125 research outputs found

    Properties of 1D two-barrier quantum pump with harmonically oscillating barriers

    Full text link
    We study a one-dimensional quantum pump composed of two oscillating delta-functional barriers. The linear and non-linear regimes are considered. The harmonic signal applied to any or both barriers causes the stationary current. The direction and value of the current depend on the frequency, distance between barriers, value of stationary and oscillating parts of barrier potential and the phase shift between alternating voltages.Comment: 7 pages, 8 figure

    Social Project as a New Method Which Forms Children’s and Juvenile’s Media Literacy

    Full text link
    We introduce a new method which forms children’s and juvenile’s media literacy – social projects. We also show the implementation of our social project named «My media safety» using the experience of press-center «VLyceum» of General Educational Municipal Budget school «Chelyabinsk Lyceum № 88».В нашей статье мы знакомим с принципиально новым инструментом развития медиакомпетенций подростков и детей – социальным проектированием. Рассказываем о реализации социального проекта «Моя медиабезопасность» на примере опыта пресс-центра «ВЛицее» МБОУ «Лицей № 88 г. Челябинска»

    Theory of one-dimensional double-barrier quantum pump in two-frequency signal regime

    Full text link
    A one-dimensional system with two δ\delta-like barriers or wells bi-chromaticaly oscillating at frequencies ω\omega and 2ω2\omega is considered. The alternating signal leads to the direct current across the structure (even in a symmetric system). The properties of this quantum pump are studied in a wide range of the system parameters.Comment: 4 pages, 5 figure

    Ground increase of cosmic ray intensity on February 16, 1984

    Get PDF
    The event of February 16, 1984 is one of the two largest ground increases of solar cosmic rays (CR) in the last two cycles of solar activity. This event happended at a decrease of the 21-st cycle against a quiet background. Although at the beginning of 1984 the observed indices of solar activity were higher than those at the end of 1983, the day of February 16 16 may be characterized as very quiet. On that day the geomagnetic perturbance (Sigma F sub p = 14, A sub p = 7) was the lowest in February. After a small Forbush decrease due to the magnetic storm of February 12-13, the CR intensity almost completely recovered by February 16. Thus, the solar particles that came to the Earth on February 16 got into a practically unperturbed magnetosphere, and the variations of secondary CR induced by these particles were not superimposed on any other substantial variations of extraterrestrial or magnetospheric origin

    Thermal radiation of conducting nanoparticles

    Full text link
    The thermal radiation of small conducting particles was investigated in the region where the Stephan-Boltzmann law is not valid and strongly overestimates radiation losses. The new criterion for the particle size, at which black body radiation law fails, was formulated. The approach is based on the magnetic particle polarization, which is valid until very small sizes (cluster size) where due to drop of particle conductivity the electric polarization prevails over the magnetic one. It was also shown that the radiation power of clusters, estimated on the basis of the experimental data, is lower than that given by the Stephan-Boltzmann law.Comment: 12 pages, 5 figures, 1 tabl

    On the Lebesgue measure of Li-Yorke pairs for interval maps

    Get PDF
    We investigate the prevalence of Li-Yorke pairs for C2C^2 and C3C^3 multimodal maps ff with non-flat critical points. We show that every measurable scrambled set has zero Lebesgue measure and that all strongly wandering sets have zero Lebesgue measure, as does the set of pairs of asymptotic (but not asymptotically periodic) points. If ff is topologically mixing and has no Cantor attractor, then typical (w.r.t. two-dimensional Lebesgue measure) pairs are Li-Yorke; if additionally ff admits an absolutely continuous invariant probability measure (acip), then typical pairs have a dense orbit for f×ff \times f. These results make use of so-called nice neighborhoods of the critical set of general multimodal maps, and hence uniformly expanding Markov induced maps, the existence of either is proved in this paper as well. For the setting where ff has a Cantor attractor, we present a trichotomy explaining when the set of Li-Yorke pairs and distal pairs have positive two-dimensional Lebesgue measure.Comment: 41 pages, 3 figure

    Energy Spectra, Altitude Profiles and Charge Ratios of Atmospheric Muons

    Full text link
    We present a new measurement of air shower muons made during atmospheric ascent of the High Energy Antimatter Telescope balloon experiment. The muon charge ratio mu+ / mu- is presented as a function of atmospheric depth in the momentum interval 0.3-0.9 GeV/c. The differential mu- momentum spectra are presented between 0.3 and about 50 GeV/c at atmospheric depths between 13 and 960 g/cm^2. We compare our measurements with other recent data and with Monte Carlo calculations of the same type as those used in predicting atmospheric neutrino fluxes. We find that our measured mu- fluxes are smaller than the predictions by as much as 70% at shallow atmospheric depths, by about 20% at the depth of shower maximum, and are in good agreement with the predictions at greater depths. We explore the consequences of this on the question of atmospheric neutrino production.Comment: 11 pages, 8 figures, to appear in Phys. Rev. D (2000

    On the retrofitting and repowering of coal power plants with post-combustion carbon capture: An advanced integration option with a gas turbine windbox

    Get PDF
    Retrofitting a significant fraction of existing coal-fired power plants is likely to be an important part of a global rollout of carbon capture and storage. For plants suited for a retrofit, the energy penalty for post-combustion carbon capture can be minimised by effective integration of the capture system with the power cycle. Previous work on effective integration options has typically been focused on either steam extraction from the power cycle with a reduction of the site power output, or the supply of heat and electricity to the capture system via the combustion of natural gas, with little consideration for the associated carbon emissions. This article proposes an advanced integration concept between the gas turbine, the existing coal plant and post-combustion capture processes with capture of carbon emissions from both fuels. The exhaust gas of the gas turbine enters the existing coal boiler via the windbox for sequential combustion to allow capture in a single dedicated capture plant, with a lower flow rate and a higher CO2 concentration of the resulting flue gas. With effective integration of the heat recovery steam generator with the boiler, the existing steam cycle and the carbon capture process, the reference subcritical unit used in this study can be repowered with an electricity output penalty of 295 kWh/tCO2 – 5% lower than a conventional steam extraction retrofit of the same unit – and marginal thermal efficiency of natural gas combustion of 50% LHV – 5% point higher than in a configuration where the gas turbine has a dedicated capture unit

    Epidemiological Situation on Tick-Borne Borreliosis in the Russian Federation in 2019 Compared to the Period of 2002–2018

    Get PDF
    Objective: to analyze the epidemiological situation on Ixodidae tick-borne borreliosis in the Russian Federation in 2019 in comparison with the period of 2002–2018.Materials and methods. The paper uses the data contained in Form No. 2 of the state statistical reporting for 2002–2019 and information obtained by the Reference Center for Monitoring Borreliosis of the Omsk Research Institute of Natural Focal Infections from 74 constituent entities of Russia in 2019. The main research method is epidemiological one with the use of modern information technologies.Results and discussion. In Russia, 8048 cases of tick-borne borreliosis (Lyme disease – LD) were recorded (5.48 0/0000) in 2019. The actual indicators of the LD incidence for the whole country and federal districts (FD) in 2019 were within the confidence limits predicted with linear regression based on the study of the dynamics of the epidemic process in 2002–2018 in the vast majority of cases. A steady upward trend in the LD incidence was observed during 2002–2019 in the Central Federal District due to 10 out of 18 entities (Moscow, Belgorod, Lipetsk, Moscow, Bryansk, Voronezh, Kursk, Ryazan, Tambov, Tula regions); in the Southern Federal District because of the Krasnodar Territory and the Volgograd Region; in the North Caucasus Federal District – because of the Stavropol Territory. Despite the fact that a downward trend in the incidence of LD has been established over the past 18 years in the North-West, Volga and Ural Federal Districts, in some subjects of these regions a trend towards an aggravation of the epidemiological situation is observed (the Komi Republic and Chuvashia, Penza Region). In the absence of a pronounced tendency to change in the incidence rate of LD in the Siberian and Far Eastern Federal Districts, Kemerovo Region-Kuzbass, the Republic of Tuva and the Trans-Baikal Territory where a growing trend has been identified require special attention. In the Ural and Siberian Federal Districts, the share of non-erythema forms among laboratory-confirmed cases of LD was higher than in other regions, which merits further study of the genome-specific features of borrelia populations and their carriers. Effective control of the LD epidemiological situation in Russia is possible provided that the control is improved and maintained, and the capacity of preventive measures and zoological-entomological monitoring of the activity and structure of the natural foci of LD is enhanced in the entities with the long-term tendency towards increase in the incidence of the disease
    corecore