Experiment and simulation demonstrate high power microwave generation at 9 GHz using a 9-cm-diam, 44%keV, 7-kA annular electron beam. The beam is propagated in a coaxial drift tube between inner and outer conductors, a configuration which increases the available beam current and reduces the surface fields from existing high power sources. The microwave interaction is provided by an extended len...

We propose and analyze a plasmonic lens that is illuminated by a radially polarized light. The lens is made of a coax-like geometry consisting of an annular dielectric slit surrounded by metal. Focusing efficiency is enhanced by the use of a circular grating assisting the coupling of light into surface plasmons. Further enhancement is obtained by introducing a circular Bragg grating on top of t...

We consider Laplace operators and Schrödinger operators with potentials containing curvature on certain regions of nontrivial topology, especially closed curves, annular domains, and shells. Dirichlet boundary conditions are imposed on any boundaries. Under suitable assumptions we prove that the fundamental eigenvalue is maximized when the geometry is round. We also comment on the use of coordi...

We consider diffusion-controlled release of particles from d-dimensional radially-symmetric geometries. A quantity commonly used to characterise such diffusive processes is the proportion remaining within geometry over time, denoted as P(t). The stochastic approach for computing P(t) time-consuming and lacks analytical insight into key parameters while continuum yields complicated expressions t...

INTRODUCTION Laparoscopic duodenal atresia repair is an advanced procedure performed in select pediatric surgical centers. Recently, sub-6mm endosurgical staplers have been introduced, facilitating and accelerating the creation of intracorporeal intestinal anastomoses. PRESENTATION OF CASE We performed a laparoscopic duodenojejunostomy in a one-day-old child with duodenal atresia due to annul...

In this paper, numerical investigation of upward two phase flow of air-water has been studied. Different conditions of flow regimes including annular, wispy annular, slug, churn and bubbly are simulated based on Hewitt and Roberts map, and a good agreement between the experimental data of the map and the numerical simulation has been observed. Accordingly, a proper CFD model in CFD software of ...