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Belogolovskii M.,Donetsk Institute for Physics and Engineering | Lacquaniti V.,National Institute of Metrological Research
Springer Proceedings in Physics | Year: 2014

Theoretical and experimental analysis of electron transport across ultrathin, homogeneously disordered oxide layers is presented with particular regard to the question of how much the effects are universal. We show that (i) distribution of transparencies across dirty subnanometer-thick insulating films is bimodal and (ii) conductance-voltage characteristics of oxide layers with thicknesses increased up to several nanometers are power functions with an index near 1.3. The universality of transport properties is explained as an effect of strong local barrier-height fluctuations generated by the presence of oxygen vacancies. © Springer International Publishing Switzerland 2014.

Gorb E.V.,University of Kiel | Filippov A.E.,University of Kiel | Filippov A.E.,Donetsk Institute for Physics and Engineering | Gorb S.N.,University of Kiel
Arthropod-Plant Interactions | Year: 2013

Myrmecochory or seed dispersal by ants is a widely spread phenomenon, and myrmecochorous plants constitute a large portion of species in many ecosystems. Since the ant species complex in the ecosystem is continuously changing in time and space, the long-term effects of such ant-plant interactions on the plant community remained unclear. The manifold information obtained in numerous previous studies from one ecosystem in the deciduous forests of Central Ukraine allowed us to simulate the possible scenarios for plant survival and distribution in the ecosystem after a reduction in the number or local extinction of one of the ant species. The results of the virtual long-term experiment show that the abundance and spatial distribution of myrmecochorous plants strongly depends on both the abundance of ants and their species composition in the ecosystem. The positive role of ant species diversity for maintaining myrmecochorous plant species diversity is shown. Competition between plant species for seed dispersers is influenced by the ant community in such a way that the disappearance of one ant species may lead to the reduction or even local extinction of a particular plant population. © 2012 Springer Science+Business Media Dordrecht.

Mitsiuk V.I.,National Academy of Sciences of Belarus | Tkachenka T.M.,National Academy of Sciences of Belarus | Budzynski M.,Maria Curie Sklodowska University | Surowiec Z.,Maria Curie Sklodowska University | Valkov V.I.,Donetsk Institute for Physics and Engineering
Nukleonika | Year: 2013

Magnetic and Mössbauer measurements were performed for Mn2-xFexP0.5As0.5, 0.5 ≤ x ≤ 1.0. It was shown that with decreasing Fe content magnetic interaction significantly weakens. Low temperature magnetic structure could be explained as a superposition of ferromagnetic and antiferromagnetic contributions to the whole magnetic moment of the alloy.

Lyashenko I.A.,Sumy State University | Metlov L.S.,Donetsk Institute for Physics and Engineering | Khomenko A.V.,Sumy State University | Chepulskyi S.N.,Sumy State University
Journal of Nano- and Electronic Physics | Year: 2011

A non-equilibrium thermodynamic model describing the behavior of an ultrathin lubricating material film confined between two atomically-smooth solid surfaces is proposed. As the order parameter the excess volume is chosen whose value increases with melting and subsequent fluidization of lubricant. It is shown that the external pressure, applied perpendicularly to the friction surfaces, influences crucially the lubricant behavior. The total system of kinetic equations is written down in which the relative shear velocity of rubbing surfaces, their temperature, and external normal pressure are the control parameters. Phase diagram with domains of different friction regimes is built. © 2011 SumDU.

Krasnyuk I.B.,Donetsk Institute for Physics and Engineering | Taranets R.M.,Ukrainian Academy of Sciences | Chugunova M.,Claremont Graduate University
Physica A: Statistical Mechanics and its Applications | Year: 2014

This paper examines surface-induced ordering in confined binary alloys. The hyperbolic initial boundary value problem (IBVP) is used to describe a scenario of spatiotemporal ordering in a disordered phase for concentration of one component of binary alloy and order parameter with non-linear dynamic boundary conditions. This hyperbolic model consists of two coupled second order differential equations for order parameter and concentration. It also takes into account effects of the "memory" on the ordering of atoms and their densities in the alloy. The boundary conditions characterize surface velocities of order parameter and concentration changing which is due to surface (super)cooling on walls confining the binary alloy. It is shown that for large times there are three classes of dynamic non-linear boundary conditions which lead to three different types of attractor's elements for the IBVP. Namely, the elements of attractor are the limit periodic simple shock waves with fronts of "discontinuities" Γ. If Γ is finite, then the attractor contains spatiotemporal functions of relaxation type. If Γ is infinite and countable then we observe the functions of pre-turbulent type. If Γ is infinite and uncountable then we obtain the functions of turbulent type. © 2014 Published by Elsevier Ltd.

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