Advanced Materials Research Vols. 295-297

Abstract: In this paper, the impact deformation behavior of the as-rolled and annealed Mg-3%Li-1%Nd alloy was investigated by using the Hopkinson compressive bar. The effects of rolling and annealing on the high speed impact deformation behavior were analyzed. The relationship between microstructure evolution and impact fracture mechanism was discussed.

Abstract: The paper overviewed the recovery methods of germanium, summarized the feature of those methods such as leaching with sulphuric acid, chlorination leaching- distillation, alkali decomposion, leaching with hydrofluoric acid, extracting, reduction and leaching germanium with microorganism. And introduced the principles ,technologies and disadvantages of those methods. Finally, prospected that microwave pretreatment technology and microwave directly leaching can be used in traditional methods such as acid leaching and alkali decomposion to improve the recovery rate of germanium by change insoluable germanium into soluble germanium and upgrade the leaching rate of germanium.

Abstract: Fault feature extraction using wavelet decomposition and probabilistic neural network fault diagnosis technology is presented in this paper. Fault diagnosis based on wavelet transformation and neural network data fusion is studied. The fault diagnosis in rotating machinery vibration of the aero-engine is simulated in Matlab. Our recent investigations demonstrate that using wavelet decomposition extract fault characteristics of the energy vector has strong generalization ability and anti-noise ability. Integration of the wavelet and neural network application can provide a better classification of diagnosis results, reliability and accuracy. This technique is suitable for the mechanical vibration fault diagnosis applications of steam turbine and gas turbine.

Abstract: To provide essential data for an efficient utilization of vitrified bottom ash slag, the thermodynamic properties of the CaO-Al₂O₃-SiO₂-FeO_x-MgO-Na₂O oxide system is highly required. As one of the related oxide subsystems, the equilibrium phase relations and liquidus of CaO-SiO₂-FeO_x-Al₂O₃ system is of great significance to interpret and predict the thermodynamic properties in multi-component oxide systems. In this paper, phase diagrams for the CaO-Al₂O₃-FeO_x and SiO₂-Al₂O₃-FeO_x systems were calculated by using CALPHAD method with FactSage program. The liquid phase area changed with changing oxygen partial pressure from 1Pa to 10^-3Pa and temperature from 1673K to 1773K. The equilibrium phase relations of CaO-Al₂O₃-FeO_x and SiO₂-Al₂O₃-FeO_x systems were discussed.

Abstract: The Cockcroft-Latham (CL) damage factor has been calculated, using FEM simulation, during equal channel angular extrusion (ECAE) of strain hardening materials. A high CL damage factor was predicted inside the billet and the damage was increased with the increasing strain hardening coefficient. This was closely related to a generation of increasingly high tensile stress in the deformation zone inside the billet due to an inhomogeneous deformation. The possibility of cracking inside the ECAE billets was confirmed in the ECAE processing of Ti-0.34O-0.95Fe and Ti-0.5Fe billets. The simulation further predicted that CL damage factor can be reduced by applying back pressure or friction force.

Abstract: The composition change of slag and alloy phases were investigated during the process of selective reduction by thermodynamic calculating the selective reduction of the slag components with different modified slag composition, addition of reducing agent and reduction temperature. The results showed that the process of the selective reduction will be promoted by raising the temperature and the ratio of modifier to slag. The solubility of SiO₂ increased as temperature increased. Selecting the appropriate amount of modifier will promote the selective reduction. In the first stage, Fe was reduced from the slag, followed by the reduction of P, Mn and Si. Finally, Fe-Si-Mn metal was obtained as a result of the selective reduction.

Abstract: A novel method, aiming at solving the problem that the ultra-high-speed electric spindle tends to vibrate as its stiffness is small, using the repulsion of permanent magnets based on the theory that repulsion increased while the two magnets come close, is provided in this paper to design a electric spindle within additional support bearing system consist of two radial permanent magnet rings against each other. This paper also analyses the dynamic performance of radial permanent magnet bearings additional supporting system for ultra-high speed electric rotor system, result shows that the radial permanent magnetic bearings additional supporting system designed for improving the critical speed of the rotor system, reducing the rotor radial dynamic response, can effectively improve the dynamic performance and operational stability of ultra-high speed electric spindle rotor system.

Abstract: Presence problem of exhaust muffler is anal sized, using three three-dimension numerical calculation of fluid and sound field improvement on original structure is performed, and improving results are certificated. It is shown that insert loss under every rotational speed all reach to the standard of 28dB（A）, and the noises of stationary end tube on the attention frequency band are all smaller than 5 dB（A） , and its pressure loss is decreased by about 32% than 7.6kPa of original structure muffler. So performance of the muffler is evidence increased, an important method is provided for decreasing whole vehicle noise, improving aerodynamic quality and reducing environmental pollution.

Abstract: Bridge is an important part of transport system, especially for the long-span bridges of important route. And it belongs to the lifeline project. It is an important measure for reducing the secondary disaster to ensure bridge’s normality in traffic after the earthquake. Currently, the isolation seismic design of long-span bridges with the special structure is used to reduce damage of bridges by the reason of the earthquake. Based on damping principle of the viscous dampers, the calculation and analysis of what the effect of shock absorption done by damper in decorate position of long-span cable-stayed bridge to structure of bridges are formulated in this paper.

Abstract: This paper deeply studied the limitation of evaluating the thermal shock resistance of Al₂O₃-SiO2 refractory by measuring Strength Loss Rate (SLR). By means of supersonic, X-ray diffraction (XRD), the results were drawn as followed.1)After the thermal shock experiment for mullite based A-S refractory, which were composed by mullite and corundum, the supersonic velocity slowed down as it going through the sample while the cold crushing strength abnormally increased at initial state.2) The strength increased remarkably with the ascending of mullite fraction.3)It is inadequate to evaluate the thermal shock resistance of mullite based A-S refractory by strength loss rate.