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51.
A. B. Drovosekov N. M. Kreines D. I. Kholin A. V. Korolev M. A. Milayev L. N. Romashev V. V. Ustinov 《JETP Letters》2008,88(2):118-122
The evolution of the magnetic properties of Fe/Cr superlattices with a decrease in the nominal thickness of the iron layers down to atomic dimensions at which these layers are not continuous has been analyzed. Investigations have been carried out with multilayer samples with Fe-layer thicknesses in a range of 2–6 Å and Cr-layer thicknesses of 10 and 20 Å. It has been found that the system with various Fe-layer thicknesses and at various temperatures exhibits various magnetic phases—superparamagnetic, magnetically ordered, and nonergodic—characterized by the dependence of the magnetization of the sample on its magnetic prehistory. It has been shown that the observed nonergodic phase has the properties of a spin glass. A qualitative phase diagram of the magnetic states of the system has been obtained. 相似文献
52.
E. V. Cherdantseva D. V. Starichenko P. A. Slepukhin R. I. Ishmetova Yu. N. Shvachko A. V. Korolev G. L. Rusinov V. V. Ustinov A. I. Matern V. N. Charushin 《Russian Chemical Bulletin》2010,59(4):717-723
Dinuclear complexes of CuII with 3-(3,5-dimethylpyrazol-1-yl)-6-(2-hydroxyethylami-no)-1,2,4,5-tetrazine (1) and CoII with 3-(3,5-dimethylpyrazol-1-yl)-6-(piperidin-1-yl)-1,2,4,5- tetrazine (2) were synthesized and structurally characterized, and the magnetic (SQUID) and resonance (EPR) properties of van der Waals crystals based on these complexes were studied. Unusual behavior of the effective magnetic moment μeff(T) is observed at T < 60 K. A nonmonotonic increase in μeff(?) for 1 (s~6 %) and a 20% reduction of μeff(?) for 2 have a common origin and are due to the influence of spin-orbital coupling on the character of the splitting between the t2g and eg levels of the central ion. Distortions of the coordination site “switch on” a positive (1) or negative (2) contribution of the orbital magnetic moment near 6 K. Irreversible temperature behavior of μeff(T) in the heating and cooling regimes in the vicinity of 60 K suggests that the character of structural distortions and the magnetic properties are related to ligand geometry. This factor plays a significant role in crystal engineering of magnetoactive structures with polynitrogen ligands. 相似文献
53.
Ustinov AB Demidov VE Kondrashov AV Kalinikos BA Demokritov SO 《Physical review letters》2011,106(1):017201
The transition from stationary to chaotic spin-wave soliton trains has been observed. The experiment utilized cw excitation of envelope solitons through self-modulation instability of spin waves. By increasing the spin-wave power, the secondary self-modulation instability succeeded the primary modulation instability, resulting in after-modulation of the soliton train amplitude. Further increase of the spin-wave power led to development of the higher-order instabilities, resulting in formation of the chaotic soliton train. 相似文献
54.
A. B. Ustinov P. I. Kolkov A. A. Nikitin B. A. Kalinikos Y. K. Fetisov G. Srinivasan 《Technical Physics》2011,56(6):821-825
Planar phase shifters fabricated based on ferrite-ferroelectric layered structures are studied experimentally. The structures
served as waveguides for spin-electromagnetic waves, whose phase shift was controlled by both electric and magnetic fields.
The measurements were performed in the magnetic field range from 900 to 2100 Oe, which corresponds to operating frequencies
from 4.0 to 8.5 GHz, with 5- to 20-μm-thick yttrium-iron garnet ferrite films and 200- to 500-μm-thick barium-strontium titanate
ferroelectric plates. It is shown that the phase shift may exceed 180° and is a function of the magnetic and electric fields
and also of the thickness of the ferrite and ferroelectric layers. 相似文献
55.
The synthesis of a phosphoramidite reagent for 5′-modification of oligonucleotides by introducing an arylacetylene residue
has been described. Using the reaction with 3-(perylen-3-yl)propyl azide as an example, it was shown that the acetylene derivatives
of oligonucleotides synthesized using this reagent undergo CuI-catalyzed [3+2] dipolar cycloaddition. Fluorescent conjugates were obtained in high yields and characterized by mass spectra.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1220–1226, July, 2006. 相似文献
56.
S. F. Grebennikov N. N. Udal'tsova E. A. Ustinov 《Russian Journal of Applied Chemistry》2005,78(10):1586-1590
The dependence of the microporous structure of activated carbon fibers on the carbonization temperature of hydrate-cellulose fibers was studied by BET, TVFMP, and Horvath and Kawazoe techniques and methods of the nonlocal density functional theory. The surface energy distribution function was obtained, together with the micropore size distribution curves. It was shown that the effective micropore sizes calculated by the TVFMP method are close to the maximum of the distribution function found in terms of the theory of the density functional. 相似文献
57.
V. M. Buznik L. N. Ignat’eva V. G. Kuryavyi E. B. Merkulov N. N. Savchenko A. Yu. Ustinov A. B. Slobodyuk L. N. Nikitin 《Polymer Science Series A》2010,52(12):1334-1343
Microsized spherical core-shell particles consisting of hydrocarbon cores encapsulated into fluoropolymer shells are obtained
in supercritical carbon dioxide. Paraffins serve as a core material, while the polymer shell is formed from ultradispersed
polytetrafluoroethylene. The morphology and molecular structure in the bulk and on the surface of the particles and the influence
of conditions of particle formation on the shell thickness and the thermal properties of the materials are studied. The materials
are composites comprised of paraffin cores coated with shells of loosened globular fluoropolymer particles with sizes of 0.2–1.7
μm. The shells is built of low- and high-molecular-mass fractions consisting of CF3(CF2)nCF3 molecular chains with different lengths. The shell thickness is governed by preparation conditions, exposure time, and the
percentage of the polymer in the initial dispersion. 相似文献
58.
We study the interaction between longitudinal-transverse acoustic pulses and a system of paramagnetic impurities with the
effective spin S = 1 in a statically deformed crystal. We show that the dynamics of a pulse propagating at an arbitrary angle
to the static-deformation direction and of the effective spins satisfy the modified reduced Maxwell-Bloch equations and, if
the spectrum of the acoustic pulse overlaps the quantum transitions between spin sublevels, the modified sine-Gordon equation.
These equations generalize the well-known models in the theory of the inverse scattering method and in the theory of self-induced
transparency and also belong to the class of integrable equations. Analyzing soliton solutions shows that the pulse-medium
interaction reveals some qualitatively new features in these models compared with the cases of purely transverse or purely
longitudinal acoustic fields.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 151, No. 2, pp. 228–247, May, 2007. 相似文献
59.
G. M. Ustinov 《Siberian Mathematical Journal》1995,36(4):792-799
Translated fromSibirskii Matematicheskii Zhurnal, Vol. 36, No. 4, pp. 917–926, July–August, 1995. 相似文献
60.
C. Guasch C.M. Sotomayor Torres N.N. Ledentsov D. Bimberg V.M. Ustinov P.S. Kop'ev 《Superlattices and Microstructures》1997,21(4):509-516
Resonant luminescence studies of InAs quantum dots (QDs) embedded in a GaAs matrix grown by molecular beam epitaxy are presented, showing marked differences for modulation-doped and undoped QDs and indicating that the doping leads to different exciton formation and carrier relaxation mechanisms. The LO-phonon assisted relaxatioin of excitons between sub-levels is identified for the modulation-doped QDs. 相似文献