Abstract: Using a friction-abrasion testing machine with a constant speed, the friction and wear properties of sisal fibre reinforced resin composites containing different sisal fibre contents at a series of friction temperatures were investigated, and its tribology mechanisms were discussed. The results shown that the friction and wear properties of sisal fibre reinforced composites reach the optimum value when the mass ratio of resin to sisal fibre is 3/4. To compare with asbestos fibre, mineral fibre and steel fibre, the optimized sisal fibre reinforced composite has the best stability of friction coefficient with a low wear rate at different friction temperatures. The sisal is an ideal substitute of asbestos for resin matrix frictional composite.
Abstract: MnO2 nanostructure was synthesized via a redox reaction of potassium permanganate in hydrochloric acid solution below 100°C at open environment. The effects of pH value in solution and reaction temperature on the crystal structure and morphology of MnO2 were investigated. It was revealed that layer folded δ-MnO2 microspheres were obtained at low reaction temperature and low HCl concentration, whereas α-MnO2 single-crystal nanorods were fabricated with increasing reaction temperature and HCl concentration. The possible formation mechanism of δ-MnO2 microspheres and α-MnO2 nanorods is suggested.
Abstract: The development inevitable tendency of automatic & informational mine is the comprehensive integration of safe production condition, system automation and administration information. The introduction of OPC to the mine comprehensive monitoring system solve the problem of information sharing among various subsystems and offer the base for construction of mine comprehensive monitoring system. The automatic remote control system of underground drainage system illustrates the application of the technology.
Abstract: Nanofibrous scaffolds of PVA and HA were prepared by electrospinning. SEM showed the scaffolds had porous nanoﬁbrous morphology, and the diameter of the fibers was in the range of 200-1000 nm. FTIR and XRD showed the presence of HA in the scaffolds. The mechanical properties of the scaffolds changed by the adding content of HA. For the nanoscaffolds with 2wt % HA, the ultimate tensile strength and the elongation at break was 7.5 MPa and 17%. The PVA/HA nanoscaffolds prepared by electrospinning indicated good properties, and had a potential applications in bone tissue engineering and drug delivery systems.
Abstract: Graphene nanoplatelet（GN）/ Magnetite compound powders with magnetite nano-particles coated on the surface of graphite sheets has been successfully prepared by the wet-chemical co-precipitation. The effects of reaction temperature and mole ratio of Fe2+/Fe3+ on ultimate products were investigated. It has been found that excellent magnetite/GN compound powders were obtained at 30 °C with the Fe2+/Fe3+ mole ratio of 5:1. The composition, structure and the electric and magnetic properties of products were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, vibrating-sample magnetometer and four-point probe resistivity measurement.The compound powders have also exhibited the ferromagnetic properties at room temperature.
Abstract: Based on practical engineering this paper introduced cement stabilized cool regeneration technology and application test results. It expounds application of cement stabilized cool regeneration technology and points out the advantages of cold recycling technology; It can make full use of the dead mile of the original way, and saving a lot of building materials. It Avoid waste material to protect the ecological environment; It saved the resources, reduced cost and accord with the requirement for sustainable development; In highway maintenance field it has wide application prospects.
Abstract: In this paper, the effect of soaking temperature during continuous annealing on mechanical property of high-tensile cold rolled bake-hardening steel was studied by using hot-dip process simulator. The results show that it can finish re-crystallization process when the soaking temperature increased from 740°C to 850°C. As the temperature increased, the yield strength, tension strength and microhardness monotone decreased and the n value monotone increased by contrast. At the same time, the total elongation and r value of BH steel increased at the beginning and decreased later, they would all reached a peak value at about 820°C.
Abstract: The microstructure and tribological properties of space copper-based friction material fabricated by Powder Metallurgy technology were studied using optical metallographic microscope and MM-1000-type tribo-tester, respectively. The results are shown as follows: The lubricant MoS2 was resolved during sintering, resulting in the loss of S element. MoS2 and its resolvents reacted with other components into some new compounds which contribute to the tribological properties of friction material. The lubrication mechanism of these new compounds showed essential difference in comparison to that for MoS2; the friction coefficient was higher under atmospheric condition than that under vacuum conditions, but almost the same under low and high vacuum conditions. It decreased under both atmospheric and low vacuum conditions with the increase of load. The environmental temperature had insignificant effect on the friction coefficient; under atmospheric condition as load increased, the mass loss of material decreased linearly, then increased. With regard to low vacuum condition as load increased, the mass loss of material increased, then decreased; the stable coefficient of friction material under vacuum condition was higher than that under atmospheric condition.
Abstract: Kaolinite-formamide intercalation compound was prepared by solution intercalation method. The intercalation ratio(I.R.) was evaluated based on the ratio of II /(II+IK).The influence factors on intercalation efficiency such as the type and contents of solvent, the temperature of intercalation reaction and the particle size of kaolinite sample were studied. The results shown that the highest intercalation ratio was 96% under room temperature. The formamide solution with vol.9% of water, methanol or ethanol is propitious to intercalation. The kaolinite sample with particle size more than 1.5μm, high purity and good dispersion in solution, is adequate for preparation high I.R. intercalation compound.
Abstract: On the basis of the shear-lag theory, an analysis was presented for stress redistributions of cross-ply laminates with a transverse matrix crack in the 90º ply under bending by establishing a layered shear-lag model. The present results show that approximate solutions of displacement and stress distributions for cross-ply laminates with a transverse crack under bending can be obtained by using a shear-lag method. The present paper therefore affords a new approach for studying the stress redistributions and failure mechanism for cross-ply laminates with flaw under bending.