排序方式: 共有7条查询结果,搜索用时 15 毫秒
1
1.
半绝缘6H型碳化硅(6H-SiC)具有高电阻率性质,在可见光照射下进行光电导测量时,通常光生电流很小;然而经过飞秒激光辐照改性之后,发现在可见光波段的光电导有明显的增益.本文利用紫外-可见-近红外吸收谱、X射线光电子能谱和发光光谱测量分析了激光改性之后碳化硅样品的光谱吸收、发射和晶体元素比例变化情况.分析认为碳化硅光电导增益的原因是飞秒激光辐照过程改变了碳化硅表面的硅碳元素的原子浓度比,形成新的物质结构形式,从而导致了表面光电导性能的提高. 相似文献
2.
3.
The Mazhuang gas reservoir is located in the eastern part of the Junggar Basin. Itsgas-producing pool is averagely 2000 m deep. It is a mid-shallow reservoir. The natural gasrich 2--7% of C_2-C_4 gaseous hydrocarbons is mainly composed of methane. δ~(13)C_(CH_4). valuesare--47----45‰, heavier than microbiogenic gas, and lighter than coal--type gas as well asoil--associated gas. The maternal materials of gas source rocks are primarily from the type-Ⅲ organic matter at the low--mature stage (0.5%相似文献
4.
Size-dependent nonlinear absorption and refraction of Ag nanoparticles excited by femtosecond lasers 下载免费PDF全文
Silver (Ag) nanoparticles with different average sizes are prepared, and the nonlinear absorption and refraction of these nanoparticles are investigated with femtosecond laser pulses at 800 nm. The smallest Ag nanoparticles show insignificant nonlinear absorption, whereas the larger ones show saturable absorption. By considering the previously reported positive nonlinear absorption of 9 nm Ag nanoparticles, the nonlinear absorptions of Ag nanoparticles are found to be size-dependent. All these nonlinear absorptions can be compatibly explained from the viewpoints of electronic transitions, energy bands and electronic structures in the conduction band of Ag nanoparticles. The nonlinear refraction is attributed to the effect of hot electrons arising from the intraband transition in the s–p conduction band of Ag nanoparticles. 相似文献
5.
均值不等式推广的应用举例 总被引:1,自引:0,他引:1
文献介绍了均值不等式的推广,它造形美,含意深,应用广,读后受益非浅。用它来证明某些重要不等式和较难不等式,颇见成效,而且具有一定的规律和数学模式。本文主要给出均值不等式推广的应用。 相似文献
6.
7.
The dipole resonances of gold nanocages were investigated theoretically using finite difference time domain method.The results show that field enhancement is obtained at the walls of the gold nanocages.It is believed that the effect can cause a strong optical nonlinear property.To test the hypothesis,nonlinear absorption was investigated using a broadband 5 ns Z scan.It was found that at low intensities the sample shows saturable absorption(SA),while at higher intensities a switch from SA to reverse SA occurs.Moreover,the nonlinear absorption of the sample is sensitively wavelength-dependent,and,in the resonant region,saturation intensity is the largest. 相似文献
1