387 research outputs found

    On Mechanics of Light Propagation in Free Space with Final Temperature

    Get PDF
    Features of electromagnetic waves propagation of light range are considered in free space with final temperature 2.725K. The presence in space of temperature (and final density) allows justification to introduce the longitudinal component of electromagnetic field. A modified theory of electromagnetic waves propagation in free space is offered. Exact solutions of the nonlinear equations system in the presence of electric and gasdynamic interaction are obtained. Some of demonstrated exact solutions have a nature of continues and decretive spectrum

    Spin current in (110)-oriented GaAs quantum wells

    Get PDF
    We consider a possibility of generation of the stationary spin current in (110) – oriented GaAs-basedsymmetric quantum well due to the nonlinear response to externalperiodic electric field. The model includes the Dresselhaus spin-orbit interaction and the random Rashbaspin-orbit coupling. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2055

    Synthesis of Stable Aqueous Ceria Sols and Study of Their Toxicity

    Get PDF
    Cerium dioxide is a unique material which is promising for biomedical applications. The properties of ceria are definitely determined by synthesis procedure and further treatment conditions. The vast majority of currently existing methods of synthesis lead to formation of CeO2 in the form of nanopowders, but in some cases (e.g., in biological applications), such powders can not be used because they do not quite satisfy practical requirements. So, in this work we succeed in synthesis of ceria-stable sols with controlled small particle size (2-4 nm) using an inexpensive and facile method and investigated the effect of changing the concentrations and the molar ratio of initial reagents on particle size of CeO2. In this paper we also propose a method of evaluation of toxicity of ceria sols using bioluminescent microorganism Vibrio fischeri. According to the results obtained CeO2 sols of different concentrations (6.3*10-4 – 0,02M) are not toxic to Vibrio fischeri. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3495

    New exact solutions in standard inflationary models

    Get PDF
    The exact solutions in the standard inflationary model based on the self-interacting scalar field minimally coupled to gravity are considered. The shape's freedom of the self-interacting potential V(ϕ)V(\phi) is postulated to obtain a new set of the exact solutions in the framework of Friedmann-Robertson-Walker Universes. The general solution was found in the case of power law inflation. We obtained new solutions and compared them with obtained ones earlir for the exponential type inflation.Comment: 12 pages, Latex, to appear in: Phys.Lett.

    First-principles study of electron transport through C20C_{20} cages

    Full text link
    Electron transport properties of C20_{20} molecules suspended between gold electrodes are investigated using first-principles calculations. Our study reveals that the conductances are quite sensitive to the number of C20_{20} molecules between electrodes: the conductances of C20_{20} monomers are near 1 G0_{0}, while those of dimers are markedly smaller, since incident electrons easily pass the C20_{20} molecules and are predominantly scattered at the C20_{20}-C20_{20} junctions. Moreover, we find both channel currents locally circulating the outermost carbon atoms.Comment: 8 pages and 3 figure

    Formalism of collective electron excitations in fullerenes

    Full text link
    We present a detailed formalism for the description of collective electron excitations in fullerenes in the process of the electron inelastic scattering. Considering the system as a spherical shell of a finite width, we show that the differential cross section is defined by three plasmon excitations, namely two coupled modes of the surface plasmon and the volume plasmon. The interplay of the three plasmons appears due to the electron diffraction of the fullerene shell. Plasmon modes of different angular momenta provide dominating contributions to the differential cross section depending on the transferred momentum.Comment: 11 pages, 2 figures; submitted to the special issue "Atomic Cluster Collisions: Structure and Dynamics from the Nuclear to the Biological Scale" of Eur. Phys. J.

    Multifractal stationary random measures and multifractal random walks with log-infinitely divisible scaling laws

    Full text link
    We define a large class of continuous time multifractal random measures and processes with arbitrary log-infinitely divisible exact or asymptotic scaling law. These processes generalize within a unified framework both the recently defined log-normal Multifractal Random Walk (MRW) [Bacry-Delour-Muzy] and the log-Poisson "product of cynlindrical pulses" [Barral-Mandelbrot]. Our construction is based on some ``continuous stochastic multiplication'' from coarse to fine scales that can be seen as a continuous interpolation of discrete multiplicative cascades. We prove the stochastic convergence of the defined processes and study their main statistical properties. The question of genericity (universality) of limit multifractal processes is addressed within this new framework. We finally provide some methods for numerical simulations and discuss some specific examples.Comment: 24 pages, 4 figure

    ϒ production in p–Pb collisions at √sNN=8.16 TeV

    Get PDF
    ϒ production in p–Pb interactions is studied at the centre-of-mass energy per nucleon–nucleon collision √sNN = 8.16 TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and −4.46 < ycms < −2.96, down to zero transverse momentum. In this work, results on the ϒ(1S) production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the ϒ(1S) yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the ϒ(2S) nuclear modification factor is evaluated, suggesting a suppression similar to that of the ϒ(1S). A first measurement of the ϒ(3S) has also been performed. Finally, results are compared with previous ALICE measurements in p–Pb collisions at √sNN = 5.02 TeV and with theoretical calculations.publishedVersio
    corecore