On Aging of Acid-Catalyzed Silica Sols—A Dynamic Light Scattering Study

Dynamic light scattering experiments in acid-catalyzed silica sols are discussed. It is shown that in spite of limited parameter accuracy and limited absolute knowledge of the particle sizes, the scattering data from various experiments are comparable with one another and give information about structural differences. Measurements at various angles indicate changes between non-spherical and nearly spherical particles and allow the estimation of gelling times before gelation.     

合成气制低碳烯烃K－Fe－MnO／MgO催化剂的研究Ⅰ．MnO助剂的作用

采用ＣＯ加氢反应、ＣＯ－ＴＰＤ、ＣＯ／Ｈ＿２－ＴＰＳＲ及Ｃ＿２Ｈ＿４／Ｈ＿２－ＴＰＳＲ等手段，研究合成气制低碳烯烃反应Ｋ－Ｆｅ－ＭｎＯ／ＭｇＯ催化剂中ＭｎＯ的助剂作用。结果表明ＭｎＯ能大幅度提高低碳烯烃的选择性，尤其是乙烯的选择性；ＭｎＯ能抑制催化剂表面的乙烯加氢，因而有利于提高低碳烯烃的选择性及烯／烷的比值。     

Preparation and characterization of nitrogen-doped TiO2 photocatalyst in different acid environments

Nitrogen-doped TiO₂ powders were successfully prepared by a wet method, i.e., a micro-emulsion-hydrothermal method, in different acid environments. Several characterization techniques, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance spectra, were combined to determine the crystal phase, concentration and chemical states of the nitrogen doped in TiO₂. The high photocatalytic activity of the nitrogen-doped TiO₂ was evaluated through the decomposition of rhodanmine B under visible light irradiation. It was suggested that the doped nitrogen formed oxynitride (NO) and produced impurity states at higher above the valence band of TiO₂. Therefore, the nitrogen doping could enhance the response of photocatalyst to the visible light and improve the photocatalytic activity because of the narrowing of band gap of TiO₂.     

轻稀土硝酸盐与邻菲罗啉(Phen)高配比混配配合物的合成和表征

本文采用水-有机溶剂合成了三个稀土硝酸盐与邻菲罗啉的混配配合物,通过元素分析、红外、差示扫描和热重等分析测试手段,确证了配合物的组成为Ln(Phcn)_4(NO_3)_3·3H_2O,并研究了它们的性质。     

A resonance light scattering method for determination of DNA using Ru(bpy)2PIP(V)2+

A novel method for DNA detection is proposed that is based on the enhancement of resonance light scattering (RLS) of Ru(bpy)₂PIP(V)²⁺ at pH 2.7. Under optimum conditions, good linear relationships were obtained in the wide concentration range of 16–5120 ng mL⁻¹. The linear equation is I _RLS = 13.15 + 171.4 c (μg mL⁻¹), the correlation coefficient (r) is 0.9999. The detection limit of calf thymus DNA is 5.02 ng mL⁻¹. Plasmid DNA extracted from bacillus subtilis was determined by the method with satisfactory results.     

TiO(2) porous electrodes with hierarchical branched inner channels for charge transport in viscous electrolytes.

Titanium dioxide (TiO(2)) photoelectrodes with micro/nano hierarchical branched inner channels have been prepared by an electrohydrodynamic (EHD) technique and assembled to form dye-sensitized solar cells (DSSCs). Excellent penetration of ionic-liquid electrolytes and enhanced light harvesting in the longer wavelength region are realized within the composite-structure electrode, thus a better fill factor (ff) of 75.3 % and higher conversion efficiency (eta) of 7.1 % are obtained for viscous ionic-liquid electrolytes compared to pure nanostructured films. Hierarchical branched channels in the photoanodes can efficiently improve the transport properties of redox-active species in viscous electrolytes, which is demonstrated by electrical impedance spectroscopy (EIS). The incident monochromatic photon-to-electron conversion efficiency (IPCE) shows that enhanced light scattering in the composite film is of benefit for light harvesting and thus for solar energy conversion efficiency.     

稀土发光材料在固体白光LED照明中的应用

固体白光发光二极管将成为21世纪新一代的节能光源. 要实现白光发射的重要途径之一是利用稀土发光材料的荧光转换技术, 把InGaN半导体管芯发射的460 nm蓝光或400 nm近紫外光转换成白光. 分别就这两种管芯报道了我们研制的发射蓝、绿、黄、红等不同颜色的稀土发光材料： YAG：Ce, Ca1-xSrxS：Eu^2＋, Ga2S3：Eu^2＋, MGa2S4：Eu^2＋（M=Ca, Sr, Ba）, SrGa^2＋xS4＋y：Eu^2＋, （Ca1-xSrx）Se：Eu^2＋, SrLaGa3S6O：Eu^2＋, （M1, M2）10（PO4）6X2, （M1=Ca, Sr, Ba; M2=Eu, Mn; X=F, Cl, Br）, NaEu0.92Sm0.08（MoO4）2, 并报道了由它们制成的白光发光二极管的色坐标、相关色温和显色指数等参数.     

一种新型联萘基旋光共轭聚合物的圆二色谱和圆偏振荧光光谱

众所周知 ,聚合物的光电性质依赖于聚合物链的构象和 (或 )组成 ,通过在聚合物上引入手性单元 ,采用圆二色谱 ( CD)和圆偏振荧光光谱 ( CPL)等方法可表征聚合物结构 [1] .近年来 ,由于圆偏振光可用作光数据存储和液晶显示器背景光 [2 ] ,人们开始注重共轭聚合物圆偏振光材料的研究 .共轭聚合物的光致和电致圆偏振光的现象由一种带手性侧链的聚噻吩[3 ] 和一种带手性侧链的聚 (对苯撑乙烯 ) [4 ]产生 ,但它们的圆偏振荧光度 (用不对称因子 glum=2 ( IL-IR) / ( IL+IR)表示 ,IL 和 IR 分别指左圆偏振光强度和右圆偏振光强度 )相对较低 …     

中性芳烃稀土有机配合物的合成、结构及性能研究——Ⅲ.RE(C_6H_6)(AlCl_4)_3C_6H_6(RE=La,Nd)的合成及Nd(C_6H_6)(AlCl_4)_3C_6H_6的晶体结构

将加热活化的AlCl_3与三氯化稀土在苯溶液中反应,合成了2个新的轻稀土中性芳烃配合物RE(C_6H_6)(AlCl_4)_3C_6H_6(RE=La或Nd)。并用元素分析和红外光谱对其进行了表征。测定了含Nd配合物的晶体结构。对2个配合物结构的比较表明,中心金属离子对配合物的结构无明显影响,其键参数的差别主要来自“镧系收缩”。     

对杂散光测试材料要求的探讨

从分光光度计杂散光测试原理出发,对我国目前在用的几种杂散光测试材料特性进行了分析。通过实验验证,指出了其中的不合理处,并提出了对杂散光测试材料特性的基本要求。 ,