Vol 63, No 3 (2018)

The symmetry of direct and reciprocal lattices and the symmetry of bend contours present in the electron microscopy images of nanothin crystals with elastic rotational distortion of the lattice are examined using the example of nanothin selenium crystals.

ITER plasma with parameters close to those with the inductive scenario is considered. The distribution functions of fast ions of deuterium D and tritium T are calculated while taking into account the elastic nuclear collisions with alpha particles ⁴He using the code FPP-3D. The D and T energy spectra detected by the neutral-particle analyzer (NPA) are determined. The plasma mixing effect on these spectra during sawtooth oscillations is studied. It is shown that the NPA makes it possible to detect sawtooth plasma oscillations in ITER and determine the percentage composition of the D‒T mixture in it both with the presence of instabilities and without them. A conclusion is drawn on the prospects of using NPA data in automatic controllers of thermonuclear fuel isotopic composition control and plasma oscillation regulation in ITER.

The specific features pertinent to the temperature dependence of the electronic and atomic properties of liquid bismuth that have been observed in experiments are investigated according to the ab initio molecular dynamics method using the SIESTA open software package. The density of electronic states, the radial distribution function of atoms, and the self-diffusion coefficient are calculated for the temperature range from the melting point equal to 545 K to 1500 K. The calculated data are in good agreement with the experimental data. It is found that the position of the first peak in the radial distribution function of atoms and the self-diffusion coefficient are characterized by a nonmonotonic dependence under the conditions of superheating by approximately 150 K above the melting temperature. In the authors’ opinion, this dependence feature is attributed to a change in the liquid short-range order structure.

At various structural-scale levels, the interaction between the aluminum alloy DT1 and a liquid eutectoid mixture of gallium and indium under the action of mechanical waves of the ultrasonic range is investigated. It is established that the deep penetration of the eutectoid mixture into the solid metal under ultrasonic action is due to the formation of channels along which the mixture moves. These channels are observed in both the axial and radial directions.

The results of simulation of detonation in a curved three-dimensional channel with a circular cross section of constant width blown through by a supersonic flow of a stoichiometric propane−air mixture are presented. In the bending zone, the channel wall was toroidal. The study was carried out within the framework of the one-stage combustion kinetics by the numerical method based on Godunov’s scheme in the original software package developed for multiparameter calculations and visualization of flows. The initiation of detonation occurs as a result of the formation of the shockwave configurations associated with the flow turn in the channel. Unsteady flow patterns are obtained, and their dependence on the parameters of the problem is investigated. The flow regime without detonation, the mode with the detonation wave emerging from the channel through the input cross section, and the mode with steady detonation are obtained.

The fundamental properties of parametrically excited oscillatory systems of the Kochin oscillator type with double degeneracy of frequencies are investigated. The qualitative phenomenon of their absence is established for arbitrarily small actions of a dissipative nature. As a result, the resonance motions of the first mode prove to be relatively more substantial; the excitation of subsequent odd modes is difficult in the applied aspect and requires a significant increase in the eigenvalue of the corresponding parameter.