392 research outputs found

    КОМБИНИРОВАННАЯ ИМИТАЦИОННО-АНАЛИТИЧЕСКАЯ МОДЕЛЬ ПРОПУСКНОЙ СПОСОБНОСТИ АЭРОДРОМНОЙ ВОЗДУШНОЙ ЗОНЫ

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    An approach to the problem of estimating an aerodrome airspace capacity based on the idea of airspace «quantization» and transition to discrete time while imposing restrictions on the filling of quantum states by aircrafts has been developed in this paper. It is shown that such a formalism can significantly reduce the complexity of aircrafts movement simulation in the airfield zone, to take into account the restrictions imposed on the aerodrome airspace capacity by intersections of arrival and departure routes. The paper presents the results of the simulation experiment, illustrating the dependence of the aerodrome airspace capacity upon the number of aircraft routes intersections, [email protected].В работе развивается подход к задаче оценки пропускной способности воздушной аэродромной зоны, основанный на идее «квантования» воздушного пространства, перехода в дискретное время при наложении ограничений на заполнение квантовых состояний воздушными судами [4-6]. Показано, что такой формализм позволяет существенно снизить трудоемкость задачи имитационного моделирования движения воздушных судов в аэродромной зоне, учесть ограничения, накладываемые на ее пропускную способность пересечениями маршрутов прилета и вылета ВС. В статье приводятся результаты проведенного имитационного эксперимента, иллюстрирующие зависимость пропускной способности зоны от количества пересечений маршрутов воздушных судов

    Embedded systems with remote access in education

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    Предложен новый метод организации удаленного доступа к лабораторным установкам на основе использования языка РНР для управления через СОМ-порт.It is proposed a new method of remote access to laboratory apparatus with use of language PHP for management through Com port

    Аппаратный и программный интерфейс для оптических исследований на основе ПЗС-линейки

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    The report shows how to solve problems updating experimental laboratory facilities for the study of optical phenomena related to the use of new computers and operating systems.В докладе показано, как решать проблемы обновления экспериментальных лабораторных комплексов по исследованию оптических явлений, связанные с использованием новых компьютеров и операционных систем

    First πK\pi K atom lifetime and πK\pi K scattering length measurements

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    The results of a search for hydrogen-like atoms consisting of πK±\pi^{\mp}K^{\pm} mesons are presented. Evidence for πK\pi K atom production by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen in terms of characteristic πK\pi K pairs from their breakup in the same target (178±49178 \pm 49) and from Coulomb final state interaction (653±42653 \pm 42). Using these results the analysis yields a first value for the πK\pi K atom lifetime of τ=(2.51.8+3.0)\tau=(2.5_{-1.8}^{+3.0}) fs and a first model-independent measurement of the S-wave isospin-odd πK\pi K scattering length a0=13a1/2a3/2=(0.110.04+0.09)Mπ1\left|a_0^-\right|=\frac{1}{3}\left|a_{1/2}-a_{3/2}\right|= \left(0.11_{-0.04}^{+0.09} \right)M_{\pi}^{-1} (aIa_I for isospin II).Comment: 14 pages, 8 figure

    Determination of ππ\pi\pi scattering lengths from measurement of π+π\pi^+\pi^- atom lifetime

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    The DIRAC experiment at CERN has achieved a sizeable production of π+π\pi^+\pi^- atoms and has significantly improved the precision on its lifetime determination. From a sample of 21227 atomic pairs, a 4% measurement of the S-wave ππ\pi\pi scattering length difference a0a2=(.0.25330.0078+0.0080stat.0.0073+0.0078syst)Mπ+1|a_0-a_2| = (.0.2533^{+0.0080}_{-0.0078}|_\mathrm{stat}.{}^{+0.0078}_{-0.0073}|_\mathrm{syst})M_{\pi^+}^{-1} has been attained, providing an important test of Chiral Perturbation Theory.Comment: 6 pages, 6 figure

    Detection of π+π\pi^+\pi^-atoms with the DIRAC spectrometer at CERN

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    The goal of the DIRAC experiment at CERN is to measure with high precision the lifetime of the π+π\pi^+\pi^- atom (A2πA_{2\pi}), which is of order 3×10153\times10^{-15} s, and thus to determine the s-wave ππ\pi\pi-scattering lengths difference a0a2|a_{0}-a_{2}|. A2πA_{2\pi} atoms are detected through the characteristic features of π+π\pi^+\pi^- pairs from the atom break-up (ionization) in the target. We report on a first high statistics atomic data sample obtained from p Ni interactions at 24 GeV/cc proton momentum and present the methods to separate the signal from the background.Comment: 19 pages, 12 figures, 1 tabl

    Comprehensive analysis of the chromatin landscape in Drosophila melanogaster.

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    Chromatin is composed of DNA and a variety of modified histones and non-histone proteins, which have an impact on cell differentiation, gene regulation and other key cellular processes. Here we present a genome-wide chromatin landscape for Drosophila melanogaster based on eighteen histone modifications, summarized by nine prevalent combinatorial patterns. Integrative analysis with other data (non-histone chromatin proteins, DNase I hypersensitivity, GRO-Seq reads produced by engaged polymerase, short/long RNA products) reveals discrete characteristics of chromosomes, genes, regulatory elements and other functional domains. We find that active genes display distinct chromatin signatures that are correlated with disparate gene lengths, exon patterns, regulatory functions and genomic contexts. We also demonstrate a diversity of signatures among Polycomb targets that include a subset with paused polymerase. This systematic profiling and integrative analysis of chromatin signatures provides insights into how genomic elements are regulated, and will serve as a resource for future experimental investigations of genome structure and function

    Evidence for πK\pi K-atoms with DIRAC

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    We present evidence for the first observation of electromagnetically bound π±K\pi^\pm K^\mp-pairs (πK\pi K-atoms) with the DIRAC experiment at the CERN-PS. The πK\pi K-atoms are produced by the 24 GeV/c proton beam in a thin Pt-target and the π±\pi^\pm and KK^\mp-mesons from the atom dissociation are analyzed in a two-arm magnetic spectrometer. The observed enhancement at low relative momentum corresponds to the production of 173 ±\pm 54 πK\pi K-atoms. The mean life of πK\pi K-atoms is related to the s-wave πK\pi K-scattering lengths, the measurement of which is the goal of the experiment. From these first data we derive a lower limit for the mean life of 0.8 fs at 90% confidence level.Comment: 15 pages, 9 figure

    New data on OZI rule violation in bar{p}p annihilation at rest

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    The results of a measurement of the ratio R = Y(phi pi+ pi-) / Y(omega pi+ pi-) for antiproton annihilation at rest in a gaseous and in a liquid hydrogen target are presented. It was found that the value of this ratio increases with the decreasing of the dipion mass, which demonstrates the difference in the phi and omega production mechanisms. An indication on the momentum transfer dependence of the apparent OZI rule violation for phi production from the 3S1 initial state was found.Comment: 11 pages, 3 PostScript figures, submitted to Physics Letter

    The bound mu+ mu- system

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    We consider the hyperfine structure, the atomic spectrum and the decay channels of the bound mu+ mu- system (dimuonium). The annihilation lifetimes of low-lying atomic states of the system lie in the nanosecond range range. The decay rates could be measured by detection of the decay products (high energy photons or electron-positron pairs). The hyperfine structure splitting of the dimuonic system and its decay rate are influenced by electronic vacuum polarization effects in the far time-like asymptotic region. This constitutes a previously unexplored kinematic regime. We evaluate next--to-leading order radiative corrections to the decay rate of low-lying atomic states. We also obtain order alpha^5 corrections to the hyperfine splitting of the 1S and 2S levels.Comment: 10 figures (eps format) attached, Scheduled tentatively by PRA for Nov/Dec 199
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