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| Author |
Godunova, E. K.; Levin, V. I. |
| Title |
Some general features of heat conduction |
Type |
Journal Article |
| Year |
1966 |
Publication |
USSR Computational Mathematics and Mathematical Physics |
Abbreviated Journal |
USSR Computational Mathematics and Mathematical Physics |
| Volume |
6 |
Issue |
6 |
Pages |
212-220 |
| Keywords |
mathematics, temperature distribution, rod |
| Abstract |
LET the initial temperature distribution in an infinite insulated rod without a heat source be given by a continuously differentiable function y = f(x), having a single maximum at x = 0 and two points of inflexion. The equation f′ = 0 then has a unique solution x = 0, where f′(x) > 0 for x < 0 and f′(x) < 0 for x > 0, We shall describe this as a one-hymped distribution. We shall assume that f/(x) also satisfies: (1) f(x) > 0 for − ∞ < x < ∞; (2) f(x) and x(fx) are integrable throughout the axis. Then the distribution remains one-humped for all t > 0. |
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0041-5553 |
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Некоторые качественные вопросы теплопроводности; Одногорбое распределение останется одногорбым |
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1701 |
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| Author |
Verevkin, A. A.; Ptitsina, N. G.; Chulcova, G. M.; Gol'tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S. |
| Title |
Direct measurements of energy relaxation time of electrons in AlGaAs/GaAs heterostructures under quasi-equilibrium conditions |
Type |
Journal Article |
| Year |
1996 |
Publication |
Surface Science |
Abbreviated Journal |
Surface Science |
| Volume |
361-362 |
Issue |
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Pages |
569-573 |
| Keywords |
2DEG, AlGaAs/GaAs heterostructures |
| Abstract |
For the first time, results are presented of a direct measurement of the energy relaxation time τε of 2D electrons in an AlGaAs/GaAs heterojunction at T = 1 and 5–20 K. A weak temperature dependence of τε for the T > 4K range and a linear temperature dependence of the reciprocal of τε for T < 4K have been observed. The linear dependence τε−1 ≈ T in the Bloch-Gruneisen regime is direct evidence of the predominance of the piezo-electric mechanism of electron-phonon interaction in non-elastic electron scattering processes. The values of τε in this regime are in very good agreement with the results of the Karpus theory. At higher temperatures, where the deformation-potential scattering becomes noticeable, a substantial disagreement between the experimental data and the theoretical results is observed. |
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0039-6028 |
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1609 |
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Gershenzon, E. M.; Gershenzon, M. E.; Gol'tsman, G. N.; Semyonov, A. D.; Sergeev, A. V. |
| Title |
Heating of electrons in superconductor in the resistive state due to electromagnetic radiation |
Type |
Journal Article |
| Year |
1984 |
Publication |
Solid State Communications |
Abbreviated Journal |
Solid State Communications |
| Volume |
50 |
Issue |
3 |
Pages |
207-212 |
| Keywords |
Nb HEB |
| Abstract |
The effect of heating electrons with respect to phonons in a thin superconducting film driven into the resistive state by the current and the external magnetic field has been observed and investigated. This effect caused by the electromagnetic radiation is manifested in the increased resistance of the film and is not selective over the frequency range from 1010 to 1015 Hz. That the effect is frequency independent under the conditions of strong electron scattering caused by static defects is explained by the decisive role of electron -electron collisions in forming the distribution function. The characteristic time of resistance change, obtained experimentally, corresponds to the relaxation time of the order parameter near the superconducting transition and to the relaxation time of the nonelastic electron-phonon interaction at lower temperatures and in lower magnetic fields. |
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0038-1098 |
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1709 |
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| Author |
Bespalov, A.V.; Gol'tsman, G.N.; Semenov, A.D.; Renk, K.F. |
| Title |
Determination of the far-infrared emission characteristic of a cyclotron p-germanium laser by use of a superconducting Nb detector |
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Journal Article |
| Year |
1991 |
Publication |
Solid State Communications |
Abbreviated Journal |
Solid State Communications |
| Volume |
80 |
Issue |
7 |
Pages |
503-506 |
| Keywords |
Nb detector, applications |
| Abstract |
We studied the far-infrared emission characteristics of a cyclotron p-germanium laser using a broad-band superconducting Nb film detector. For magnetic fields between ∼25 kOe and ∼50 kOe, emission in a frequency range from ∼50 cm-1 to ∼100 cm-1 with maximum intensity around 90 cm-1 was obtained. We determined, for fixed magnetic fields, electric field dependences of the emission intensity taking into account that the total electric field is a sum of the applied and the Hall electric field. An analysis of the emission intensity characteristic gives evidence that transitions between the two lowest Landau levels of light holes are responsible for the laser action. |
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0038-1098 |
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no |
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1677 |
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| Author |
Gershenzon, E. M.; Gol'tsman, G. N.; Semenov, A. D.; Sergeev, A. V. |
| Title |
Mechanism of picosecond response of granular YBaCuO films to electromagnetic radiation |
Type |
Journal Article |
| Year |
1990 |
Publication |
Solid State Communications |
Abbreviated Journal |
Solid State Communications |
| Volume |
76 |
Issue |
4 |
Pages |
493-497 |
| Keywords |
YBCO HTS detectors |
| Abstract |
The ultrafast mechanisms of radiation detection in granular YBaCuO films are studied in the wide wavelength range from millimeter to near infrared. With the rise of radiation frequency the Josephson detection at the grain boundary weak links is replaced by electron heating into the grains. This change occurs in the submillimeter wavelength range. Electron-phonon relaxation time τeph is determined by direct measurements and analyses quasistationary electron heating. Temperature dependence of τeph at T ≤ 40 K was found to be τeph ∼ T−1. The results show that detectors with the response time of few picoseconds at nitrogen temperature are attainable. |
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0038-1098 |
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no |
| Call Number |
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1685 |
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