in this thesis, barium ferrite nano particles were prepared by sol-gel method. their structural and magnetic properties of samples have been investigated using thermo gravimetric analysis (tg-dta), x-ray powder diffractometer (xrd), fourier transform infrared (ftir), scanning electron microscopy (sem), field emission scanning electron microscopy (fesem), ac susceptometer, vibrating sample magne...

boron nitride semiconducting zigzag swcnt, $b_{cb}$$n_{cn}$$c_{1-cb-cn}$, as a potential candidate for making nanoelectronic devices was examined. in contrast to the previous dft calculations, wherein just one boron and nitrogen doping configuration have been considered, here for the average over all possible configurations, density of states (dos) was calculated in terms of boron and nitrogen ...

cohesion is an indispensable linguistic feature in discourse analysis. lexicald such a differe cohesion and conjunction in particular as two crucial elements to textual cohesion and comprehension has been the focus of a wide range of studies up to now. yet the relationship between the open register and cohesive devices has not been thoroughly investigated in discourse studies. this study concen...

growing demands and requires of high data rate systems cause significant increase of high frequency systems for wideband communication applications. as mixers are one of the main blocks of each receivers and its performance has great impact on receiver’s performance; in this thesis, a new solution for ku-band (12-18 ghz) mixer design in tsmc 0.18 µm is presented. this mixer has high linearity a...

in this thesis, phosphorus ylides [phbppy], [no2bppy] and [brbppy] have been synthesized through the formation of phosphonium salt and dihydrogenation, followed by the reaction of pd(oac)2 and the orthopalladated dinuclear complexes [pd(?-cl)(phbppy)]2, [pd(?-cl)(no2bppy)]2 and [pd(?-cl)(brbppy)]2 have been produced. the reaction of dinuclear complexes and bidentate ligands [l = bipy (2,2-bipyr...

in this research we have studied the effect of some transition-metals (cu, ag and au) substitutions on two-electron reduction potential of flavins by application of dft method. all geometries have been optimized at blyp level of theory and “6-31+g** + lanl2dz” mixed basis set. the frequency job at the same method and basis sets has been performed to obtain gibbs free energy of compounds. it h...

the methods which are used to analyze microstrip antennas, are divited into three categories: empirical methods, semi-empirical methods and full-wave analysis. empirical and semi-empirical methods are generally based on some fundamental simplifying assumptions about quality of surface current distribution and substrate thickness. thses simplificatioms cause low accuracy in field evaluation. ful...

a phase-locked loop (pll) based frequency synthesizer is an important circuit that is used in many applications, especially in communication systems such as ethernet receivers, disk drive read/write channels, digital mobile receivers, high-speed memory interfaces, system clock recovery and wireless communication system. other than requiring good signal purity such as low phase noise and low spu...