Advanced Materials Research Vols. 148-149

Abstract: TiO2 supported gold clusters are prepared by photo-deposition method. The effect of preparation parameters on the size and morphology of gold clusters are investigated. The as-prepared Au/TiO2 samples are characterized by means of ICP, XRD and TEM. Au/TiO2 samples with different gold cluster sizes are studied as possible catalysts in the selective oxidation of benzyl alcohol to benzaldehyde and smaller gold clusters are observed to exhibit higher catalytic activity.

Abstract: In this study, titania powders were prepared from 0.02M titanium tetrachloride and 0.08M sodium hydroxide in a high gravity rotary reactor. The preparation was combined with a precipitation, washing/centrifugation, hydrothermal and drying steps. The prepared titania powders were characterized by TGA, SEM, TEM, FTIR, and UV-vis analysis。TGA curves show that the titania yield was found to increase with rising hydrothermal time. TEM analysis show that the prepared titania crystalline in solution has a flake-like shape with a primary size 5~15nm and narrow size distribution. SEM images show that the primary titania crystalline aggregates to large secondary powders with a size 5~20μm。FTIR and UV-vis spectra show that the prepared precursor is titanium hydroxide that was transferred into titanium dioxide after hydrothermal process under a suitable temperature and time.

Abstract: Cu2+-doped ZnSe quantum dots (ZnSe:Cu2+ QDs) are synthesized in aqueous solution via a co-precipitation method with thioglycolic acid (TGA) as a stabilizer. Green emission is observed under 365 nm UV excitation. X-ray diffraction patterns and transmission electron microscopy image show that ZnSe:Cu2+ QDs are sphalerite cubic structure, similar to round in shape, the average diameter is 6 nm. The concentration of Cu2+ ions and TGA, pH, reaction time and aging time have influences on optical properties of ZnSe:Cu2+ QDs. The luminescence of as-prepared products with different parameters is characterized using fluorescence spectrophotometer. The high fluorescence intensity has been got when the concentration of Cu2+ ions is 4.0% (molar ratio), TGA is 83.4 μl (mol ratio Zn: TGA=1:2), pH is 9.5, reaction time is 2h. The luminous intensity increases with the extension of aging time.

Abstract: The self-assembly behaviour of a novel cationic porphyrin-anthraquione (Por-AQ) hybrid ([AQATMPyP]I3) on highly oriented pyrolytic graphite (HOPG) was studied at room temperature in air by scanning tunneling microscopy(STM). According to theoretical calculation, it is testified that [AQATMPyP]I3 molecule mainly exists in the closed structure. The STM results reveal the presence of large-scale domains of ordered adlayer of this hybrid compound on HOPG. The STM images show a structure constituted by parallel rows. The width of each row is approximately 2.5nm.

Abstract: The activated carbons(AC) with high specific area were used widely as the electrode materials for the supercapacitors. Here we report the synthesis of nano-activated carbon electrode materials with different pore size distributions by vibration milling at room temperature. The size of the active carbon particles decreased from 20 to 30~50nm depended on the experimental conditions, and the particle distribution became more reasonable. The influence of important preparation technique condition(milling time， exciting frequency， vibration additive) on the nm-AC microstructure were found. Based on SEM, AFM, XRD and BET tests, we experienced the microstructure (crystalline, surface area, pore volume, pore size) of the nm-AC materials. It is found that manganese oxide as milling additive has more notable influence on improvement of material microstructure. Active carbon samples can gain more mesopores in shorter milling time and higher exciting frequency is useful to sample microstructure improvement. In short time，we can gain mesopore structure suitable nano-activated carbon electrode materials through vibration milling method.

Abstract: Porous polydivinylbenzene particles were prepared by dispersion polymerization, using AIBN as initiator, acetonitrile as solvent, calcium carbonate and polypyrrolidone used as dispersion stabilizer and porogen. Ratio of dispersion stabilizer with monomer affects the specific surface area and porous structure. Calcium carbonate and polypyrrolidone used porogen were studied.

Abstract: Electron emission from ferroelectric cathodes is commonly suggested as an electron source for different application due to its special characteristics such as high current density, easy treatment and operation, etc. The technology of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) ferroelectric cathode is introduced in this paper. Stable emission current is obtained from the PMN-PT ferroelectric cathode and the characteristic of ferroelectric electron emission is deal with as well.

Abstract: Intelligent structure is consistently identified as one of techniques getting much attention in the 21 century. With the research and development of intelligent material with large strain, high strength and high performance, the study on the non-linear theory of intelligent structure is a hot spot for research in the future. Based on nonlinear theory, Gurtin-type quasi-variational principle of nonlinear intelligent structure is established in this paper. Finally, some correlative problems are discussed.

Abstract: Steady alkalescence monodispersed silicasol were obtained from sodium metasilicate by using chemical precipitation. The process employed low Zeta electric potential controlled growth to achieve big grain diameter 130nm. In this work, the best conditions of grain diameter growth were optimized, which included pH, reaction temperature, digestion time, and so on. The performances of the product have been studied by XRD, IR, Nano Particle Analyzer, ζ electric potential and SEM. Sphericity silica nanoparticles with good stability and high dispersion were obtained, which attained the standard of manufacturing production.

Abstract: The basic equations of electro-magneto-thermo-elasticity are very complicated. It is hard to obtain analytical solutions, even if the simplest conditions were considered. The approximate method is an effective method to solve the complicate problems. However, the variational principle is theoretical foundation of finite element method and other approximate methods. According to the corresponding relations between generalized forces and generalized displacements, the basic equations of electro-magneto-thermo-elasticity are multiplied by corresponding virtual quantities, then integrated with volume and area, then algebraically added, and integrated with time, the Hamilton-type variational principles of electro-magneto-thermo-elasto-dynamics are established. They are the theoretical foundation of approximate calculation for multi-physics fields problem of electro-magneto-thermo-elasticity-dynamics.