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31.
32.
We present the results of calculations for the characteristics of a RATAN-600 radio telescope in the radio-Schmidt telescope
mode. The plane reflector and the principal antenna mirror were calculated as a two-mirror aplanatic system with a planoidal
mirror for Schmidt correction of the wave front of the wave incident at an arbitrary angle to the horizon. Formulas were derived
and codes were developed to calculate the configuration of the antenna-system mirrors and optimize the basic parameters of
the system. It is shown that a long-term (up to one-hour) tracking of cosmic sources is possible in this operation mode at
wavelengths greater than 2 and 4 cm for horizontal apertures of 100 and 150 m, respectively.
Special Astrophysical Observatory of the Russian Academy of Sciences, Nizhny Arkhyz, Russia. Translated from Izvestiya Vysshikh
Uchebnykh Zavedenii, Radiofizika, Vol. 43, No. 3, pp. 185–196, March, 2000 相似文献
33.
A. G. Merzhanov É. N. Rumanov B. I. Khaikin 《Journal of Applied Mechanics and Technical Physics》1972,13(6):845-850
In the general case the combustion of condensed systems is of a stage-wise character and the combustion front is multizone [1, 2]. Following the investigation of two-zone models [3–5] it became clear that, during multizone combustion, one of the zones of heat evolution is the controlling zone. The velocity of the front is equal to the velocity of the controlling zone; however, with a change in the parameters of the system, there is the possibility of a transition of the controlling role from one zone to another, as well as of the coalescence and splitting of zones. This paper discusses a generalization of the two-zone problem which makes it possible to go over to the analysis of a complex, multizone front and shows that, for a front with two reactions (in the condensed phase and in the gas) and with dispersion, there are in all three possible arrangements of the zones of heat evolution (two three-zone variants and one two-zone variant). All possible types of dependence of the combustion rate on the depth of the dispersion are found.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 6, pp. 99–105, November–December, 1972. 相似文献
34.
I. E. Makarov E. L. Protasova G. I. Khaikin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(11):1833-1837
Pulsed radiolysis and computer simulation of gamma radiolytic decomposition of organic nitrates in aqueous solutions were performed to determine the rate constants for reactions with the participation of intermediates determining the mechanism of the process. 2,4,6-Trinitrotoluene, 2,4-dinitrotoluene, and cyclic nitramine, cyclotrimethylene-trinitramine, were used as substrates. The bimolecular rate constants for the reactions of hydrated electrons (e aq ? ) and hydroxyl radicals (?OH) with the substrates and constants for the recombination of electron adducts and carbon-centered radicals (the products of the detachment of the H atom from the nitro compound molecule by the OH radical) were determined by direct measurements with the use of high-speed spectrophotometry. Computer simulation of the reaction scheme was used to estimate the rate constant for significant reactions, monomolecular forward and back reactions of electron adducts and electron transfer to molecular oxygen, and refine the rate constant for the reaction of e aq ? with tert-butanol. 相似文献
35.
Vogt N Khaikin LS Grikina OE Rykov AN Vogt J 《The journal of physical chemistry. A》2008,112(33):7662-7670
Thymine is one of the nucleobases which forms the nucleic acid (NA) base pair with adenine in DNA. The study of molecular structure and dynamics of nucleobases can help to understand and explain some processes in biological systems and therefore it is of interest. Because the scattered intensities on the C, N, and O atoms as well as some bond lengths in thymine are close to each other the structural problem cannot been solved by the gas phase electron diffraction (GED) method alone. Therefore the rotational constants from microvawe (MW) studies and differences in the groups of N-C, C=O, N-H, and C-H bond lengths from MP2 (full)/cc-pVQZ calculations were used as supplementary data. The analysis of GED data was based on the C(s) molecular symmetry according to results of the structure optimizations at the MP2 (full) level using 6-311G (d,p), cc-pVTZ, and cc-pVQZ basis sets confirmed by vibrational frequency calculations with 6-311G (d,p) and cc-pVTZ basis sets. Mean-square amplitudes as well as harmonic and anharmonic vibrational corrections to the internuclear distances (r(e)-r(a)) and to the rotational constants (B(e)(k)-B(0)(k), where k = A, B, C) were calculated from the quadratic (MP2 (full)/cc-pVTZ) and cubic (MP2 (full)/6-311G (d,p)) force constants (the latter were used only for anharmonic corrections). The harmonic force field was scaled using published IR and Raman spectra of the parent and N1,N3-dideuterated species, which were for the first time completely assigned in the present work. The main equilibrium structural parameters of the thymine molecule determined from GED data supplemented by MW rotational constants and results of MP2 calculations are the following (bond lengths in Angstroms and bond angles in degrees with 3sigma in parentheses): r(e) (C5=C6) = 1.344 (16), r(e) (C5-C9) = 1.487 (8), r(e) (N1-C6) = 1.372 (3), r(e) (N1-C2) = 1.377 (3), r(e) (C2-N3) = 1.378 (3), r(e) (N3-C4) = 1.395 (3), r(e) (C2=O7) = 1.210 (1), r(e) (C4=O8) = 1.215 (1), angle e (N1-C6=C5) = 123.1 (5), angle e (C2-N1-C6) = 123.7 (5), angle e (N1-C2-N3) = 112.8 (5), angle e (C2-N3-C4) = 128.0 (5), angle e (N3-C4-C5) = 114.8 (5), angle e (C6=C5-C9) = 124.4 (9). The experimental structural parameters are in good agreement with those from MP2 (full) calculations with use of cc-pVTZ and cc-pVQZ basis sets. 相似文献
36.
37.
Yu. V. Kul’velis V. T. Lebedev V. A. Trunov S. S. Ivanchev O. N. Primanchenko S. Ya. Khaikin 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2012,6(5):825-832
The method of small-angle neutron scattering has been used for the investigation of hydrogels synthesized on the basis of a cross-linked copolymer of 2-hydroxyethyl methacrylate and functional monomers (acrylic acid or dimethylaminoethyl methacrylate) which possess the memory effect with respect to the target pharmaceutical substance — cefazolin. The difference in the structure of anionic, cationic and amphiphilic hydrogels has been shown as well as the relation between the structure and the ability of a hydrogel for water sorption in the presence and in the absence of cefazolin. Certain structural features of the hydrogels confirmed the conditions for the appearance of the memory effect for the sorption and liberation of cefazolin. 相似文献
38.
A. A. Revina G. I. Khaikin E. L. Protasova N. B. Mezentseva E. V. Stepanova O. V. Skorobogat'ko 《Russian Chemical Bulletin》2000,49(8):1464-1467
The optical absorption spectra of laccases in aqueous solutions were found to undergo reversible changes in the presence of
O2. It was suggested that dioxygen is coordinated in the active center of the completely oxidized native enzyme. Abnormal behavior
of superoxide radical anions upon variation of the laccase concentration was found by pulse radiolysis.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1471–1474, August, 2000. 相似文献
39.
L. S. Khaikin O. E. Grikina V. A. Sipachev A. V. Belyakov E. T. Bogoradovskii 《Russian Chemical Bulletin》2000,49(4):631-641
The electron diffraction data on bis(trimethylstannyl)acetylene, Me3SnC≡CSnMe3, were analyzed in the framework of the one-dimensional dynamic model of free internal rotation of the SnMe3 group about the axis of the Sn−C≡C−Sn linear fragment. The root-mean-square amplitudes and harmonic shrinkage corrections used in the analysis were calculated from the scaled quantum-chemical force field (i) taking into account nonlinear relations between Cartesian and internal vibrational coordinates at the first-order level of perturbation theory (h1) and (ii) using a conventional approach (h0). Ther h1 parameters of internuclear distances describe the equilibrium geometry of the Me3SnC≡CSnMe3 molecule much better than the commonly accepted parametersr α ≡r h0 . Substituent effects on the geometry of the acetylene fragment are discussed. 相似文献
40.
Khaikin L. S. Grikina O. E. Kramarenko S. S. Zhilinskaya E. A. Zhilinskii B. I. 《Russian Chemical Bulletin》2001,50(9):1550-1562
Geometric parameters and force fields of two stable isomers of dimethylaminodichlorophosphine molecule, a gauche-conformer with C1 symmetry (A) and anti-conformer with C
s
symmetry (D), resulting from internal rotation about the P—N bond, were calculated in the RHF/6-31G* approximation. Using the scaled quantum-chemical force field for the most stable conformer A, the first reliable interpretation of the vibrational spectra of the light and perdeuterated isotopomers of dimethylaminodichlorophosphine was obtained. The root-mean-square vibrational amplitudes, harmonic and anharmonic vibrational corrections, and centrifugal distortion corrections were also calculated. Structural analysis of electron diffraction data was performed with consideration of nonlinear kinematic effects at the first-order level of perturbation theory. The experimental values of the equilibrium geometric parameters were estimated. The results obtained suggest a nonplanar equilibrium configuration of the amino group in the dimethylaminodichlorophosphine molecule. 相似文献