circularly-polarized antenna is built based on new siw(substrate integrated waveguide)structure which contains cavity-backed resonator and a conventional polarized ring with twosquare slits in inner and outer ring that differ 90° at position and is proposed for right-handedcircular polarization (rhcp) and fabricated in two separate layers. a broadband impedancebandwidth of 13.9% and a rhcp axia...

circularly-polarized antenna is built based on a new siw (substrate integrated waveguide)structure which contains cavity-backed resonator and a conventional polarized ring with twosquare slits in inner and outer ring that differ 90° at position and is proposed for right-handedcircular polarization (rhcp) and fabricated in two separate layers. a broadband impedancebandwidth of 13.9% and a rhcp a...

The conformation of alinidine a new and specific bradycardic agent was studied using MNDO method. It has been found that the rotation of both phenyl and imidazoline ring of this compound is restricted. Of two possible isomers of irnidazoline ring, the one with NH in the cis position to allyl side chain is slightly more stable. On the other hand, the allyl group can rotate freely and at leas...

In this paper a Frequency Selective Surface (FSS) as a UWB electromagnetic shield is introduced. The proposed FSS comprises a quasi-J.C-Jerusalem Cross- and a copper ring, which are located at both sides of a FR4 substrate and can represent a S.E -Shielding Effectiveness- better than 20dB in 90% bandwidth of Ultra Wide Band frequency. This structure is compact and thin. Each cell comprises J.C ...

 Letbe a ring with an endomorphism and an -derivationAntoine studied the structure of the set of nilpotent elements in Armendariz rings and introduced nil-Armendariz rings. In this paper we introduce and investigate the notion of nil--compatible rings. The class of nil--compatible rings are extended through various ring extensions and many classes of nil--compatible rings are constructed. We al...

let $r$ be an associative ring with identity and $z^*(r)$ be its set of non-zero zero divisors.  the zero-divisor graph of $r$, denoted by $gamma(r)$, is the graph whose vertices are the non-zero  zero-divisors of  $r$, and two distinct vertices $r$ and $s$ are adjacent if and only if $rs=0$ or $sr=0$.  in this paper, we bring some results about undirected zero-divisor graph of a monoid ring ov...

in this note we introduce the notion of weak mccoy rings as a generalization of mccoy rings, and investigate their properties. also we show that, if is a semi-commutative ring, then is weak mccoy if and only if is weak mccoy.

the conformation of alinidine a new and specific bradycardic agent was studied using mndo method. it has been found that the rotation of both phenyl and imidazoline ring of this compound is restricted. of two possible isomers of irnidazoline ring, the one with nh in the cis position to allyl side chain is slightly more stable. on the other hand, the allyl group can rotate freely and at least si...