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71.
利用不同加热机制产生的超热电子所导致的相干渡越辐射(CTR)在谐波分量强度比上的不同,给出了区分飞秒激光等离子体相互作用产生超热电子过程中的主要与次要加热机制的一种可能方法.得到了加热周期不同的加热机制所产生超热电子的比例与CTR谐波分量的二倍频和一倍频的强度比之间的具体关系式.如果在实验上测到此谐波分量强度比,就可以推出不同加热机制在加热过程中所起作用的大致比例关系.另外,CTR谐波分量的强度比还与超热电子的温度、实验上所使用靶的厚度有一定依赖关系,对此作了较为详细的讨论.
关键词:
相干渡越辐射
超热电子
加热机制 相似文献
72.
73.
Effect of Electric Field on Spin Polarized Current in Ferromagnetic/Organic Semiconductor Systems
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Considering the special carriers in organic semiconductors, the spin polarized current under electric field in a ferromagnetic/organic semiconductor system is theoretically studied. Based on the spin-diffusion theory, the current spin polarization under the electric field is obtained. It is found that electric field can enhance the current spin polarization. 相似文献
74.
Nonadiabatic Geometric Phase and Induced Persistent Current in Mesoscopic Square Circuit with Tilted Magnetic Field at Edges
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We investigate the geometric phase produced by nonadiabatic transition of spin states at corners of mesoscopic square circuit with tilted magnetic field at its edges, From the Schrodlnger equation, the transitions of electron spin state at corners are described by the transfer matrices. The eigenenergies and eigenstates are obtained from the cyclic condition and the multiplying of the transfer matrices. We show that there exist persistent charge and spin currents in such a system due to the lift of degeneracy between the opposite moving directions in the presence of the tilted magnetic field. The dependences of eigenenergies, geometric phase, charge and spin persistent currents on the tilting angles of magnetic field are analysed. 相似文献
75.
Influence of Vacuum Organic Contaminations on Laser-Induced Damage of 1064 nm Anti-Reflective Coatings
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We investigate the influence of vacuum organic contaminations on laser-induced damage threshold (LIDT) of optical coatings. Anti-reflective (AIR) coatings at 1064 nm made by Ta2 O5/SiO2 are deposited by the ion beam sputtering method. The LIDTs of AR coatings are measured in vacuum and in atmosphere, respectively. It is exhibited that contaminations in vacuum are easily to be absorbed onto optical surface because of lower pressure, and they become origins of damage, resulting in the decrease of LIDT from 24.5J/cm^2 in air to 15.TJ/cm^2 in vacuum. The LIDT of coatings in vacuum has is slightly changed compared with the value in atmosphere after the organic contaminations are wiped off. These results indicate that organic contaminations are the main reason of the LIDT decrease in vacuum. Additionally, damage morphologies have distinct changes from vacuum to atmosphere because of the differences between the residual stress and thermal decomposability of filmy materials. 相似文献
76.
We investigate the phase coherent transport in a single channel system.The theory that the tranmission zeros lead to abrupt phase change and in-phase resonances in confirmed numerically in two tight-binding models.After calculating the eigenvalues and eigenvectors of the Hamiltonians we also confirmed that the same symmetry of the eigenvectors also leads to the abrupt phase change and in-phase resonances that equal the transmission zero. 相似文献
78.
79.
Shi-Jie Zhang 《合成通讯》2013,43(20):3093-3100
Synthesis of (E)-β,γ-unsaturated acids from aldehydes with malonic acid has been explored under solvent-free conditions. The modified Knoevenagel condensation reaction with N-methyl morpholine (NMM) as catalyst exhibits highly β,γ-regioselectivity and exclusively E-stereoselectivity. A mechanism accounting for both regio- and stereoselectivity has been proposed and preliminarily studied. 相似文献
80.