Yields of photonuclear reactions on the natural mixture of titanium isotopes were measured under exposure to a beam of bremsstrahlung $γ$-quanta with the end-point energy of 55 MeV. The results are compared with computations based on the TALYS model. It is shown that description of cross sections of photonuclear reactions on Ti isotopes requires the proper account for isospin and configuration splitting of the giant dipole resonance.
Show AbstractThe analytic solution to the problem of the Gaussian beam propagation through the non-uniform atmosphere has been derived.
Show AbstractA study of the acoustic irradiation of a moving uniform linear array consisting of a transverse distribution of quadrupoles with an arbitrary disposition of radiators is described. Analytic expressions for the acoustic irradiation were obtained. A mathematical simulation of the pressure amplitude-angle curve vs. array speed, aerial element number, and radiation frequency was performed. The findings may be applied to the interpretation of experimental data related to gas-jet acoustics.
Show AbstractThe dependence of the average binding energy of the resonance $g$-state of a D$^−_2$ center on the induction of an external magnetic field in a quantum well with a parabolic confining potential is studied using the zero-range potential method. It has been shown that with an increasing exchange interaction, the character of the dependence of the average binding energy of the resonance $g$-state of the D$^−_2$ center on the induction of the external magnetic field changes. It has been assumed that in $GaAs/AlGaAs$ quantum wells alloyed with small Si donors, resonance D$^−_2$ states can exist under conditions of exchange interaction. It has been found that in spectra of impurity magneto-optical absorption in multiwall quantum structures, exchange interaction manifests itself as oscillations of interference origin.
Show AbstractA space-time model that treats the urban ecosystem as a superposition of active media is expanded to take the heterogeneity of anthropogenic and natural factors into account. The approach is based on representation of urban ecosystems as conjugated active media and is aimed at identifying the threshold values of control parameters. The theoretical basis of the system analysis of the stability of urban ecosystems is provided by synergetic ideas concerning autowave self-organization in active media.
Show AbstractThe analysis of polarized fluorescence of the fluorescein family markers was conducted and parameters of their rotational diffusion in bovine serum albumin solutions (BSA) were determined. The degree of fluorescence anisotropy of the markers increases in the BSA solutions, as well as the time of rotational relaxation of the markers, while the rotational-diffusion coefficient of the markers decreases. The differences in the rotational-diffusion parameters between the markers are determined by the values of the electronegativity of the atoms in their structural formulas: the increase of the electronegativity of the atoms in the structural formulas of the markers results in the increase of the degree of fluorescence anisotropy, a decrease of the rotational-diffusion coefficient, and in the increase of the rotational-relaxation time both in the solutions without the protein and with BSA.
Show AbstractIn accordance with the Heisenberg uncertainty principle, a similar dynamics (behavior) for complex biosystems is postulated. Five peculiar properties and thirteen differences of these specific three-type systems (complexity) from traditional deterministic and stochastic systems determine the need for introducing the uncertainty principle for these specific systems. The value of the special boundary volume of the phase space, V$_{min}^G$, (which is considered as quasiattractor) inside of which the state vector of a biosystem moves chaotically and permanently, is the right side of this inequality. The volumes V$_{min}^G$n andV$_{max}^G$ really represent the peculiar properties of each dynamic biosystem (or each three-type system) as complexity. Particular examples from biomechanics prove the impossibility of using the deterministic or stochastic approach for the description of complexity, and only methods of the new theory of chaos (self-organization) can be useful for the description of complex biosystems. The possibilities of the practical application of this theory in various fields of biology and medicine are also discussed.
Show AbstractResults of studying the origin of “meander”-like and “slit”-like variations in fluxes of solar cosmic rays (SCR) are presented as exemplified by the events that occurred on March 19, 1990 and December 14–15, 2006. Experimental data that were obtained by the GRANAT, ACE, Wind, STEREO-A, and STEREO-B spasecrafts are used. The analysis is based on the data of observations of dynamic structures in the solar atmosphere and their continuation in the heliosphere, as well as on an empirical “reflection” model of the movement, accumulation, and modulation of cosmic rays. A structural source of these variations on the Sun is discussed, which is shaped as discrete magnetic plasma loops and arches located between active regions. Such structures in the form of magnetic-plasma tubes transferred from the chromosphere and corona and filled with SCR rotate together with the Sun and, when crossing the detector location region, cause space-time variations in meander-like and slit-like variations in SCR.
Show AbstractA closure scheme for Kolmogorov spectrum at low and high frequencies is proposed. It allows us to validate second Kolmogorov hypothesis if expand the first one. The proposed closure scheme adds energy of turbulence to the list of controlling parameters and explains energy transfer over the spectrum by wave interaction between incompressible and adiabatic components of turbulence.
Show AbstractThe results of an in-situ study and mathematical modeling of a system of currents with wind-induced and density flows are presented. The model is based on the obtained dependences of its key parameters on the density-field characteristics, changes in the water level, and the water-reservoir topography. The revealed features of the of shear-velocity profile are indicated and a function of its distribution from the bottom to the open surface of the water is given. The model that was developed is verified by the data from measuring the parameters of currents and composition of water in the Petrozavodsk Bay of Onega Lake in September 2007. The regularities for the evolution of distributions of the coefficient of the turbulent exchange and current velocity over depth and in time are revealed.
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