Vol 88, No 4 (2024)

Within the framework of a new approach to the problem of calculating the total energy of a diatomic molecule in the first order of perturbation theory, it is shown that the potential energy screening function is a solution to a diffusion-type equation in which the role of a time variable is played by the average square of the amplitude of collective oscillations of electrons per one degree of freedom. The total energy of two carbon atoms in the ground and excited states is calculated.

Experimental data are presented on the minimum values of energies and flux densities of electrons, the impact of which on the cover glasses of solar batteries and reflecting elements of thermoradiators of artificial Earth satellites leads to electrostatic discharges. It has been established that the addition of protons to the composition of the particle flux acting on the studied samples can suppress the development of discharges. For a qualitative interpretation of the results obtained, a mathematical model is proposed.

We presented the results of an experimental study and numerical simulation of the ion beam current distribution on the target of a collapsible miniature linear accelerator. The comparison of the experimental results with the simulation results is carried out. It is shown that the computational model makes it possible to estimate the effect of an ion beam on target sputtering in a miniature linear accelerator.

We discussed the development of cathodic electrochemical exfoliation of graphite, accompanied by a plasma discharge with a voltage of 200V DC, in an aqueous solution of various electrolytes. The method of cathodic electrochemical exfoliation of graphite has established itself as a promising eco-friendly industrial method for producing nanographite with subsequent grinding by ultrasound into low-layer graphene (FLG). Cathodic exfoliation allows selective doping of nanographite oxygen atoms.

We presented the results of a computational study on optimizing the shape of the main elements of a radio-frequency ion thruster – the discharge chamber and the ion-extraction system grids. The possibility of improving the integral characteristics of thrusters and ion sources due to the use of an additional magnetostatic field in the RF discharge region was considered. The performed series of calculations made it possible to determine the optimal geometry of the discharge chamber and of the RIT ion-extraction system grids, as well as the configuration of the additional magnetic field, at which the best values of the integral characteristics were achieved.

We presented the results of studying the features of various resonant modes excitation in a spatially non-homogeneous magnetophotonic crystal with a plasmonic coating. It has been shown that in a such crystal several resonant Fabry-Perot modes and the Tamm plasmon mode are generated at once, which undergo a spectral shift inside the photonic bandgap when the thicknesses of the optical and magnetic layers of magnetophotonic crystal is change.

The composition and magnetic properties of foraminifers from bottom sediments of the Mid-Atlantic Ridge and their artificial analogues obtained by hydrothermal synthesis have been studied. The presence of magnetic hysteresis and theoretical modeling of hysteresis characteristics made it possible to assume the presence of grains of nonstoichiometric magnetite in single and low-domain states.

Ferrihydrite nanoparticles have been synthesized and characterized. The dependences of the temperature increment of powders in the pumping mode by a high-frequency electromagnetic field in a constant magnetic field are studied. It is shown that the experimental dependence of the particle temperature on the dc magnetic field strength is in good agreement with the theory of ferromagnetic resonance for an isotropic superparamagnetic.

The influence of the dispersion of the particles of the synthesized nickel-zinc ferrite powder on its structural and magnetic properties is shown. Ferrite powder was produced using ceramic technology. The average particle size was varied using the mechanical activation method. According to X-ray diffraction analysis, laser diffraction and thermal analysis, regularities were established for the formation of the properties of nickel-zinc ferrite depending on the modes of mechanical activation.

Results of theoretical study of kinetics of the remagnetization of an ensemble of interacting ferromagnetic particles immobilized in a host non -magnetic medium are presented. The results show that the influence of interparticle interaction on the remagnetization is determined by the amplitude of the applied alternating field: it slows down this process in a weak field and accelerates it in a strong field. The interaction of particles increases both components of the complex magnetic susceptibility of the composite.

We examined the impact of the percentage of lead zirconate-titanate microparticles as a filler in a polyvinylidene fluoride-based composite material on its mechanical, piezoelectric, and structural properties. Our findings revealed that the incorporation of 10% lead zirconate titanate particles resulted in an enhanced piezoelectric response due to a significant increase in the degree of polymer crystallinity for this concentration on the condition of conservation of the ultimate stresses value of the material in the acceptable range for the implementation of mechanical stress sensors.

The possibility to determine the magnetostriction coefficient a of a magnetoactive elastomer is theoretically demonstrated by way of simple isometric experiment, when the force is measured that emerges in result of application of a field in the direction along which the dimension of the sample is fixed. It is shown that the value of a may be found from analyzing the dependence of the force (or surface pression) on the aspect ratio of the sample.

We studied the coefficient of reflection and transversal Kerr effect for a series of two-dimensional magnetoplasmonic crystals based on silver, permalloy Ni₈₀Fe₂₀ and silicon nitride Si₃N₄. It is shown that the filling factor of the samples has a nonlinear effect on their optical and magneto-optical properties. The maximum value of the Kerr effect is 0.88% with a filling factor of 0.77.