Advanced Materials Research Vols. 415-417

Abstract: The layered K₂La₂Ti₃O₁₀ photocatalyst was synthesized via a stearic acid method. The structure of the photocatalyst was determined by means of powder X-ray diffraction, scanning electron microscope and UV-Vis spectroscopy. The photocatalytic properties for hydrogen evolution of the photocatalyst were examined under ultraviolet irradiation. The results showed that, the sample which synthesized under 1000°C for 2 h via stearic acid method has the highest crystallinity and the amount of photocatalytic hydrogen production activity was 6.43 mmol/(g cat) under UV light irradiation for three hours.

Abstract: In this paper, glass wools were prepared under different vitreous fluid temperature (vary from 1100oC to 1300oC) by centrifugal-spinneret-blow process. The effect of vitreous fluid temperature on fiber diameter and surface topography of glass wool has been studied by Scanning Electron Microscopy and Vertical Optical Microscope. With the increase of vitreous fluid temperature (T) from 1100oC to 1250oC, the mean fiber diameter decreased from 6.6µm to 3.9µm. When vitreous fluid temperature goes up to 1300oC, the mean fiber diameter increased to 4.1µm, slightly bigger than that of 1250oC. There are many protuberances in the fiber for T=1100oC and 1150oC because the surface tension is very strong at low temperature. The surface topography of fiber becomes smooth when the temperature is higher than 1200oC. The results show that the vitreous fluid temperature has a direct and pronounced effect on fiber diameter and surface topography. The optimum vitreous fluid temperature is about 1250oC.

Abstract: The well-distributed porous magnesium was prepared through powder metallurgy route basing on space-holding method. The damping behavior of the porous magnesium was characterized by internal friction and measured by a multi-function internal friction apparatus. Experimental results revealed that the damping capacity of the porous magnesium was increased compared to that of the bulk magnesium, which can be understood by a dislocation damping mechanism associated with an inhomogeneous stress and strain distribution around the pores. In addition, an internal friction peak was observed in the spectra of internal friction against temperature. It was suggested that the dislocation sliding arising from a thermal activation process should be responsible for the peak appearance.

Abstract: To obtain ZnO varistors with high voltage gradient, ZnO varistors were fabricated by traditional ceramic sintering technique, which were sintered from 1135 to 1155 °C, the microstructure and properties of varistors were characterized by SEM, X-rays diffraction and DC parameter instrument for varistors. The experimental results show that the spinel phase Zn₇Sb₂O₁₂ generated during sintering process, very thin amorphous Bi rich films are formed between the ZnO/ZnO grain boundaries, with increasement of sintering temperature, the grain size of ZnO varistor ceramic becomes bigger, the voltage gradient of varistor decreases and the density is improved. The optimized parameters are that when the sintering temperature is at 1140 °C, the voltage gradient of varistor is 301V/mm, the leakage current is 4μA and the density is 96.6%, the comprehensive electrical properties of ZnO varistors reach maximum.

Abstract: The energy saving principle of phase change materials is introduced briefly， the current status of the energy saving phase change materials and the newest progress are also discussed. The promising development trend of the energy saving phase change materials is prospected. With the effect of energy crisis, the difficult problem which we face is the energy consumption, energy saving and emission reduction is the first question that should be solved in all works of life. As the living standard improved, the human comfort require of indoor environment become more strict. Because of air conditioning making the power system load too large, energy saving technology has been paid a high degree of attention, and energy saving phase change materials ,as a new materials, has gradually become a focus in the study of energy utilization and material science.

Abstract: The adsorption and desorption property of total flavonoids with ion-exchange fiber were studied. The kinetic study on dynamic adsorption and desorption indicates that the adsorption and desorption property of fiber is function of the concentration、pH value and flow velocity of column liquid. Flavonoids can be effectively desorbed by ethanol.

Abstract: Porous organosilica is a promising material to be applied in water treatment due to high adsorption capacity of contaminants. Sol-gel method was used to fabricate mesoporous organosilioca from triblock copolymers, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) as the template and tetraethylorthosilicate as silicate source. The organosilica is doped with Al powder and Al₂SO₃ in order to evaluate the effect of ions on their adsorption capacity. It was demonstrated that the adsorption capacity is proportional to Al concentration, and inversely proportional to porosity. Metallic compound doped in organosilica enhances the remediation process and optimize the water treatment process. Moreover, impregnation the samples into cellulosic sponge improves the adsorption efficiency by 25%.

Abstract: Waterborne polyurethane (WPU) has its main applications in coatings and adhesives. Compared with the competing PU products from solvent-based processes, it has a more environmentally friendly manufacturing process. Its economic competitiveness could also be improved by the use of aromatic isocyanates that are widely available and cheaper than the currently used aliphatic isocyanates. We report on the synthesis and properties of WPU, based on natural rubber (NR) whose molecular structure has been altered, in combination with an aromatic isocyanate. The NR modification is by hydroxyl termination, with experiments using two chain lengths (HT600 and HT1000, named after molecular weight). The aromatic isocyanates used are 4,4’-Methylene bis (phenyl isocyanate) (MDI) and polymethylene polyphenyl polyisocyanate (p-MDI). The synthesized chemical structure is characterized using ATR-FTIR, while the key material properties reported here are the pH value, mean particle size and size distribution, and glass transition temperature. The WPU achieved suitable material properties, with small particles sizes and good dispersion, for applications in coatings.

Abstract: A Photoelectrochemical Biofuel Cell (PEBFC) generating electrical energy directly from sunlight and biomass was investigated. In this paper,the PEBFC had a triarylamine dye-sensitized titanium dioxide(TiO₂) film photoanode and Pt black cathode. The electron transport process of the PEBFC was also described. The performances of the PEBFC were obtained by photocurrent–photovoltage characteristic curves.The open-circuit photovoltage(V_oc), the short-circuit photocurrent (I_sc) and the maximum power density (P_max) was 0.82V, 69.00 μAcm^-2 and14.00μWcm^-2 at 0.27 V, respectively. The fill factor (FF) was 0.25 and the incident photo-to-current efficiency (IPCE) was 3.5% at 441 nm.

Abstract: A new type of parallel tire building drum mechanism is proposed. The structure of the mechanism is analyzed, and the degree of freedom is calculated .The solid model of the mechanism is established by UG, and then the kinematics of the mechanism is analyzed through the establishment of the Lagrange Dynamic Equations. The kinematics simulation is conducted using software code of ADAMS.