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71.
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
72.
Vlasta Závišová Martina KonerackáMarta Mú?ková Jana LazováAlena Juríková Gábor LanczNatália Tomašovi?ová Milan TimkoJozef Ková? Ivo VávraMartin Fabián Artem V. Feoktystov Vasil M. GaramusMikhail V. Avdeev Peter Kop?anský 《Journal of magnetism and magnetic materials》2011,323(10):1408-1412
Poly(ethylene glycol) (PEG)-containing magnetic fluids - magnetite (Fe3O4) stabilized by sodium oleate - were prepared. Magnetic measurements confirmed superparamagnetic behaviour at room temperature. The structure of that kind of magnetic fluid was characterized using different techniques, including electron microscopy, photon cross correlation spectroscopy and small-angle neutron scattering, while the adsorption of PEG on magnetic particles was analyzed by differential scanning calorimetry and Fourier transform infrared spectroscopy. From the in vitro toxicity tests it was found that a magnetic fluid containing PEG (MFPEG) partially inhibited the growth of cancerous B16 cells at the highest tested dose (2.1 mg/ml of Fe3O4 in MFPEG). 相似文献
73.
V. A. Vasil’ev 《Vestnik St. Petersburg University: Mathematics》2011,44(3):167-170
The paper shows that a linear system may be studied using approximate calculations by means of constructing another linear
system which is arbitrarily close to the given one and whose fundamental matrix of solutions coincides with the approximate
fundamental matrix of solutions of the system under study. 相似文献
74.
75.
The determination of the energy of activation (barrier height) of elementary events involved in relaxation (fluctuation) transitions
in polymers from the temperature dependence of the specific heat is discussed. The dependence is derived by the method of
differential scanning calorimetry. It is emphasized that the correct determination of the energy of activation must include
the temperature variation of the barrier. The deviation of the preexponential in the Arrhenius temperature dependence from
the value predicted theoretically demonstrates that the barrier does depend on temperature. Experimental data from which the
realistic energy of activation of the α relaxation in polymers can be found are given. 相似文献
76.
The structure of a metallic-phase film produced by mechanical polishing of polycrystalline SmS 总被引:1,自引:0,他引:1
N. V. Sharenkova V. V. Kaminskii A. V. Golubkov L. N. Vasil’ev G. A. Kamenskaya 《Physics of the Solid State》2005,47(4):622-626
X-ray diffraction is used to study the structure of a metallic-phase film that forms during controlled polishing of homogeneous polycrystalline semiconducting Sm1+xS samples. Structural changes that appear in the semiconducting phase under these conditions were studied. The x dependence of the thickness of the metallic layer forming on the sample surface is analyzed to explain the effect of excess samarium ions on the transformation parameters. The cause of the stabilization of the metallic modification of SmS after polishing is terminated is explained using estimates based on the measured sizes of coherent domains in samples of different compositions. The appearance and stabilization of the metallic phase are related to a decrease in and subsequent conservation of the coherent-domain size, respectively. 相似文献
77.
We demonstrate that the lowest threshold of spin-wave excitation in an in-plane magnetized magnetic nanocontact driven by spin-polarized current is achieved for a nonlinear self-localized spin-wave mode-standing spin-wave bullet--stabilized by current-induced nonlinear dissipation. This nonlinear mode has a nonpropagating evanescent character, is localized in the region comparable with the contact radius, and has a frequency that is lower than the frequency of the linear ferromagnetic resonance. The threshold current and generated frequency at the threshold theoretically calculated for this mode are in quantitative agreement with experiment. 相似文献
78.
A. N. Vasil’ev O. L. Ignatchik A. N. Sokolov Z. Hiroi M. Isobe Y. Ueda 《JETP Letters》2003,78(9):551-554
Formation of a long-range magnetic order is observed at low temperatures in NaCrSi2O6 and NaCrGe2O6 quasi-one-dimensional metal oxide compounds with a pyroxene structure. The first of these compounds, NaCrSi2O6, is an antiferromagnet with the Néel temperature T N =3 K, while the second, NaCrGe2O6, is a ferromagnet with the Curie temperature T C =6 K. From the measurements of magnetization and specific heat of these compounds, the main parameters of their magnetic subsystems are determined. In NaCrSi2O6, a spin-flip transition is observed. A change in the type of magnetic order that accompanies the replacement of Si by Ge can be attributed to a change in the parameters of the competing direct antiferromagnetic Cr-Cr and indirect ferromagnetic Cr-O-Cr interactions in isolated chains of CrO6 octahedra. 相似文献
79.
V. F. Agekyan N. N. Vasil’ev V. I. Konstantinov A. Yu. Serov N. G. Filosofov V. N. Yakimovich 《Physics of the Solid State》2003,45(8):1435-1439
Intracenter luminescence (IL) of Mn2+ in Zn1?xMnxSe (x=0.07, 0.02) was studied under pulsed excitation by the neodymium laser second harmonic. At 4 K, the IL saturation originates from the nonlinearity of the system only at the instant of excitation, the IL decay kinetics after the exciting pulse termination depending only weakly on the pumping level. At 77 K, the decay kinetics in Zn0.93Mn0.07Se depends substantially on the pumping level, because the migration of intracenter excitation over the manganese ions initiates up-conversion, which is a slow nonlinear process. As shown by IL decay measurements in Zn0.98Mn0.02Se (x=0.02), excitation migration over the Mn2+ ions is insignificant even at a high temperature and under strong optical pumping. 相似文献
80.
S. S. Vasil’ev V. A. Dergachev 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(7):1006-1009
The long-term variations in the production rate of 10Be and 14C in the Earth’s atmosphere during the last 10 thousand years caused by the geomagnetic-field effect have been investigated. It is shown that the difference in the correlation coefficient between the production rate of 10Be and 14C and variations in the dipole magnetic moment of the Earth is due to the lack of knowledge about the 14C exchange parameter for the carbon reservoir. The optimal parameters of the reservoir model of radiocarbon exchange, averaged over 10 thousand years, are found. 相似文献