Chisinau, Moldova

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Agency: Cordis | Branch: FP7 | Program: MC-IRSES | Phase: FP7-PEOPLE-2012-IRSES | Award Amount: 500.00K | Year: 2012

The main objective of this project is to create fundamental understanding in dynamical systems theory and to apply this theory in formulating and analyzing real world models met especially in Neuroscience, Plasma Physics and Medicine. The specific objectives, tasks and methodology of this proposal are contained in the 5 WPs of the project. In WP1 we want to develop new methods for the center and isochronicity problems for analytic and non-analytic systems, study bifurcations of limit cycles and critical periods, including time-reversible systems with perturbations, and investigate reaction-diffusion and fractional differential equations. In WP2 we deal with the problem of integrability for some differential systems with invariant algebraic curves, classification of cubic systems with a given number of invariant lines, study global attractors of almost periodic dynamical systems and their topological structure, respectively, Levitan/Bohr almost periodic motions of differential/difference equations. The main objective of WP3 is to study dynamics of some classes of continuous and discontinuous vector fields, preserving, respectively, breaking some symmetries, study of their singularities and closed orbits for classes of piecewise linear vector fields. WP4 deals with Hamiltonian systems in Plasma Physics, twist and non-twist area preserving maps, further studies of a recent model proposed to study some phenomena occurring in the process of plasmas fusion in Tokamaks, numerical methods, and the study of symmetries of certain kinds of k-cosymplectic Hamiltonians. The last WP tackles mathematical models in Neuroscience and Medicine. Firstly, we study several ODE-based and map-based neuronal models, survey in vivo results with respect to Autism Spectrum Disorder (ASD) and propose a model for ASD. Secondly, we study several approaches to mathematical models for diabetes. Finally, bone remodeling by means of convection-diffusion-reaction equations is our last task.

Stamov I.G.,Tiraspol State University | Syrbu N.N.,Stefan Cel Mare University of Suceava | Dorogan A.V.,Stefan Cel Mare University of Suceava
Physica B: Condensed Matter | Year: 2013

Optical functions n, k, ε1, ε2 and d 2ε2/dE2 have been determined from experimental reflection spectra in the region of 1-10 eV. The revealed electronic transitions are localized in the Brillouin zone. The magnitude of valence band splitting caused by the spin-orbital interaction ΔSO is lower than the splitting caused by the crystal field ΔCR in the center of Brillouin zone and L and X points. The switching effects are investigated in Zn3P2 crystals. The characteristics of experimental samples with electric switching, adjustable resistors, and time relays based on Zn3P2 are presented. © 2012 Elsevier B.V. All rights reserved.

Sinyavskii E.P.,Moldova Academy of Sciences | Karapetyan S.A.,Tiraspol State University
Semiconductors | Year: 2011

The mobility of charge carriers μ in a parabolic quantum well in an electric field E directed along the size-confinement axis is calculated. With consideration for scattering of charge carriers at a rough surface, the mobility μ is shown to decrease with increasing E. A physical interpretation of this effect is proposed. © 2011 Pleiades Publishing, Ltd.

Khadzhi P.I.,Moldova Academy of Sciences | Vasilieva O.V.,Tiraspol State University
Journal of Nanoelectronics and Optoelectronics | Year: 2011

The dynamics of tunneling of Bose condensed atoms through a barrier between two wells taking into account elastic interparticle interations was examined using the Gross-Pitaevskii equation. The analytic solutions of the set of nonlinear differential equations were obtained that describe the dependences of the time evolution of atoms in the wells versus the initial densities of atoms, the initial phase difference, and the resonance detuning. It is shown that the time evolution of the system is substantially defined by the initial conditions. It manifests itself as a periodic or aperiodic variation of the density of atoms or a state of rest for non-zero initial densities of atoms in the wells. The found peculiarities of the dependences of time evolution of the density of atoms versus the initial phase difference suggest that it is possible to perform a phase control of the system. © 2011 American Scientific Publishers All rights reserved.

Sinyavskii E.P.,Moldova Academy of Sciences | Karapetyan S.A.,Tiraspol State University
Semiconductors | Year: 2012

For nanowires with a parabolic potential, the effect of an electric field E orthogonal to the system's axis on the mobility of charge carriers μ is investigated. With consideration for the interaction of charge carriers with a rough surface, it is shown that, for a nondegenerate electron (hole) gas, the mobility μ decreases with increasing E. For a degenerate electron (hole) gas, the dependence of μ on E is described by a nonmonotonic oscillating function. A physical interpretation of the predicted effect is proposed. © 2012 Pleiades Publishing, Ltd.

The results of the application of nanostructured coatings, obtained at electrodischarge treatment by toolelectrodes from Al-Sn alloy for restore and repair of machine parts are presented. © Springer Science+Business Media Singapore 2016.

Barengolts Y.A.,Tiraspol State University
Technical Physics Letters | Year: 2012

The influence of atoms, molecules, or layers adsorbed on the cathode surface on the initiation of high-voltage gas discharge is considered. It is shown that the presence of island films of an adsorbate leads to an increase in the field-induced electron emission current that initiates breakdown of the gas-filled interelectrode gap. The formation of a continuous adsorbed film on the cathode accounts for the subsequent weak dependence of the emission characteristics in high-voltage (in particular, picosecond pulsed) discharge on the gas phase composition. © 2012 Pleiades Publishing, Ltd.

Barengolts Yu.A.,Tiraspol State University | Beril S.I.,Tiraspol State University
Proceedings - International Symposium on Discharges and Electrical Insulation in Vacuum, ISDEIV | Year: 2012

The presence of adsorbed atoms or nonpolar molecules on the surface of a cathode results in an insignificant increase in field-emission current density over that observed for clean metal surfaces. If the adsorbate consists of polar molecules, at fields over 1 MV/cm, the current density can increase by an order of magnitude and more. When the adlayer thickness is several nanometers, the quantum nature of the image forces must be taken into consideration. Calculations show that in this case, owing to the polaron effect, the tunnel emission current is substantially lower than that typical of cathode surfaces free from foreign microinclusions and films. © 2012 IEEE.

Korovai O.V.,Tiraspol State University
Physics of the Solid State | Year: 2015

The theory of nonlinear s-polarized surface waves, which propagate in a symmetric planar threelayered structure with a metamaterial core and nonlinear coverings, has been constructed. It has been shown that the occurrence of only nonlinear quasi-surface waves is possible in such a structure. Dispersion laws and energy fluxes of symmetric, even, and odd modes at different parameters have been found and investigated. The qualitative behavior of dispersion laws substantially depends on the core thickness. © 2015, Pleiades Publishing, Ltd.

Barengolts Y.A.,Tiraspol State University | Beril S.I.,Tiraspol State University
IEEE Transactions on Plasma Science | Year: 2014

Relationships inherent in the processes that occur at the initial stage of a high-voltage (electric field strength E>1~MV/cm gas discharge with participation of nonmetal nanofilms adsorbed to the cathode are considered. It is shown that the current-voltage characteristic of the prebreakdown current obeys the Fowler-Nordheim equation corrected for the quantum character of image forces. Based on electronic polaron theory, a general expression for the field emission current at the interface between two media is obtained. It is shown that for the abovementioned fields, the field dependence of the electron tunneling current is appreciably different from the well-known classical relations. © 2014 IEEE.

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