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31.
32.
The technique of the prepagation of the tunnel junctions with a barrier made of AlN has been presented. To produce a barrier layer a freshly evaporated Al film was exposed to a glow discharge in atmosphere of pure ammonia. The features shown in the tunnel spectra of these junctions have been interpreted as AlN optic phonons and a vibration spectrum of NH3 molecules adsorbed in the junctions. 相似文献
33.
A program based on the method of least squares and written in the ALGOL-60 code was developed for data processing in the activation
analysis of biological substances. The applicability of the program was checked on synthetic mixtures of the radioisotopes64Cu,69mZn and56Mn measured with a scintillation γ-spectrometer. 相似文献
34.
Bocang Qiu Stewart McDougall Dan Yanson John H. Marsh 《Optical and Quantum Electronics》2008,40(14-15):1149-1154
The effect of quantum well (QW) strain on the thermal performance of InGaP/InGaAlP lasers emitting at around 635 nm is investigated theoretically. It is found that compressively-strained QWs offer superior thermal performance due to an increased barrier height for electrons, leading to a reduced electron leakage. The theoretical predictions are supported by experimental data from red-emitting laser diodes with an improved characteristic temperature T 0. 相似文献
35.
A numerical model in terms of rate equations for lateral mode amplitudes for analysing static and dynamic properties of moderately broad stripe (tens of microns) laser diodes is proposed and used for modeling lasers with longitudinally or laterally intermixed passive areas. Introduction of passive diffractive regions is shown to offer some improvement of the laser beam, and the potential of further improvement of the beam by Intermixing lateral fringes along the stripe is discussed. 相似文献
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Z. A. Yanson 《Journal of Mathematical Sciences》1998,91(2):2883-2893
The asymptotics of high-frequency surface waves in elastic media is studied for a special case of anisotropy, namely, for
transversely isotropic media (where the parameters of elasticity are invariant with respect to rotations about one of the
coordinate axes). In the zeroth asymptotic approximation, the slow Rayleigh waves (of SV type) under study are polarized in
the plane of the normal section of the surface. The principal term of the asymptotics (which has the form of a space-time
(caustic) expansion) is found, and calculations related to the necessity of introducing two additional faster waves with complex
eikonals are carried out. The conditions on the elasticity parameters of the medium that insure the origination of the surface
waves in question are obtained. Due to the specific structure of the elasticity tensor under consideration, the boundary of
the medium is necesarily plane. For appropriate values of elastic parameters, the resulting formulas coincide with the corresponding
expressions in the isotropic case. Bibliography: 8 titles.
Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 230, 1995, pp. 278–293.
Translated by Z. A. Yanson 相似文献
38.
Z. A. Yanson 《Journal of Mathematical Sciences》2002,108(5):879-895
A uniform asymptotics of the surface Love modes for a special case of anisotropy (tranverse isotropy) of an elastic media is obtained. In constructing the asymptotics of surface waves, the space-time (ST) ray method is employed. The wave field of each Love mode is represented as the sum of the ST caustic expansion involving the Airy functions with a real eikonal and two correction terms that are ST ray solutions, which in fact are inhomogeneous waves with complex eikonals. The eikonals and coefficients of the caustic and ray series are sought in the form of expansions in powers of two variables. The first variable is the distance from the surface, whereas the other characterizes the proximity of the caustic of a ray field to the boundary surface. Thanks to the specific structure of the elasticity tensor for a transversely isotropic medium, the boundary surface is necessarily a plane. A recursion process of computation of higher terms of the asymptotic expansion allows one to trace the conversion of the formulas obtained to the known ray solutions for isotropic elastic media. Relations between the elasticity parameters of a medium are obtained that ensure the existence of SH Love waves in a transversely isotropic medium and that are consistent with the conditions of the positiveness of the elastic energy of deformation. Bibliography: 6 titles. 相似文献
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