Thermal dissociation of diatomic molecules in a nonisothermal two-temperature boundary layer

Nonequilibrium thermal dissociation in a nonisothermal boundary layer in a mixture of Morse anharmonic oscillators — molecules of a diatomic gas and its atoms — is considered within the framework of the ladder mechanism. The local nonlinear nonequilibrium corrections to the two-temperature macroscopic dissociation rate, which depend, in particular, on the translational and vibrational temperature gradients and the degree of dissociation, are determined.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 191–201, March–April, 1996.     

Methods of Coherent X-Ray Diffraction Imaging

Crystallography Reports - Methods of coherent X-ray diffraction imaging of the spatial structure of noncrystalline objects and nanocrystals (nanostructures) are considered. Particular attention is...     

Time and space domain separation of pulsed X-ray beams diffracted from vibrating crystals

It is known that a set of additional reflections (satellites) may arise on rocking curves in the case of X-ray diffraction in the Bragg geometry from crystals where high-frequency ultrasonic vibrations are excited. It is shown that, under certain conditions, the pulse wave fields of the satellites and main reflection may be intersected in space (playing the role of pump and probe beams) and in time (forming interference superlattices).     

The principle of material frame-indifference and cylindrical couette flow of a rarified gas

The problem of a free molecular cylindrical Couette flow in a rotating coordinate system at different temperatures and the same angular velocities of the walls is considered. It is proved that, in an approximation which is linear in the angular velocities, the azimuthal thermal flux is proportional to the angular velocities of the walls in a fixed system of coordinates. An example of the flow of a gas which does not satisfy the principle of material frame-indifference (PMI) in the axiomatic theory of the mechanics of continuous media is thereby constructed and, consequently, the above-mentioned principle is not a universal principle of mechanics.     

Boundary conditions for the equations of two-temperature gas dynamics of a binary mixture with strongly differing masses of the components

A study is made of the problem of the boundary conditions for the equations of two-temperature gas dynamics for a binary mixture with strongly differing masses when (m/M)^1/2 Kn 1 (Kn is the Knudsen number, m is the mass of the light molecules, and M the mass of the heavy molecules). The flow structure is established at velocities of the light and heavy components of the order of the velocity of sound of the heavy component. The formulation of the boundary conditions for the gas-dynamic equations is investigated. It is shown that the only closed boundary layer theory is Prandtl's theory taking into account terms of order Kn^1/2.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 93–98, September–October, 1982.I thank M. N. Kogan, N. K. Makashev, and E. S. Asmolov for assistance in the work and valuable discussions.     

Modification of the burnett equations and shock wave structure

Questions of the applicability of simplifying modifications of the Burnett equations are studied with reference to the problem of the shock wave structure in a monatomic gas. As distinct from the complete system of Burnett equations, the order of the systems of modified equations is the same as that of the Navier-Stokes equations, and the equations are stable with respect to shortwave perturbations. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 164–176, May–June, 1998. The work was carried out with financial support from the Russian Foundation for Basic Research (project No. 96-01-01244).     

Suppression of anomalous X-ray transmission under the effect of periodic nonresonance deformations

An analytical theory for interpreting the suppression of the Borrmann effect in the Laue diffraction from thick crystals with the deformation superlattice with the period exceeding the extinction length has been developed. The theory has been used to describe the diffraction from hematite crystals in which the domain structure is rearranged in an applied magnetic field.     

Recent advances in (hetero)cyclizations of N-vinylazoles (microreview)

Chemistry of Heterocyclic Compounds - Recent advances in chemistry of N-vinylazoles are surveyed in this microreview, including results published in the last decade. In particular, reactions...