Active Phase Conjugating Lens With Sub-Wavelength Resolution Capability

Experimental results are presented for the focusing capability of an active phase conjugating lens for a single and a dipole source pair and these are compared with predictions. In addition for a single source we illustrate the ability of the lens to project a null at the lens focus instead of a peak. A scheme is also presented such that when a source or pair of sources is imaged through an identical pair of passive scatterers located symmetrically about the lens that imaging with sub-wavelength resolution is possible. The rationale for the operation of the lens and aberrations observed due to its finite array size is discussed and is supported throughout by means of numerical simulation.

325GHz Single Layer Sub-Millimeter Wave FSS Based Split Ring Linear to Circular Polarisation Convertor

A single layer, frequency selective surface based, sub-millimeter wave transmission polarizer is presented that converts incident slant linear 45° polarization into circular polarization upon transmission. The polarization convertor consists of a 30 mm diameter 10 thick silicon reinforced metalized screen containing 2700 resonator cells and perforated with nested split ring slot apertures. The screen was designed and optimized using CST Microwave Studio and predictions were validated experimentally by transmission measurements over the 250-365 GHz frequency range. This frequency range is used for remote environmental monitoring and 325 GHz represents a molecular emission line for H2O. The results obtained show good agreement between measured and modeled predictions. The measured 3 dB axial ratio bandwidth was 11.75%, measured minimum Axial Ratio was 0.19 dB and the measured insertion loss of the single layer screen was 3.38 dB

Performance, représentation et (il)lisibilité du genre dans la fiction sandienne des années 1830

Dans son premier roman, Indiana (1832), Sand établit un réseau de correspondances entre la langue, la performance et l'identité sexuelle qui n'ont pas encore fait l'objet d'une étude approfondie. Or, ces correspondances sous-tendent d'autres romans des années 1830, notamment Lélia (1833), Le Secrétaire intime (1834) et Gabriel (1839). Deux concepts – la performance et la lisibilité – fondent en fait les réflexions de Sand sur la représentation et le genre. Il s'agit dans cet article d'étudier ce réseau d'associations et d'explorer son évolution dans la fiction sandienne des années 1830. Cette analyse permettra de souligner comment, chez Sand, la performativité du genre met en question et trouble la représentation mimétique.

Rare occurrence of a bigeye tuna Thunnus obesus in British waters, with notes on other occurrences of sub-tropical tunas

A freshly dead bigeye tuna Thunnus obesus was washed ashore near Burry Port, Wales (51 degrees 40' N; 4 degrees 15' W) in August, 2006. This is only the third occasion that the species has been observed in British waters, and is the largest and most northerly recorded specimen.