Advanced Materials Research Vols. 399-401

Abstract: The phase equilibria in Al-rich corner of the Al-Zn-Ti ternary system at 400 °C were determined by means of optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS) and X-ray powder diffraction (XRD). The results showed that this section consisted of three ternary-phase regions, namely, L+(Al)+τ, Ti₂Al₅+τ+(Al) and Ti₂Al₅+TiAl₃+(Al). The XRD patterns and EDS confirmed that a Ti₂Al₅-structured phase with containing 4 at.% Zn was stable at 400 °C. Furthermore, the ternary new phase (τ phase) was identified in samples and in equilibrium with (Al), Ti₂Al₅ and liquid, respectively.

Abstract: The electronic properties of Al-, P-doped, and Al, P co-doped in a (6, 6) BN nanotubes were obtained using the first principle calculation based on the density functional theory. For the doped BNNTs, the structures are with ignorable deformation observed around the doping atoms. The analysis of the formation energies shows that aluminum replacement to be favorable, particularly in the case of the low concentration, and the stability of nanotubes has nothing to do with the doping position. The electronic band structure and DOS for the systems of Al-, and P-doped BNNTs all behave as impurity-doped widegap semiconductor. And as to the P-doped BNNTs, the conductivity becomes stronger with the higher concentration. Whereas, the results of the system of Al, P co-doped BNNTs illustrate that the electronic properties of nanotubes have nothing to do with the doping positions of impurity atoms.

Abstract: A mathematical models for the coupled problem is established by considering heat and mass transfer and phase change for rock mass at low temperature, according to the theory of heat and mass transfer for porous media. It is considered of the influences of fluid transfer on the heat conduction and the temperature gradient on the seepage. By adopting the finite element method, the numerical simulation is done to study the range of frost-thaw of surrounding rock and the effects of insulation material in cold regions, which analysis the influence of tunnel depth and surrounding rock class on the range of frost-thaw, the change law of the frost-thaw area of different insulation material and the relationship between the frost-thaw area and the thickness of insulation material.

Abstract: After nearly fifty years of development, HAZOP (Hazard and Operability study /analysis) has become the most widely used process hazard identifications method, basically covering all areas of petrochemical industry. As technology advancing and people continuing to increase safety requirements, HAZOP quantitative analysis has become a major trend. This paper gives an integration of traditional HAZOP procedure with Dynamic Simulation to quantify the HAZOP deviations and improve the operability of action required. A natural gas gathering process is selected to the application example. Uses the advanced process simulation software ASPEN HYSYS to set the modeling of the gas gathering process, and carry out the dynamic modeling in the light of main problems, and combing the dynamic simulation analysis gets the quantitative analysis results.

Abstract: In the present work, a new method for the analysis of the substituent group content in silicones by automatic elemental analyzer has been developed. Because of the number of substituent group effect on the physical and chemical properties about polysiloxane very much, its analysis by traditional techniques is tedious and costly. The novelty of this study relies on the fast and universal application of the automatic elemental analyzer to the quantitative analysis of the substituent groups. With this purpose, analysis of the quality percentage content of C and H in four different kinds of difunctional polysiloxane in automatic elemental analyzer, then compute the formula weight of a basic structure unit to deduce the content of the substituent group. The result was validated by 1H NMR.

Abstract: Abstract: The fatigue behavior of cast steel ZG20SiMn under strain control mode was investigated, and the influence of imposed total strain amplitude on the cyclic deformation and fracture behavior of the cast steel ZG20SiMn was determined. The experimental results reveal that during fatigue deformation, the cast steel ZG20SiMn may exhibit the cyclic strain hardening and stable cyclic stress response behavior, which mainly depends on the imposed total strain amplitude. The relationship between plastic and elastic strain amplitudes with reversals to failure shows a single linear behavior, and can be well described by the Coffin-Manson and Basquin equations, respectively. At different total strain amplitudes, the fatigue cracks initiate at the free surface of fatigue specimens and propagate for the cast steel ZG20SiMn.

Abstract: In this paper, the standard entropy, heat capacity at constant pressure, standard enthalpy and standard Gibbs free energy of formation are estimated by application of two-parameter model. The model is relatively simple, accurate and practical. Based on the thermodynamic data for related pure compositions are reported, the five possible chemical reactions in the Cu₂O-In₂O₃ system are studied in the process of preparation CuInO₂ by solid reaction method. The relations between equilibrium constant and temperature is plotted. The curves of -T and lgK-1/T for the chemical reactions in the system have also been fitted. The results show that the Cu₂O is easy to be oxidized into CuO, which reacts with In₂O₃ to yield Cu₂In₂O₅ at lower temperature. However, the CuInO₂, which is prepared from the Cu₂O-In₂O₃ system, is oxidized into Cu₂In₂O₅ easily in the oxygen atmosphere. The reaction of preparing CIO was reversible and incomplete. Therefore, preparation CIO is very difficult by solid reaction method whether in atmospheric pressure or isolated air and gas shield conditions, because K1 >-40kJ/mol.

Abstract: Specific capacity and thermal conductivity are two very important physical quantities that characterize the heat performance of heat storage material. This paper measured the specific capacities and thermal conductivities of binary systems formed by NPG、TRIS and PE in the temperature range from 30oC to 70 oC and analyzed the experimental results from the point of view of crystal vibration. Hydrogen bonds exert great influence on the thermophysical properties of the binary systems. Although the components are only simply blended, substitutional impurity defects are incurred. As a result hydrogen bond will be affected in a complex way. There is no uniform trend between the value of x and specific capacity. Because of the influence of structure defect, specific capacity and phonon speed which all change with the strength of hydrogen bond, the relationship between thermal conductivity and the value of x is non-linear too. Because 40oC is near the phase transition temperature of NPGxTRIS1-x (x=0.618), its specific capacity at 40oC decreases and thermal conductivity increases. Because hydrogen bond changes with temperature, specific capacity of PExTRIS1-x (x=0.618) rises. Since 60oC is near the phase transition temperature, its specific capacity at 60oC falls. PExTRIS1-x (x=0.618) shows smaller thermal conductivities at temperatures higher than 30oC. This is because the hydrogen bonds become weaker with temperature. Blending impurities possessing longer mean free path with polyalcohol can change the thermal conductivity.

Abstract: Cracks of different severities will appear on the beams, precast panels and building blocks and those found in current residential dwellings belong to the cracks due to temperature- shrinks and will not impact the structural safety mainly, nevertheless, they affect the appearance and decorative qualities, even cause leaking. Measures shall be done to treat them economically and practically.

Abstract: The microstructure and tensile properties of cobalt-base elastic alloy Co40NiCrMo are investigated. The results show that, fcc structure is the crystal structure of Co40NiCrMo alloy after solution treatment and hard-draw. The slipping and twinning are the modes of plastic deformation during the hard-draw. Twinning is the main deformation mode of Co40NiCrMo alloy after hard-draw when more deformation is made.