Advanced Materials Research Vols. 512-515

Abstract: Two-step preparation technology was used to prepare anodic aluminum oxide (AAO) templates. Then deposit Ni nanowire arrays in nanopores of AAO templates by direct current deposition. TEM spectra of nanowires show that the length of nanowires is uniform and that the shape of nanowires is the same with that of nanopores. Finally, reaction activation energy of Ni growing in nanopores was calculated by experimental data. Results show that Ni growing in the smaller nanopores is much easier than in the bigger nanopores.

Abstract: Thin film thermocouples (TFTCs) have vast vistas owing to their advantages, such as thin junction, small volume, fast response rate, high sensitivity and so on. In this investigation, a transient temperature sensor of TFTCs was fabricated to measure the surface transient temperature by vacuum coating technology. Silicon dioxide was selected as insulating substrate, the overall dimension of which was 8 mm long, 8 mm wide, and 0.1 mm thick. Two different metal layers were sandwiched between silicon dioxide 2 insulating substrate and silicon dioxide protective layer: cuprum and nickel films, which were 0.08 μm thick. TFTCs consist of 13 Cu-Ni junctions, which are connected in series. The whole TFTCs area is 4.6mm × 4.6 mm. The aggregate thickness of the transient temperature sensor is 0.17 μm. To protect Cu and Ni films, a silicon dioxide layer thickness of 0.01 μm was evaporated on metal layers excluding terminal points. This research carried out static and dynamic calibration to TFTCs. The Seebeck coefficient of the thin film thermocouple is 0.83843 μV/°C. The dynamic performance of TFTCs exhibited dynamic behavior corresponding to the heat flux change on the surface of thin film thermocouple.

Abstract: Owning to the robust characteristics of diamonds, a nano-tip array structured mold was fabricated with diamond, we can then use this mold to produce anti-reflection (AR) films with nanoimprint lithography. Taking advantage of the self-ordered characteristic of anodic aluminum oxide (AAO), we can obtain the diamond mold by depositing a layer of diamond on the AAO using hot filament chemical vapor deposition (HFCVD). Then taking advantage of the high through-put characteristics of nanoimprint lithography, AR films can be mass produced. The AR films were subjected to reflectivity inspections, a 5.5% reduction in reflectivity was obtained.

Abstract: The influence of heat-treatment in nitrogen atmosphere at different temperatures, time and stress on the physical–chemical properties and the surface of PBO fibers were investigated through Single fiber tensile, TG and SEM analysis. The results show that the tensile strength of PBO fibers dose not change so much before 600°C, but for heat-treatment at 650°C, there is a significant decrease in strength. Heat-treatment also makes the surface of fibers rougher than untreated fibers.

Abstract: Au supported titania composite photocatalyst was prepared by one-pot synthesis method where titanate nanotubes as supports and which was subsequently transformed into anatase TiO₂ during the water vapor treatment. The composite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N₂ isothermal adsorption-desorption. Au nanoparticles in the crystallite size of 10-15 nm were uniformly deposited onto the surface of titanate nanotubes or anatase TiO₂ nanoparticles. Some nanotubes were kept even at 120 °C and the composite had specific surface areas ranged from 163 to 310 m².g¹ depending on the vapor temperature. The photocatalytic activity of the composite photocatalyst was evaluated in the degradation of dyes acid red G (ARG) and methylene blue (MB) under UV irradiation. Au supported TiO₂ had good adsorption ability to dyes, and showed an enhanced photocatalytic efficiency compared to the pristine titanate nanotubes.

Abstract: In this context,the sol-gel approach to the preparation of solid-phase microextraction fibers is applied for extracting of benzene and mathanol from enviromental water samples.Therefore,two different substances such as PEG and MWCNTs is added to the coating.PEG/MWCNTs fibers are prepared using sol-gel technology as a process.MWCNTs is immobilized as microspheres in the pores of PEG coating using Scanning Electron Microscope(SEM).At last, the results show that PEG/MWCNTs fibers are higher extraction efficiency than PEG fibers. Several factors also are considered and optimized,such as extraction temperature, extraction time,inoic strength,stirring speed,desorption temperature and desorption time.LOD(S/N=5) and LOQ(S/N=10) for sol-gel PEG/MWCNTs fibers for extraction of benzene and methanol is 1µg/L and 2µg/L, linear range is 2-2800µg/mL and 2-3000µg/L, linear correlation coefficient is 0.9937 and 0.9940, the RSDs (RSD, n = 7) is 5.1%. and 6.7%, respectively.

Abstract: Being an advantageous combustion technology, flameless combustion is being widely investigated mainly with gaseous fuels for its high efficiency and low pollution. In this paper the realization of liquid flameless combustion in micro turbine environment is investigated. It is indicated that air preheating is not the essential condition to attain flameless mode and the air injection speed is more important to lower the whole reaction rate. Flameless combustion was described in terms of the realization mechanism, flow field, flame shape, temperature, and emissions. Finally the heat transfer model of the recirculated gas applicable to liquid fuel flameless combustion based on the combustor structure is presented.

Abstract: Simulated service condition of aluminum ingot casting molds, samples of ductile iron was tested in a temperature Cycle from750°C and water-cooled to 25°C till a crack appeared in the sample. its thermal fatigue resistance of samples based various microstructure included as—casting, annealing or alloying ferritic matrix structure, or alloying pearlitic structure and the upper or low the bainitic structure had been researched. The study shows that the thermal fatigue resistance of the annealing ferritic nodular cast iron was superior to the others.

Abstract: Abstract. Two fluorosilicone oils as additives were evaluated using an Optimol SRV reciprocating friction and wear tester by gray cast iron disc against AISI 52100 steel ball at 20 N and sliding speed of 0.20 m/s, respectively. The morphologies of worn surface of the disc were examined using a scanning electron microscope (SEM). In addition, the elemental compositions and chemical states of several typical elements on the worn surfaces of the gray cast iron discs were examined by means of X-ray photoelectron spectroscopy (XPS). Results indicate that PAO(Poly-alpha-olefin)+F-Si-E exhibite excellent tribological properties. This is partly attributed to material properties and tribological reaction between the lubricant and the sliding surface.

Abstract: The paper developed the new compound accelerator contains liquid hydrocarbons and surfactants, using the hydrate generator to experiment. On the basis of the researches on the generating conditions, mechanism of gas hydrate and experimental phenomena, the new kinetics model considering the compound accelerator affecting is built. A program which can compute the model is designed by Visual B compiler language. The induction time in the conditions of different pressures, different solutions and different gases is respectively calculated. The calculation is good agreement with the experimental data and the theory, we obtained that the calculated data are validated. The results show that the model can express completely the process of NGH formation, and provide the theory and model for its industry application.