36,771 research outputs found
Arbitrary beam control using passive lossless metasurfaces enabled by orthogonally-polarized custom surface waves
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
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
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
In this letter, we compute the corrections to the Cardy-Verlinde formula of
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
and the central charge .Comment: 8 page
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