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101.
The sound velocity, internal friction, and thermal expansion in a single crystal of La0.85Sr0.15MnO3
R. I. Zainullina N. G. Bebenin V. V. Mashkautsan A. M. Burkhanov V. S. Gaviko V. V. Ustinov Ya. M. Mukovskii D. A. Shulyatev V. G. Vasil’ev 《Journal of Experimental and Theoretical Physics》2001,93(1):121-125
The results are given of the investigation of the temperature dependence of the sound velocity v, internal friction Q ?1, and thermal expansion ΔL/L of a single crystal of La0.85Sr0.15MnO3 in the temperature range from 5 to 400 K. Clearly defined singularities of the elastic properties at a temperature of charge ordering T co≈200 K are revealed. The results of X-ray diffraction studies performed at room temperature are used to determine the orientations and estimate the sizes of twins. The correlation between magnetic and structure inhomogeneities is established. Based on the results of analysis of the temperature dependence of internal friction and thermal expansion, an assumption is made of the presence in a single crystal of La0.85Sr0.15MnO3 of a structural transition in the temperature range from 15 to 60 K that has not been observed previously. 相似文献
102.
N. G. Bebenin R. I. Zainullina V. V. Mashkautsan V. V. Ustinov V. G. Vasil’ev B. V. Slobodin 《Physics of the Solid State》2001,43(3):501-507
An experimental study is reported on the temperature dependences of the magnetic susceptibility, electrical resistivity, magnetoresistance, thermo-and magnetothermopower, and on the Hall effect of the polycrystalline lanthanum manganites La0.67?x R x Sr0.33MnO3 (x=0 and 0.07, R=Eu, Gd) within the 77-to 430-K temperature range. Replacement of a small amount of lanthanum by europium or gadolinium was found to result in a considerable decrease in the resistivity and in a change in the pattern of its temperature dependence. The temperature dependence of both the ordinary and anomalous Hall coefficients near the Curie temperature is shown to be determined by the change in the number of carriers in delocalized states. A method is proposed for separation of the hole and electronic contributions to thermopower in the ferromagnetic region. The conduction mechanisms are discussed in terms of the concept of mobility edge motion. 相似文献
103.
Gubkina M. L. Polyakov N. S. Petukhova G. A. Kalmykova O. V. Ustinov E. A. 《Russian Chemical Bulletin》2001,50(4):595-598
The isotherms of water adsorption in the presence of an organic substance vapor with a specified concentration are calculated from experimental data on the joint frontal dynamics of adsorption of water vapor and several organic substances (benzene, hexane, cyclohexane, tetrachloromethane, and perfluorotripropylamine) on two samples of activated carbons. The influence of the organic substances on the equilibrium water adsorption decreases with an increase in the molecule size. 相似文献
104.
M. V. Ustinov 《Journal of Applied Mechanics and Technical Physics》2000,41(4):658-665
The flow past a flat plate with a blunted leading edge by a flow of a viscous incompressible fluid with a small spanwise-periodic,
steady nonuniformity of the velocity profile is considered. Such a flow simulates the interaction of one type of vortex disturbances
of a turbulent external flow with the boundary layer. The solution obtained predicts generation of strong disturbances in
the boundary layer, which are similar to the streaky structure observed in the case of high free-stream turbulence. It is
shown that the boundary-layer flow on blunted bodies is more sensitive to vortex disturbances than on a plate with a sharp
leading edge.
Central Aerohydrodynamic Institute, Zhukovskii, 140160. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol.
41, No. 4, pp. 93–100, July–August, 2000. 相似文献
105.
106.
107.
Russian Journal of Organic Chemistry - 相似文献
108.
N. G. Bebenin R. I. Zainullina V. V. Mashkautsan A. M. Burkhanov V. V. Ustinov V. V. Vasil’ev B. V. Slobodin 《Journal of Experimental and Theoretical Physics》1998,86(3):534-537
The Hall effect in polycrystalline barium-substituted lanthanum manganite La0.67Ba0.33MnO3 has been investigated in the temperature interval 298<T<355 K. It is found that the anomalous Hall coefficient in this material is two orders of magnitude greater than the normal
coefficient. At T
0=333 K the normal Hall coefficient changes sign, which indicates a change in the type of conductivity. The temperature dependence
of the normal Hall coefficient, electrical conductivity, and magnetoresistance is explained on the basis of the concept of
motion of the mobility edge attendant as the temperature changes.
Zh. éksp. Teor. Fiz. 113, 981–987 (March 1998) 相似文献
109.
110.
L. E. Vorob’ev V. Yu. Panevin N. K. Fedosov D. A. Firsov V. A. Shalygin S. Hanna A. Seilmeier Kh. Moumanis F. Julien A. E. Zhukov V. M. Ustinov 《Physics of the Solid State》2004,46(1):118-121
High-resolution spectroscopy in the mid-infrared spectral range is used to study electronic transitions between size-quantization subbands in stepped quantum wells under picosecond interband excitation. The contributions from intersubband and intrasubband absorption of light are separated by using the difference in time profiles of the absorption coefficient for these cases. For stepped quantum wells, spontaneous interband luminescence and superluminescence are studied for different excitation levels. For structures with quantum dots, the intraband absorption spectra for n-and p-type structures and the spectra of photoinduced intraband absorption and emission (for polarized radiation) for undoped structures are studied. 相似文献