Advanced Materials Research Vols. 652-654

Abstract: In this study, polyhedral oligomeric silsesquioxane (POSS) were blenged with epoxy acrylate (EA) and photoinitiator to prepare nanocomposites through UV-curing process. The vinyl-POSS nanoparticles were added to EA by physically blending at loadings between 0% and 15wt%. Through the FTIR analysis, we found that the POSS nanocomposites didn’t affect the extent of UV curing reactions; the curing reactions were performed to be completed in all POSS containing composites. The XRD analysis convinced the existing of phase separation between EA matrix and vinyl-POSS monomer. The impact resistance and coating adhesion were all enhanced by POSS nanocomposites at low content.

Abstract: In this study, polylactic acid(PLA)/ketoconazole(KCZ) composite microspheres were prepared by oil/water solvent evaporation method. Those drug-loaded microspheres were characterized in morphology using the scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FT-IR) was used to determine the chemical functional groups in the sample and to analysis whether a chemical reaction occured between PLA and KCZ. The thermogravimetric spectra of PLA and PLA/KCZ microspheres were used to analyse the influence of KCZ on the thermal decomposition mechanism of PLA. Crystallinities of the KCZ and PLA/KCZ were analyzed by X-ray diffraction analysis (XRD).

Abstract: Focused ion beam (FIB) is an important tool in microfabrication technique. In recent years, FIB was used to fabricate the nanodevices. In this paper, Pt nanowires with differ radius were deposited with FIB. The component and resistance of nanowires were investigated. Results indicate that the component of Pt naowires is mainly Pt, C and Ga. The high content of Pt in nanowires is 49.36%. The resistivity of Pt nanowire is from 545.74µΩ•cm to 5.16µΩ•cm. Pt nanowires with the diameter up to 60nm take on characteristic of metal; others take on that of semiconductor.

Abstract: Structure stability and electronic properties of Fe-doped boron carbides (B₁₃C₂) were studied using the first principle calculations based on plane wave pseudo-potential theory. The calculated results showed that the Fe-doped boron carbide representative stable structural is Fe substituting C atom on the end of chain C-B-C. The band structure and density of states (DOS) indicated that the coexistence of [C-B-Fe] ε+-[B11C] ε- structural unit made electrical conductivity increased. As the covalent bond of Fe-B was weaker than those of B-B and B-C, the thermal conductivity decreased for Fe-doped B13C2, thermoelectric property of Fe-doped boron carbides has been improved.

Abstract: The spinel CoxMn3-x O4 nanoparticles (SCMN) have been successfully grown on graphene sheets (GS) with a low cost in situ method in diethylene glycol (DEG) solution by using manganese acetate (Mn(OAc)2), cobalt acetate (Co(OAc)2) and graphene oxide as precursors. Excellent electrocatalytic activity and stability for oxygen reduction reaction (ORR) compared with those of commercial 20%Pt on Vulcan XC-72 (20%Pt@C) in alkaline solutions have been obtained.

Abstract: In this paper, the optimal projection recognition (OPR) developed in our lab has been used to find the regularities of forming dendritic Co₃O₄ superstructures. The criteria for predicting dendritic Co3O4 superstructures can be obtained by using OPR method among different kinds of pattern recognition diagrams. The new samples predicted to be dendritic Co₃O₄ superstructures were designed by using the inverse projection based on the OPR method. The predicted results agreed well with our experiments. Therefore, the work presented is very useful not only inthe shape-controlled synthesis of dendritic Co₃O4 superstructures but also in materials design of other nanomaterials.

Abstract: The silicon-boron(Si-B) pitch was successfully synthesized by solution-thermal treatment method using coal pitch, polycarbosilane and borane pyridine as starting materials. The B-Si pitch carbonization product was attained by carbonization in the temperature 900°C under flowing argon. The Si-B pitch prepared and its carbonization product were characterized by SEM, FT-IR, TG-DSC and XRD. The results show that the carbonization product has C-Si and C-B bonds and the silicon and boron components of the product is still amorphous when it is treated at 900°C. The weight loss of the Si-B pitch carbonization product at 900°C for 12h in air atmosphere is only 3.76wt%. The weight loss of the product is less than 4 wt% when the oxidation temperature reaches 1180°C. The prepared B-Si pitch carbonization product possesses good anti-oxidation property at high temperature in air atmosphere.

Abstract: Hydrogen and methane have been regarded as the main energy for future. In recent years, membrane technology has developed to be an attractive technology to separate them. In this paper, porous anodic alumina membranes at different thickness were prepared for separation of hydrogen and methane. The thickness varied from about 77 to 250 μm, moreover, the SEM (Scanning Electron Microscopy) images show a good linear relationship between the thickness (y) and anodizing time (x), with the fitting being y = 22.56x - 36.082. Gas permeance and separation index for hydrogen and methane were measured at different conditions, such as thickness and temperature. With the thickness increased, the permeances of two gases were decreased quickly but separation index vice versa. In this research, the actual separation index changed from 1.9 to 3.2.

Abstract: The piezoelectric ceramic of PMN-PZT was prepared by gelcasting using N-hydroxymothl acrylamide(NMAM) as monomer. The green bodies with different microstructure and properties were obtained by changing solid contents of slurry. The effects of solid volume fraction in slurries on properties of PMN-PZT green bodies were investigated. The results that green shrinkage reduced from 5.95% to 1.47%, the green density increased from 3.51g/cm3 to 4.69g/cm³, and green bending strength increased firstly then decreased when solid content of slurry changed from 45vol% to 60vol%. SEM photographs revealed that^{Superscript text} the green body had a uniform microstructure and few agglomerates when the solid loading was 50vol%.

Abstract: Al films (about 40 nm) were prepared on quartz substrates by thermal evaporation technique, and subsequently annealed in air for 1h at temperature ranging from 600 to 1300oC. The characteristics of the annealed films were investigated in this paper. The measurement results of XRD and Raman show that crystalline phase transformations of the annealed films will convert from γ, γ and α, up to α-Al2O3 with the increasing of the annealing temperature at 600 oC, 1200 oC, to 1300oC. AFM and transmission spectra reveal the effects of phase transformations on their morphology and optical properties.