We present experimental and theoretical work showing that a flat metallic slab can collimate and focus light impinging on the slab from a point source. The effect is optimized when the radiation is around the bulk, not at the surface, plasma frequency. Also, the smaller the imaginary part of the permittivity is, the better the collimation. Experiments for Ag in the visible as well as calculatio...

The current trend in building medium-size telescopes for wide-field imaging is to use a Ritchey-Chrétien (RC) design with a multilens corrector near the focus. Our goal is to find a cost-effective alternative design to the RC system for seeing-limited observations. We present an f/4.5 all-spherical catadioptric system with a 1.5° field of view. The system consists of a 0.8 m spherical primary a...

Abstract In some concrete structures, openings are placed because of the need for several utility requirements. These could affect strength structural members. So behavior reinforcement (RC) cantilever slab containing and its effect is subject study. Opening shapes, numbers sizes main variables that have been studied in this research. Five RC slabs were cast tested; one without other four with ...

This study investigates the deterioration process and mechanism of reinforced concrete (RC) slabs in road bridges under dry stagnant water (wet) conditions. Previous studies used a simple-plate model (SPM) to predict fatigue life RC decks by considering conservative assumptions for safer assessment different environmental processes. To obtain more detailed analysis clarify result mechanism, ful...

In this paper we study the characteristics of subwavelength imaging of a photonic crystal (PhC) superlens under the influence of source displacement. For square and triangular lattice photonic crystal lenses, we investigate the influence of changing the lateral position of a single point source on imaging uniformity and stability. We also study the effect of changing the geometrical center of a...