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排序方式: 共有9907条查询结果,搜索用时 31 毫秒
991.
A. Stierle C. TiegH. Dosch V. FormosoE. Lundgren J.N. AndersenL. Köhler G. Kresse 《Surface science》2003,529(3):L263
Using high resolution core level spectroscopy, a surface core level shift towards lower binding energy of −0.13 eV is determined for the 2p level of the outwardly relaxed Al surface atoms on NiAl(1 1 0). Density functional theory based calculations with inclusion of final state effects yield a value of −0.14 eV for this shift in excellent agreement with experiment. We show that the initial state approximation yields a value of +0.09 eV, i.e. the inclusion of final state relaxation effects is vital not only to obtain the correct value but even the correct sign for this shift. 相似文献
992.
L. G. Samsonova N. S. Eremina V. A. Svetlichnyi T. N. Kopylova G. V. Maier N. S. Kobotaeva E. E. Sirotkina 《Journal of Applied Spectroscopy》2006,73(2):194-199
We have studied the spectral and lasing properties of 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM)
in polyepoxypropylcarbazole (PEPK), polybutylcarbazole (PBK), and polyvinylcarbazole (PVK) films when excited by emission
from a XeCl laser (λ = 308 nm) and the second harmonic of a YAGNd laser (λ = 532 nm). Stimulated emission was excited without
an external cavity in the traveling wave mode in films of thickness 0.5–0.8 μm, obtained by the centrifuging method.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 177–181, March–April, 2006. 相似文献
993.
By employing an output-power clamping technique, a dual-order Raman fiber laser (RFL) is theoretically presented with suppressed low-frequency relative-intensity-noise (RIN) transfer from pump sources to both first- and second-order Stokes output. Their powers can be easily tuned in a large dynamic range. Furthermore, the second-order output power can be individually controlled, which makes it flexible to adjust the ratio of the first- to second-order output power. In addition, the stabilization of low-power second-order output is also accomplished in the RFL setup. These properties fit the proposed RFL for use as dual-order pump sources in Raman fiber amplifiers. 相似文献
994.
Prior to the flashover across an insulator in vacuum, the insulator surface is usually charged. It is of great importance to investigate the charging phenomena for better understanding the flashover characteristics. It is considered that there are two kinds of mechanisms closely related to the surface charging of insulator i.e., the secondary electron emission occurred over an insulator, and while employing a perfect electrode contact ahead of electron emission into vacuum, the charge injection and accumulation occurred inside the surface layer of an insulator. Based on the rigorous analysis of the kinetic processes of both primary and secondary electrons, the related surface charges were theoretically deduced. Involving the detrapping of charges trapped and the recombination of charges injected, the charging process due to charge injection and accumulation was analyzed. Some formulas were given to express the density of surface charges. 相似文献
995.
996.
997.
998.
J. D. Shakos A. M. Cox D. P. West K. S. West F. A. Wade T. A. King R. D. Blackburn 《Optics Communications》1998,150(1-6):230-234
The processes limiting the rate of response of highly diffractive, reorientationally enhanced photorefractive polymer composite materials are identified from a series of degenerate four wave mixing and Mach–Zehnder interferometric measurements. In the regime of low intensity writing beams charge generation limits the rate of holographic grating formation, but at higher intensities charge transport or reorientation of dye molecules can restrict the rate of grating formation more strongly. A grating risetime of 540 ms is observed in a composite of high dye content with high reorientational mobility of the dye molecules. In this case it is proposed that the charge carrier mobility of the doped poly(N-vinylcarbazole):2,4,7-trinitro-9-fluorenone (PVK:TNF) matrix is the principal limiting factor in grating response rates. 相似文献
999.
1000.