Investigation of rare-earth manganates and manganites by the µ<Emphasis Type="Italic">SR</Emphasis>-method

The present paper is devoted to studying the multiferroics HoMnO₃, YMnO₃, EuMn₂O₅, and GdMn₂O₅ by means of the µSR-method. Determination of the dynamic relaxation parameter 7n and the distribution of the local magnetic fields results in a clear phase diagram.     

A distortion of the aromatic character of 7-azaindole in solid-state after its N7 protonation: linear polarized IR-spectroscopy of embedded chemicals in nematic host

The effect of N7 protonation on the IR-spectroscopic characteristics in solid-state and aromatic character of 7-azaindole (7AI) are elucidated by means of linear-polarized IR-spectroscopy of oriented colloids in nematic host. A comparison between the data of neutral and protonated form of 7AI is done. The experimental data are supported by theoretical ab initio ones and experimental UV-spectroscopic measurements.     

Solution of problems of oblique penetration of axisymmetric projectiles into soft soil based on local interaction models

A comparative analysis of the solutions of the three-dimensional problem of the oblique penetration of a rigid body into soft soil is carried out arsing interaction models based on one-dimensional solutions of the problem of the spherical cavity expansion. Both the well-known self-similar analytical solutions for an incompressible medium as well as the generalized solution for a compressible elastoplastic medium with separation of the shock wave which arises are considered. Use of the incompressible medium hypothesis, disregarding flow separation, in estimating the maximum values of the resistive forces leads to large errors. Taking account of compressibility enables the resistive forces to be refined appreciably and enables a satisfactory estimate of the deviation of the trajectories of bodies from the initial direction of motion to the obtained. In the proposed method of solving oblique penetration problems, a three-dimensional problem is reduced, on the basis of the plane sections hypothesis and disregarding peripheral mass and momentum flows, to the combined solution of a number of axisymmetric problems for each meridional section. It is shown that, with well-known local interaction models, this approach enables the reliability of the calculation of both the force and the kinematic characteristics of the penetration process to be increased considerably due to the fact that the dynamics of the free surface and cavitation effects of the covitating flow are taken into account.     

Nucleophilic Replacement of Hydrogen in para-Substituted Nitrobenzenes by Phenylacetonitrile Carbanion

The kinetic relations holding in nucleophilic replacement of hydrogen in para-substituted nitrobenzenes by phenylacetonitrile carbanion suggest a complex reaction mechanism involving two alternative pathways. The direction of the process is determined by the structure of intermediate -complex.     

Tautomerism of 2,2′-dihydroxyazobenzene

Conclusions A study of the structure of 2,2-dihydroxyazobenzene employing the methods of IR spectroscopy and LCAO MO as the Pariser-Parr approximation disclosed that this compound exists as a mixture of two tautomeric forms, the stability of which is approximately the same.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1334–1336, June, 1973.