70,745 research outputs found

    Inner Disk Oscillations and QPOs in Relativistic Jet Sources

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    Recent results on the inner disk oscillations found in GRS 1915+105 are reviewed. QPOs during the low state are used as a marker for such oscillations and the physical picture emerging from a combined X-ray spectral and timing analysis is examined. The relationship between inner disk oscillations and synchrotron radio emission is critically evaluated.Comment: 8 pages, LaTeX, kluwer.cls, 2 figures, to be published in `Proceedings of the Third Microquasar Workshop: Granada Workshop on galactic relativistic jet sources', Eds A.J. Castro-Tirado, J. Greiner and J.M. Paredes, Astrophysics and Space Science, in pres

    A Model of High-Frequency Self-Mixing in Double-Barrier Rectifier

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    In this paper, a new model of the frequency dependence of the double-barrier THz rectifier is presented. The new structure is of interest because it can be realized by CMOS image sensor technology. Its application in a complex field such as that of THz receivers requires the availability of an analytical model, which is reliable and able to highlight the dependence on the parameters of the physical structure. The model is based on the hydrodynamic semiconductor equations, solved in the small signal approximation. The model depicts the mechanisms of the THz modulation of the charge in the depleted regions of the double-barrier device and explains the self-mixing process, the frequency dependence, and the detection capability of the structure. The model thus substantially improves the analytical models of the THz rectification available in literature, mainly based on lamped equivalent circuits
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