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1.
I. N. Ivchenko S. K. Loyalka R. V. Tompson 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2002,25(6):58-72
The slip phenomena in gas mixtures are of fundamental significance in the specification of boundary conditions for flows in the slip regime. In a recent paper, new explicit results for the slip coefficients appropriate to binary gas mixtures were reported. The present work being reported extends the previous work to a higher level of accuracy by involving a higher order Chapman-Enskog expansion. In particular, new expressions for the slip coefficients are presented which are applicable for arbitrary models of the intermolecular interaction. Limiting expressions for the slip coefficients are given (for a simple gas) and the accuracy of the theory is discussed. Numerical calculations of the slip coefficients for different binary gas mixtures using the first and second order Chapman-Enskog approximations and the rigid sphere and Lennard-Jones (12-6) potential models have been carried out. The thermal creep and diffusion slip coefficients are found to be sensitive to the order of the approximation and to the potential model used. A comparison of the new higher order results with some of our previously obtained experimental data for the thermal transpiration effect has also been carried out and shows excellent agreement between the theory and the experiments which confirms the accuracy of the theory. 相似文献
2.
Alkynyl-substituted indene was first used as a ligand for the synthesis of transition metal complexes. ansa-Zirconocenes containing ethylene and dimethylsilylene bridges were synthesized starting from 2-(phenylethynyl)-1H-indene. The structure of the former compound was established by X-ray diffraction.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 68–73, January, 2007. 相似文献
3.
V. A. Ivchenko 《Technical Physics》2014,59(9):1403-1405
Experimental results on atomic-spatial investigation of radiative defect formation in surface layers of materials, initiated by neutron bombardment (of Pt, E > 0.1 MeV) and ion implantation (in Cu3Au: E = 40 keV, F = 1016 ion/m2, j = 10?3 A/cm2), are considered. Quantitative estimates are obtained for the size, shape, and volume fraction of cascades of atomic displacements formed under various types of irradiation in the surface layers of the materials. It is shown that the average size of radiation clusters after irradiation of platinum to a fast neutron fluence of 6.7 × 1022 m?2 (E > 0.1 MeV) is about 3.8 nm. The experimentally established average size of a radiation cluster (disordered zone) in the alloy after ion bombardment is 4 × 4 × 1.5 nm. 相似文献
4.
5.
Ivchenko N Hughes CE Levitt MH 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2003,164(2):286-293
Cogwheel phase-cycling schemes are applied to sideband suppression and sideband separation experiments in solid-state NMR. It is shown that cogwheel phase cycles lead to the elimination of most pulse imperfection effects, while using far fewer experimental signal acquisitions than conventional phase-cycling methods. 相似文献
6.
The fine structure of the exciton ground level in a spherical nanocrystal of a zincblende or a wurtzite structure semiconductor was calculated with the inclusion of short-and long-range (nonanalytical), exchange-interaction components. The band-parameter dependence of the long-range exchange-interaction contribution to the spin Hamiltonian describing the exciton ground-level splitting was found. A study was made of the effect exerted on the exciton-level fine structure by the difference between the background dielectric permittivities of the nanocrystal and of the dielectric host in which it was grown. 相似文献
7.
P. V. Ivchenko I. E. Nifant’ev L. Yu. Ustynyuk V. A. Ezerskii 《Russian Chemical Bulletin》2009,58(5):929-935
The acid-catalyzed cyclization of 1-(3,4-dialkylaryl)-3-chloropropan-1-ones to dialkylindanones via the intermediate formation of (3,4-dialkylaryl)propenones was studied. This reaction affords isomeric products: 5,6-dialkylindan-1-ones
and 4,5-dialkylindan-1-ones. The DFT quantum chemical calculation results correlate with the experimental data and suggest
that the structural factors affect the ratio of products. 相似文献
8.
T. M. Ushakova E. E. Starchak V. G. Krasheninnikov A. A. Samoilenko P. V. Ivchenko I. E. Nifant’ev L. A. Novokshonova 《Kinetics and Catalysis》2012,53(1):75-83
Ethylene polymerization and ethylene-1-hexene copolymerization in the presence of metallocene catalysts based on Cp2ZrCl2, rac-Et(Ind)2ZrCl2, rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2, and rac-Me2Si(2-Me-4-Ph-Ind)2HfCl2 been investigated. The catalysts have been immobilized on montmorillonite (MMT) containing methylaluminoxanes (MMT-H2O)/AlMe3 or isobutylaluminoxanes (MMT-H2O)/ Ali-Bu3 synthesized directly on the support surface. The immobilized catalysts, with the general formula (MMT-H2O)/AlR3/Zr(Hf)-cene, show a high activity comparable with the activity of the respective homogeneous systems, which depends on the
nature of the metal and on the metallocene composition and structure. The catalytic properties of the metallocene systems
depend strongly on the nature of the activator as a component of the catalytic complex. (MMT-H2O)/Ali-Bu3 is a more effective activator of the hafnocene precatalyst in the polymerization processes than oligomeric methylaluminoxane
or methylaluminoxane synthesized on the support. The immobilization of the metallocenes on (MMT-H2O)/AlR3 leads to an increase in the molar mass of polyethylene and ethylene-1-hexene copolymers relative to the molar mass of the
polymers synthesized using the respective homogeneous systems. The immobilized metallocene catalysts display high selectivity
toward the insertion of a higher α-olefin (1-hexene) into the polymer chain, retaining this important property of their homogeneous
counterparts. 相似文献
9.
A two-parameter generalization of Jaccard's index of similarity is proposed as a class of measures for testing the homogeneity of two independent multinomial samples. The power approach used in modern asymptotic theory of decomposable statistics is applied to the asymptotic analysis of these measures. The asymptotic analysis is amplified by numerical tabulation yielding an asymptotically optimal similarity test in this class of measures.Translated fromMatematicheskie Zametki, Vol. 58, No. 4, pp. 536–546, October, 1995. 相似文献
10.
I. E. Nifant’ev P. V. Ivchenko A. V. Shlyakhtin A. V. Ivanyuk 《Polymer Science Series B》2017,59(2):147-156
Using quantum-chemical calculations (DFT, program Priroda), the formation of a catalyst species on the basis of magnesium complexes with 2,6-di-tert-butyl-4-methylphenol is discussed. A comparative theoretical and experimental study of the ring-opening polymerization of trimethylene carbonate, 1,4-dioxanone, δ-valerolactone, and ε-caprolactone in the presence of the monoionolate magnesium complex is performed. It is shown that the calculated values of activation barriers correlate with the observed order of activity of cyclic esters. The maximum rate of polymerization is exhibited by trimethylene carbonate. 相似文献