Advanced Materials Research Vols. 295-297

Abstract: Ag-doped porous SnO₂ nanopowders were synthesized via a facile glucan-assisted template method combined with subsequent calcinations. Morphology, crystal structure, and H₂S gas sensing properties of pure and Ag-doped porous SnO₂ nanopowders were investigated. In comparison with undoped SnO₂ nanopowders, the Ag-doped porous SnO₂ nanopowders demonstrated enhanced H₂S sensing behavior with high sensitivity, short response and recovery time, relatively low response concentration of 50 ppm, and good selectivity. The dramatic improvement in H₂S gas sensing characteristics was explained in terms of rapid gas diffusion onto the entire sensing surface due to the less-agglomerated and porous structure of SnO₂ nanopowders and the catalytic effect of doped-Ag element. The main objective of this research is to develop a new method to introduce catalysts on gas-sensing materials with less-agglomerated and porous structure.

Abstract: The SnO₂ nanomaterial for highly reversible lithium storage was successfully synthesized via a simple solvothermal route at a low temperature. According to the XRD and TEM analysis, the nanostructure and the morphology of the obtained samples were constructed by ultrathin SnO₂ nanorods with diameter of about 10 nm and length of 30 nm. When used as anode materials for lithium ion batteries, the prepared SnO₂ nanomaterial exhibited a relatively high reversible capacity of 950.9 mAh·g^-1 and excellent cycling stability. The enhanced electrochemical performance of the SnO₂ nanomaterial could be attributed to the unique nanostructure, which could accommodate the large volume change during cycling and provide an excellent electronic conduction pathway.

Abstract: For plastic air intake manifold, the warpage is difficult to solve. By simulating injection process with Moldflow, researched warpage, air traps, weld lines of intake manifold. Analytic result showed four gates are better to Xiali 4GB plastic air intake manifold, and obtained the best gate’s location. Summarized some important experience on designing injection mould of plastic air intake manifold. Made out very instructive work to succeed to design injection mould of plastic air intake manifold.

Abstract: The non-combustibility of PTFE fabric0s was investigated by Cone Calorimeter in this paper. Ignition parameter, heat release parameter, mass loss parameter and smoke parameter of PTFE fabrics were obtained. The Time to Ignition of PTFE fabric and PTFE/Nomex fabric were 60 and 24s respectively, and the Heat Release Rate were 9.28 and 65.52kw/m² respectively. The Total Heat Release of PTFE fabric and PTFE/Nomex fabric increased with time, and the Total Heat Release of PTFE/Nomex was much higher than that of PTFE fabric. The Effective Heat of Combustion were 5.06 and 9.94mj/kg respectively, the maximum of mass loss rate of PTFE fabric was larger than that of PTFE/Nomex fabric, and the curve of mass loss rate of PTFE fabric changed rather slightly. It can be concluded that the non-flame properties of PTFE fabric was more remarkable than that of PTFE/Nomex fabric.

Abstract: Through scientific experiments, we studied the binder, diamond, solder, uniform distribution and heating curves in brazing. We selected DH temporary binder, compared two kinds of diamond, selected the diamond with fine thermal stability. The experiments adopted diamond with uniform templates, experimenting 13 kinds of solder of which 9 were mixed with diamond for comparison of brazing effects and thermal damage. We optimized solder and brazing process and comprehensive analyzed experimental results. The analysis showed a small amount of DH temporary binder residue in brazing, fine effect in case of low alloy solder brazing temperature, better adhesion of solder and diamond achieved by elements formed by Cr and other strong carbides, sufficient volatilization of temporary binder and other impurities achieved by insulation before 500°C, heating rate of 1°C/min when the temperature it is higher than 20°C-50°C, the solder melting point, and that cooling should be carried out under high vacuum, brazing diamond should have fine thermal stability.

Abstract: The characteristics and functions of blast furnace grouting material were briefly introduced in this paper. The affects of matrix aggregate formulation, binder types and binder addition to the grouting material were discussed. Based on series of tests and experiments, the optimized matrix aggregate formulation, binder type and binder addition were confirmed. A new grouting material with excellent characteristic parameters was developed.

Abstract: The objective of this investigation is to study the rapid forming based on robot GMAW forming. The work may be divided into two sections. First study the modeling of weld bead profile. Self adaptive layered algorithm of variable direction is employed, which changes the forming direction on the basis of parts geometric character. In addition, the microstructure and performance characteristics of the formed parts are investigated. Its metallographic microstructure along the deposition direction shows obviously layered characteristic. The micro hardness values closely relate to the microstructure characteristics. The fracture mechanism of the part belongs to quasi-cleavage crack.

Abstract: VO₂(A) nanobelts have been synthesized using V₂O₅, H₂O₂, ethanol, H₂O as the starting materials through a facile hydrothermal method. The as-obtained products were characterized by X-ray powder diffraction (XRD), X-ray photoelecton spectroscopy (XPS), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). Some parameters, such as, the reaction time, reaction temperature and the ratio of EtOH/H₂O, have greatly influenced on the phases and morphologies of the final products. It was found that VO₂(A) can be converted to VO₂(M) at 700 °C for 2 h for the first time. Furthermore, the phase transition properties of VO₂(A) and VO₂(M) phases were respectively studied.

Abstract: A novel rhenium complex material, i.e., Re-APPP, (APPP, 2,3-acenaphtho[1,2-b]pyrazino [2,3-f][1,10]phenanthroline) was designed, synthesized in five steps from commercially available starting materials and characterized by FTIR, ¹H NMR and mass spectroscopy. The photophysical properties of this complex were studied. The absorption bands centered at ca. 326, 366 and 450nm of Re-APPP were attributed to the ligand-centered p→p* transition and the metal-to-ligand charge transfer dπ(Re)→π*(APPP) transition, respectively. Re-APPP was thermally stable with high decomposition temperature of 302°C. The organic light-emitting diodes using Re-APPP as a dopant emitter with the structures of ITO/m-MTDATA(10nm)/NPB(20nm)/CBP: Re-APPP(30nm)/BCP(10nm)/Alq₃(30nm)/LiF(1nm)/Al(100nm) were fabricated and a broad electroluminescent peak at 550nm was observed. More importantly, the devices exhibited very small efficiency roll-off of only ca.45% which was probably attributed to its short luminescent lifetime.

Abstract: As one of the geological disasters, rockburst is often generated in underground engineering under excavation unloading conditions in high geostress areas. Taking advantage of the simulation test especially for the rock mass under high hydrostatic stress, the dynamic failure rockburst style resulted from instantaneous unloading in one direction was studied, whose peak velocity and acting time are analyzed. The results indicate that the formula for calculating peak velocity and the kinetic energy is proper and the kinetic energy is little portion of the recovery strain energy, most of which is dissipation in different ways; the unloading time at different positions apart from the free surface is nearly the same and more larger than the unloading wave’s disturbance time.