共查询到19条相似文献,搜索用时 93 毫秒
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用1064nm激发的近红外傅里叶变换表面增强拉曼散射技术研究腺嘌呤系列胡凤霞方炎(首都师范大学综合技术研究所,北京100037)FourierTransformSurface-EnhancedRamanSpectroscopyofSeriesofAd... 相似文献
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SERS活性体系中光吸收带电磁和化学增强机制归属的认证研究方炎王四海(首都师范大学综合技术研究所,北京100037)AssignmentofEMandCTEnhancementsonOpticalAbsorptionSpectraofColoidal... 相似文献
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用同步辐射原位高压能散X射线衍射技术,对碳纳米管进行了结构和物性的研究,压力达50.7 GPa。在室温常压下,碳纳米管的结构和石墨的hcp结构相似,其(002)衍射线的面间距为d002=0.340 4 nm,(100)衍射线的面间距为d100=0.211 6 nm。从高压X射线衍射实验看到,当压力升到8 GPa以上时,(002)线变宽变弱,碳纳米管部分非晶化。而当压力从10 GPa或20 GPa卸压至零时,(002)线部分恢复。但当压力升高至最高压力50.7 GPa时,碳纳米管完全非晶化,而且这个非晶化相变是不可逆的。用Birch-Murnaghan方程拟合实验数据,得到体弹模量为K0=(54.3±3.2)GPa(当K′0=4.0时)。 相似文献
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C. Krull S. Valencia J. I. Pascual W. Theis 《Applied Physics A: Materials Science & Processing》2009,95(1):297-301
Here, we report on the assembly of thymine molecules into extended straight chains of single and multiple dimer rows on a
Si(111)/Ag
R30° surface. Using variable temperature scanning tunneling microscopy, we follow the nucleation process and formation of
self-assembled structures. Submonolayer coverages at 120 K are disordered and exhibit a high density of thymine dimers. Upon
annealing the dimers assemble into extended dimer chains along three equivalent high-symmetry surface directions. At low coverages
single dimer rows are favored. At increased coverage chains with multiple dimer rows are observed, with a preference to an
even multiplicity. We show that a complex cross-talk between H-bond thymine–thymine interactions and commensurization of dimer
chains to the Ag/Si surface leads to this specific layout. 相似文献
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基于复合纳米结构的局域表面等离子体光学传感器 总被引:1,自引:0,他引:1
局域表面等离子体光学传感器由于其体积小、灵敏度高、免标记等特点成为目前传感器研究热点之一。然而由于银纳米结构的生物兼容性以及氧化问题,成为该传感器发展的瓶颈。提出了利用金/银混合的金属纳米结构克服上述困难,并从有限时域差分数值计算方法入手,设计了银层50nm,金层5nm的六边形分布三角形复合传感结构,并利用纳米球自组装技术实现了该类型传感器。同时,与生物分子蛋白A的结合实验结果表明,该传感器在生物分子溶液浓度213.85nM的条件下仍然具有较高的灵敏度。 相似文献
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Density functional theory calculations are performed to investigate the C diffusion through the surface and subsurface of Ag/Ni(1 0 0) and reconstructed Ag/Ni(1 0 0). The calculated geometric parameters indicate the center of doped Ag is located above the Ni(1 0 0) surface owing to the size mismatch. The C binding on the alloy surface is substantially weakened, arising from the less attractive interaction between C and Ag atoms, while in the subsurface, the C adsorption is promoted as the Ag coverage is increased. The effect of substitutional Ag on the adsorption property of Ni(1 0 0) is rather short-range, which agrees well with the analysis of the projected density of states. Seven pathways are constructed to explore the C diffusion behavior on the bimetallic surface. Along the most kinetically favorable pathway, a C atom hops between two fourfold hollow sites via an adjacent octahedral site in the subsurface of reconstructed Ag/Ni(1 0 0). The “clock” reconstruction which tends to improve the surface mobility, is more favorable on the alloy surface because the c(2 × 2) symmetry is inherently broken by the Ag impurity. As a consequence, the local lattice strain induced by the C transport is effectively relieved by the Ag-enhanced surface mobility and the C diffusion barrier is lowered from 1.16 to 0.76 eV. 相似文献