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61.
E. A. Popova N. Tristan C. Hess R. Klingeler B. Büchner L. N. Bezmaternykh V. L. Temerov A. N. Vasil’ev 《Journal of Experimental and Theoretical Physics》2007,105(1):105-107
The neodymium ferroborate NdFe3(BO3)4 undergoes an antiferromagnetic transition at T N = 30 K, which manifests itself as a λ-type anomaly in the temperature dependence of the specific heat C and as inflection points in the temperature dependences of the magnetic susceptibility χ measured at various directions of an applied magnetic field with respect to the crystallographic axes of the sample. Magnetic ordering occurs only in the subsystem of Fe3+ ions, whereas the subsystem of Nd3+ ions remains polarized by the magnetic field of the iron subsystem. A change in the population of the levels of the ground Kramers doublet of neodymium ions manifests itself as Schottky-type anomalies in the C(T) and χ(T) dependences at low temperatures. At low temperatures, the magnetic properties of single-crystal NdFe3(BO3)4 are substantially anisotropic, which is determined by the anisotropic contribution of the rare-earth subsystem to the magnetization. The experimental data obtained are used to propose a model for the magnetic structure of NdFe3(BO3)4. 相似文献
62.
V. F. Agekyan I. Akai N. N. Vasil’ev T. Karasawa G. Karczewski A. Yu. Serov N. G. Filosofov 《Physics of the Solid State》2007,49(6):1175-1183
The emission spectra of Zn1?x Mn x Te/Zn0.6Mg0.4Te and Cd1?x Mn x Te/Cd0.5Mg0.5Te quantum-well structures with different manganese concentrations and quantum-well widths are studied at excitation power densities ranging from 105 to 107 W cm?2. Under strong optical pumping, intracenter luminescence of Mn2+ ions degrades as a result of the interaction of excited managanese ions with high-density excitons. This process is accompanied by a strong broadening of the emission band of quantum-well excitons due to the exciton-exciton interaction and saturation of the exciton ground state. Under pumping at a power density of 105 W cm?2, stimulated emission of quantum-well excitons arises in CdTe/Cd0.5Mg0.5Te. The luminescence kinetics of the quantum-well and barrier excitons is investigated with a high temporal resolution. The effect of the quantum-well width and the managanese concentration on the kinetics and band shape of the Mn2+ intracenter luminescence characterized by the contribution of the manganese interface ions is determined. 相似文献
63.
A. Yu. Vasil’ev I. V. Kolesnichenko A. D. Mamykin P. G. Frick R. I. Khalilov S. A. Rogozhkin V. V. Pakholkov 《Technical Physics》2015,60(9):1305-1309
Turbulent free convection of liquid sodium in a straight thermally insulated tube with a length equal to 20 diameters and with end heat exchangers ensuring a fixed temperature drop is investigated experimentally. The experiments are performed for a fixed Rayleigh number Ra = 2.4 × 106 and various angles of inclination of the tube relative to the vertical. A strong dependence of the power transferred along the tube on the angle of inclination is revealed: the Nusselt number in the angular range under investigation changes by an order of magnitude with a maximum at the angle of 65° with the vertical. The characteristics of large-scale circulation and turbulent temperature pulsations show that convective heat transfer is mainly determined by the velocity of large-scale circulation of sodium. Turbulent pulsations are maximal for small angles of inclination (α = 20°–30°) and reduce the heat flux along the channel, although in the limit of small angles (vertical tube), there is no large-scale circulation, and the convective heat flux, which is an order of magnitude larger than the molecular heat flux, is ensured only by small scale (turbulent) flow. 相似文献
64.
Emission spectrum and intensity of picosecond intraband luminescence for single parabolic band approximation of electron conduction band in insulating crystals are calculated. It is shown that the spectral intensity of this intraband emission increases approximately as (?ω)?1/2 with decrease in photon energy, while the spectral density of photons increases as (?ω)?3/2. The intensity of this emission is inversely proportional to the longitudinal optical phonon frequency. The total emission yield in this approximation is low, less than 10 photons in the spectral window of silicon photomultipliers per MeV of ionizing particle energy. 相似文献
65.
V.?L.?KornienkoEmail author G.?A.?Kolyagin G.?V.?Kornienko N.?V.?Chaenko A.?M.?Kosheleva T.?A.?Kenova I.?S.?Vasil’eva 《Russian Journal of Applied Chemistry》2014,87(1):1-15
The achievements and prospects in the use of aqueous hydrogen peroxide solutions prepared by cathodic reduction of oxygen in carbon black gas-diffusion and graphite electrodes for indirect oxidation of organic and inorganic substrates in situ are analyzed. Specific examples demonstrate the efficiency of using hydrogen peroxide solutions for in situ indirect electrocatalytic oxidation of organic and inorganic substrates to target products (indirect electrochemical synthesis), for decomposition (mineralization) of organic and inorganic pollutants in industrial waters and wastewaters, and for preparation of organic peroxy acids and inorganic peroxy solvates. 相似文献
66.
Fluid Dynamics - Steady-state subsonic flows of nonequilibrium air plasma past a cylindrical body with plane face and heat transfer are investigated under the conditions characteristic of testing... 相似文献
67.
V. G. Vlasenko I. S. Vasil’chenko Ya. V. Zubavichus T. A. Kuz’menko L. N. Divaeva A. D. Garnovskii 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(4):649-653
Local atom environment in binuclear chelate Cu(II) complexes on the basis of azomethine ligands was investigated by extended
X-ray absorption fine structure spectroscopy. The temperature magnetic measurements indicated ferro- or antiferromagnetic
exchange in these complexes. A direct correlation between the character of the exchange magnetic interaction and the type
of the ligand coordination in these complexes was established. 相似文献
68.
Georgy Ivanov Nam-Gyu Kang Alexander Vasil’ev 《Complex Analysis and Operator Theory》2016,10(7):1591-1617
It was realized recently that the chordal, radial and dipolar Schramm–Löwner evolution (SLEs) are special cases of a general slit holomorphic stochastic flow. We characterize those slit holomorphic stochastic flows which generate level lines of the Gaussian free field. In particular, we describe the modifications of the Gaussian free field (GFF) corresponding to the chordal and dipolar SLE with drifts. Finally, we develop a version of conformal field theory based on the background charge and Dirichlet boundary condition modifications of GFF and present martingale-observables for these types of SLEs. 相似文献
69.
G. V. Kornienko N. V. Chaenko I. S. Vasil’eva G. A. Kolyagin V. L. Kornienko 《Russian Journal of Applied Chemistry》2010,83(2):253-257
Effect of the porosity and thickness of hydrophobized gas-diffusion air electrodes composed of A 437-E acetylene black or
its mixture with P 702 and P 701 furnace blacks on the efficiency of electroreduction of atmospheric oxygen to H2O2 in 0.5 M NaOH was studied. 相似文献
70.
D. I. Sevostianov V. P. Yakovlev A. N. Kozlov V. V. Vasil’ev S. A. Zibrov V. L. Velichansky 《Bulletin of the Lebedev Physics Institute》2014,41(4):89-94
Modulation characteristics of absorption at the resonance D 1 line of cesium atoms in a cell with antirelaxation coating are studied. It is experimentally shown that the minimum of the response to harmonic modulation in a certain frequency band coincides with Maxwellian velocity distribution maximum, despite the line profile distortion observed during linear frequency scanning [1]. The effect is theoretically explained. 相似文献