The structural and electronic properties of diamond and graphite were investigated by the first-principles total-energy pseudopotential method based on density functional theory. The band structure, DOS and PDOS were calculated. Results showed that diamond had a wide band gap, and its direct transition energy is 6.0 eV. But graphite’s band gap is about zero, meaning without transition energy. That explains the reasons of diamond acting as an insulator but graphite acting as a conductor. DOS and PDOS analysis results indicate both diamond and graphite are sp hybridization and p states contribute mostly to the bonding of crystal. While their covalent bonds style are different.

In the paper, the characteristic of intergranular corrosion on austenitic stainless steel is presented. The principles and the influencing factors of intergranular corrosion are analyzed in detail. Furthermore, the effective measures to prevent intergranular corrosion are proposed. Finally, the evaluation methods of sensitivity to intergranular corrosion are introduced.

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Ethylene methacrylate (EMA) copolymer toughened acrylonitrile-butadiene-styrene (ABS)/polymethyl methacrylate (PMMA) were prepared in a co-rotating twin-screw extruder. The effect of EMA on mechanical properties and surface gloss of ABS/PMMA blends was investigated. Experiment results show that the toughness of ABS/PMMA is improved effectively with the incorporation of EMA, while the tensile strength and glossiness decrease slightly. ABS/PMMA/EMA blends present optimum mechanical and luster properties when the content of EMA is 6wt%.