The scattering of charged particles in the magnetic fields of current sheets with bell-shaped and double-humped current density profiles has been studied analytically and numerically. The particle scattering processes are shown to depend significantly on the structure of the current sheet. Thus, for example, when particles are scattered in double current sheets, a regime under which the compensation of two successive jumps in particle magnetic moments can lead to a quasi-regular type of motion, instead of a chaotic one, can be maintained in the system.
Show AbstractWe have obtained an exact solution to the Dirac equation for an electron in a constant uniform magnetic field by taking into account the anomalous magnetic moment and Lorentz invariance violation in minimal CPT-odd form. Based on the solution found, we have calculated synchrotron radiation characteristics and predicted possible observable effects attributable to the Lorentz invariance violation.
Show AbstractThe Jacobi equation on a geodesic of a Riemannian manifold with random curvature describes the propagation of light in a Universe with inhomogeneities. A formula for the effective space curvature is derived within the framework of a model with a gradual loss of memory. This curvature is shown to be negative for any correlation radius. The results are compared with the well-known results obtained within the framework of models with piecewise constant random curvature and a small correlation radius of curvature.
Show AbstractA method for analysis of a multiparticle event with a complicated structure is developed on the discrete wavelet transform basis. Two-dimensional histograms corresponding to a given function and the events simulated by a generator of nucleus-nucleus collisions at the center-of-mass energy $\sqrt{s}=5.5$ TeV are analyzed. It is shown that the wavelet analysis efficiently removes the background, distinguishes the ring structure of the multiparticle event, and allows the decrease in the threshold transverse jet energy required for the separation of the jet from the background.
Show AbstractA dynamical-statistical approach to the description of induced fission of heavy nuclei allowing for the nuclear dissipation phenomenon is proposed. The potential of the approach is demonstrated in processing experimental data on the fission probabilities for Pu isotopes, yields of shape isomers, and total fission time for the $\alpha+{}^{238}$U reaction at $E_{\alpha}=(20\div32)$ MeV.
Show AbstractThe physical series of the perturbation theory is defined for the case of multiparticle Coulomb scattering and the results of numerical calculations are given for the contribution of higher Born terms to the amplitude of the electron-induced quasielastic knockout of an electron from the hydrogen atom. The purpose is to find the range of applicability of the basic theory of such reactions.
Show AbstractA complex investigation of the structure and emission characteristics of linear-chain carbon is accomplished. This material is demonstrated to be stable at high temperature (700°C), and the thermal emission is shown to be governed by the Schottky mechanism with the material characteristics reaching record-breaking values: an emission threshold of 800 V/mm and a thermoionic work function of 0.43 eV. These values are found to arise during $sp^1$ carbon crystallization and vanish after its graphitization. The very low value of the work function of linear-chain carbon is theoretically substantiated.
Show AbstractThe model problem of a shock pulse incident on a spherical lipid membrane is used to calculate membrane deformation. Areas with a high probability of formation of unstable defects can be identified by analyzing the resulting solution and comparing the surface curvature with relative local changes in the surface area of the membrane elements.
Show AbstractHydrophobic association in a microphase-separated hydrogel of hydrophobically modified polyacrylic acid is studied by methods of small-angle neutron scattering and fluorescent spectroscopy with the use of pyrene as a probe substance. A fluorescence quenching technique is developed for determining the aggregation numbers of hydrophobic domains in weakly swollen polymeric gels. It is shown that the introduction of charged units into the gel leads to a decrease in the domains’ aggregation number because of the electrostatic repulsion of similarly charged units on their surface.
Show AbstractAn extension of a recently proposed compensation technique [1, 2] is elaborated to measure the thermal expansion coefficient of conducting fluids. The method is based on simultaneously exerting two modulation effects of different physical natures on a studied sample. This technique enables direct local measurements of the thermal expansion coefficient expressed in absolute units.
Show AbstractMossbauer spectroscopy and X-ray diffraction are used for structural study of nanopowders resulting from a 60% Fe + 40% Al mixture after mechanical activation, as well as their nanocomposite derivatives arising in the process of self-propagating high-temperature synthesis. The different nature of the iron-aluminum interaction in these nanotechnological processes is demonstrated.
Show AbstractThe main factors affecting the thermal properties of bottom sediments and their variability under the actual conditions of aqueous areas (using the Black Sea as an example) are analyzed on the basis of extensive experimental data obtained in the course of long-term expedition research. The results obtained are discussed in relation to problems concerning the accuracy of determining the density of heat flows through the bottoms of inland and marginal seas.
Show AbstractNew approaches to the study of the geomagnetic field history, rock magnetism, and the global features of rock magnetism are discussed in relation to the Earth’s evolution. A method for solving the problem of the existence of reversals by investigating the phenomenon of self-reversal in rocks is proposed.
Show AbstractAn abrupt rise of the permittivity ɛ of nickel ferrite-chromite (NiFeCrO$_4$) is discovered near the compensation temperature $T_c$. The hysteresis character of this increase is demonstrated. Correlation between the magnetic and electrical properties of the ferrite under study is revealed. The observed anomalous behavior of permittivity is thought to be due to a direct overlap of the $t_{2g}$ orbitals of the Cr$^{3+}$ ions in octahedral nodes.
Show AbstractThe measurement reduction method is used to restore the magnetic phase diagram for a system of superparamagnetic particles with different dispersion abilities. It is shown that using this method makes it possible to considerably reduce the consequences of the particle size spread and determine the domains of existence of different magnetic phases at the phase diagram.
Show AbstractIgnition of supersonic propane-air flows by electrode discharge is experimentally investigated for various propane supply systems, electrode-flow relative configurations, and durations of energy deposition.
Show AbstractExperimental results concerning the interaction of pulsed volume ionization with the supersonic gas flow in a shock tube are described. The spatiotemporal and spectral characteristics of a nanosecond volume discharge plasma with ultraviolet preionization from plasma electrodes are presented. It is shown that the ionization region can be localized using gasdynamic discontinuities. The coincidence of the glow region with the discharge energy release region is discussed.
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