Advanced Materials Research Vols. 148-149

Abstract: A promising basic microporous catalytic material is prepared by nitridation of dehydrated NaY zeolite. The base strength of zeolite framework is enhanced due to the replacement of oxygen by nitrogen with lower electronegativity. Various characterization methods, including XRD, CHN elemental analysis, SEM and FTIR spectra of CO adsorption, are employed to analyze the physico-chemical properties of the nitrogen-incorporated NaY zeolite. High crystallinity and high specific surface areas of NaY are well preserved in nitrogen-incorporated NaY. Compared to parent NaY zeolite, the nitridized materials exhibit improved basic catalytic performances in Knoevenagel condensation reaction and side-chain monomethylation reaction of phenylacetonitrile.

Abstract: Non-stoichiometric tungsten oxide nanorods with length up to few microns and diameters of 5-20 nm were initially prepared using a simple solvothermal method. The as-synthesized tungsten oxide nanorods were found to exhibit excellent photocatalytic properties under visible light irradiation. The degradation ratio of the methyl orange solutions by the tungsten oxide nanorods was as high as 98% under irradiation for 2.5 h. The excellent visible-light-driven photocatalytic properties of the hydrothermally-prepared nanorods may be due to a combination of their unique structure, outstanding light adsorption feature and high specific surface area.

Abstract: Mono-dispersed mesoporous silica spheres with highly ordered hexagonal regularity were synthesized by hydrothermal method with tetraethoxysilane (TEOS) as silica source, cetyltrimethylammonium chloride (C16TAC) as template, methanol as co-solvent, and sodium hydroxide as alkali source. The influence of the C16TAC concentration, TEOS concentration, methanol/water ratio and the synthesis temperature on morphology and mesostructure of the prepared silica particles were investigated in detail. The results showed that the synthesized mono-dispersed spherical silica particles have ordered hexagonal mesoporous structure, high specific surface area and uniform pore size distribution.

Abstract: There are many uncertain sensitive issues such as parameter disturbance and edge effect when PMLSM running. In order to solve these problems, a method called mixed robust optimal and H controller is presented. Robust optimal and H∞ control strategy is made use to design the mixed robust optimal and H controller of PMLSM. Large external disturbance and internal nonlinear perturbations can well be eliminated by this controller, and it’s easy to be practiced. MATLAB/SIMULINK is made use to simulate the system. With the help of PMAC board and COPLY controller permanent brushless motor controller, hardware test platform is built. The test results show that mixed robust optimal and H controller has strong robustness and traceability compared with traditional PID control method.

Abstract: The nano poly(phenylsilsesquioxane) particles (nano-PPSQ) were prepared with both basic and acidic catalyzed processes and the PP/nano-PPSQ composites were prepared by melt blending method. The morphology and thermal stability of PP/nano-PPSQ composites were characterized by SEM, XRD and TGA. The SEM results showed that the particles were well dispersed in the PP matrix and the XRD revealed that the addition of nano-PPSQ influences the crystallinity of PP. The thermogravimetric analysis results of the PP/ nano-PPSQ composites indicated that the incorporation of nano-PPSQ can improve the thermal stability of PP obviously.

Abstract: Carbon nanotubes (CNTs) demonstrate attractive characteristics as cold cathode emitters for high aspect ratio, small radius of curvature, high mechanical strength and chemical stability. In this article, Ag-CNTs were prepared by a series of processes including acid-treating, sensitizing, activating and electroless plating. Then Ag-CNTs cathode were sucessfully fabricated by electrophoresis deposition (EPD) method. The morphologies of Ag-CNTs cathode and pristine CNTs cathode were observed by scanning electron microscopy (SEM). The results showed that the field emission properties of Ag-CNTs cathode were better than pristine CNTs cathode, for presenting lower turn-on field, larger emission current density, more stabilization and longer lifetime. Thus it can be seen that the Ag-CNTs cathode can improve the characteristics of carbon nanotubes field emission display (CNT-FED).

Abstract: In order to evaluate the pavement performance of recycled asphalt mixture processed by microwave, an experimental method was designed to compare the microwave heating with the conventional heating in recycling affection of asphalt mixture. The samples AC-13 were produced. Conventional and microwave heating performance of modified asphalt recycling test including the rutting test, the trabecular cold bending test, the Marshall immersion test, the freeze-thaw split test, and the splitting strength mechanical properties were test. The experimental results show that it is roughly the same in the high temperature stability and mechanical properties of these two areas, and at low temperature cracking resistance the use of microwave processing can improve the low temperature flexibility to reduce the surface temperature seasonal prone temperature shrinkage cracks and fatigue cracks. The stability on the water by using microwave processing can enhance the asphalt and aggregate adhesion so that mixture enhanced resistance to water damage, there is a better role in improving the water stability. These results could promote microwave recycling and provide the basis for the promotion applications.

Abstract: A novel jujube cake-like pH/temperature responsive hydrogel, as a drug delivery system, was prepared by two steps in this paper. The intelligent copolymer hydrogel (PME) was obtained from N-acryloylglycinate methyl ester (AGME) and N-acryloylglycinate ethyl ester (AGEE), using sodium laurate (SL) as an emulsifier and N, N '-methylenebisacrylamide (NMBA) as a crosslinking agent. Selecting indomethacin as a model drug, in vitro drug release behaviors were investigated at different temperatures, phosphate buffer solutions (PBS) and emulsifier content. The cumulative release of indomethacin from the pH/temperature sensitive hydrogel was apparently increased as the emulsifier content increased, the pH value increased and the temperature decreased. 48% indomethacin from the hydrogel PME was released in pH 7.4 PBS at 18 oC within 600 minutes, whereas only 17% indomethacin diffused into pH 2.1 PBS.

Abstract: Spinel CoFe2O4 nano-particles were synthesized by hydrothermal traditionally and Ethylene Glycol (EG) assisted hydrothermal process originally. The effects of reaction temperatures from 140°C to 200°C, different OH- provider and EG/water ratio on the nano-particles’ structure, morphology and magnetic properties of composition were studied by X-ray diffractometer (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The possible mechanism for the effects on the properties was also discussed in details. The results showed that NaAC as OH- provider and higher EG/water ratio in solvent were benefit for getting smaller CoFe2O4 nano-particles. And existence of EG is also important to remove the α-Fe2O3 phase.

Abstract: The effect of α-Al2O3 nano-additives on anodic oxide film-forming and film performance was studied. The morphology and phase compositions of the anodic oxide films were analyzed by scanning electronic microscope (SEM) and X-ray diffraction (XRD). The corrosion resistance of the anodic films with nano-Al2O3 was investigated by immersion test and potentiodynamic polarization technique. The results show that anodic oxide films mainly consists of Mg, Al12Mg17, γ-Al2O3, a little of Si and α-Al2O3. The corrosion resistance property of magnesium alloy can be improved with the addition of α-Al2O3 nano-additives.