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131.
A non-interacting s-d band model is used to evaluate ?2(ω) in copper. The free electron approximation is used for electrons in s-band, while a simplified tight-binding scheme is used for the d-electrons. It is found that only d-bands with m = 0 contribute to optical transitions. The transition matrix elements are explicitly calculated. The calculated ?2(ω) gives reasonable agreement with measured optical conductivity. 相似文献
132.
Mohan Joshi 《Proceedings Mathematical Sciences》1983,92(1):61-65
An approximate solvability scheme for equations of the typeu+K u(u)=w, in a closed convex subsetA of a Hilbert spaceX is given. Here, for eachu ∈ A, K u: X → X is a bounded linear operator. 相似文献
133.
Katsouleas T.C. Clayton C.E. Serafini L. Pellegrini C. Joshi C. Dawson J. Castellano P. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1996,24(2):443-447
A technique for producing ultra-short electron bunches (e.g., ⩽100 fs) from a continuous electron beam using a short plasma wave section and a drift space is explored. The bunches are a fraction of a plasma wavelength long and are spaced by a plasma wavelength, making them of interest for injection into plasma accelerators or for driving a klystron-like structure to produce infrared radiation 相似文献
134.
Poor beam collimation leads to overcompensation of suppression of coherent bremsstrahlung in the axial channelling case. This fact has been used to study the effect of beam divergence on the radiation emitted by relativistic (axially) channelled positrons. It has been found that due to beam divergence in the experiment of Alguard and co-workers in which radiation of 56 MeV positrons channelling along 〈110〉 rows of a silicon crystal is observed, coherent bremsstrahlung becomes an important contributing factor to the high frequency part of the observed spectrum. 相似文献
135.
Summary The photoconductivity of the magnetic semiconductor compound Cd1−x
Mn
x
Se has been studied at 300 K and at 77K for the first time for several Bridgman-grown single crystals. With this technique
it was possible to detect the Mn 3d level. Experimental data found in this investigation reveal that the Mn 3d level is pinned at 1.9 eV below the bottom of the conduction band,i.e. it is independent of temperature and insensitive to the amount of manganese.
Paper presented at the ?V International Conference on Ternary and Multinary Compounds?, held in Cagliari, September 14–16,
1982. 相似文献
136.
137.
Six biscoclaurine alkaloids have been isolated from Cocculus pendulus (Forsk) Diels. Of these cocsulin (1), cocsolin (2), cocsulinin 15) and pendulinin (21) have been assigned structures and stereochemistry by a series of chemical transformations and spectral studies. 相似文献
138.
The superposition of the non-abelian potentials of the formA′μ=Aαμ+aβ
μ andB′μ=Bγμ+bημ are considered and the necessary as well as the sufficient conditions are obtained. The significance of the conditions is
discussed and the constrained isotopic spins of the perturbation potentials (aβ
μ,bημ) are shown to be necessary for the superposition of these potenitals.
Work under the projecthcs/dst/1081/81 相似文献
139.
140.