4,735 research outputs found

    Thermal conductivity of suspended pristine graphene measured by Raman spectroscopy

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    The thermal conductivity of suspended single-layer graphene was measured as a function of temperature using Raman scattering spectroscopy on clean samples prepared directly on a prepatterned substrate by mechanical exfoliation without chemical treatments. The temperature at the laser spot was monitored by the frequency of the Raman 2DD band of the Raman scattering spectrum, and the thermal conductivity was deduced by analyzing heat diffusion equations assuming that the substrate is a heat sink at ambient temperature. The obtained thermal conductivity values range from ∼\sim1800 Wm−1^{-1}K−1^{-1} near 325 K to ∼\sim710 Wm−1^{-1}K−1^{-1} at 500 K.Comment: 4pages, 3 figure

    Tracking Moving Objects by a Mobile Camera

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    A system for video tracking of a moving object by the robot-held camera is presented, and efficient tracking methods are proposed. We describe our initial implementation of a system which is capable of tracking a single moving object against highly textured background. A pyramid-based image processor, PVM-1 is employed to support some fast algorithms in locating the moving object from the difference image. Object tracking is accomplished in the static look-and-move mode by the translational motion of a CCD camera mounted on the robot arm. Discussion is given on the implementation of tracking filters and on the effective utilization of multi-resolution processing for the object searching. Finally a method for dynamic look-and-move tracking is proposed for the future improvement of tracking performance
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