Applied Mechanics and Materials Vols. 268-270

Abstract: This paper by cold isostatic pressing and sintering of combining the method of preparation of silicon carbide enhance aluminum functional gradient materials, and the microstructure, density, impact toughness are analyzed, the results of experiments showed that in the aluminum gradient to join in the silicon carbide enhance particles, The impact toughness of the material has been obviously improved. Using ANSYS Numerical simulation Impact process, the simulation results anastomosis with the experimental results.

Abstract: Thermal stability can reflect the thermal degradation speed of polymers during the melt processing. In this paper, we used Kissinger, Flynn-Wall-Ozawa and Coats-Redfern method to study the kinetics of non-isothermal degradation of PFA. The thermal degradation activation energy obtained from the Kissinger method, Flynn-Wall-Ozawa method and Coats-Redfern method is 228.5 kJ/mol, 213.9 kJ/mol and 237.4 kJ/mol respectively. The Flynn-Wall-Ozawa method indicates the thermal degradation reaction PFA is a secondary reaction.

Abstract: PMMA/PS copolymers were synthesized by radical polymerization techniques. And the 1H NMR results illustrate that the molar contents of PMMA are respectively 19%, 53%, 69% and 84%. The coatings of those PMMA/PS copolymers were prepared by spin-coating. The surface structures and protein resistance of copolymer coatings were investigated respectively by AFM and BSA absorption experiment. It is showed that the copolymer coating surfaces have micro-phase separation structure. Furthermore, with the increase in the PMMA content, the surface pattern changes from interpenetration network pattern to island structure that the PMMA-rich phase surrounded by the PS-rich phase. In addition, all coatings prepared in this study, especially the coating with PMMA content of 69%, have good resistance to BSA protein.

Abstract: The effect of compaction and preforming parameters on the fiber volume content of bindered textile preforms during a compaction experiment was investigated by using Taguchi method. Four compaction and preforming parameters of compaction temperature, binder activation temperature, binder content and binder activation time were selected and optimized with respect to the fiber volume content at specified compaction pressure (0.2 MPa). The results reveal that the compaction behavior of bindered textile preforms has significantly influenced due to the presence of binder. The fiber volume content during compaction was correlated with the compaction and preforming parameters using a modified four-parameter-compaction-model which has been proposed for describing the compaction behavior of bindered textile preforms.

Abstract: Co3O4 nanowire arrays freely standing on nickel foam are prepared via a template-free growth method，and it is doped by Ag via electrodeposition method (denoted as NWA-Ag/Co3O4，NWA represents Nanowire Arrays). The morphology of NWA-Ag/Co3O4 is examined by scanning electron microscopy. The phase structure of the NWA-Ag/Co3O4 electrode is characterized by X-ray diffraction spectroscopy. The supercapacitance behavior of the NWA-Ag/Co3O4 electrodes is investigated by cyclic voltammetry, galvanostatic charge/discharge test and electrochemical impedance spectroscopy. The results show that the nanowire arrays densely cover the nickel foam substrate and have diameters around 250 nm. The NWA-Ag/Co3O4 electrodes exhibit a specific capacitance of 1009 F g−1 at a current density of 5 mA cm-2 in 6.0 mol dm-3 KOH electrolyte. The capacitance loss is less than 6.5% after 500 charge/discharge cycles at 10 mA cm-2 and with columbic efficiency higher than 97.5%.

Abstract: MnO₂ nanoparticle was produced using liquid coprecipitation method, and nanorod and nanowire were produced using hydrothermal method and annealing. SEM and EDS were used to examine the morphology and the elements of the samples. The diameter of particle is about 300nm, the diameter of rod is about 200-300nm, the diameter of wire is about 50-70nm. The electrochemical characteristics were tested using galvanostatic charge-discharge cycling. The results demonstrat that the prepared MnO₂ have a good pseudocapacitance behavior and power characteristic. And the specific capacitor (SC) is up to 260.09F/g.

Abstract: In this paper, the axial tensile process of single crystal titanium nano-rod is simulated based on the Finnis-Sinclair embedded atom potential by molecular dynamics. The mechanical properties of the titanium nano-rod with different cross-section dimension along three orientations ([0001]、[-12-10]、[10-10]) are analyzed. The results show as follows: 1) The tension process of titanium nano-rod along three orientations all includes four stages which are elastic deformation, uniform plastic deformation, localized necking and fault stage. 2) The larger the cross-section is, the smaller the yield stress is. 3) Along the [0001] orientation the yield stress and elastic modulus of titanium nano-rod is the largest, but fracture strain is the smallest; along the [-12-10] orientation the yield stress and elastic modulus is the smallest, but the fracture strain is the largest; along the [10-10] orientation the tension mechanical properties is in the middle of the other two orientations.

Abstract: By using tetrabutyl titanate as the main material, TiO₂ nanoparticles / CNTs composite particles have been prepared in acidic abundant aqueous solution at low temperature without calcination. The microstructure of the composite particles, including surface morphology, phase composition and specific surface area was characterized by SEM, TEM, Raman, XPS and BET. The results reveal that TiO₂ nanoparticles coated uniformly on CNTs surfaces were mainly anatase type. The surface roughness of CNTs was remarkably increased after coating. However, the specific surface area of composite particles decreased by 23.4 m²•g^-1 than that of CNTs with uncoated TiO₂. Photocatalytic activity of TiO₂ nanoparticles / CNTs composite particles shows a significant increase of absorption intensity both in ultraviolet band and visible light band according to UV-vis spectra.

Abstract: In the present paper, the tungsten oxide nanoparticles were fabricated via a hydrothermal treatment of the H2WO4 precursors. The H2WO4 precursors were prepared by method of precipitation reaction between aqueous Na2WO4 and HCl solution. The products are characterized in detail by multiform techniques: scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis. The results show that products are WO3 nanoparticles with diameter of about 100-150 nm.

Abstract: Cerium oxide is an important material having been applied to a variety of commercial fields. Many methods such as precipitation, hydrothermal route and sol-gel techniques have been used to produce the nanocrystalline ceria. This study, based on the precipitation method, used ceric nitrate as cerium source, anionic surfactant (sodium dodecyl sulphate) as template, and urea as the precipitating agent to synthesize ceria. The effects of several factors, such as the molar ratio of reactants and reaction temperature on the morphology and crystal structure of ceria were investigated, which were determined by XRD and SEM methods. According to the results, 70°C is best experimental conditions and preferable molar ratio of chemicals mentioned above is 1:2:30 for single factor experiment.