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101.
The effect of spin injection on the spin resonance associated with itinerant electrons in a nonmagnetic semi-conductor has been studied within the phenomenological approach. The power absorbed under the resonance conditions has been analyzed as a function of the frequency, effective g-factor, and magnetic field direction. It is shown that the power absorbed by the spin-polarized charge carriers under the resonance conditions can provide a tool for studying the spin injection. 相似文献
102.
M. V. Ustinov 《Fluid Dynamics》2014,49(4):468-480
The problem of freestream-turbulence-generated instability waves in the flat-plate boundary layer is solved on the basis of a nonlinear turbulence model admitting the deviation of the speed of propagation of vortex disturbances from the flow velocity. The solution obtained well describes the experimental dependence of the laminar-turbulent transition Reynolds number on the freestream turbulence degree. 相似文献
103.
We obtain the correction due to van der Waals forces to the flexural rigidity of a layer. The cases of a monolayer and a film consisting of several monolayers are considered. The correction due to van der Waals interaction to the force acting on an indentor is obtained. Two versions of determining the elastic forces at the microlevel are considered. Numerical estimates of the parameter values for which the correction is essential are given. 相似文献
104.
V. M. Ustinov A. F. Tsatsulnikov V. V. Lundin A. V. Sakharov A. E. Nikolaev E. E. Zavarin A. L. Zakgeim A. E. Chernyakov M. N. Mizerov N. A. Cherkashin M. Hytch 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2012,6(3):501-504
The results of investigations of monolithic white InGaAlN LEDs with an active region containing several thin InGaN layers, emitting in the range from blue to yellow-green, and separated by short-period InGaN/GaN superlattices, are presented. The influence of the growth conditions and layer sequence in the active region on the optical properties of monolithic white LEDs was studied with the aim of controlling their color parameters. 相似文献
105.
N.G. Bebenin R.I. ZainullinaV.V. Ustinov Ya.M. Mukovskii 《Journal of magnetism and magnetic materials》2012,324(6):1112-1116
The effect of magnetic inhomogeneity on magnetic, magnetocaloric, and transport properties of the colossal magnetoresistance manganites with first order ferromagnetic-to-paramagnetic phase transition is studied. The experiments were performed on the single-crystalline samples of La0.6Pr0.1Ca0.3MnO3. The inhomogeneity is described by the Curie temperature distribution function, which is found from the magnetization data. The temperature dependence of the magnetic field induced change in the entropy is shown to be determined by the distribution function and the shift of the transition temperature in a magnetic field. Similarly, magnetoresistance in the transition region is determined by the resistivity at H=0 and the shift of the transition temperature. The maximum entropy change as well as maximum magnetoresistance can be achieved in the magnetic field of order δTC/BM where δTC is the transition width and BM is the rate of change of the Curie temperature with magnetic field.Our approach to analysis of the effects of inhomogeneity is general and therefore can be used for all compounds with the first order magnetic phase transition. 相似文献
106.
K. B. Ustinov 《Mechanics of Solids》2010,45(2):238-246
By passing to the limit in the general solution, we obtain several exact asymptotic formulas for the energy of an inhomogeneity
in a body located in an external stress field. The parameters determining the type of the asymptotic behavior are the inclusion
semiaxis ratio and the inclusion-matrix elastic modulus ratio. In the case of a large simultaneous deviation of the parameters
from unity, we distinguish seven regions corresponding to various successive passages to the limit as these parameters approach
zero (or infinity). 相似文献
107.
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
108.
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
109.
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
110.
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