Localized gap modes in nonlinear dimerized Lieb lattices

Compact localized modes of ring type exist in many two-dimensional lattices with a flat linear band, such as the Lieb lattice. The uniform Lieb lattice is gapless, but gaps surrounding the flat band can be induced by various types of bond alternations (dimerizations) without destroying the compact linear eigenmodes. Here, we investigate the conditions under which such diffractionless modes can be formed and propagated also in the presence of a cubic on-site (Kerr) nonlinearity. For the simplest type of dimerization with a three-site unit cell, nonlinearity destroys the exact compactness, but strongly localized modes with frequencies inside the gap are still found to propagate stably for certain regimes of system parameters. By contrast, introducing a dimerization with a 12-site unit cell, compact (diffractionless) gap modes are found to exist as exact nonlinear solutions in continuation of flat band linear eigenmodes. These modes appear to be generally weakly unstable, but dynamical simulations show parameter regimes where localization would persist for propagation lengths much larger than the size of typical experimental waveguide array configurations. Our findings represent an attempt to realize conditions for full control of light propagation in photonic environments.Funding Agencies|Swedish Research Council [348-2013-6752]; Ministry of Education, Science and Technological Development of the Republic of Serbia [III 45010]</p

Localized modes in nonlinear binary kagome ribbons

The localized mode propagation in binary nonlinear kagome ribbons is investigated with the premise to ensure controlled light propagation through photonic lattice media. Particularity of the linear system characterized by the dispersionless flat band in the spectrum is the opening of new minigaps due to the "binarism." Together with the presence of nonlinearity, this determines the guiding mode types and properties. Nonlinearity destabilizes the staggered rings found to be nondiffracting in the linear system, but can give rise to dynamically stable ringlike solutions of several types: unstaggered rings, low-power staggered rings, hour-glass-like solutions, and vortex rings with high power. The type of solutions, i.e., the energy and angular momentum circulation through the nonlinear lattice, can be controlled by suitable initial excitation of the ribbon. In addition, by controlling the system "binarism" various localized modes can be generated and guided through the system, owing to the opening of the minigaps in the spectrum. All these findings offer diverse technical possibilities, especially with respect to the high-speed optical communications and high-power lasers.Funding Agencies|Swedish Research Council within the Swedish Research Links programme [348-2013-6752]; Sweden-Chilean-Serbian trilateral project "Control of light and matter waves propagation and localization in photonic lattices"; Ministry of Education, Science and Technological Development of Republic of Serbia [III45010]; Fondecyt Grant [1151444]; Programa ICM [RC-130001]; Programa de Financiamiento Basal [FB0824]</p

Нормирование труда

Рассмотрены проблемы формирования системы нормирования труда на предприятии, выбора метода нормирования труда, установления норм труда в условиях модернизации национальной экономики Республики Беларусь, экономии и бережливости. Для студентов специальности 1-26 02 02 «Менеджмент (по направлениям)» дневной и заоч- ной форм обучения

Status report of the VINCY Cyclotron

The VINCY Cyclotron is the main part of the TESLA Accelerator Installation. The diameter of the pole of this machine is 2000 mm. Its bending constant is 145 MeV while its focusing constant is 75 MeV. The radiofrequency system of the machine consists of two l/4-resonators with the eigenfrequency in the range from 17 to 31 MHz. Ions coming from a heavy ion source or a light ion source will be injected into the machine axially. They will be introduced into its median plane by a spiral inflector. Heavy ions accelerated in the machine will be extracted from it by a foil stripping system or by an electrostatic deflection system. Light ions will be extracted from it by the foil stripping system. The first programs of use of the VINCY Cyclotron are related to routine and experimental production of radioisotopes and radiopharmaceuticals, and to biomedical research with ion beams. The first beam extracted from the machine will be the proton beam of the energy of 22 MeV obtained from the H2+ beam extracted from the light ion source. This beam will be used first for production of radioisotope 18F and radio-pharmaceutical 18FDG, to be employed for positron emission tomograph