Surface response of spherical core-shell structured nanoparticle by optically induced elastic oscillations of soft shell against hard core

The optically induced oscillatory response of a spherical two-component, shell-core structured, nanoparticle by nodeless elastic vibrations of soft peripheral shell against hard and dynamically immobile inner core is considered. The eigenfrequencies of the even-parity, spheroidal and odd-parity torsional vibrational modes trapped in the finite-depth shell are obtained which are of practical interest for modal specification of individual resonances in spectra of resonant scattering of long wavelength electromagnetic waves by ultrafine particles.Comment: Surface Review and Letters (World Scientific) Year: 2009 Vol: 16 Issue: 1 (February 2009) Page: 5 - 1

Elasticity of nuclear medium as a principal macrodynamical promoter of electric dipole pygmy resonance

Motivated by arguments of the nuclear core-layer model formulated in [S.I. Bastrukov, J.A. Maruhn, Z.Phys. A 335 (1990) 139], the macroscopic excitation mechanism of electric pygmy dipole resonance (PDR) is considered as owing its origin to perturbation-induced effective decomposition of nucleus into two spherical domains - undisturbed inner region treated as static core and dynamical layer undergoing elastic shear vibrations. The focus is placed on the imprinted in the core-layer model mechanism of emergence of the low-energy dipole electric resonant excitation as Goldstone soft mode of translation layer-against-core oscillations. To accentuate this attitude we regain the obtained in the above paper spectral equation for the frequency of spheroidal elastic vibrations trapped in the finite-depth layer, but by working from canonical equation of elastic dynamics of continuous medium. The obtained analytic equations for the frequency of dipole vibrational state in question and its excitation strength exhibit fundamental character of this soft dipole mode of nuclear resonant response.Comment: Accepted in Phys.Lett.

Torsional nodeless vibrations of quaking neutron star restored by combined forces of shear elastic and magnetic field stresses

Within the framework of Newtonian magneto-solid-mechanics, relying on equations appropriate for a perfectly conducting elastic continuous medium threaded by a uniform magnetic field, the asteroseismic model of a neutron star undergoing axisymmetric global torsional nodeless vibrations under the combined action of Hooke's elastic and Lorentz magnetic forces is considered with emphasis on a toroidal Alfv\'en mode of differentially rotational vibrations about the dipole magnetic moment axis of the star. The obtained spectral equation for frequency is applied to $\ell$-pole identification of quasi-periodic oscillations (QPOs) of X-ray flux during the giant flares of SGR 1806-20 and SGR 1900+14. Our calculations suggest that detected QPOs can be consistently interpreted, within the framework of this model, as produced by global torsional nodeless vibrations of quaking magnetar if they are considered to be restored by the joint action of bulk forces of shear elastic and magnetic field stresses.Comment: 18 pages, 5 figures; accepted in Ap

Object Classificators Using the AdaBoost Algorithm and Neural Networks

The construction of image object detectors is still a relevant task, due to dynamic developments in the field of computer vision. In this work, we combined neural network technologies with existing data processing algorithms to obtain effective object classifiers. We demonstrate our approach on the example of face detection

Production of {\pi}+ and K+ mesons in argon-nucleus interactions at 3.2 AGeV

First physics results of the BM@N experiment at the Nuclotron/NICA complex are presented on {\pi}+ and K+ meson production in interactions of an argon beam with fixed targets of C, Al, Cu, Sn and Pb at 3.2 AGeV. Transverse momentum distributions, rapidity spectra and multiplicities of {\pi}+ and K+ mesons are measured. The results are compared with predictions of theoretical models and with other measurements at lower energies.Comment: 29 pages, 20 figure

The development of distributed computing technologies and BigData in LIT-JINR

The main activities of the Laboratory of Information Technologies (LIT) of the Joint Institute for Nuclear Research (JINR) are addressed with emphasis on the development of distributed computing. The contribution of the LIT staff to the development of computational models for experiments done at the Large Hadron Collider (LHC) at CERN is briefly described. A brief overview is given of projects devoted to the development of distributed computations with LIT involvement in Russia, CERN, the USA, China, JINR Member States. Particular attention is devoted to the creation of a CMS Tier1 center in JINR and the development of computational models for the mega-project NICA. The report ends with the LIT work on the integration of the HPC, grid, cloud, and BigData technologies in large scale international projects