Advanced Materials Research Vols. 750-752

Abstract: The gasoline combustion dusts was analyzed by accelerated solvent extraction-high performance liquid chromatography(ASE-HPLC) in this paper. The optimum extraction conditions were that extraction time was 30min, temperature was 120°C and the pressure was 100Mpa. It is a efficient extraction method for a laboratory to quickly extract gasoline combustion dust samples.

Abstract: The toluene soluble (TS) fraction prepared from a middle-temperature coal tar pitch was subjected to a series of thermal treatments at the various temperatures from 410 °C to 470 °C for different periods of time. The samples obtained after heat treatment was quenched to ambient temperature. Mesophase spheres were separated from the quenched samples using washing oil and quinoline. The kinetics of mesophase sphere formation of the TS fraction was studied, based on the data derived from the time-dependent changes in the mesophase sphere content. It was clarified that the mesophase sphere formation of TS fraction was an autocatalytic type reaction. The rate law and the rate constants for the mesophase sphere formation at holding temperatures of 410°C, 430°C, 450°C and 470°C were determined. The rate constants of the mesophase sphere formation follow the Arrhenius equation. The Arrhenius parameters of the mesophase sphere formation are 200.2 kJ mol^-1 of the activation energy and 2.71x1012 % -1 h-1 of the pre-exponential factor. The treatment temperature had a greater effect on the formation of mesophase spheres than the treatment time.

Abstract: Activation energy is the minimum energy that must have molecules that on their mutual collision has occurred chemical reaction. Activation energy can be calculated by quantum-mechanical relations for the binding energy, or the experimentally determined from the temperature dependence of the rate constant. Paper deals with the calculation of the activation energy using the results of experimental determination of ignition temperatures of food dust.

Abstract: To explore environmentally benign method for preparing TiO₂, composite photocatalysts TiO₂ immobilized on activated carbon fibers (TiO₂/ACF) were prepared in caprolactam tetrabutyl ammonium bromide ionic liquid (CPL-TBAB ILs). The TiO₂/ACF composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that nanoTiO₂ particles of mixed grain phase were well deposited on the activated carbon fiber surface.

Abstract: The electronic structures of ZnO were calculated by using a accurate full-potential linerized plane-wave and supercell method. To research on the influence of the intrinsic defects such as O vacancies and Zn vacancies on the magnetism of ZnO thin film, we built 2x2x2 supercells of ZnO, Zn₁₆O₁₅ and Zn₁₅O_16. The results indicate that the pure ZnO and ZnO with O vacancies are non-magnetic, but ZnO with Zn acancies is magnetic. The magnetism originates from the spin-polarized O atoms around the Zn vacancy. We can draw a conclusion that Zn vacancies are the origin of magnetism in ZnO films.

Abstract: A novel model consisting of basic micro-processes has been developed on the basis of the classic diffusion theory. It is first time that the concept of exchange rate has introduced，and the growing process of surfactant-mediated epitaxial thin-film growth has been simulated with Kinetic Monte Carlo (KMC) technique. The results of simulation found that the exchange reaction of RLA model is a combination of the basic micro-processes. The majorities of exchange are not complete position exchange and the exchange rate doesn’t always equal one. Both surfactant atoms and adatoms would diffuse from one layer to another. The diffusion happens mostly between single atoms and the diffusing atoms increase with substrate temperature.

Abstract: Titanium and aluminum films were deposited on oxygen-free copper substrates by electron beam evaporation method to obtain Al/Cu and Al/Ti/Cu layer composites. Evolution of microstructure and properties of Al/Cu and Al/Ti/Cu thin film during heat treatment processes were investigated by XRD, SEM and electrical properties analysis. The introduce of Ti layer can prevent the formation of Cu-Al intermetallic compounds, and has no obvious influence on the electrical resistivity of Al/Cu thin film, which can be used as a pad in microelectronic package and devices.

Abstract: Polycrystalline aluminum nitride (AlN) thin films were deposited by pulsed DC reactive magnetron sputtering in the mixed gas of argon, nitrogen and hydrogen. The deposited films were characterized by XRD, SEM, EDS, AFM, UV-vis spectroscopy and scratch test. The results show that hydrogen significantly affects the microstructures and properties of AlN films. The preferred orientation of AlN thin film transforms from c-axis to a-axis with the increase of hydrogen content. The mean transmittance and adhesive strength increases obviously when AlN films was deposited at high hydrogen content atmosphere.

Abstract: In this article, we report the surface modification results of Parylene C Film by solution of sodium naphthalene complex and its application. In this work, the function group and the crystal structure of the film were characterized separately with Attenuated Total Reflection Fourier transformation infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD).The result of test shows that the bond of carbon (C) and chlorine (Cl) is damaged; The crystalline of the film reduces, and the NaCl crystal exist on the film surface. The surface energy of the film is increased from 28.64mJ/m² to 41.48mJ/m², and the shearing tension of modified film was reached over 212.8kPa.The generalized analysis result indicated that nucleophilic reagent destructs the C-Cl bond on the benzene ring, the chlorine (Cl) atom on the benzene ring and the sodium ion in modified reagent forms the sodium chloride which adheres to the film surface.

Abstract: Al₂O₃ films have been deposited at room temperature on polyimide substrates using oxygen ion beam assisted pulse reactive magnetron sputtering system in which aluminium sputtering is simultaneous with oxygen ion beam irradiation. A set of samples were prepared at different oxygen content and film characterizations have been carried out using X-ray diffraction (XRD) for film crystallization, atomic force microscopy (AFM) for surface morphology, and X-ray photoelectron spectroscopy (XPS) for elemental composition measurements and chemical bonding states. The films are smoother and near stoichiometric aluminum oxide as oxygen content increases up to 86%. All films are kept in amorphous structure. The optical properties of the films showed sensitive with oxygen content. Transparent films of refractive index 1.63 are obtained with a deposition rate as high as 70.3 nm/min by 86% oxygen ion beam assisted, which is about 5 times than the films by conventional reactive magnetron sputtering.