11,700 research outputs found

    Antenna beam-shaping apparatus Patent

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    Device for improving efficiency of parabolic horn antenna system for linearly polarized signal

    Parabolic reflector horn feed with spillover correction Patent

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    Device for improving efficiency of parabolic reflector horn for linearly or circularly polarized wave

    Improved insertion-loss tester

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    An improved test method accurately measures the insertion loss of RF components while avoiding amplifier drift. Currents are balanced across a bridge transformer with shorted probes and then with each component to be tested. Differences in adjustments indicate the loss

    Insertion loss measuring apparatus having transformer means connected across a pair of bolometers Patent

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    High impedance alternating current sensing transformer device between two bolometers for measuring insertion loss of test componen

    Imaging of Thermal Domains in ultrathin NbN films for Hot Electron Bolometers

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    We present low-temperature scanning electron microscopy (LTSEM) investigations of superconducting microbridges made from ultrathin NbN films as used for hot electron bolometers. LTSEM probes the thermal structure within the microbridges under various dc current bias conditions, either via electron-beam-induced generation of an unstable hotspot, or via the beam-induced growth of a stable hotspot. Such measurements reveal inhomogeneities on a micron scale, which may be due to spatial variations in the NbN film or film-interface properties. Comparison with model calculations for the stable hotspot regime confirm the basic features of common hot spot models.Comment: 3 pages, 3 figure

    Investigation of ground effects on large and small scale models of a three fan V/STOL aircraft configuration

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    Induced lift of a subsonic, three fan, lift/cruise, V/STOL aircraft configuration was investigated using scale modes of a multimission aircraft whose design incorporates a nose mounted lift fan and two lift/cruise units located over the wing. Configuration effects were assessed for lift improvement devices, lift/cruise nozzle rails, nozzle perimeter plates, and alternate nose fan exit hubs. Tests were conducted at four model heights (H/D = 0.95, 1.53, 3.06 and 6.45, where D is the average nozzle exit diameter equal to 0.997 m.) Results are presented and discussed
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