The magnetic and electronic properties of the polar-ZnO surface system with adsorbed manganese and cobalt were investigated using the ab initio projector-augmented-wave method. It is found that the Mn and Co adsorbed polar-ZnO surfaces show stable ferromagnetism. The O-terminated ZnO:Mn surface system is predicted to have a half-metallic property with a wide spin band gap and stable ferromagnetism of 4.98 B magnetic moment, which is a desirable property for application to spintronic devices.

We propose the simple codoping method for improving the productivity of silicon single-crystal growth by controlling axial specific resistivity distribution. Numerical simulations have been performed to study the transport phenomena of dopant impurities in conventional and proposed Bridgman silicon growth using the finite element method and implicit Euler time integration. It has been demonstrated using mathematical models and by numerical analysis that the axial specific resistivity distribution can be modified in horizontal Bridgman silicon growth and relatively uniform its profile is feasible by the proposed doping method.

This paper investigates the influence of structural parameters on the performance of an optical fiber wound mandrel hydrophone by using the finite element method (FEM). A hydrophone should exhibit the highest possible sensitivity, the widest possible flat frequency response, and an omni-directional sensitivity pattern within the frequency range. The parameters studied included the mandrel geometry, the thickness of the molding coated over the fiber, and the material properties of the constituent parts of the hydrophone. The analysis results showed that the pressure sensitivity of a hydrophone increases in relation to the length of the mandrel and the thickness of the molding. A higher pressure-sensitivity also requires a mandrel or molding material with a relatively low Young’s modulus and Poisson’s ratio. On the other hand, the flat frequency response of a hydrophone increases when either the mandrel length is shortened or the mandrel material is hardened. The omni-directional characteristic is also improved with a shorter mandrel. Therefore, a hydrophone with the best performance must balance the tradeoff between the geometrical and material parameters. The analysis discussion is focused on a representative specification of a frequency range of up to 5 kHz.

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This paper described finite element analysis (FEA) for fabrication processes of PZT perform using ceramic injection molding (CIM). The viscosity and the PVT characteristics of the manufactured PZT feedstock were measured. The filling patterns, pressure and temperature distributions of the preform were analyzed with TIMON 3D packages during CIM process. The geometrical variables such as gate type, location, and base thickness of the preform were considered. Also the fabrication conditions of the preform were optimized during the entire CIM process. Based on the simulated results, the various good perform was easily fabricated with the CIM process.