Applied Mechanics and Materials Vols. 130-134

Abstract: Theoretical studies of ZnSe epitaxy growth on GaA (001) surface were performed with first principle calculation, the bonding energy of absorbing monolayer atoms, charge and binding properties of the interface atoms were investigated to account for the growth of ZnSe films on different GaAs (001) surface. And it’s concluded that As-terminated stable AsGa (001) substrate placed in Zn atmosphere, with absorption of Zn atoms on AsGa (001) substrate, which can be a counterweight to form a neutral GaAs/ZnSe interface, may be helpful in reducing the defects of the ZnSe epitaxy growth on GaAs (001) substrate.

Abstract: This paper presents in detail optical fiber fault locator's operation principle, fabrication technology and application. A prototype apparatus has been fabricated, which reaches commercial standard, resolves the problem of traditional OTDR price expensive and the operation complicated . All component s including optical devices, electronic devices and data measurement are demonstrated. Furthermore, through measuring the fiber sample, the function and measurement efficiency of this apparatus is analyzed.

Abstract: In this work, numerical simulations have been conducted to investigate the particle mixing feature in a stirred vessel driven by an impeller. The Eulerian multi-fluid model has been employed along with the standard k–ε turbulence model to simulate the gas-liquid-solid three-phase flow in the stirred vessel. The effects of impeller speed and immersion depth of impeller on the particle distribution are discussed. The results show that the particle volume fractions nearby the vessel bottom are large on the vicinity of the side walls of the vessel and small in the vessel middle region at different impeller speeds and immersion depths.

Abstract: Based on the non-Fourier law and thermo-elastic theory, the non-Fourier expressions of the temperature field and the thermal stress field of metal material under multi-pulse laser irradiation were deduced. Taken stainless metal and two pulse width (ω=4ps,4fs) as an example, The effects that distributions and variations of transient temperature and thermal stress are influenced by laser pulse width are studied. The results show that the magnitude and frequency of transient temperature and thermal stress are seriously affected by the laser pulse width. More narrower the laser pulse width, faster and higher the local temperature rise; as well as the thermal stresses.

Abstract: The basic optical and electro-optical effects observed in polymer-liquid crystal composites are described. Special attention is paid to the methods of optimizing polymer-liquid crystal composites optical and electro-optical properties. Finally, the applications of polymer-liquid crystal composites optical properties are given.

Abstract: In this paper, the effects of Ta₂O₅ addition on the electrical and physical properties of 0.98(Na_0.5K_0.5)NbO₃-0.02(Na_0.5Bi_0.5)TiO₃ were investigated. The 0.98(Na_0.5K_0.5)NbO₃ -0.02(Na_0.5Bi_0.5)TiO₃ [0.98NKN-0.02NBT] ceramics with the addition of 0~0.5 wt% Ta₂O₅ have been prepared following the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all of the (Na_0.5Bi_0.5)TiO₃ diffuse into the lattice of (Na_0.5K_0.5)NbO₃ to form a solid solution, in which a orthorhombic phase with a perovskite structure was found. For 0.98NKN-0.02NBT ceramics by doping 0.1 wt% Ta₂O₅, the poled dielectric constant (K₃₃^T) is 1090. The electromechanical coupling coefficients of the planar mode k_p and the thickness mode k_t reach 0.39 and 0.48, respectively. Our results show that 0.98NKN-0.02NBT with the addition of 0.1 wt% Ta₂O₅ is a good lead-free piezoelectric ceramic.

Abstract: The structure reliability of the diamond saw blade in milling process is studied. With probability design features of ANSYS, take the flange diameter ,thickness, diameter of the diamond saw blade and load suffered in the milling process as input variables, and take the maximum equivalent stress of dangerous parts of the diamond saw blades stress as output variable. The diamond saw blade structure reliability is analysed using Monte Carlo method and the maximum equivalent stress value cumulative distribution and dangerous parts of various parameters on the distribution of the maximum equivalent stress sensitivity under the impact of the load are got. The result provides a theoretical basis for improving the parameters of diamond saw blade and has the significant practical and theoretical value for the stone processing theory and diamond saw blade study.

Abstract: The commercial greases for bearing applications should meet the requirements of the severe conditions of use (high load, low friction and low noise etc.). A kind of overbased calcium sulfonate complex greases was evaluated using an UMT-II friction tester, the commercial lithium greases as reference. The morphologies of the worn surfaces were observed using a scanning electron microscope (SEM). The results show that the overbased calcium sulfonate complex greases have stable friction coefficients as low as 0.090-0.094. At the same time, the overbased calcium sulfonate complex greases exhibited higher wear resistance than that of commercial lithium greases.

Abstract: The Cu2ZnSnSe4 (CZTSe) thin films were prepared by co-electroplating Cu-Zn-Sn precursors followed by selenization at different substrate temperatures. The effect of substrate temperatures on the morphologies and structures of CZTSe films were characterized using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Raman scattering spectrum respectively. The results revealed that the impurity phases in CZTSe thin films such as CuSe and SnSe disappeared when the substrate temperatures were increased. The surface morphologies of CZTSe thin films were also strongly dependent on the substrate temperature treatment in the selenization process though the selenium temperature was kept at 340°C.

Abstract: Hydroxyapatite (HA) is a calcium phosphate ceramics and HA coating is essential for the medical metallic implants. This paper presents a computational model of HA particle impact behavior in cold spraying. The impact pressure at the predefined contact surface between the HA particle and the Ti substrate is investigated numerically using ABAQUS/Explicit. The effects of particle size, particle velocity and substrate temperature on the impact pressure are examined. A Taguchi’s orthogonal array is employed to arrange the simulation conditions and the simulation results are analyzed to reveal the main factors influencing the impact pressure, which provides a better understanding of the bonding mechanism during cold spraying.