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The Raman spectra of several locally stable structures of the graphene oxide (GO) have been simulated by ab initio calculations. Compared to graphite, the G band of GO is broadened and blueshifted due to the emergence of a series of new Raman peaks. The Raman intensities and positions of the D and G bands depend sensitively on the local atomic configurations. In addition to the normal epoxy and hydroxyl groups, other oxidation groups such as epoxy pairs are also studied. Epoxy pairs induce large blueshift of G band with respect to that of the graphite. 相似文献
43.
Xu X Huang J Li J Yan J Qin J Li Z 《Chemical communications (Cambridge, England)》2011,47(45):12385-12387
Graphene oxide (GO) was found to effectively enhance the selectivity of aggregation-induced emission (AIE) biosensors, and a new method based on GO and AIE molecules was proposed to detect bovine serum albumin (BSA) with high sensitivity and selectivity. 相似文献
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本主考虑在边界脉冲源激发下,二维波动方程的势函数反演问题.利用并间测量数据及地表测量数据重建势函数q(x,z),利用反演问题的算子方程形式,通过Frechet导数及对时间卷积的方法,得到了重建q(x,z)的迭代方法. 相似文献
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Zhou Z Zhao J Chen Z Gao X Yan T Wen B Schleyer Pv 《The journal of physical chemistry. B》2006,110(27):13363-13369
The physisorption and chemisorption of hydrogen in BN nanotubes, investigated by density functional theory (DFT), were compared with carbon nanotubes. The physisorption of H2 on BN nanotubes is less favorable energetically than on carbon nanotubes; BN nanotubes cannot adsorb hydrogen molecules effectively in this manner. Chemisorption of H2 molecules on pristine BN nanotubes is endothermic. Consequently, perfect BN nanotubes are not good candidates for hydrogen storage by either mechanism. Other strategies must be utilized if BN nanotubes are to be employed as hydrogen storage media such as utilizing them as supporting media for hydrogen-absorbing metal nanoclusters. 相似文献
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In this paper, we deal with the acoustic inverse scattering problem for reconstructing cracks of possibly different types from the far‐field map. The scattering problem models the diffraction of waves by thin two‐sided cylindrical screens. The cracks are characterized by their shapes, the type of boundary conditions and the boundary coefficients (surface impedance). We give explicit formulas of the indicator function of the probe method, which can be used to reconstruct the shape of the cracks, distinguish their types of boundary conditions, the two faces of each of them and reconstruct the possible material coefficients on them by using the far‐field map. To test the validity of these formulas, we present some numerical implementations for a single crack, which show the efficiency of the proposed method for suitably distributed surface impedances. The difficulties for numerically recovering the properties of the crack in the concave side as well as near the tips are presented and some explanations are given. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
49.
基于资源环境基础数据库,构建土地生态敏感性评价指标体系,进行中国土地资源生态敏感性评价,揭示土地生态敏感性的空间分布特点,进而对不同土地资源和不同农业区土地资源的生态敏感性进行差异分析,得到如下结果.1)中国土地资源生态敏感性空间差异显著,高度生态敏感区集中在4个区域:北方干旱/半干旱沙漠(地)的土地沙化敏感区、黄土高... 相似文献
50.
癫痫患者发病期间脑电图表现为高幅同步节律波,可显著地在患者脑电图中观测到棘、尖波以及棘慢复合波等特征波形。本文根据癫痫波形特征,利用小波变换的时频局部化特性,提出了另一种高效的脑电图癫痫波形自动检测方法。 相似文献