Vol 59, No 10 (2017)

To confirm the hypothesis on the shock-wave nature of long-range effects upon corpuscular irradiation of condensed media presumably caused by emission and propagation of post-cascade shock waves, comparative experiments on ion beam modification and mechanical shock-wave loading of specimens of VD1 and D16 alloys of the Al–Cu–Mg system are performed. Direct analogy between the processes of microstructural change of cold-deformed VD1 and D16 alloys under mechanical shock loading and irradiation by beams of accelerated Ar⁺ ions (E = 20–40 keV) with low fluences (10¹⁵–10¹⁶ cm^–2) is established. This demonstrates the important role of the dynamic long-range effects that have not yet been considered in classical radiation physics of solids.

The paper discusses morphological structure peculiarities of nano- and microcrystals with pentagonal symmetry formed in the process of nickel electrodeposition when varying the technological parameters (current density, overvoltage, temperature, deposition time, electrolyte acidity) and offers the corresponding experimental data.

Based on the molecular and kinetic concepts, the paper presents the theory of phase transformations in lithium alanates with the release of hydrogen. The calculations are given for free energies of phases and their dependences on pressure, temperature, hydrogen concentration, and energy parameters are determined. The equations are derived for the thermodynamically-equilibrium states which determine the Pressure-Temperature-Concentration diagram and estimate the energy parameters with the use of experimental results taken from the literature. The investigation of the detected temperature/concentration dependence in crystals shows the impossibility of a complete hydrogen release from alanates. The paper contains isotherm and isopleth plots. A possibility is established for the hysteresis effect. A comparison is given to the theoretical and experimental results.

Size dependences of the nanocrystal sublimation and the evaporation heats of the corresponding nanodrops are investigated using the isothermal molecular dynamics and the tight-binding potential (on examples of Ni and Au nanoparticles). Results of computer simulation demonstrating linear dependences of the evaporation and sublimation heats on the particle reciprocal radius are compared with results of thermodynamic calculations as well as with experimental data for bulk phases of the same metals. It has been found that the size dependences of the evaporation and sublimation heats are directly related with the behavior of the size dependence of the melting heat that in its turn correlates with structural transformations in nanoparticles induced by the change of their size. The conclusion is drawn that there is some characteristic nanoparticle size (of the order of 1 nm) at which its crystal and liquid states become indistinguishable.

Using a novel ejection spraying unit and relying on new approaches, fibers are formed by the method of pneumatic melt blowing of polycarbonate, polypropylene, and polyethylene terephthalate. The proposed approach is based on the concepts of atomization of the polymer melt flow as a preferential regime for fibermaterial formation. From the analysis of the values of numerical characteristics in the zone of atomization and the physical background of the criteria under study a conclusion is drawn that the essential role in destruction of the jet belongs to the formation of a boundary layer in the melt under the action of friction forces, followed by its separation. An assumption is made on the prevailing action of the separating destruction of the melt jet via the mechanism of ‘skinning’ of the boundary layer of the melt due to a shorter time of its persistence compared to the development of the Kelvin–Helmholtz instability.

The methods of Mössbauer spectroscopy with X-ray phase analysis and Rutherford backscattering of protons were used to study the kinetics of diffusion and phase transformations in the layered iron-beryllium system. For the first time, the authors suggested and implemented a method for retardation of diffusion and phase formation processes in the layered iron-beryllium system using the barrier layer. It was established that the barrier layer limits the zone of beryllium dissolution in the area of implanted layer. The impact of the barrier layer on kinetics of thermally induced processes of diffusion and phase transformations in the layered Fe–Be system was determined using the example of Fe (10 μm): O⁺ – Be (0.7 μm) – ⁵⁷Fe (0.1 μm). The authors suggested and implemented a method for recovery of the distribution function of the admixture atom concentration in the solid matrix–admixture solution on the basis of the X-ray diffraction data. The kinetics of mutual diffusion was determined for Fe and Be atoms in the α-Fe(Be) solution for both sides of the layered systems with a barrier layer and without it using the suggested method for recovery of the distribution function of the Be atom concentration. It was established that for the system without a barrier layer, the share of iron atoms ends at t_ann ~ 5 h on the coating side and at t_ann ~ 7.5 h on the iron side, while for the barrier layer case – at t_ann ~ 20 h on the coating side and at t_ann ~ 40 h on the iron side.

X-ray photoelectron spectra, reflection electron energy loss spectra, and inelastic electron scattering cross section spectra of iron monosilicide FeSi are investigated. It is shown that the spectra of inelastic electron scattering cross section have advantages over the reflection electron energy loss spectra in studying the processes of electron energy losses. An analysis of the fine structure of the inelastic electron scattering cross section spectra allows previously unresolved peaks to be identified and their energy, intensity, and nature to be determined. The difference between energies of fitting loss peaks in the spectra of inelastic electron scattering cross section of FeSi and pure Fe are more substantial than the chemical shifts in X-ray photoelectron spectra, which indicates the possibility of application of the fine structure of the spectra of inelastic electron scattering cross section for elemental analysis.

The problem of the interaction in the η–⁶Li system is solved. To solve this problem, we used the cluster model in which the ⁶Li nucleus is described as a bound state of a deuteron and an α-particle. The cluster approach allows one to reduce the many-body problem to the interaction in a system of three particles: η–d–α. To solve the corresponding three-body equations, we used the separable representation of two-body driving potentials. Calculated values of the η⁶Li scattering length are presented.

A solution for the Potts model with arbitrary number of states on a Bethe lattice in a nonzero external field has been obtained. A line of first-order phase transitions has been constructed in the temperature – external-field plane, terminating at the point of the second-order phase transition. The magnitude of the magnetization jump on the phase-transition lines has been found, as well as some of the critical exponents characterizing this phase transition.

A general method for constructing first-order symmetry operators for the stationary Schrödinger and Pauli equations is proposed. It is proven that the Lie algebra of these symmetry operators is a one-dimensional extension of some subalgebra of an e(3) algebra. We also assemble a classification of stationary electromagnetic fields for which the Schrödinger (or Pauli) equation admits a Lie algebra of first-order symmetry operators.

A method for detection of impact orbits of near-Earth asteroids is considered. The method uses splitting of initial confidence region into a sequence of ellipsoidal hypersurfaces corresponding to preset values of the confidence coefficient. The method uses parametric equations of confidence ellipsoid in the six-dimensional phase space. The method is tested for detecting impact orbits of potentially dangerous near-Earth asteroids 1994 WR12 and 2015 RN35 posing an impact threat to the Earth.

The possibility is shown of a directional change of the dielectric permittivity of carbon foam promising for the use in shielding devices in the microwave frequency range. The frequency dependences of the transmission (T) and reflection (R) coefficients in the Ka-band are experimentally analyzed for the foams with the reticular structure. By the methods of 3D-modeling, the effect of the skeleton conductivity and pore and windows size on the value of electromagnetic shielding provided by such a medium is considered.

Results of investigation of lasing of epoxy polymer compositions with phenalemine 512 and ZnO nanoparticles are given. It is shown that incorporation of ZnO nanoparticles affects the lasing efficiency without reducing the operating lifetime. The material is promising for the development of laser-active media.

The aim of this work is to describe a method of numerical solution of the stationary Schrödinger equation based on the integral equation that is identical to the Schrödinger equation. The method considered here allows one to find the eigenvalues and eigensolutions for quantum-mechanical problems of different dimensionality. The method is tested by solving problems for one-dimensional and two-dimensional quantum oscillators, and results of these tests are presented. Satisfactory agreement of the results obtained using this numerical method with well-known analytical solutions is demonstrated.

Analytical expressions are obtained for the energy of a quasi-two-dimensional electron-hole liquid (EHL) and the threshold value of the barrier height for electrons, above which formation of the direct EHL is impossible. It is shown that the state with a quasi-two-dimensional EHL can be energetically favorable in semiconductors with the anisotropy of masses and (or) a large number of equivalent valleys. A comparison of the calculation results with the experimental data for the Si/SiGe/Si structure is made.

A new express method of indirect assessment of ¹³C/¹²C isotope ratio on ¹H nuclei is developed to verify the authenticity of ethanol origin in alcohol-water-based fluids and assess the facts of various alcoholic beverages falsification. It is established that in water-based alcohol-containing systems, side satellites for the signals of ethanol methyl and methylene protons in the NMR spectra on ¹H nuclei, correspond to the protons associated with ¹³C nuclei. There is a direct correlation between the intensities of the signals of ethanol methyl and methylene protons’ ¹H- NMR and their side satellites, therefore, the data obtained can be used to assess ¹³C/¹²C isotope ratio in water-based alcohol-containing systems. The analysis of integrated intensities of main and satellite signals of methyl and methylene protons of ethanol obtained by NMR on ¹H nuclei makes it possible to differentiate between ethanol of synthetic and natural origin. Furthermore, the method proposed made it possible to differentiate between wheat and corn ethanol.