ABSTRACT:In an attempt to enhance the mechanical properties of epoxy/graphene-based composites, the interface was engineered through the functionalization of graphene oxide (GO) sheets with p-phenylenediamine; this resulted in p-phenylenediamine functionalized graphene oxide (GO-pPDA). The morphology and chemical structure of the GO-pPDA sheets were studied by spectroscopic methods, thermal analysis, X-ray diffraction, and transmission electron microscopy. The characterization results show the successful covalent functionalization of GO sheets through the formation of amide bonds. In addition, p-phenylenediamine were polymerized on graphene sheets to form crystalline nanospheres; this resulted in a GO/poly(p-phenylenediamine) hybrid. The mechanical properties of the epoxy/ GO-pPDA composite were assessed. Although the Young's modulus showed improvement, more significant improvements were observed in the strength, fracture strain, and plane-strain fracture toughness. These improvements were attributed to the unique microstructure and strong interface between GO-pPDA and the epoxy matrix.

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>> In order to achieve simultaneously the ultra-low NOx, the high power and the high efficiency in a hydrogen-fueled engine with SI and the external mixture, the effects of low temperature combustion, performance and exhaust are compared and analyzed by the application of the lean boosting. As the results, the decrease rate of the high temperature in the hydrogen is less decreased than the other fuels by high constant-volume specific heat. However, when the conditions of 1.7bar and Φ=0.33 are reached by the lean boosting, the maximum gas temperature of hydrogen is decreased under the temperature of NOx formation and it is possible to stabilize combustion below 2% of COVimep. Also, at that condition, it is feasible to achieve simultaneously NOx-free and the power of gasoline level. Therefore, it is found that the lean boosting is useful in the hydrogen-fueled engine.