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41.
42.
Yu. G. Abov D. S. Denisov N. O. Elyutin S. K. Matveev Yu. I. Smirnov A. O. Éidlin F. S. Dzheparov D. V. L’vov 《Journal of Experimental and Theoretical Physics》1998,87(6):1195-1200
The asymptotic behavior of the spectra for large values of the scattering vector for the case of elastic multiple small-angle
neutron scattering (SANS) is investigated theoretically and experimentally. An expansion of the spectrum in terms of the reciprocal
of the magnitude of the momentum transfer is obtained taking account of the influence of the instrumental line. It is shown
that, to within some factor, the leading term of the expansion is identical to the differential single-scattering cross section
averaged over a statistical ensemble of particles; several subsequent terms in the expansion are calculated and the range
of applicability of the resulting expressions is determined. The asymptotic behavior of the multiple SANS spectrum is measured,
using a two-crystal neutron spectrometer, for samples of an HTSC ceramic, the alloy Fe-Ni, and Al powder. The agreement between
the experimental results and the theoretical predictions is analyzed.
Zh. éksp. Teor. Fiz. 114, 2194–2203 (December 1998) 相似文献
43.
44.
A. I. Khil’ko A. G. Luchinin V. G. Burdukovskaya I. P. Smirnov 《Acoustical Physics》2007,53(3):381-392
Potentialities of observing spatially localized inhomogeneities by the low-frequency low-mode pulsed diffraction tomography in a shallow sea are analyzed. A numerically simulated model is used to study the procedure of reconstructing the parameters of inhomogeneities by coprocessing the signals of the tomographic projections formed at the multistatic excitation and reception of low-frequency low-mode acoustic pulses. 相似文献
45.
Th. Brückel Y. Chernenkov B. Dorner V. P. Plakhty O. P. Smirnov 《Zeitschrift für Physik B Condensed Matter》1990,79(3):389-395
We have measured the spin wave spectrum for the garnet Ca3Cr2Ge3O12 by means of inelastic neutron scattering. The data can be well described in the framework of linear spin wave theory if we assume a Heisenberg model with two exchange parameters up to the next nearest neighbours (J
1 andJ
2) and a staggered anisotropy field (A). A least squares fit to the observed dispersion relations yield the following values for these parameters: J
1=–0.582(8)K,J
2=0.416(4)K,A=0.25(8)K. Although symmetry requires that two nearest neighbour exchange constantsJ
1 andJ
1
'
must be distinguished, only the average J
1=(J
1+3J
1
'
)/4 and the condition –0.35 K <J
1=J
1-J
1
'
<0.50 K could be deduced from the experiment. The most striking result is the positive value ofJ
2. We discuss the implications for an understanding of superexchange mediated by more than one oxygen atom. In an extension of the conventional analysis we have calculated the integrated intensities in order to check the eigenvectors directly. Good agreement between observed and calculated intensities was obtained. 相似文献
46.
First example of the formation of bipolar spiro σ-complexes from 6-bromo-5,7-dinitrobenzo[e]-1,2,3,4-tetrazine 1,3-di-N-oxide 总被引:1,自引:0,他引:1
Voronina V. A. Frumkin A. E. Kurbatov S. V. Churakov A. M. Smirnov O. Yu. Olekhnovich L. P. 《Russian Chemical Bulletin》2002,51(4):668-670
The reactions of 3,5,7-trimethyltropolone and 2-(N-benzylamino)tropone with 6-bromo-5,7-dinitrobenzo[e]-1,2,3,4-tetrazine 1,3-di-N-oxide afforded novel bipolar spiro -complexes. The kinetic and activation parameters of the R,S-enantiotopomerization of a chiral spiro -complex of 2-(N-benzylamino)tropone were determined using dynamic 1H NMR spectroscopy. 相似文献
47.
Dissociative adsorption at 300 K is shown to proceed only on unreconstructed Pt(100)–(1×1) surface. When heated, NO (ad) layers behave in a similar way on both surfaces. Dissociation products are N2 and O(ad). Adsorption on the (hex) surface is supported to occur in islands. The island size in the saturation layer appears to be 40 Å. 相似文献
48.
49.
V. A. Smirnov V. A. Tushnalobova D. P. Semchenko 《Chemistry of Heterocyclic Compounds》1968,4(4):430-431
The possibility of reducing furfural to furyl alcohol with potassium and sodium amalgams under the conditions of neutralizing the alkali formed with carbon dioxide has been investigated. The reduction of furfural can be directed to the predominant formation of furyl alcohol by regulating the rate of feed of furfural into the reaction vessel. 相似文献
50.
Smirnov Yu. N. Komarov B. A. Kushch P. P. Ponomareva T. I. Lantsov V. M. 《Russian Journal of Applied Chemistry》2002,75(2):265-275
To control the structural contributions of the polycondensation and polymerization curing of epoxy resins, the curing kinetics of the composites diepoxide-tertiary amine and diepoxide-(primary + tertiary) amines is studied by the isothermal calorimetry. 相似文献