Numerical modeling of the reflection coefficients for the plane sound wave reflection from a layered elastic bottom

The matrix method and its numerical realization are considered in calculating the complex reflection coefficients and refraction indices of plane sound waves for geoacoustic models of the ocean bottom in the form of homogeneous elastic (liquid) absorbing layers overlying an elastic halfspace. In calculating the reflection coefficients at high frequencies or in the presence of a large numbers of sedimentary layers, a passage from the Thomson-Haskell matrix approach to the Dunkin-Thrower computational scheme is performed. The results of test calculations are presented. With the aim of developing resonance methods for the reconstruction of the parameters of layered elastic media, the behavior of the frequency-angular dependences of the reflection coefficient are studied for various geoacoustic bottom models. The structure of the angular and frequency resonances of the reflection coefficients is revealed. The dependence of the structure (the position, width, and amplitude) of two types of resonances on the parameters of the layered bottom is considered.     

Diffusion and virial coefficient in a mercury-argon gas mixture

Theoretical and experimental data on molecular beams and the mutual diffusion coefficient (MDC) and second virial coefficient (SVC) for an Hg-Ar gas mixture as a representative of the mercuryinert gas family are matched on basis of the Morse potential and the relations of the molecular kinetic theory of rarefied gases. Tables of the MDC and SVC values in the temperature range of 200–2000 K are calculated, and estimates of their accuracy are presented.     

Fluorosulfation of fluoroalkyl halides

The basic characteristics of fluorosulfation of fluoroalkylhalides (effect of the structure of the polyfluoroalkyl, nature of the halogen, acid catalysis, etc.) with halogen fluorosulfates and peroxydisulfuryl difluoride were investigated. A mechanism was proposed for formation of fluorosulfonic acid fluoroalkyl esters based on the experimental and quantum chemical data.A. N. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1718–1732, August, 1992.     

Reactions of highly electrophilic polyfluorocarbonyl compounds with primary arylamines

C-Hydroxyalkylation of primary arylamines by highly electrophilic polyfluorocarbonyl compounds results from the direct reaction of the initial reagents and is competitively inhibited by equilibrium N-hydroxyalkylation. The presence of steric hindrances to the formation of N-hydroxyalkylation products and an increase in the ring C-nucleophilicity facilitate the C-hydroxyalkylation reaction.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 383–389, February, 1990.     

Maximization of the lift/drag ratio of airfoils with a turbulent boundary layer

The problem of seeking the maximum life/drag ratio for airfoils in an incompressible separationless high-Re flow is considered in the turbulent boundary layer approximation. Within the framework of this model, the maximization of the L/D ratio is redwed to the determination of a conditional extremum for a convex functional. An explicit analytical expression for the extremal solution is obtained. The angle-of-attack dependence of the L/D ratio is demonstrated. The global maximum of the L/D ratio is determined. The results are compared with the known data of numerical optimization. Kazan’. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 177–184, May–June, 1998.