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The role of sulphuric acid (H2SO4) in fabrication graphene oxide besides as intercalant has not been well addressed. In this work, Raman spectroscopy is used to monitor structural evolution in chemical vapor deposition (CVD) graphene chemically oxidized by dilute H2SO4. From the analysis of Raman spectra of oxidized graphene, we propose that oxidation first initiates at preexisting defects, and vacancy-like defects are formed. Following is the radial growth of the vacancy, and oxidation pits appear in graphene. This assumption is further confirmed by atomic force microscope measurement. It is also found that with increase of amounts of defects, G peak is blue shift, and this is explained by defect and hole doping effect. Hole doping in graphene is much stronger at hexagon regions near the oxidation pits. This work helps in understanding the role of H2SO4 in fabrication graphene oxide as oxidizer as well as helps in obtaining structure information of graphene oxide. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The 88-storey Jin Mao Building located in Shanghai has a height of 420.5 m and is the highest building in mainland China. Dynamic wind force components on the super-tall building were measured by high-frequency force balance technique in a boundary layer wind tunnel for the cases of an isolated Jin Mao Building and the existing surrounding condition under suburban and urban boundary layer flow configurations. Spectral characteristics of along-wind and across-wind components and, in particular, the cross-correlation and coherence among various wind loading components are presented and discussed in detail. Furthermore, the effects of upstream terrain conditions and surrounding buildings on the spectra, cross-correlation and coherence are investigated. The experimental results show that such effects are significant. Finally, an empirical formula for estimation of the across-wind overturning moment spectrum for the super-tall building is presented. Comparisons of the spectra determined by the proposed formula and those obtained from wind tunnel tests are made to examine the applicability of the proposed formula. [ABSTRACT FROM AUTHOR]