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991.
V. I. Maslov 《Russian Physics Journal》2007,50(5):425-428
An abrupt rise of the field electron emission (FEE) current from a high-temperature superconductor (HTSC) being in the normal
state has been detected. The current amplification with a factor reaching ∼106 occurs as an HTSC emitter is heated in the temperature range 110–170 K. The features of the temperature dependence of FEE
are discussed. Measured parameters of the effect observed are presented. Possible mechanisms of the process under consideration
are discussed.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 13–16, May, 2007. 相似文献
992.
In recent publications, it has been shown that high-order harmonic generation can be manipulated by employing a time delayed attosecond-pulse train superposed to a strong, near-infrared laser field. It is an open question, however, which is the most adequate way to approximate the attosecond-pulse train in a semianalytic framework. Employing the strong-field approximation and saddle-point methods, we make a detailed assessment of the spectra obtained by modeling the attosecond-pulse train by either a monochromatic wave or a Dirac-Delta comb. These are the two extreme limits of a real train, which is composed by a finite set of harmonics. Specifically, in the monochromatic limit, we find the downhill and uphill sets of orbits reported in the literature, and analyze their influence on the high-harmonic spectra. We show that, in principle, the downhill trajectories lead to stronger harmonics, and pronounced enhancements in the low plateau region. These features are analyzed in terms of quantum interference effects between pairs of quantum orbits, and compared to those obtained in the Dirac-Delta limit. 相似文献
993.
M.C. Ubaldi V. Stasi U. Colombo D. Piccinin M. Martinelli 《Photonics and Nanostructures》2007,5(2-3):145-148
Roughness reduction of a submicron waveguide profile in chemically amplified negative resist is here performed by proper selection of an alkali-based developer, taking into account that its smaller molecules lead to smoother resist surface by altering the developing mechanism of aggregate extraction performed with standard quaternary ammonium hydroxide. Roughness is then analyzed by means of classical Atomic Force Microscope inspection; furthermore, a non-invasive line edge roughness analysis approach based on top-down scanning electron microscope acquisition gives comparable results, in terms of standard deviation and molecular aggregate periodicity. 相似文献
994.
G. Bouwmans B. Ségard P. Glorieux P. A. Khandokhin N. D. Milovsky E. Yu. Shirokov 《Radiophysics and Quantum Electronics》2004,47(10-11):729-742
This paper is devoted to the polarization dynamics of a longitudinally monomode bipolarized Nd:YAG laser: the low-frequency polarization dynamics of a microchip laser is studied experimentally and theoretically. The intensities and the relaxation oscillation spectrum of orthogonally polarized modes versus the direction of pump polarization is observed. A phase-sensitive model of a longitudinally monomode bipolarized solid-state laser with linear polarized diode laser pump is developed to account for the experimental observations. 相似文献
995.
996.
This paper studies isentropic solutions of quasilinear first-order equations with two independent variables and a flux function
that is only continuous. The isentropic solutions are characterized by the requirement that the S. N. Kruzhkov entropy conditions
hold for these solution with the equality sign. It turns out that the existence of a nonconstant isentropic solution imposes
rather strong restrictions on the nonlinearity. In particular, it is shown that on the minimal interval containing the essential
image of the isentropic solution, the flux function satisfies the local Lipschitz condition, and its generalized derivative
is a function of locally bounded variation. Also, it is proved that when the flux function is nonlinear, any isentropic solution
is continuous on nondegenerate intervals.
__________
Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 33, Suzdal
Conference-2004, Part 1, 2005. 相似文献
997.
998.
In quasi-steady operation, convection currents in a Bridgmandevice, used for producing a semi-conductor crystal, createinhomogeneities that may make the crystal unusable. It has oftenbeen suggested that additional forces due to rotation or magnetismmight be efficacious in reducing the segregation of the elementsof the alloy. It has been found that, over a wide range of rotationrates, there is no improvement in performance due to rotationabout the vertical axis. However, numerical results that havebeen obtained previously (Lee & Pearlstein, J. Crys. Growth240, 2002) indicate that, when effects of centrifugal buoyancyare introduced, a substantial reduction in segregation is achieved.In the work reported here, by contrast, in which we extend previouslarge-Rayleigh-number asymptotic analysis to include centrifugalbuoyancy, we find no improvement in radial segregation, butrather increasing segregation with increasing rotation rate. 相似文献
999.
1000.
T. V. Gubaidulina N. I. Chistyakova V. S. Rusakov 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(9):1269-1272
Natural and synthetic layered iron hydroxysulfides: tochilinite and valleriite, have been investigated by Mössbauer spectroscopy. Tochilinite, magnetite, troilite, and pyrite phases were found in the products of tochilinite synthesis under different conditions. The relative contents of the phases found are determined as functions of the relative magnesium content in the initial mixture. Crystallochemical identification of the 57Fe subspectra of valleriite has been performed. 相似文献