Sharif Digital Repository

In this article we present an all passive optical iterative interference cancellation method for optical CDMA. We propose the receiver structure based on advanced binary optical logic gates (ABOLGs). Since the performance bottleneck in optical communication systems is the conversion from optical to electronic domains for optical detectors, the interference cancellation has been performed in the optical domain. In incoherent optical communication systems, we have only the positive values for the optical signals. In the proposed system, we bypass the negative values using logic arrays. In the simulations we consider multiple access interference and neglect other sources of noise. Simulation... 

Dirac electrons in clean graphene can mediate the interactions between two localized magnetic moments. The functional form of the RKKY interaction in pristine graphene is specified by two main features: (i) an atomic-scale oscillatory part determined by a wavevector → connecting the two valleys; with doping another longer range oscillation appears which arises from the existence of an extended Fermi surface characterized by a momentum scale kF; (ii) an algebraic Rα decay in large distances where the exponent α=-3 is a distinct feature of undoped Dirac sea in two dimensions. In this work, we investigate the effect of a few per cent vacancies on the above properties. Depending on the doping... 

The bio-microfluidic systems are usually encountered with non-Newtonian behaviors of working fluids. The rheological behavior of some bio-fluids can be described by differential viscoelastic constitutive equations that are related to PTT and FENE-P models. In the present work, thermal transport characteristics of the steady fully developed electroosmotic flow of these fluids in a slit microchannel with constant wall heat fluxes have been investigated. The Debye-Huckel linearization is adopted and the effects of viscous dissipation and Joule heating are taken into account. Analytical solutions are obtained for the transverse distributions of velocity and temperature and finally for Nusselt...