Sol-gel derived oxides and mixed oxides catalysts with narrow mesoporous distribution

A novel sol-gel process for preparing oxides and mixed oxides sols from precipitation and peptization process is reported in this article. Inorganic salts are used as raw materials in this study. It is found that the amount of acid has great influence on the stability and particle diameter distribution of the precursor sols. Ultrasonic treatment is used to prepare alumina sol at room temperature. The result of Al-27 NMR shows that there exist Al-13(7+) species in the sol. By controlling the sol particles with narrow particle diameter distribution, alumina, titania and silica-alumina (SA) materials with narrow mesoporous distribution are formed by regular packing of sol particles during gelation without using any templates. The results also show that the structure and particle diameter distribution of precursor sol determine the final materials' texture.

基于U形塑料光纤的氧气传感器

报道了一种基于荧光猝灭原理的光纤氧气传感器.采用塑料光纤作为传感和传光元件进行氧气传感,传感头制成U形.以邻菲咯啉钌作为荧光标记物,用溶胶-凝胶法制备敏感材料.采用相移法来实现对荧光寿命的测定.测量了不同弯曲半径传感头对氧气传感的灵敏度,发现当U形光纤的弯曲半径较小时系统的灵敏度较高.对荧光寿命和氧气浓度的关系进行了测量,发现二者呈亚线性关系,提出双荧光体模型解释这一实验现象.

磷酸盐激光玻璃聚（CH3）2Si（OC2H5）2防潮膜

以（CH3）2Si（OC2H5）2为前驱体，采用溶胶-凝胶与有机合成相结合的方法，制得稳定性良好的涂膜液。采用旋转涂膜法在掺钕磷酸盐激光玻璃棒端面涂制防潮膜，膜层固化后透过率达96．5％，获得的膜层表面粗糙度优良，均方根表面粗糙度（RMS）为1．659nm，平均粗糙度（RA）平均为1．321nm；在激光波长1053nm，脉冲宽度1 ns条件下膜层的激光破坏闽值可达10～14 J／cm^2。经过“神光Ⅱ”高功率激光器物理实验运行，膜层使用期为五年，并且已经在我国“神光Ⅲ”原型装置上试用。

Effect of processing parameters on the optical properties of TiO2/ormosil planar waveguide

Hybrid TiO2/ormosil waveguiding films have been prepared by the sol-gel method at low thermal treatment temperature of 150° C. The influence of processing parameters including the molar ratios of titanium butoxide (Ti(OBu)(4))/3-glycidoxypropyltrimethoxysilane (GLYMO) and H2O/Ti(OBu)(4) (expressed as R), especially aging of sot on the optical properties was investigated. The optical properties of films were measured with scanning electron microscope (SEM), UV/VIS/NIR spectrophotometer (UV-Vis), m-line and the scattering-detection method. The results indicate that the film thickness increases with the increase of sol aging time, but the variation of refractive index as a function of sot aging time depends on the relative ratios of GLYMO to Ti(OBu)(4). Higher transmittance and lower attenuation of the planar waveguide can be obtained in the sol with lower Ti(OBu)(4) contents and shorter aging time.

Study of hybrid TiO2/ormosil films doped with laser dyes

TiO2/ormosil films doped with laser dyes have been prepared by the sol-gel method. Spectroscopic properties of the entrapped dyes are studied by the absorption and emission techniques. The results indicate that the absorption and fluorescence spectra of kiton red depend strongly on the properties of the ormosil matrices. The heat-treatment of the kiton red-doped film obviously leads to the increasing fluorescence intensity and the largest fluorescence intensity is obtained after heat-treatment of 150 degrees C for 2 h. However, the fluorescence intensity of the rhodamine 6G-doped film decreases with the increase of the heat-treatment temperature. (c) 2005 Elsevier B.V. All rights reserved.

Preparation and characterization of hybrid ZnO/ormosils films

Hybrid ZnO/ormosils Elms are prepared by the sol-gel method. A FT-IR spectrometer, 900 UV/VIS/NIR spectrophotometer, atomic force microscope, and ellipsometer are employed to investigate microstructure and optical properties of the films fired at different temperatures. The results show that the films with high transmittance and low surface roughness could be obtained at the heat-treatment temperature of 150 degrees C, the refractive index and thickness of the film are 1.413, 2.11 mu m, respectively. Higher temperatures (350 degrees C, 550 degrees C) change the Elm microstructure severely, and then decrease the transmittance of the films.

低损耗TiO2/Ormosil平面波导的制备及表征

abstract = {TiO₂/ormosil planar waveguide was prepared by sol-gel method at low thermal treatment temperature ( less than or equal 200°C). Scanning electron microscope, FT-IR spectrometer, spectrophotometer, atomic force microscopy, thermal analyzer, and dark m-line spectroscopy were used with the method of scattering-detection to investigate optical and structural properties. High optical quality waveguide film was obtained. The propagation loss of film was 0.569 dB/cm at a wavelength of 632.8 nm.

Solid-state NMR study of bioactive binary borosilicate glasses

A series of binary borosilicate glasses prepared by the sol-gel method are shown to be bioactive. Tetraethyl orthosilicate (TEOS) and trimethylborate (TMB) in acidic medium are used to prepare xB(2)O(3)center dot(1-x)SiO2 glass systems for x = 0.045-0.167. The formation of a layer of apatite-like mineral on the glass surface becomes apparent after soaking in simulated body fluid for 48 h. We have measured the B-11-B-11 homonuclear second moments of the borosilicate glasses and inferred that no macroscopic phase separation occurred in our glasses. The B-11 chemical shift data also show that the formation of clustered boroxol rings is negligible in our glass system. Although the bioactivity of our borosilicate glasses is less than that of CaO-SiO2 sol-gel glasses, these simple binary systems could be taken as reference glass systems for the search of new bioactive borosilicate glasses. (C) 2008 Elsevier Ltd. All rights reserved.

NiFeMnO4系列热敏电阻的溶胶-凝胶制备技术研究

用溶胶-凝胶（Sol-gel）技术以及柠檬酸自燃方法制备了NiMn2.0-xFexO4（x=0、0．1、0．15、0．2、0．3）纳米氧化物粉体，并将得到的超细粉体进行压片、烧结、封装等工艺制得热敏电阻。用XRD、SEM、电阻测量等手段表征了烧结体材料的晶相、微观形貌以及电阻性能。电阻测量结果表明：随着铁离子的增加，所得热敏电阻的阻值增大。在所有获得的材料中，其灵敏度B值大于4300K，可认为是一种具有实际应用价值的负系数热敏电阻。

溶胶-凝胶法制备MgxZn1-xO及其特性

采用溶胶-凝胶法制备了不同组分（x=0．1—0．3）的MgxZn1-xO前驱体，并对它进行不同温度的热处理（550℃-1000℃）。X射线衍射（XRD）结果表明，Mg0.1Zn0.9O具有和ZnO一样的衍射谱，为六方纤锌矿结构，而且随着热处理温度的升高，ZnO衍射峰的强度逐渐增强，半高宽不断减小；Mg元素掺杂浓度增大后，出现了MgO的峰位。扫描电子显微镜（SEM）显示Mg0．1Zn0.9O晶粒粒径分布较均匀；热处理温度升高，晶粒的尺寸不断变大。用室温荧光光谱（PL）分析了经过550—1000℃热处理获得的

LiAlO2衬底上ZnO薄膜的溶胶-凝胶法制备和表征

采用溶胶凝胶法在LiAlO2（302）衬底上制备了ZnO薄膜。用X射线衍射（XRD）和扫描电镜（SEM）对样品的结构和形貌进行了表征。XRD结果表明,随着热处理温度的升高（350℃、450℃、550℃、600℃、800℃）,所得到的薄膜分别为单相ZnAl2O4（350℃）,ZnAl2O4和ZnO的混合相（450℃）以及单相的ZnO（550℃、600℃、800℃）,并且ZnO薄膜C轴择优取向的生长趋势随温度升高相应明显。SEM图像显示,随着热处理温度的升高,ZnO薄膜的粒径相应变大。

Surface characteristics of SiO2-TiO2 strip fabricated by laser direct writing

SiO2-TiO2 sol-gel films are deposited on SiO2/Si by dip-coating technique. The SiO2-TiO2 strips are fabricated by laser direct writing using all ytterbium fiber laser and followed by chemical etching. Surface structures, morphologies and roughness of the films and strips are characterized. The experimental results demonstrate that the SiO2-TiO2 sol-gel film is loose in Structure and a shrinkage concave groove forms if the film is irradiated by laser beam. The surface roughness of both non-irradiated and laser irradiated areas increases with the chemical etching time. But the roughness of laser irradiated area increases more than that of non-irradiated area under the same etching time. After being etched for 28 s, the surface roughness value of the laser irradiated area increases from 0.3 nm to 3.1 nm.

Surface characterization study on SnO2 powder modified by thiourea

The SnO2 material prepared by sol-gel method was modified by thiourea solution in different concentrations (0.05, 0.1 and 0.2 mol dm(-3)). Then the structure and the average grain size of the SnO2 material were investigated by X-ray power diffraction. In order to understand the nature of the species on the SnO2 surfaces, the thermal gravimetric and differential thermal analyzer (TG-DTA) and IR spectra of these modified and unmodified sample were taken. The result indicates that the stability of oxygen adsorbed on thiourea-modified surface was improved and the amount of surface hydroxyl groups adsorbed on this grain surface was decreased. The thiourea adsorbed on SnO2 grain surface is translated to SO42- after sintered at 600 degrees C. SO42- species stabilize the resistance of the SnO2 sensor. (c) 2005 Elsevier B.V. All rights reserved.

Structure and visible luminescence of ZnO nanoparticles

ZnO nanoparticles were synthesized in ethanolic solution using a sol-gel method. The structural and optical properties were investigated by X-ray diffraction, transmission electron microscopy, UV absorption, and photoluminescence. After annealing at 200 degrees C, the particle size is increased and the peak of defect luminescence in the visible region is changed. A yellow emission was observed in the as-prepared sample and a green emission in the annealed sample. The change of the visible emission is related to oxygen defects. Annealing in the absence of oxygen would increase oxygen vacancies. (c) 2006 Elsevier Ltd. All rights reserved.