A nonstationary form of the range refraction parabolic equation and its application as an artificial boundary condition for the wave equation in a waveguide

The time-dependent form of Tappert's range refraction parabolic equation is derived using Daletskiy-Krein formula form noncommutative analysis and proposed as an artificial boundary condition for the wave equation in a waveguide. The numerical comparison with Higdon's absorbing boundary conditions shows sufficiently good quality of the new boundary condition at low computational cost.Comment: 12 pages, 9 figure

Extension of the Space Experiment GRIS Onboard the ISS Capabilities: Registration of Short Gamma-ray Bursts and TGF

The unique capabilities of the detector, based on the CeBr3 crystal (very short flashing time) allow us to expand the range of problems solved in the GRIS experiment. In addition to registering solar flares that have characteristic times per second÷minute, this detector allows solving problems in identifying and recording characteristics of geophysical and astrophysical events (short gamma-ray bursts - SGRB and terrestial gamma-ray flares - TGF) in the time range of 10μs÷1 ms. The modification of the hardware of the GRIS device for solving these problems is described and discussed in this paper

Notion of territorial system's structure and some approaches to their modeling

Development, forming and functioning of the territorial systems of each level of hierarchy and form are complicated and durable processes. The notion of stability occupies the central place and connects with the presence in territorial system some unchangeable invariant, which serves as a starting point of stability. As an example of such invariant (the base carrier of invariant on time characteristics) the usage of structural sistem is proposed. Assignment of territorial system's structure as a function carrier and simultaneous as an invariant in time permits to state the question of the system management by influence on the structure. Ability of the structure for improvement mainly determines peculiarities of the territorial system's behavior and possibilities of their management. Proposed approach permits to use for modeling structure (general and special) multitude theory, which in one tern gives the possibility to determine the corresponding models and modeling structures, pick up special structures in accordance to their inner condition, use their different combinations as multitude of relations and multitude of operations as a base for the modeling structures, etc

Complex ecological-economical systems: Problems of study (economical aspect)

Economical mechanism of the regional land use has been studied as a basis of sustainable development. System of payment for the natural resources considered as a base of it. These payments reflect the diversity of economical forms of property rights by the subjects of the Russian Federation to the natural resources. Rent can serve as a basis for forming the rates of payments, as in the market economy the price for the natural resources is the capitalised rent. It is stated that the payment for the natural resources is the economical form of treatment, which has been pooling together during the process of their owing, using and ordering between their owners and users. The region appropriate the rent, as it is the owner of the bowels of the earth, and in some cases the land rent or the tax on it (under the presence of the private property to the land). The interconnection of such notions as economical growth, land use and protection of the environment has been proofed. The common goals and specific tasks of coming to a cooperative decision has been put, which are necessary for the land use

Neutrinos in a spherical box

In the present paper we study some neutrino properties as they may appear in the low energy neutrinos emitted in triton decay with maximum neutrino energy of 18.6 keV. The technical challenges to this end can be achieved by building a very large TPC capable of detecting low energy recoils, down to a a few tenths of a keV, within the required low background constraints. More specifically We propose the development of a spherical gaseous TPC of about 10-m in radius and a 200 Mcurie triton source in the center of curvature. One can list a number of exciting studies, concerning fundamental physics issues, that could be made using a large volume TPC and low energy antineutrinos: 1) The oscillation length involving the small angle of the neutrino mixing matrix, directly measured in this disappearance experiment, is fully contained inside the detector. Measuring the counting rate of neutrino-electron elastic scattering as a function of the distance of the source will give a precise and unambiguous measurement of the oscillation parameters free of systematic errors. In fact first estimates show that even with a year's data taking a sensitivity of a few percent for the measurement of the above angle will be achieved. 2) The low energy detection threshold offers a unique sensitivity for the neutrino magnetic moment which is about two orders of magnitude beyond the current experimental limit. 3) Scattering at such low neutrino energies has never been studied and any departure from the expected behavior may be an indication of new physics beyond the standard model. In this work we mainly focus on the various theoretical issues involved including a precise determination of the Weinberg angle at very low momentum transfer.Comment: 16 Pages, LaTex, 7 figures, talk given at NANP 2003, Dubna, Russia, June 23, 200

Electrochemical Synthesis of Nano-sized Silicon from KCI–K2SiF6 Melts for Powerful Lithium-Ion Batteries

Currently, silicon and silicon-based composite materials are widely used in microelectronics and solar energy devices. At the same time, silicon in the form of nanoscale fibers and various particles morphology is required for lithium-ion batteries with increased capacity. In this work, we studied the electrolytic production of nanosized silicon from low-fluoride KCl–K2SiF6 and KCl–K2SiF6–SiO2 melts. The effect of SiO2 addition on the morphology and composition of electrolytic silicon deposits was studied under the conditions of potentiostatic electrolysis (cathode overvoltage of 0.1, 0.15, and 0.25 V vs. the potential of a quasi-reference electrode). The obtained silicon deposits were separated from the electrolyte residues, analyzed by scanning electron microscopy and spectral analysis, and then used to fabricate a composite Si/C anode for a lithium-ion battery. The energy characteristics of the manufactured anode half-cells were measured by the galvanostatic cycling method. Cycling revealed better capacity retention and higher coulombic efficiency of the Si/C composite based on silicon synthesized from KCl–K2SiF6–SiO2 melt. After 15 cycles at 200 mA·g−1, material obtained at 0.15 V overvoltage demonstrates capacity of 850 mAh·g−1 . © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This research received no external funding. This work is performed in the frame of the State Assignment number 075-032020-582/1, dated 18 February 2020 (the theme number 0836-2020-0037)

Singularities, Lax degeneracies and Maslov indices of the periodic Toda chain

The n-particle periodic Toda chain is a well known example of an integrable but nonseparable Hamiltonian system in R^{2n}. We show that Sigma_k, the k-fold singularities of the Toda chain, ie points where there exist k independent linear relations amongst the gradients of the integrals of motion, coincide with points where there are k (doubly) degenerate eigenvalues of representatives L and Lbar of the two inequivalent classes of Lax matrices (corresponding to degenerate periodic or antiperiodic solutions of the associated second-order difference equation). The singularities are shown to be nondegenerate, so that Sigma_k is a codimension-2k symplectic submanifold. Sigma_k is shown to be of elliptic type, and the frequencies of transverse oscillations under Hamiltonians which fix Sigma_k are computed in terms of spectral data of the Lax matrices. If mu(C) is the (even) Maslov index of a closed curve C in the regular component of R^{2n}, then (-1)^{\mu(C)/2} is given by the product of the holonomies (equal to +/- 1) of the even- (or odd-) indexed eigenvector bundles of L and Lmat.Comment: 25 pages; published versio

Kinetic Inductance and Penetration Depth of Thin Superconducting Films Measured by THz Pulse Spectroscopy

We measure the transmission of THz pulses through thin films of YBCO at temperatures between 10K and 300K. The pulses possess a useable bandwidth extending from 0.1 -- 1.5 THz (3.3 cm^-1 -- 50 cm^-1). Below T_c we observe pulse reshaping caused by the kinetic inductance of the superconducting charge carriers. From transmission data, we extract values of the London penetration depth as a function of temperature, and find that it agrees well with a functional form (\lambda(0)/\lambda(T))^2 = 1 - (T/T_c)^{\alpha}, where \lambda(0) = 148 nm, and \alpha = 2. *****Figures available upon request*****Comment: 7 Pages, LaTe

Extremely polysubstituted magnetic material based on magnetoplumbite with a hexagonal structure: Synthesis, structure, properties, prospects

Crystalline high-entropy single-phase products with a magnetoplumbite structure with grains in the µm range were obtained using solid-state sintering. The synthesis temperature was up to 1400 °C. The morphology, chemical composition, crystal structure, magnetic, and electrodynamic properties were studied and compared with pure barium hexaferrite BaFe 12 O 19 matrix. The polysubstituted high-entropy single-phase product contains five doping elements at a high concentration level. According to the EDX data, the new compound has a formula of Ba(Fe6Ga1.25In1.17Ti1.21Cr1.22Co1.15)O19. The calculated cell parameter values were a = 5.9253(5) Å, c = 23.5257(22) Å, and V = 715.32(9) Å3. The increase in the unit cell for the substituted sample was expected due to the different ionic radius of Ti/In/Ga/Cr/Co compared with Fe3+. The electrodynamicmeasurements were performed. The dielectric and magnetic permeabilities were stable in the frequency range from 2 to 12 GHz. In this frequency range, the dielectric and magnetic losses were??0.2/0.2. Due to these electrodynamic parameters, this material can be used in the design of microwave strip devices. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The work was supported by the Russian Science Foundation, project No. 18-73-10049