光反射和吸收、同步辐射红外光谱等一系列高压物性和相变研究 .从而确定了固体氢的三个相 ,并提出了可能的相结构 .     

Schottky Barrier Height Inhomogeneity of Ti／n—GaAs Contact Studied by the I—V—T Technique

The current-voltage characteristics of Ti/n-GaAs Schottky diodes measured over a temperature range of 78-299K have been interpreted on the basis of thermionic emission across an inhomogeneous Schottky contact.The experiment shows that the apparent barrier height (φap) increases from 0.437eV at 78K to 0.698eV at room temperature.the plot of φap versus 1/T does not exhibit a simple linear relationship over the whole temperature range,indicating that the barrier height distribution is more complicated than the frequently observed single Gaussian distribution.A new multi-Gaussian distribution model is developed.Our experimental results can be explained by a double Gaussian distribution of the barrier heights.The weight,the mean barrier height,and the standard deviation of the two Gaussian functions are 0.00001 and 0.99999,0.721 and 0.696,0.069 and 0.012eV,respectively.     

Photoluminescence Characterization of Silicon Nanoparticles Hybridized Europium Complex

A europium complex Eu (DBM)3 TPPO (Eu tris(benzoylmethide)-(triphenylphosphine oxide)) and silicon nanoparticles have been hybridized.The hybridization can evidently change the photoluminescence (PL) characteristics of the Eu complex in the following aspects:under an excitation of 390nm,the intensity of the PL peak at 611nm due to the ^5Du-^7F2 transition of the Eu^3 ions has been increased by 30%,and thc integrated PL intensity in the visible range has been increased by nearly 3 times;the PL excitation efficiency beyond 440nm has been improved cvidently;the peak in the PL excitation spectrum shifts from 408nm to 388nm,and the PL decay time decreases from 2.07 to 0.96μs,The experimental results indicatde that in the PL process,the photoexcited energy may transfer from the silicon nanoparticlcs to the Eu^3 ions.     

Fluorescence Microscopy of Nanoscale Silver Oxide Thin Films

The experimental conditions for photoactivated intermittent fluorescence from nanoscale silver oxide were studied with fluorescence microscopy.Strong fluorescence was observed from the Ag2O particles with size of 10-20nm excited with both blue and green light .We observed the saturation of Photoexcitation with blue light and explained the experimental results using the model of agglomeration of silver atoms to form small clusters and the fluorescence of Ag2 and Ag3 clusters.     

纳米Ti02／碳化树脂复合催化剂的合成及其光催化性能研究

利用一种简单、快速的方法合成了纳米TiO2／碳化树脂(B)复合催化剂。对其组成、结构、尺寸及其光催化性能进行了表征。结果表明，该复合材料为由碳、氢、氧和钛等4种元素组成的纳米材料，尺寸约30nm，其中Ti和O的堆积结构为锐钛矿型；在该复合材料中，B为具有活性基团和不同长度碳—碳共轭链的大分子，且与TiO2之间存在着某种化学作用,复合材料所具有的特殊电子结构不仅使其能吸收紫外—可见区的全程光波。而且对光生电荷具有很高的分离能力，从而表现出较高的光催化活性。     

稀土的发射光谱分析

本文介绍了稀土分析的发射光谱法，包括（1）痕量稀土镧和钆的粉末筛选电极法，镧、钆、铕、镨、钕和钐的载体分馏法。（2）岩石和矿物中稀土分析的直接法（Pyc-aHOB法）和化学光谱法（ЛaКTИOHOBa法）。（3）氧化铕中稀土元素及杂质的光谱分析的全能量法和分馏法，稀土元素氧化物混合物的光谱全分析法。（4）钢中铈、镧和钡的测定（CopoКИHa法），钢、金属和合金中稀土元素的化学光谱测定，纯金属、钢及镍合金中铈、镧、钕、镨、铒、铥、钐和钇的测定等。     

氧化硅气凝胶的超临界制备及纳米结构

简要介绍了用溶胶－凝胶法制备新型功能材料氧化硅气凝胶的方法，着重阐述了氧化硅气凝胶的各种干燥过程对其纳米结构的影响，说明了超临界干燥工艺在保持气凝胶的纳米多孔结构方面的突出重要地位，同时，用比表面积测量，扫描电镜，小角Ｘ射线菜射等研究了这种轻质纳米多孔非晶固态材料的结构特性，介绍了这种材料的应用前景。