Advanced Materials Research Vol. 703

Abstract: By using a two-stage light gas gun, two experiments of shock recovery experiments with initial sample of Fe+(Mg, Fe)SiO₃ (En) were conducted between 78 and 113 GPa shock pressure (the corresponding temperature is estimated as 3000~5000K). The recovered samples were analyzed by X-ray Diffraction (XRD).The XRD observation at the middle section of two recovered samples illustrates the new composition of recovered samples is (Mg, Fe)₂SiO₄.Comparing with the recovery experiments of MgO+SiO₂ ,we can infer that iron and perovskite react to form SiO₂ and (Mg, Fe)O. The experiments result indicates that reaction between liquid iron and (Mg, Fe)SiO₃ perovskite may occur at the core-mantle boundary in geological history. The reaction creates a very heterogeneous zone at the base of the mantle. Si and O dissolved in liquid iron are rapidly dispersed by the flow of the liquid outer core.

Abstract: In this paper, the system of chemical materials with design of chemical molecular structure images identification is introduced in detail. In order to reduce the algorithm complexity, increase the program execution efficiency, the system is completed based on the hybrid programming of VC++6.0 and MATLAB. The method proposed combines the advantages of VC++ and MATLAB, it shortens the time to write code algorithm, reduces the workload in programming and simultaneously increases the execution efficiency.

Abstract: This study aimed at the application conditions of environmental materials in sweet potato starch wastewater by hydrolysis acidification process. The removal rates of COD and soluble protein were investigated to find suitable natural setting time, the quantity of acidic steeping liquor and pH. The results showed that traditional fermentation not only consumes time but also scarcely removal efficiency in short time. 40% acidic steeping liquor was added as an optimum dosage for effective treatment. In addition, the effort of pH (3.0-9.0) on the hydrolysis acidification of wastewater was investigated. The removal rates of COD and soluble protein reached 26.9% and 76.3% respectively at pH4.0. Therefore, pH was adjusted to isoelectric point that can effectively reduce the burden of subsequent wastewater treatment.

Abstract: In order to prepare polysulfone (PSF) hollow-fiber ultrafiltration (UF) membrane with ideal hydrophilicity, TiO₂ nanoparticle was introduced to casting solution. Furthermore, the effect of TiO₂ nanoparticle concentration on structure and performance of membrane were investigated. It was found that with the addition of TiO₂ nanoparticle, the structure and performance are influenced obviously. With the increase of TiO₂ concentration, the porosity increase, the tensile strength and fracture length have maximum values when TiO₂ concentration is 1 wt%. The water flux increase obviously and the retention rate decrease slowly with the increase of operating pressure, considering water flux and retention rate of the membrane, the best operating pressure is 0.2 MPa.

Abstract: In this paper, we investigated the characterization of a gallium co-doping multicrystalline silicon ingot made of solar-grade silicon purified by metallurgical route. It is shown that the addition of gallium yields a fully p-type ingot and resistivity distribution in the range from 1.2 Ω.cm to1.7 Ω.cm along the full ingot height. Minority carrier lifetime measurements indicate that this material is suitable for the production of solar cells with comparable efficiencies to standard material. In addition, gallium addition in compensated silicon during ingot casting is proved to be very prospective for controlling the resistivity and increasing material yield of ingot.

Abstract: Wide-band gap semiconductor GaN is a promising material for direct-conversion nuclear micro-batteries to meet energy requirement for micro-systems. The properties of semiconductor GaN materials were studied by the interaction of beta radiation with GaN. By the Monte Carlo simulation, the trajectories of incident beta particles in GaN and the total energy deposition were obtained, which provide an optimal design in p-n junction width of GaN.

Abstract: Calculations have been performed for the structures and electronic properties of GaN nanoribbons with armchair edge (AGaNNRs), using the first-principles projector-augmented wave (PAW) potential within density functional theory (DFT) framework. The lowest unoccupied conduction band (LUCB) and the highest occupied valence band (HOVB) are always separated, representing a semiconductor character for the AGaNNRs. In addition, the majority and minority spin bands are fully superposition and therefore the AGaNNRs are non-magnetic. As the nanoribbons width increase, band gaps of AGaNNRs decrease monotonically and become close to their asymptotic limit of a single layer of GaN sheet.

Abstract: The diffused fractal growth has a wide range of applications in material fields, especially the diffusion limited aggregation. As a result, the research of fractal growth has important significance in material science. In this paper, iterative steps are introduced in Laplace's equation based on the meaning of random walk, and computer simulation is used to analysis the influence of steps' change on fractal growth.

Abstract: This paper summarized the application of main artificial biomaterials and tissue engineering on repair of exercise-induced wrist ligament injury, on the basis of analysis about artificial biomaterial intervention of wrist ligament injury. At present, the anatomical, histological and biomechanical properties of wrist ligament has been studied in the domestic and foreign research; however, the studies about the application of artificial biomaterials and tissue engineering technology in the repair or reconstruction of exercise-induced Wrist ligament injury were very rare. With the development and progress of cell biology and molecular biology methods and technology, the research of ligament injury repair has entered a new stage, the new development of artificial biomaterials and tissue engineering provide a new direction for the Treatment and rehabilitation of exercise-induced wrist ligament injury.

Abstract: A preliminary study of welding CuW alloy to Cu substrate via microwave energy was investigated. Different proportions of CuW alloy powders were directly consolidated on clean Cu substrate surface. Then, they were heated at a certain temperature in a high vacuum microwave furnace. The results show that the appropriate conditions of 20°C/min heating rate, 900°C welding temperature and 5 minutes soaking time can weld CuW alloy to Cu substrate well, and the whole processing cycle is approximately 40 min. SEM morphologys reveal that the combination between CuW and Cu substrate is firm. The surface hardness of CuW alloy layer is 257HV, which is 2.5 times than that of Cu substrate. This technology reduces the processing cycle and has a positive significance on the surface modification and wear resistance of copper parts.