36,771 research outputs found

    Arbitrary beam control using passive lossless metasurfaces enabled by orthogonally-polarized custom surface waves

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    For passive, lossless impenetrable metasurfaces, a design technique for arbitrary beam control of receiving, guiding, and launching is presented. Arbitrary control is enabled by a custom surface wave in an orthogonal polarization such that its addition to the incident (input) and the desired scattered (output) fields is supported by a reactive surface impedance everywhere on the reflecting surface. Such a custom surface wave (SW) takes the form of an evanescent wave propagating along the surface with a spatially varying envelope. A growing SW appears when an illuminating beam is received. The SW amplitude stays constant when power is guided along the surface. The amplitude diminishes as a propagating wave (PW) is launched from the surface as a leaky wave. The resulting reactive tensor impedance profile may be realized as an array of anisotropic metallic resonators printed on a grounded dielectric substrate. Illustrative design examples of a Gaussian beam translator-reflector, a probe-fed beam launcher, and a near-field focusing lens are provided

    Balloon occlusion retrograde transvenous obliteration of gastric varices in two non-cirrhotic patients with portal vein thrombosis

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    This report describes two non-cirrhotic patients with portal vein thrombosis who underwent successful balloon occlusion retrograde transvenous obliteration (BRTO) of gastric varices with a satisfactory response and no complications. One patient was a 35-year-old female with a history of Crohn's disease, status post-total abdominal colectomy, and portal vein and mesenteric vein thrombosis. The other patient was a 51-year-old female with necrotizing pancreatitis, portal vein thrombosis, and gastric varices. The BRTO procedure was a useful treatment for gastric varices in non-cirrhotic patients with portal vein thrombosis in the presence of a gastrorenal shunt

    Multidimensional Bosonization

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    Bosonization of degenerate fermions yields insight both into Landau Fermi liquids, and into non-Fermi liquids. We begin our review with a pedagogical introduction to bosonization, emphasizing its applicability in spatial dimensions greater than one. After a brief historical overview, we present the essentials of the method. Well known results of Landau theory are recovered, demonstrating that this new tool of many-body theory is robust. Limits of multidimensional bosonization are tested by considering several examples of non-Fermi liquids, in particular the composite fermion theory of the half-filled Landau level. Nested Fermi surfaces present a different challenge, and these may be relevant in the cuprate superconductors. We conclude by discussing the future of multidimensional bosonization.Comment: 91 pages, 15 eps figures, LaTeX. Minor changes to match the published versio

    Semiclassical Corrections to the Cardy-Verlinde Formula of Kerr Black Holes

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    In this letter, we compute the corrections to the Cardy-Verlinde formula of 4−4-dimensional Kerr black hole. These corrections are considered within the context of KKW analysis and arise as a result of the self-gravitational effect. Then we show, one can taking into account the semiclassical corrections of the Cardy-Verlinde entropy formula by just redefining the Virasoro operator L0L_0 and the central charge cc.Comment: 8 page
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