Certain aspects of spin-dependent kinetic theory of conductivity for Fe-containing graphite composites have been considered, in particular those concerning charge transport along carbon nanotubes. Band structure simulations have been performed taking into account spin polarization and assumption of ferromagnetic ordering of Fe atoms in graphite composite. It has been demonstrated that infinite log-like barriers which corresponded to Coulomb screening potential in 1D wires are partially penetrable for stochastically driven particle in diffusion approximation.
The long-range charge transfer correlated with the existence of fractal nanostructure for thin Fe-containing Langmuir-Blodgett (LB) films of thiophene derivatives has been experimentally observed. Band structure of the film with hexagon crystal structure has been simulated assuming 26 carbon atoms and one(or two) Fe atom in cluster in elementar cell and validity of adiabatic approximation. The simulations display, that the energy of the structure is reduced when taking into account the ferromagnetic ordering. This leads to the stabilization of the structure. Dynamically invertible instability of band structure at changes of spin polarization is considered as appearance of photo-induced quasi-steady states of nanostructured LB-films. Temperature Green function method has been proposed to examine relativistic corrections for Fermi system which are caused by non-sphericity of atom potential in leaky packed solids. The origin of quasi-stationary modes in Dirac problem is considered for an electron in the vicinity of the ionization threshold in a strong oscillating magnetic field.
We demonstrate that quasi-steady states for a highly excited atom in the vicinity of ionization threshold in a strong self-consistent oscillating magnetic field can be represented in the form of an expansion on coherent states of a Dirac electron moving in self-consistent atomic potential. The asymptotic solutions have been constructed based on the perturbation theory.
Two-level quantum system, described by non-relativistic Schroedinger equations in a matrix form with a potential, causing quantum deterministic chaos through the cascade of period doubling bifurcations has been considered. Bifurcations in this case correspond to series of quantum nutation of nutations. It was shown that quantum computation underlie the working of biological neural networks.
The asymptotic expansions of the solutions within the framework of been found phase-space geometry for oscillatory neural model are constructed. The oscillatory neural networks consist of non-identical neurons are examined. The phenomenon of mutual neurons' synchronization has been analyzed.
The oscillatory model of neuronal networks with dynamical chaos has been examined. The neurons in this model are shown to be considered as the coupled nonlinear oscillators. The instanton-like solution obtained is most applicable for information transmittance due to its small dissipation.
The dynamics of pulsed pumped dye lasers with transversal excitation geometry with linearly polarized pumping when the absorption dipole is perpendicular to the emission dipole have been theoretically and experimentally investigated. The theoretical model is based on balance equations and takes orientational relaxation processes into account. Experimental results have been obtained on Rhodamine 6G in Ethyleneglycol under pulsed transversal polarized pumping from a N<SUB>2</SUB> laser. The theoretical and experimental results obtained allow us to call the new effect: orientational self-bleaching.
A oscillatory model of a Hodgkin and Huxley's neuron was proposed. It was shown that the unfolding degeneracy of this system in the vicinity of homoclinic trajectory go to a cascade of period-doubling bifurcations with the subsequent transition in deterministic chaos. A method of finding of homoclinic points in a system of ODE, based on the consideration of a system of partial differential equations of lower dimension in WKB-approximation is proposed.
In this paper a new method of dynamic operations control has been built for a dye laser with a saturable absorber. It has been shown that one can transform specific types of auto-oscillations to steady state operation by means of changing pumping anisotropy.
In this work an analysis of the nonlinear dynamics of an anisotropic dye laser with a saturable absorber has been carried out. Radiationless energy transfer in the absorber was taken into account. It has been shown that a specific type of auto-oscillation appears because of the interaction of the polarization modes caused by the radiationless energy transfer and by the anisotropy in the active medium induced by linearly polarized light pulse. This oscillation is characterized by a half-period shift of the radiation-density maxima of one polarization mode relative to the maxima of the other and is called an anti-symmetric oscillation. It has been noted that in the limit of the high energy migration rate these anti-symmetric oscillations disappear and the anisotropic laser with saturable absorber looks like an isotropic one.