Advanced Materials Research Vols. 399-401

Abstract: We prepared nanometer-sized nickel oxide by hydrothermal decomposition. In this work, NiSO₄•6H₂O and Na₂CO₃ were used as raw materials to prepare the precursors. Nanometer-sized nickel oxide was obtained after calcining the precursors. The temperature of the calcination process affects the morphology and size of the nanometer-sized nickel oxide. The precursors and products were analyzed by TG, XRD and SEM. Sheet nanometer-sized nickel oxide was obtained and characterized by its high purity, smooth surface, regular hexagon shape, average size of 500 nm and 30-60 nm thickness. The results indicate that the NiO particles become open pore structures at a calcination temperature above 500 °C

Abstract: A modified seed-mediated growth method was developed for in situ controllable preparation of gold nanoparticles (GNPs) within P(AMPS-co-HEMA) hydrogel networks. When the time of cycles absorbing procedure increased in mother solutions under given temperature during the processing stage, the number of GNPs was significantly increased and networks were utilized for in situ nanoparticles synthesis by reduction of glod ion absorbed. TEM images confirmed that GNPs were between 100 and 200 nm in size and distributed uniformly in gel. The network embedded GNPs also endows the composite gel with selective catalytic activity for selective catalysis in the reduction of nitro compound (2-NP, 3-NP and 4-NP). The kinetics of the reduction reaction were investigated under the same condition, the result showed the GNPs gel system was found to have an excellent catalytic activity and high conversion for 4-NP reduction among nitrophenol homologue, the nitrophenol hydrogenation rate got to 6.63 mol/g min for reducing of 4-NP compared to 3.69 mol/g min, the rate of 2-NP. It was almost zero for 3-NP implying no catalytic activity, even though they were isomeride.

Abstract: Sacking fault energy (SFE) plays a significant role for metals or alloys to getting high strength and expected ductility simultaneously. Here the effect of SFE variation on mechanical properties has been studied in cold-rolling Cu and Cu-Al-Zn alloys. Tensile testing results show that the strength and ductility of the materials increase simultaneously with decreasing SFE. X-ray diffraction measurements indicate the peak broadening for the crystallite size decreasing and the lattice strain increasing with the stacking fault energy lowering . The relationship between the microstructure and mechanical properties of the materials is briefly discussed in this paper.

Abstract: Uniformly-sized, molecularly imprinted polymers (MIPs) for (D)-naproxen have been prepared by a precipitation polymerization method using methacrylic acid (MAA) as a functional monomer and divinylbenzene (DVB) as a cross-linker in acetonitrile or a mixture of toluene and acetonitrile(1:3). The (D)-naproxen-imprinted MAA-co-DVB polymers were monodispersed microspheres with size in the range of 1.5 to 3.6µm. Enantioseparation of naproxen was attained using the (D)-naproxen-imprinted MAA-co-DVB polymer microspheres. When Ethylene glycol dimethacrylate(EGDMA) was used as a cross-linker, the MAA-co -EGDMA polymers were sub-microspheres with the average size of 350nm and showed very low affinity for the template (D)-naproxen . The (D)-naproxen-imprinted MAA-co-DVB polymer microspheres prepared in the mixture of toluene showed the highest molecular recognition ability and with the biggest size of 3.6µm.

Abstract: The micro/nano particles of silicone rubber were prepared with α, ω-dihydroxy polyorganosiloxane, as basic polymer and crosslinking agent via emulsion polymerization method at room temperature. The structure and performance of the particles were characterized by transmission electron microscopy (TEM), FT-IR, thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The results indicated that the particles had certain ordered structure and thermal stability.

Abstract: In this paper, Cu-Ce/TiO₂ nano-particles, whose molar ratio account for 2%,2.5%,3%,3.5% and 4% respectively, were synthesized by sol-gel method, using Ti(C₄H₉O)₄ as the raw material, And the photocatalytic activities of the prepared samples were investigated by degrading formaldehyde gas under pure visible light through simulating indoor environment in the environmental test chamber. Moreover, X-Ray Powder Diffraction (XRD) and Ultraviolet-visible spectrophotometer were applied to analyze the crystallite size and optical properties of the samples. It is indicated that the sample of 2.5% performs best in the test. Besides, photocatalytic mechanism of co-doping of Cu-Ce was discussed.

Abstract: SnO₂ nanorods with rutile structure were successfully synthesized by solid state reaction in the presence of NaCl-KCl. Indirect-heating sensors based on nanorods were fabricated and investigated for the gas sensing properties to ethanol. The results showed that the response of sensor to 1000 ppm ethanol is up to 114.3, the export voltage to 1 ppm ethanol can attain 2.0 V at 275 °C, and the response time and recovery time are no longer than 10 s.

Abstract: Precursor of tungsten was obtained by spray drying process with high purity APT crystal liquor as material. The precursor was analysized by electron microscopy and X-ray. A suitable spray drying process was found through the morphology and powder structure. The influence of atomization disk rotational speed, the concentration ratio of ammonia to WO₃ in APT liquor and APT liquor’s concentration on particle size, structure and morphology of the ball precursor were studied. Uniformity superfine WO₃ was obtained from precursor by calcined.

Abstract: Strontium ferrite micro- and nanofibers have been prepared by the sol-gel process and the electrospinning with diameters about 1 μm and 100 nm, respectively. Single phase strontium ferrite fibers are formed after calcined at 750 °C for 2 hours for both the sol-gel and electrospinning processes. These strontium ferrite fibers are fabricated of nanosized particles with a hexagonal plate-like morphology, which grow with the calcination temperature. The microfiber cross-section contains multi-nanoparticles whilst the nanofiber with a necklace-like morphology is linked by nanoparticles at the calcination temperature range from 850 to 1050 °C. The magnetic properties of strontium ferrite fibers are mainly influenced by the grain size and fiber diameter. Both the strontium ferrite micro- and nanofibers calcined at 900°C for 2 hours are fabricated from single-domain grains around 56 nm and exhibit the specific saturation magnetization of 60.8 A•m²•kg^-1 (microfibers) and 59.9 A•m²•kg^-1 (nanofibers) and coercivity of 361.9 kA•m^-1 (micronfibers) and 523.6 kA•m^-1 (nanofibers). The coercivity difference between the micro- and nanofibers can be attributed to the different shape anisotropy energies arising from various magnetization reversal behaviors for the micro- and nanofibers.

Abstract: This paper firstly attempt to use microwave technology to assist carbon nanotubes by chemical copper plating, and comparated with the conventional method of copper plating, concluded the advantages of the microwave-assisted chemical deposition ,and try to develop a new technology of carbon nanotube composites.