Chemical doping with foreign atoms is an effective method to intrinsically modify the properties of the host materials. In this paper, we report a facile strategy to prepare nitrogen and boron doped monolayer graphene by using urea and boric acid as solid precursors. By adjusting the elemental precursors, the nitrogen content could be modulated from 0.9 to 4.8% for nitrogen doped graphene and the boron content from 0.7 to 4.3% for boron doped graphene respectively, as estimated by X-ray photoelectron spectroscopy. The mobilities of the nitrogen and boron doped graphene-based back-gate field-effect transistors are about 350-550 cm 2 V À1 s À1 and 450-650 cm 2 V À1 s À1 respectively. Our results are better than plasma treated nitrogen and boron doped graphene. Therefore the synthesis of nitrogen and boron doped graphene sheets by a solid doping elemental precursor method is considered to be an efficient approach to producing graphene with excellent optical and electrical performances at relatively low cost.

Graphene was synthesized by chemical vapor deposition using polystyrene as the solid carbon source. The number of graphene layers could be controlled by regulating the weight of polystyrene under atmospheric pressure at 1000 °C. Silver nanoparticles were then deposited on the graphene by a citrate reduction method. The interaction between graphene and silver was investigated by suface-enhanced Raman scattering spectra and X-ray photoelectron spectroscopy. The change in the G band position indicates n-type doping of the graphene due to an interaction between the silver and the graphene. Silver interlayer doped four-layer graphene shows a sheet resistance of 63 Ω/sq and a light transmittance of 85.4% at 550 nm. The optical and electrical quality of graphene exceeds the minimum industry standard for indium tin oxide replacement materials. It is clearly understood that the environmental sheet resistance stability of the interlayer doped graphene film is better than that of surface doped graphene sheets. The presence of graphene at the surface also acts as a protective layer for the inner silver ions and clusters.

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The effects of alloy chemistry and thermal processing on corrosion performance of Zircaloy are shown to provide significant insights into the mechanisms governing nodular corrosion formation. Nucleation and growth behavior of nodular oxide in ex-reactor and in-reactor tests were studied phenomenologically, with the results suggesting that the behavior is similar in both environments. The sites of nodular oxide nucleation were found not to be at large precipitates or grain boundaries; rather, the sites were identified, though not unambiguously, to be free of precipitates. Zircaloy-2 and Zircaloy-4 show significant differences in response to heat treatment in the high alpha phase region; only Zircaloy-2 shows improvement in nodular corrosion resistance. Both alloys, however, become highly resistant to nodular corrosion after receiving heat treatment in the alpha-beta or beta phase fields at temperatures above 830°C. Both the high alpha annealing improvement of Zircaloy-2 and alpha-beta or beta annealing improvement of Zircaloy-2 and -4 are attributed to a redistribution of solute elements into the Zircaloy matrix. A nodular corrosion mechanism based on local solute depletion and its effects on the stoichiometric structure of the initial black oxide is proposed.