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131.
Yu. A. Kalinin A. V. Starodubov 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(12):1624-1627
An experimental investigation of the chaotic signals of a microwave generator with electron feedback (based on a virtual cathode)
was carried out. It was found that microwave chaos generators with electron feedback are of ultraband generation. The statistical
properties of the generated chaotic signals were shown. The perspective fields of application for the considered ultrabroadband
chaos generators were given. 相似文献
132.
A. V. Ivanov Yu. E. Kalinin V. N. Nechaev A. V. Sitnikov 《Physics of the Solid State》2009,51(12):2474-2479
The concentration dependences of the electrical resistivity and complex permeability of [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
multilayer structures and (Co45Fe45Zr10)
x
(Al2O3)100 − x
composites have been studied. It has been established that introduction of a semiconductor interlayer into the (Co45Fe45Zr10)
x
(Al2O3)100 − x
composites substantially decreases the electrical resistivity of [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
multilayer structures. The concentration dependences of the real and imaginary parts of the complex permeability of the [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
nanomultilayer structures substantially differ from those of the (Co45Fe45Zr10)
x
(Al2O3)100 − x
composites. The real part of the complex permeability of the [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
nanomultilayer structures follows the curve with a minimum near the percolation threshold of the composite, and the imaginary
part smoothly decreases as the ferromagnetic phase concentration increases. The results obtained are explained by the increase
in the bifurcation temperature due to the conduction electrons of the semiconductor interlayer, which favor magnetic ordering
of ferromagnetic grains. 相似文献
133.
Mamedov V. A. Kalinin A. A. Rizvanov I. Kh. Bauer I. Habicher V. D. 《Russian Chemical Bulletin》2009,58(7):1493-1503
A three-step method for the construction of di(imidazo[1,5-a]quinoxalina)-2(1,3)-benza-dithiacycloalkaphanes has been developed, which includes introduction of a haloalkyl group of various
length and nature into 1,3-bis(4(5H)-oxo-3-phenylimidazo[1,5-a]quinoxalin-1-yl)-benzene at the carbamoyl fragment, transformation of the bishalo-substituted compound thus obtained to bisthiol,
and coupling of the latter to a disulfide. 相似文献
134.
A two-step procedure has been developed for the synthesis of 3-alkylquinoxalin-2(1H)-ones from o-phenylenediamine and ethyl 2-oxoalkanoates prepared by the Grignard reaction of diethyl oxalate with alkyl bromides. Analogous reaction with α,ω-dibromoalkanes instead of alkyl bromides leads to the formation of 3,3′-(alkane-α,ω-diyl)di[quinoxalin-2(1H)-ones]. 相似文献
135.
A. M. Denisov E. V. Zakharov A. V. Kalinin V. V. Kalinin 《Differential Equations》2009,45(7):1034-1043
We consider numerical methods for solving inverse problems that arise in heart electrophysiology. The first inverse problem
is the Cauchy problem for the Laplace equation. Its solution algorithm is based on the Tikhonov regularization method and
the method of boundary integral equations. The second inverse problem is the problem of finding the discontinuity surface
of the coefficient of conductivity of a medium on the basis of the potential and its normal derivative given on the exterior
surface. For its numerical solution, we suggest a method based on the method of boundary integral equations and the assumption
on a special representation of the unknown surface. 相似文献
136.
I. V. Kalinin V. M. Morozov A. G. Novikov A. V. Puchkov V. V. Savostin V. V. Sudarev A. P. Bulkin S. I. Kalinin V. M. Pusenkov V. A. Ul’yanov 《Technical Physics》2014,59(2):307-310
The basic characteristics of the upgraded DIN-2PI spectrometer are reported. Based on experimental data and numerical calculation results, it is concluded that a supermirror neutron concentrator, with which the DIN-2PI spectrometer is equipped, raises the density of the cold neutron flux at the sample almost by an order of magnitude. The use of a grooved moderator in channel no. 2 and upgrading of the core of the IBR-2M reactor increases the neutron flux density on the sample by about 40% more. 相似文献
137.
Silchenko AS Kalinovsky AI Avilov SA Andryjaschenko PV Dmitrenok PS Yurchenko EA Kalinin VI 《Natural product research》2012,26(19):1765-1774
New triterpene glycosides, cucumariosides H? (1), H? (2) and H? (3), have been isolated from the Far Eastern sea cucumber Eupentacta fraudatrix. The structures of 1-3 were elucidated using extensive NMR spectroscopy (1H- and 13C-NMR, DEPT, 1H-1H COSY, 1D TOCSY, H2BC, HMBC, heteronuclear single-quantum coherence, and NOESY) and ESI-MS. Glycosides 1-3 are monosulphated branched pentaosides having rare 3-O-methyl-D-xylose as a terminal monosaccharide. Glycosides 1 and 3 contain holostane aglycones, whereas 2 has a 23,24,25,26,27-pentanorlanostane aglycone with an 18(16)-lactone, which is also uncommon for the sea cucumbers. Glycoside 3 contains a very rare ethoxyl radical at C-25 of the aglycone side chain, and it is most probably an artefact that was formed during long storage of the ethanolic extract. Cytotoxic activities of 1-3 against mouse spleen lymphocytes, haemolytic activity against mouse erythrocytes and Ehrlich carcinoma cells have been studied. The presence of 25-hydroxy group in aglycone moiety significantly decreased the activities. 相似文献
138.
L. Yu. Korotkova Yu. B. Gurov E. M. Kalinin V. S. Karpukhin S. V. Lapushkin V. G. Sandukovskii B. A. Chernyshev T. D. Shchurenkova 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(4):400-403
The origin of the 9Li isotope is sought in missing-mass spectra measured in 11B(π−, d)X, 12C(π−, pd)X, and 14C(π−, dt)X stopped-pion absorption reactions. The parameters of the three observed low-lying excited states coincide with the literature
data. A state with excitation energy E
x
= 9.1 ± 0.1 MeV, lying above the threshold of 9Li decay into 6He + t, is observed for the first time. 相似文献
139.
Stolichnov I Maksymovych P Mikheev E Kalinin SV Tagantsev AK Setter N 《Physical review letters》2012,108(2):027603
Polarization reversal in ferroelectric nanomesas of polyvinylidene fluoride with trifluoroethylene has been probed by ultrahigh vacuum piezoresponse force microscopy in a wide temperature range from 89 to 326 K. In dramatic contrast to the macroscopic data, the piezoresponse force microscopy local switching was nonthermally activated and, at the same time, occurring at electric fields significantly lower than the intrinsic switching threshold. A "cold-field" defect-mediated extrinsic switching is shown to be an adequate scenario describing this peculiar switching behavior. The extrinsic character of the observed polarization reversal suggests that there is no fundamental bar for lowering the coercive field in ferroelectric polymer nanostructures, which is of importance for their applications in functional electronics. 相似文献
140.
Petr A. Kalinin Vitaly V. Kocharovsky Vladimir V. Kocharovsky 《Solid State Communications》2012,152(12):1008-1011
We consider exciton recombination lasing in heterostructure traps for Bose–Einstein condensation of dipolar excitons. We show that such structures suit well for class D lasers where cavity decay strongly exceeds polarization decay. We evaluate lasing threshold taking into account specific inhomogeneous broadening of the exciton spectral line owing to Bose–Einstein condensation phenomenon under quasi-equilibrium conditions.It is found that narrowing of the exciton momentum distribution just before the condensation onset considerably lowers lasing threshold. At the same time, it is pointed out that a subsequent formation of condensate itself does not help lasing much. We conclude that it is possible to achieve lasing on polariton modes in nowadays experiments aimed on Bose–Einstein condensation of excitons. 相似文献