Time-frequency analysis of patterns in activity of brain neuron ensemble by means of wavelet transform
Time-frequency analysis of patterns in activity of brain neuron ensemble by means of wavelet transform
V.V. Grubov$^{1,2}$, A.A. Koronovskii$^{1,3}$, E.Yu. Sitnikova$^{4}$, A.E. Hramov$^{1,2}$
In present work time-frequency characteristics of sleep spindles on EEG of WAG/Rij rats were studied by means of continuous wavelet transform. General frequency structure and average length was revealed, also complex dynamics during sleep spindle was discovered and tendency to growth of frequency from beginning to end of sleep spindle was shown. Structure changes in sleep spindles caused by aging of rats and evolving of epilepsy were discovered. Dynamics of sleep spindles appearing on EEG was studied and it was shown that it could be described by means of on-off intermittency theory.
Show AbstractDensity plasma excitations of two-dimensional semiconductor superlattice in a wide range of parameters
Density plasma excitations of two-dimensional semiconductor superlattice in a wide range of parameters
S.Yu. Glazov$^1$, I.S. Gromyshov$^1$, N.E. Mescheryakova$^2$
Investigated plasma density excitations in two-dimensional semiconductor superlattice depending on the period and the width of the potential wells, forming a superlattice. Calculations were performed on base of the quantum theory plasma oscillations in random phase approximation taking into account the umklapp processes. Estimation of parameters of superlattice was performed using the Kronig–Penney model.
Show AbstractS–polarized spectrum of one-dimensional photonic crystal with anisotropic nanocomposite defect layer
S–polarized spectrum of one-dimensional photonic crystal with anisotropic nanocomposite defect layer
S.Ya. Vetrov$^{1,2}$, P.S. Pankin$^2$, I.V. Timofeev$^{1,2}$
Spectral properties are investigated of one-dimensional photonic crystal with structure defect which is considered as an anisotropic nanocomposite layer embedded between two multilayer dielectric mirrors. A number of important features in the transmission spectrum of the photonic crystal are found.
Show AbstractNonlinear waves in microtubules of nerve cells
Nonlinear waves in microtubules of nerve cells
A. N. Bugay$^1$, S. Zdravkovi´c$^2$
Microtubules are important cytoskeleton element of living organisms. In this research nonlinear waves in microtubules are studied, and different types of soliton solutions are derived. Soliton solutions describe propagation of polarization and deformation waves within localized structural transition in microtubule.
Show AbstractEdge modes of two dimensional bounded photonic crystal structures composed of small plasmonic particles and their interaction with inner structure's waves
Edge modes of two dimensional bounded photonic crystal structures composed of small plasmonic particles and their interaction with inner structure's waves
Yu.N. Barabanenkov$^{1}$, M.Yu. Barabanenkov$^{2}$
Specific optical eigenmodes are considered of finite clusters of metallic nanoparticles with plasmonic resonance as well as an excitation transfer along linear chain of particles between clusters. Simple analytic and physically transparent results are presented for the problem solution of collective modes exciting inside two dimensional circular clusters and the problem excitation transfer along one dimensional linear array of coupled small plasmonic spherical particles. The results are obtained with the aid of equations’ system for self-consistent currents excited inside particles by incident electromagnetic wave field. For circular cluster of particles the coupling matrix between their currents becomes under definite conditions of such favorite properties that enables one immediately to write out the Bloch–like eigenmodes with corresponding eigenfrequencies and their half widths. What is more we get also a simple analytic expressions for coupling factor between inner part of a square structure arranged in a circular shape and its bound part. Considering linear array of particles we use a closest neighbor interaction approach which makes the linear array like the electric filter. In this approximation an analytic expression are obtained for extinction rate of exciting currents’ transfer depending on array particles number and for resonance filtering frequencies.
Show AbstractAnalysis of electrodynamic characteristics of a spiral microwave rectenna
Analysis of electrodynamic characteristics of a spiral microwave rectenna
K.T.C. Vu, R.V. Egorov, V.L. Savvin, D.A. Mikheev
The study treats properties of a microwave rectenna, consisting of a semiconductor diode and a spiral antenna, that has a resonant frequency of 10 GHz. The radiation pattern of the rectenna was demonstrated to be omnidirectional within a wide range of elevation angles.
Show AbstractGiant dipole resonance in atomic nuclei
Giant dipole resonance in atomic nuclei
B. S. Ishkhanov
Giant dipole resonance is a collective excitation of atomic nuclei. In the macroscopic interpretation giant dipole resonance is a collective oscillation of all protons against all neutrons in a nucleus. Giant dipole resonance occurs systematically in most nuclei with energies typically in the range of 10–30 MeV. GDR is an efficient tool to probe nuclear properties, for study of structure and dynamics of atomic nuclei, nuclear reaction mechanism.
Show AbstractApplication of the method of differential inequalities for the justification of the asymptotic of solution of a system of two ordinary differential equations in the form of step type contrasting structure.
Application of the method of differential inequalities for the justification of the asymptotic of solution of a system of two ordinary differential equations in the form of step type contrasting structure.
N.T. Levashova, E.S. Petrovskaya
An asymptotic expansion of the solution of a boundary value problem for a system of two ordinary differential equations in the form of step-type contrasting structures was built. Using the method of differential inequalities, was proved the existence of the considered problems of decisions of this type, for which the built decomposition is constructed asymptotic approximation.
Show AbstractCharacterization of GaN and GaN based structures by scanning electron microscopy methods
Characterization of GaN and GaN based structures by scanning electron microscopy methods
Yakimov E.B.
Results demonstrating possibilities of scanning electron microscopy methods for a characterization of GaN and GaN based light emitting structures are presented. Methods for correct excess carrier diffusion length measurementы in the structures with the small diffusion length are discussed. It is shown that the Electron Beam Induced Current (EBIC) method allows not only to measure the diffusion length in GaN films but in some cases to reconstruct also the lateral donor center distribution with a spatial resolution in the micrometer range. It is shown experimentally that in the structures with the small diffusion length the lateral resolution under extended defects revealing can be about 100 nm or even better. It is shown that channels of enhanced minority carrier transport across the active region of light emitting structures with InGaN/GaN quantum wells can be revealed by the EBIC.
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