Advanced Materials Research Vol. 981

Abstract: Ni-Cu-Zn ferrite powders were prepared by self-propagating high-temperature synthesis (SHS) using carbon powder with different mass fractions as fuel. The effects of carbon content in the raw materials on the phase composition, microstructure, density and magnetic property of the Ni-Cu-Zn powders were investigated by X-ray diffractometry(XRD), scanning electron microscope(SEM) and vibrating sample magnetometer(VSM), respectively. The results show that the use of carbon as a fuel brings no other impurities and improved the permeability. The single spinel phase powder was obtained when the precursor materials with a carbon powder of 5% in mass were used.

Abstract: This work describes the preparation and the properties of poly(vinylidene fluoride) (PVDF) porous membranes. The porous membrane was prepared using phase-inversion method by adding hydrophilic polyvinylpyrrolidone (PVP) as hole-agent. The contrastive analysis of membrane characterizations between the membrane no PVP added and the membrane added PVP were carried out by optical microscopy analysis, scanning electron microscopy, porosity, pure water flux and water contact angle. The results showed that adding PVP can induce the building of pore structure, increase the surface roughness and hydrophilicity of PVDF membrane, and then enhance its pure water flux.

Abstract: Aiming at NC milling processing simulation problem, a ball-end cutter milling force model is established, the numerical simulation analysis of aluminum alloy AL2024 milling process is conducted by using the finite element analysis software AdvantEdge finite element analysis. Focus on the Milling force simulation, the size of the milling force is obtained by simulating calculation. Using the same cutting parameters for milling experiment, the results show that simulation analysis of the cutting force values ​​are in good agreement with the experimental results，the milling force model prior established is correct. The research laid a foundation for the perfect CNC milling simulation system.

Abstract: The photo-stimulating discharge (PSD) and ultraviolet-visible spectrometry were used to characterize the polyethylene (PE) and nano-hybrid PE trap before and after ultraviolet aging. In PE with the increasing of ultraviolet aging time, shallow traps reduce gradually and deep traps increase gradually, but for the nano-hybrid PE, shallow traps increase gradually and deep traps reduce gradually. Experiments show that: in the process of aging PE produces oxidation products such as carbonyl, hydroxyl etc. The incorporation of impurities can inhibit the injection of space charges, so as to achieve the purpose of improving electric field distortion in the body of the PE.

Abstract: According to the experimental results of new type silicon magnetic sensitivity transistor (SMST), the simulation models of new type SMSTs with different base region lengths and widths were established by ATLAS software. The simulation results of optimizing the geometric parameters demonstrate that the max collector current relative magnetic sensitivity can be achieved when the base region length and width are 170 μm and 30 μm, and the simulation model of the differential structure of new type SMST was established based on it. The simulation results indicate that the max collector current relative magnetic sensitivity is 322％/T for new type SMST differential structure when the base currents are 5.0 mA and the collector voltages are 5.0 V, and it can improve the magnetic sensitivity and ameliorate temperature characteristics.

Abstract: Apatite oxides electrolytes La_9.33(SiO₄)₆O₂ was prepared following the Sol-Gel aqueous route. The structure of La_9.33(SiO₄)₆O₂ was evaluated using the X-ray diffraction patterns (PXRD). The main phase is La_9.33Si₆O₂₆ with the Minor impurity phase of La₂SiO₅ as a secondary phase. And dense La_9.33(SiO₄)₆O₂ nanoceramics with grain size of smaller than 100 nm were fabricated by high-pressure sintering, the pressure of 4.5 GPa, the sintering temperature of 1200 ^oC and dwelling time of 10 min were used. The ionic conductivity of the samples is evaluated by AC impedance spectroscopy. The conductivity of dense La_9.33(SiO₄)₆O₂ nanoceramics by high-pressure densification is one multiple higher compared with that of the microcrystalline ceramics. The activation energy in the samples by high-pressure densification and conventional sintering method was 1.06 eV and 1.44 eV, respectively.

Abstract: Polyimide-based (PI) nanocomposites possess excellent electrical and thermal performance, widely used in inverter motor. In the paper using different particle sizes made polyimide/titania (PI/TiO2) nanocomposite films in situ polymerization, including 20nm A series and 50nm B series. The results shows that A series have a larger specific surface, combination of the film and matrix is closer without affecting the imidization of PI, and there is a clear interface layer and the structure is more stable. According to the time of corona-resistant A Series films is significantly longer than B Series films, especially the A series films with 15% of which corona-resistant time is 15h, five times than the pure PI. By both SAXS and XRD particle size in the matrix can be calculated, proving small particles can be better combination of the matrix of PI, increasing the number of traps, more effectively cutting off charge corrosion and making corona resistance greater performance.

Abstract: The crystallization characteristics of the binary alloys which have InSn4 intermetallic compounds(IMC) were investigated.The influence which high undercooling had caused to the process of lattice formation,the lattice evolution in the later period of solidification,the stabilization process of the alloy property were mainly studied.The results show that the solute redistribution is restrained intensely in the rapidly solidified condition,the components of InSn4 IMC distribute uniformly,the highly undercooling structure have small sub-grain structure.X-ray diffraction analysis show that strong (0001) texture is formed in the alloys,EBSD analysis show that many sub-boundaries exist in the grains.While these unstable structures have an isothermal annealing between 20~140oC,the texure feature of the alloys weaken,and at the same time the microhardness lower in varying degrees.

Abstract: This paper presents a model of Kerr effect for the influencing factors research. The influencing factors proposed are Kerr cell voltage, charging duration time and electrode material. The experimental results show that refractive index of transformer oil will rise when Kerr cell voltage become larger; There is a period of 15 minutes called ‘polarization time’ after the beginning of the experiment and electrode material indeed has an obvious effect on the transformer oil.

Abstract: As an important semiconductor, nickel oxide (NiO) films deposited by electron beam evaporation are reported scarcely. In this study, undoped NiO films were deposited on quartz by electron beam evaporation technique, and annealed at different temperature in a pure oxygen atmosphere. The electrical characterization of NiO films were investigated using Hall effect measurements. The results show that the film conduction types of n, p, and high resistivity appear in proper order with the increasing temperature. The mechanism is further explicated by the SEM and Raman measurements. The oxygen atoms are introduced by the thermal treatment under oxygen ambience. The amount of atoms is more and more with the increasing temperature and it results in becoming larger grain size of the film while the conduction type converting. High resistivity of the film reveals that some oxygen atoms will be out of the film at a higher annealing temperature. So the amount of oxygen atoms in the film plays a key role in the conduction behavior of NiO film. Our results provide important information for the improved understanding of the conduction mechanism.