Excitation Energy Dependence of the Exciton Inner Ring

We report on the excitation energy dependence of the inner ring in the exciton emission pattern. The contrast of the inner ring is found to decrease with lowering excitation energy. Excitation by light tuned to the direct exciton resonance is found to effectively suppress excitation-induced heating of indirect excitons and facilitate the realization of a cold and dense exciton gas. The excitation energy dependence of the inner ring is explained in terms of exciton transport and cooling.Comment: 5 pages, 4 figure

Conditioned reflex activity of rats at later periods after the end of flight aboard the Kosmos-605 biosatellite

The aftereffects of spaceflight on the higher nervous activity of rats were studied. A five lane maze with a feeding terminal was used to check such factors as transfer of experience, the habit and speed of reaching the goal in the maze, long term memory, and the dynamics of errors. During the 3rd-7th postflight week, functional disturbances in the rat HNA were manifested in the deterioration of the capacity for the transfer of experience and for locating the feeding compartment in the maze, thus indicating a general decrease of work capacity. The increased number of errors and failures pointed to exhaustion of higher nervous processes and to the weakened functional activity of the brain

Transport of Indirect Excitons in a Potential Energy Gradient

We realized a potential energy gradient - a ramp - for indirect excitons using a shaped electrode at constant voltage. We studied transport of indirect excitons along the ramp and observed that the exciton transport distance increases with increasing density and temperature.Comment: 4 pages, 3 figure

On a class of C-algebras generated by a countable family of partial isometries

The paper investigates the properties of an operator T φ on the Hilbert space l 2(ℤ), which are induced by the mapping φ of the set ℤ into itself. It is shown if the mapping φ is such that every preimage has finite, but not equipotentionally bounded cardinality, then the operator T φ allows a closure and can be represented as a countable sum of partial isometries. The C-algebras U φ, P φ and U φ associated with given mappings and generated by the mentioned partial isometries are considered. Some properties of these algebras and some relations between them are given. © 2010 Allerton Press, Inc

Optically Controlled Excitonic Transistor

Optical control of exciton fluxes is realized for indirect excitons in a crossed-ramp excitonic device. The device demonstrates experimental proof of principle for all-optical excitonic transistors with a high ratio between the excitonic signal at the optical drain and the excitonic signal due to the optical gate. The device also demonstrates experimental proof of principle for all-optical excitonic routers

Oxidative dehydrogenation of 2,3,5-trimethyl-1,4-hydroquinone in the presence of titanium dioxide hydrogel

Liquid-phase oxidative dehydrogenation of 2,3,5-trimethyl-1,4-hydroquinone in the presence of titanium dioxide hydrogel was studied by a kinetic method. Associative interactions between the substrate, oxidant, and gel were detected by voltammetry and ESR and IR spectroscopy.Russian Foundation for Basic Researc

Optical studies of the X-ray transient XTE J2123-058 -I. Photometry

We present optical photometry of the X-ray transient XTE J2123-058, obtained in July-October 1998. The light curves are strongly modulated on the 5.95hrs orbital period, and exhibit dramatic changes in amplitude and form during the decline. We used synthetic models which include the effect of partial eclipses and X-ray heating effects, to estimate the system parameters, and we constrain the binary inclination to be i=73+-4 degrees. The model is successful in reproducing the light curves at different stages of the decay by requiring the accretion disc to become smaller and thinner by 30% as the system fades by 1.7 mags in the optical. From Aug 26 the system reaches quiescence with a mean magnitude of R=21.7+-0.1 and our data are consistent with the optical variability being dominated by the companion's ellipsoidal modulation.Comment: 6 pages, 6 figure

Developing Effective Roll Cooling Systems Based on Computational Simulation

In order to retrofit a roll cooling system at the JSC ‘Katur Invest’ rolling mill, computational simulation was carried out for a process of accelerated emulsion spray cooling the rolls heated during rolling. Initial and boundary conditions for the Fourier equation in the case of a body of infinite length and arbitrary cross-sectional shape were determined for the thermal state conditions of rolls in mill stands No. 1, 2, 5, 7. After model adaptation, a comparative analysis of the roll temperature field dynamics in different cooling conditions was made based on experimental data. The analysis revealed that extending the time of emulsion cooling, evenwithout any further cooling process intensification, allows to significantly reduce both the maximum temperature level in a roll and its penetration depth, which results in required roll surface temperature reduction. Based on computational simulation, cooling parameters and conditions for the retrofitted cooling system are selected. Experimental data on roll surface temperature as measured before and after retrofitting the cooling system proved its effectiveness. Keywords: rolling, rolls, accelerated cooling, temperature field, simulatio