Bulletin of the Russian Academy of Sciences: Physics最新文献

We have studied the effect of single and combined exposures to ionizing radiation and high hydrostatic pressure on Saccharomyces cerevisiae yeast. Sequential exposure to these stimuli has been shown to result in a synergistic effect. We have found equivalent values of absorbed ionizing radiation dose and hydrostatic pressure for sequential and single exposures.

An experimental study is performed of the effect high-fluence irradiation with argon ions at an energy of 30 keV has on the formation of a fuzz structure on a surface of tungsten under the exposure of stationary helium plasma. It is found that a fuzz layer approximately 1 μm thick forms only on flat areas of the ion-induced surface relief.

The properties of all polymorphs of ZrO₂—monoclinic (m-ZrO₂), tetragonal (t-ZrO₂), and cubic (c-ZrO₂) phases—were calculated using density functional theory. t-ZrO₂ activated with Y³⁺, N³⁺, and S⁴⁺ was studied. It was shown that the activation of ZrO₂ with nitrogen or sulfur extends the optical absorption edge to the visible region.

An experimental investigation is performed of physical phenomena observed upon the incidence of a superdirectional beam of backward volume spin waves on a circular hole through a tangentially magnetized ferrite film. It is found that both diffraction and scattering of the spin waves occur when they fall on the inhomogeneity, and are accompanied by the effective excitation of intrinsic spin oscillations or modes localized in the region of the ferrite film adjacent to the hole.

Expansion of the functionality of rapid monitoring into the state of condensed matter by nuclear magnetic resonance in weak fields was shown to require solving the Bloch equations considering the features of recording its signal during field modulation. New relationships were obtained for the absorption signal v and dispersion signal u, as well as the z component of the magnetization, which made it possible to obtain a new explicit dependence of the critical points of the absorption signal (for the other two quantities, these dependences are derived similarly) on the field parameters, the autodyne circuit, and the relaxation times T₁ and T₂ of the medium under study. Based on the analysis of the obtained relationships, a new expression using u and v was proposed to describe the recorded NMR signal using the modulation technique. The calculated NMR signal was compared with the experimental one. The necessity was substantiated for creating automatic adjustment of the modulating field amplitude in the design of a mobile NMR relaxometer to increase the signal-to-noise ratio and reduce the influence of modulation effects on the research results.

We presented the results of a study on the spectra of photo-, cathodo-, and X-ray luminescence of diamond samples obtained by the temperature gradient method and subjected to radiation-thermal treatment. It is shown that cathodoluminescence can be used as a rapid method for determining the impurity-defect composition of crystals. Photoluminescence allows for the localized excitation of defect centers in the crystal. X-ray luminescence proved to be the least informative in terms of determining the defect composition; however, the conducted studies demonstrated that diamond samples containing NV⁰ centers can be used as visualizers of synchrotron beams.

Research has been proposed and conducted on the modification of silicone brand M750 and silicone rubber compound IRP 1338, aimed at increasing the dielectric permittivity to specified values. Studies have also been carried out on insulation without the addition of modifying additives and modified insulation under impulse voltage. This insulation is intended for use in the electrode system of electric discharge technologies. As a result of the experiments conducted, the dielectric permittivity increased to 35.81.

A study of the propagation of a nonlinear diffusion wave of a magnetic field during the skin explosion of cylindrical hollow conductors and ones that have a deposited layer of higher conductivity was carried out on a MIG generator (current amplitude up to 2 MA with a rise time 100 ns). It was experimentally confirmed that a deposited layer with higher conductivity to a conductor slowing down the nonlinear diffusion of the magnetic field into the conductor. At the same time, despite the fact that the glow of the surface of a double-layer conductor in the visible range begins earlier, there was no difference in the velocity of expansion of the surface plasma of a homogeneous conductor and a double-layer one.

We have synthesized a new series of heteroleptic halogen-substituted complexes with the general formula [XL₂Bipy]Cl, where L = 1-(4-fluorophenyl)-3-(4-bromophenyl)-propane-1,3-dione; Bipy = 2,2'-bipyridine; and X = Fe³⁺, Ga³⁺, Eu³⁺. Their structure and phase behavior have been studied and their magnetic properties have been investigated in a wide temperature range and analyzed theoretically.

We investigated the evolution of ionization fronts and the formation of the electron energy distribution function (EEDF) in a nanosecond argon discharge with an extended hollow cathode. The calculations are performed using the Monte Carlo method at different stages of the discharge process. We describe the Monte Carlo method for calculating of the EEDF in a nanosecond pulse discharge. The results of the EEDF calculations for various stages of the discharge process at a gas pressure of 10 Torr and different distances from the bottom of the cathode cavity are presented. It is demonstrated that high-energy electrons with an energy exceeding 500 eV are generated during the discharge in this work.