Yan Yan Jiang

Pore Structure Characterization of TiO2-SiO2 Composite Aerogel Prepared via Ambient Pressure Drying by Sol Pre-Modification Process

In this paper, TiO2-SiO2 composite aerogels were prepared via ambient pressure drying by sol-gel and sol pre-modification method. The pre-modification solution consists of hexamethyldisiloxane (HMDSO) as buffering agent, trimethylchlorosilane (TMCS) as modifier and hexane as organic solvent. The pore structure of TiO2-SiO2 composite aerogels was characterized by N2 adsorption-desorption method. The effects of HMDSO/TMCS volume ratio on the pore structure and properties of TiO2-SiO2 composite aerogel were studied. The results indicate that the pre-modification of TiO2-SiO2 composite sol by adding HMDSO/TMCS/Hexane solution could shorten the preparation period. Increasing the amount of HMDSO is favorable for obtaining TiO2-SiO2 composite aerogel with higher specific surface area and pore volume. The best volume ratio of HMDSO/TMCS/composite sol for preparing mesoporous TiO2-SiO2 composite aerogels were 12:6:120 and 12:12:120, with which the specific surface area and pore volume of the obtained TiO2-SiO2 composite aerogel are 425.2～645.4 m2/g and 0.80～2.85 m3/g, respectively.

Effects of Annealing in Different Atmosphere on the Near-Infrared Shielding Properties of CsxWO3 Particles

Using sodium tungstate and cesium carbonate as raw materials, cesium tungsten bronze (CsxWO3) powders were synthesized by low temperature hydrothermal reaction with citric acid as the reducing agent. Effects of annealing in different atmosphere on the near-infrared shielding properties of CsxWO3 were investigated. The microstructure of CsxWO3 powders was characterized by X-ray diffraction. The CsxWO3 films were prepared on glass using polyvinyl alcohol solution as film-forming agent, and the optical transmission properties of CsxWO3 films were investigated. The results indicate that the near-infrared shielding ability of samples after annealed at 200°C in the air atmosphere did not deteriorate apparently, but the 400°C-annealed samples in the air atmosphere showed apparent decrease of near-infrared shielding properties. Annealing in the carbon powder atmosphere had no apparent effects on the properties of CsxWO3 particles. As for the N2 annealing, the 500°C-annealed samples showed best improved near-infrared shielding as well as high transparency in the visible light region.

Effect of Composite Pore-Forming Agent on Performance of Light-Weight Thermal Insulation Materials

Production of porous and light-weight thermal insulation materials with reduced thermal conductivity and raised porosity were accomplished using sludge (SL) and sugar filter mud (SFM) as pore-forming agent respectively and composite pore-forming agent (CPFA) at different sintered temperature and holding time. The results of thermal insulation materials with flexural strength 7.65 MPa and thermal conductivity 0.056 W•m-1•K-1, obtained at 1000 °C for 0.5 h show that its the porosity factor raised to 40.60% and the bulk density of the materials decreased down to 1.265 g/cm3 using CPFA, closed porosity and dense structure in sample was observed by SEM

Synthesis and Visible Light Photocatalytic Activity of Spinel MAl2O4 (M=Mg, Zn, Cu)

Aluminium spinel MAl2O4 (M = Mg, Zn, Cu) photocatalysts were prepared by a sol-gel method. The prepared samples were characterized by X-ray diffraction and transmission electron microscope. The results indicated that the samples possess a single spinel-type structure. Ultraviolet-visible diffuse reflectance spectra showed an extension of light absorption into the visible region. The spinel MAl2O4 photocatalysts exhibited high photocatalytic activity for the degradation of industrial dyes under high pressure mercury lamp and visible light irradiation, especially CuAl2O4. With the decrease of band gap of MAl2O4 (M = Mg, Zn, Cu), the photocatalytic activity increases. The possible reasons are discussed from the crystal field theory and energy band theory. These characteristics make the aluminium spinel MAl2O4 (M = Mg, Zn, Cu) photocatalysts to be promising candidates for the photocatalytic degradation of dyes.

Rapid Biomimetic Deposition of Drug-Loaded Apatite Coatings

In order to reduce the postoperative inflammation by the slow release of drugs at the beginning of implanting, drug-loaded apatite coatings and chitosan-apatite composite coatings on the NiTi alloy surface were prepared in the Simulated Body Fluid concentrated by five (5×SBF) under constant bubbling of carbon dioxide gas by biomimetic synthesis method. The composition and surface morphology of the coatings were studied using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Additionally, a bacterial inhibition test was conducted for evaluating the drug slow release effects from the drug-loaded coatings. The results indicated that the porous apatite coatings with the flake structure could be deposited using the 5 times Simulated Body Fluid, and the drug-loaded chitosan-apatite composite coatings with better drug slow release effect were obtained. The incorporation of chitosan into the coatings could effectively control the drug release rate and was favorable for achieving better drug slow release effects.

Effect of Acid Treatment on Surface Morphology and Strength of Float Glass under Ultrasonic Wave

The float glass was polished by acid solution (HF/H2SO4) under ultrasonic wave. The surface morphologies before and after acid etching were observed by metallographic microscope. The thickness of acid etching was measured by thickness tester, and the strength before and after acid etching was investigated via material surface and interface performance tester. The experimental conditions, such as the amount of HF and H2SO4, the temperature of acid etching and the time of acid etching were optimized under ultrasonic wave ( f =40 KHz, P=125 W) by orthogonal design test. The suitable conditions were 10% for HF, 15 min for acid etching time, 30% for H2SO4 and 25 °C for acid etching temperature, and thus the strength of float glass increased from 89.68 Mpa to 302.25 Mpa. The optimum thickness for acid etching was about 40 μm. The microscopic pictures showed that the surface defects of the glass surface such as scratch and pit weakened obviously or disappeared.

Preparation and Properties of ZnO/ZAO Double-Layers Thin Films on the Substrate of Glass

Aluminium zinc oxide(ZAO) thin films were deposited on soda-Lime-Silica glass substrate by middle frequency power magnetron sputtering. Then zinc oxide(ZnO) thin films were deposited above ZAO thin films by electrochemical deposition method at different time. ZAO thin films and ZnO/ZAO double-Layers thin films were characterized by X-Ray diffraction(XRD) and scanning electron microscope(SEM). A four-Point probe was used to determine the resistivity of the films. The optical transmittance of ZAO films and ZnO/ZAO films was measured by UV-Visible spectrum. The results represent that the transmittance of ZAO/ZnO thin films decreases gradually with deposition time increasing. When the deposition time is 5 minutes, the maximum transmittance of ZnO/ZAO films reaches to 85% at wave length from 400nm to 600nm, and the thickness and resistivity of thin film are 610nm and 2.04×10-3Ω•cm, respectively. However, the thickness and resistivity are highest when the deposition time is 20 minutes, which reaches to 808nm and 1.2×10-2Ω•cm. Meanwhile, the lattice constants a and c of ZAO/ZnO thin films demonstrate an expansion with deposition time increasing. In essence, good-Quality double-Layers thin films of ZnO/ZAO play an important role in CIGS solar cells.

Foam Glass for Soilless Cultivation Matrix Prepared by Using Boron Mud

Foam glass was prepared by boron mud, broken glass, foaming agents and fluxes. The appropriate foaming temperature and foaming time were got by sintering parameter optimization. The effects of preparation conditions on propertis of the foam glass for soilless cultivation matrix were investigated. The results show that under the optimum preparation conditions (the foaming temperature is 800 °C and foaming time is 40 min), the formula for boron mud/broken glass: Borax: Sodium nitrate: Calcium carbonate is 35/50: 5:7:3, the bulk density is 247 kg/m3, the open porosity is 70%, the water absorption rate is 202.3%, the pH value of soak solution keeps at about 6.5 with the increase of immersion time. All of these will meet the application requirement of soilless cultivation.

Effect of Cu(Cr0.2Al0.8)2O4/TiO2 Composite Film Electrodes on DSSC Photoelectric Properties

Cu(Cr0.2Al0.8)2O4/TiO2 composite film electrodes were prepared on FTO glass substrate by screen printing method after Cu(Cr0.2Al0.8)2O4 nano-particles were doped in TiO2 powers. The characteristics were studied by the X-ray diffraction for the crystalline structure of composite films, UV-Vis diffuse reflectance spectrum instruction for absorption spectrum of composite films and dye sensitized solar cells tester for the performance of DSSC. The results show doping Cu(Cr0.2Al0.8)2O4 powers could enhance UV-Vis spectral absorption strength and improve the photoelectric conversion efficiency of the solar cells when the doping content of Cu(Cr0.2Al0.8)2O4 is 3％. Compared with pure TiO2 film electrodes, the photoelectric conversion efficiency of the solar cells reaches to 3.59％.

Synthesis of Sodium Tungsten Bronze via Hydrothermal Method Assisted by Citric Acid

Sodium tungsten bronze NaxWO3 powders have been prepared by hydrothermal method using sodium tungstate as raw material and citric acid as reducing agent, followed by annealing under the inert gas N2 atmosphere. The prepared powders were confirmed as tetragonal sodium tungsten bronze Na0.1WO3 by X-ray diffraction. The SEM observation showed that the as-prepared Na0.1WO3 particles exhibited rod-like morphology with about 20 μm in length and 5 μm in diameter. The influence of pH value of the precursor solution and annealing temperature on the synthesized powders were also investigated. The results indicated that sodium tungsten bronze NaXWO3 would not be obtained when the pH value of the precursor solution decreased to pH=1 or the annealing temperature was lower than 700°C by this hydrothermal method. Additionally, as the wavelength increasing, the transmittance of prepared NaxWO3 exhibited higher visible light transparency with reaching up to about 58% and a downward trend in near-infrared area, which indicates that the prepared Na0.1WO3 have potential application as near-infrared shielding material.