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利用扫描隧道显微镜研究石墨表面的大尺度周期性图样.研究结果表明,莫尔图起源于石墨深层的缺陷,实验结果与理论完全吻合,并且第一次在实验上证明了纳米波可以穿透多层石墨而没有明显衰减. 相似文献
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The coverage and temperature-dependent nucleation behaviors of the Gd@C82 metallofullerenes on Cu(111) have been studied by low-temperature scanning tunneling microscopy (LT-STM) in detail. Upon molecular deposition at low temperature, Gd@C82 molecules preferentially decorate the steps and nucleate into single layer islands with increasing coverage. Further annealing treatment leads some of the Gd@C82 molecules to assemble into bright and dim patches, which are correlated to the adsorption induced substrate reconstruction. Upon sufficient thermal activation, Gd@C82 molecules sink into the Cu(111) surface one-copper-layer-deep, forming hexagonal close-packed molecular islands with intra-molecular details observed as striped patterns. By considering the commensurability between the Gd@C82 nearest-neighbor distance and the lattice of the underlying Cu(111), we clearly identified two kinds of in-plane molecular arrangements as (19(1/2)×19(1/2))R23.4°and (19(1/2)×19(1/2))R36.6°with respect to Cu(111). Within the assembled Gd@C82 molecular, island molecules with dim-bright contrast are spatially distributed, which may be modulated by the preexisted species on Cu(111). 相似文献
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以Cr(Ⅵ )离子、敌敌畏农药作为污染物的代表 ,研究了H2 O2 、金属离子等对Cr(Ⅵ )离子光催化还原及对敌敌畏农药光催化氧化的影响 .结果表明 ,加入少量的H2 O2 对Cr(Ⅵ )离子的光催化还原起阻碍作用 ,对敌敌畏农药的光催化氧化起促进作用 ;加入少量的Cu2 +对Cr(Ⅵ )离子光催化还原及对敌敌畏农药的光催化氧化均起促进作用 ;加入Zn2 +、Na+对Cr(Ⅵ )离子及敌敌畏农药的光催化降解均无明显的影响 ;加入甲醇、甲苯对Cr(Ⅵ )离子的光催化还原起促进作用 ,对敌敌畏农药的光催化氧化起阻碍作用 .探讨了H2 O2 、金属离子等对Cr(Ⅵ )离子光催化还原及对敌敌畏农药光催化氧化影响的机理 . 相似文献
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Temperature dependence of the photothermal laser coolina efficiency for a micro-cantilever 下载免费PDF全文
The relationship between the photothermal cooling efficiency of a micro-cantilever's mechanical mode and the en- vironmental temperature is studied. The micro-cantilever and a polished fiber end form a low finesse Fabry-Perot (FP) cavity. Experimental results in a temperature range from 77 K to 298 K show that temperature has an obvious influence on photothermal cooling efficiency. The photothermal cooling efficiency, ηph, at 100 K is 10 times that at 298 K. This accords well with the theoretical analysis that the high photothermal cooling efficiency can be achieved when photothermal response time, τph, and mechanical resonant frequency, ω0, are close to the optimal photothermal cooling condition ω0τph = 1. Our study provides an important approach for high effective photothermal cooling and high-sensitivity measurement for force microscopy. 相似文献
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