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。     

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。     

纳米硅薄膜光吸收谱的研究

用恒定光电导法测量了纳米硅(其晶粒尺寸为3-5nm,晶态成分比X_c为45％—50％)薄膜在0.9—2.5eV范围的光吸收谱。分析了在不同光子能量范围可能存在的对光电导作主要贡献的几种光跃迁过程,以及随着X_c的增加,材料由非晶、微晶转变为纳米硅薄膜时光吸收谱的变化。发现纳米硅晶粒之间的界面区(平均厚度约为1nm)中载流子的跃迁及传输过程对整个范围的光吸收谱起主导作用。联系纳米硅的这种特殊结构解释了有关实验结果。 关键词：     

金催化化学发光新体系——苯并吡喃化学发光分析法测定金矿中的痕量金

本文提出了一种测定矿样中痕量金的化学发光分析法,氯化6,7-二羟基-2,4-二甲基苯并吡喃-H_2O_2化学发光体系,方法的检出限为7ppb。工作曲线线性范围是10～1000ppbAu,测定的相对标准偏差小于7％。应用本法测定矿样中的金,结果良好。     

Structural Phase Transformations of ZnS Nanocrystalline Under High Pressure

In-situ energy dispersive x-ray diffraction on ZnS nanocrystalline was carried out under high pressure by using a diamond anvil cell. Phase transition of wurtzite of 10nm ZnS to rocksalt occurred at 16.0GPa, which was higher than that of the bulk materials. The structures of ZnS nanocrystalline at different pressures were built by using materials studio and the bulk modulus, and the pressure derivative of ZnS nanocrystalline were derived by fitting the equation of Birch-Murnaghan. The resulting modulus was higher than that of the corresponding bulk material, which indicates that the nanomaterial has higher hardness than its bulk materials.     

Preparation and Optical Properties of SnO2／SiO2 Nanocomposite

SnO2/SiO2 nanocomposites have been prepared by the soaking-thermal-decomposing method, tin oxide nanoparticles are uniformly dispersed in the mesopores of silica. The optical absorption edge of the obtained nanocomposite presents a redshift compared with bulk tin oxide, With the increasing annealing temperature during the procedure of the sample preparation, the optical absorption edge of the sample moves to shorter wavelength (blueshift). These optical properties can be ascribed to the amorphous structure and band defects of surface layers of the tin oxide nanoparticles.     

纳米WO3的制备及其光解水析氧性能研究

用溶胶凝胶法,灼烧法合成了纳米级WO3,采用X-射线衍射、紫外可见漫反射光谱对WO3进行表征.在Fe3 为电子受体、溶液酸度pH为2.0情况下,研究了纳米级WO3在365nm紫外辐射下光解水析氧的光催化活性,并讨论了不同方法制备的催化剂活性差异的原因.结果表明,结晶程度越高、尺寸越小、比表面积越大的纳米级WO3具有更高的光分解水析氧活性,电子受体的浓度、溶液的酸度对析氧活性有明显的影响.