135 research outputs found

    Concept synthesis of an equipment manipulation and transportation system EMATS

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    The European Columbus Scenario is established. One of the Columbus Elements, the Man Tended Free Flyer will be designed for fully autonomous operation in order to provide the environment for micro gravity facilities. The Concept of an autonomous automation system which perform servicing of facilities and deals with related logistic tasks is discussed

    Autonomous antenna tracking system for mobile symphonie ground stations

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    The implementation of a satellite tracking and antenna control system is described. Due to the loss of inclination control for the symphonie satellites, it became necessary to equip the parabolic antennas of the mobile Symphonie ground station with tracking facilities. For the relatively low required tracking accuracy of 0.5 dB, a low cost, step track system was selected. The step track system developed for this purpose and tested over a long period of time in 7 ground stations is based on a search step method with subsequent parabola interpolation. As compared with the real search step method, the system has the advantage of a higher pointing angle resolution, and thus a higher tracking accuracy. When the pilot signal has been switched off for a long period of time, as for instance after the eclipse, the antenna is repointed towards the satellite by an automatically initiated spiral search scan. The function and design of the tracking system are detailed, while easy handling and tracking results

    A Survey, Classification and Critical Review of Light-Emitting Diode Drivers

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    Based on a survey on over 1400 commercial LED drivers and a literature review, a range of LED driver topologies are classified according to their applications, power ratings, performance and their energy storage and regulatory requirements. Both passive and active LED drivers are included in the review and their advantages and disadvantages are discussed. This paper also presents an overall view on the technical and cost aspects of the LED technology, which is useful to both researchers and engineers in the lighting industry. Some general guidelines for selecting driver topologies are included to aid design engineers to make appropriate choices.published_or_final_versio

    Повышение эффективности проведения геолого-технических мероприятий на нефтяных месторождениях Западной Сибири

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    Рассмотрены существующие методы ГТМ, проведен анализ особенностей разных ГТМ на месторождениях Западной Сибири, предложены инновационные методы по повышению их эффективности.Existing methods of geological and technical measures are considered, the analysis of the features of different geological and technical measures at fields in Western Siberia is carried out, innovative methods for increasing their efficiency are proposed

    NO COTIDIANO DA INOVAÇÃO E A INOVAÇÃO NO COTIDIANO DA PRÁTICA PEDAGÓGICA EM EDUCAÇÃO FÍSICA

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    NO COTIDIANO DA INOVAÇÃO E A INOVAÇÃO NO COTIDIANO DA PRÁTICA PEDAGÓGICA EM EDUCAÇÃO FÍSIC

    Localization length and impurity dielectric susceptibility in the critical regime of the metal-insulator transition in homogeneously doped p-type Ge

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    We have determined the localization length \xi and the impurity dielectric susceptibility \chi_{\rm imp} as a function of Ga acceptor concentrations (N) in nominally uncompensated ^{70}Ge:Ga just below the critical concentration (N_c) for the metal-insulator transition. Both \xi and \chi_{\rm imp} diverge at N_c according to the functions \xi\propto(1-N/N_c)^{-\nu} and \chi_{\rm imp}\propto(N_c/N-1)^{-\zeta}, respectively, with \nu=1.2\pm0.3 and \zeta=2.3\pm0.6 for 0.99N_c< N< N_c. Outside of this region (N<0.99N_c), the values of the exponents drop to \nu=0.33\pm0.03 and \zeta=0.62\pm0.05. The effect of the small amount of compensating dopants that are present in our nominally uncompensated samples, may be responsible for the change of the critical exponents at N\approx0.99N_c.Comment: RevTeX, 4 pages with 5 embedded figures, final version (minor changes
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