38,044 research outputs found

    Visible and near infrared spectroscopy of Hayabusa re-entry using semi-autonomous tracking

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    A ground-based tracking camera and co-aligned slit-less spectrograph were used to measure the spectral signature of visible radiation emitted from the Hayabusa capsule as it entered into the Earth's atmosphere in June 2010. Good quality spectra were obtained that showed the presence of radiation from the heat shield of the vehicle and the shock-heated air in front of the vehicle. An analysis of the black body nature of the radiation concluded that the peak average temperature of the surface was about (3100±100) K

    Observation of narrow fluorescence from doubly driven four-level atoms at room temperature

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    Unusually narrow fluorescence peaks are seen from Rubidium-85 atoms under the action of two driving laser fields that are in a three dimensional molasses configuration. One of the lasers is held at a fixed detuning from the "cooling" transition, while the other is scanned across the "repumping" transitions. The fluorescence peaks are split into symmetric pairs, with the seperation within a pair increasing with the detuning of the cooling laser. For large detunings additional small peaks are seen. A simple model is proposed to explain these experimental observations.Comment: 8 pages, 4 figures, needs epl.cl

    An extension of a theorem of Sahab, Khan, and Sessa

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    A fixed point theorem of Fisher and Sessa is generalized to locally convex spaces and the new result is applied to extend a recent theorem on invariant approximation of Sahab, Khan, and Sessa
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