Suppression of Backscattering From 2-D Aperiodically-Ordered Thinned Patch Array Using Rudin-Shapiro Sequences

Abstract

Abstract-The discovery of "quasi-crystals," whose X-ray diffraction patterns reveal certain unusual features which do not conform with spatial periodicity, has motivated studies of the wave-dynamical implications of "aperiodic order." This paper discusses various aperiodic configurations generated by Rudin-Shapiro (RS) sequences. These RS sequences constitute ones of the simplest conceivable examples of deterministic aperiodic geometries featuring random-like (dis)order. The scattering properties of aperiodically-ordered thinned 2-D patch arrays based on RS sequences are analyzed by using physical optics approximation. Compared to a periodic case, RS-based antenna array is found to have a substantial reduction in the magnitude of the backscattering component of the scattered signal with half of the elements and the same magnitude of specular reflection. This property is verified by illustrative numerical parametric studies.

A titanium tetrachloride-based effective methodology for the synthesis of dipeptides

“…The successful outcomes obtained with the synthesis of dipeptides 1-6 prompted us to extend the developed methodology to the preparation of dipeptide systems protected on the a-amino function with the base-labile protecting group uorenylmethoxycarbonyl (Fmoc) (Scheme 3). N-Fmoc-dipeptide systems (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) were prepared in high yields without observing the formation of reaction products deprotected on the a-amino function ( Table 2).…”

“…7 Other dipeptides are then widely used in the formulation of cosmetic products for instance cysteine-containing dipeptides, 8 L-Tyr-L-Arg 9 and aspartyl dipeptides, the latter possess highly effective skin and hair caring properties. 10 Amide bond formation is an extremely important reaction in organic chemistry. 11 Numerous synthetic strategies to synthesize organic molecules containing amide bonds and peptides have been reported.…”