Sharif Digital Repository

The electrokinetic phenomena at high zeta potentials may show several unique features which are not normally observed. One of these features is the ionic size (steric) effect associated with the solutions of high ionic concentration. In the present work, attention is given to the influences of finite ionic size on the cross stream diffusion process in an electrokinetically actuated Y-shaped micromixer. The method consists of a finite difference based numerical approach for non-uniform grid which is applied to the dimensionless form of the governing equations, including the modified Poisson-Boltzmann equation. The results reveal that, neglecting the ionic size at high zeta potentials gives... 

In recent years, a range of studies have been conducted with the aim to design and characterize delivery systems that are able to release multiple therapeutic agents in controlled and programmed temporal sequences, or with spatial resolution inside the body. This sequential release occurs in response to different stimuli, including changes in pH, redox potential, enzyme activity, temperature gradients, light irradiation, and by applying external magnetic and electrical fields. Sequential release (SR)-based delivery systems, are often based on a range of different micro- or nanocarriers and may offer a silver bullet in the battle against various diseases, such as cancer. Their distinctive... 

A theory is presented for the quantum radiation emitted from a single exciton in a quantum dot. We assume that the quantum dot is in strong coupling to a slab photonic crystal cavity. A dielectric function of spatial coordinates is used to explain the effects of the macroscopic medium. It has been proved that the electric field in such a medium can be described using the so-called K-function. We derive a formula for obtaining the frequency spectrum, and present an analytical result for the optical spectrum, which is dependent on the K-function. We also have considered a slab photonic crystal configuration with hexagonal structure containing a cavity to evaluate the frequency spectrum in such... 

The effect of pulsed direct current (PDC) on solid-state diffusion in the Ni–Al binary system was investigated. Two experimental schemes were employed: in the presence and absence of an electric field. The diffusion couples were heat-treated for 1.5, 3, and 5 h at 803, 833, and 863 K. Under the investigated conditions, only two intermetallic phases (NiAl3 and Ni2Al3) formed at the boundary of the metals. It was shown that the PDC passing through the diffusion couple significantly enhanced the growth rates of both phases. The apparent reaction–diffusion coefficients were DNiAl3=4.0×10−9exp(−[Formula presented]) and DNi2Al3=9.7×10−9exp(−[Formula presented]) in the field-assisted scheme,... 

Electrophoretic technique was used to deposit micro- and nano-sized aluminum nitride coatings on stainless steel surfaces by using a well-dispersed stable suspension produced by addition of AlN powder plus a small amount of iodine to ethanol. Parabolic regime governed the deposition. Electrophoretic deposition for 240 s at 100 V resulted in formation of a uniformly dense film on the top, but a porous inhomogeneous layer at the bottom. This was attributed to fast deposition of coarse particles and/or agglomerates at large electric fields. After drying, micro-sized particles led to a uniform crack-free interface while nano-particles resulted in fragmented non-cohesive layers. Weight loss... 

In this paper we have studied both DC size effect and anomalous skin effect caused by surface and grain boundary scattering on the resistivity of Cu thin films by a Monte Carlo method. Contribution of each scattering mechanism and the interaction between them are analyzed separately. A simple and fast numerical recursive method is also introduced to guess the structure of electric field and distribution of current inside the thin film to evaluate the surface resistance instead of complicated analytical formulas  

We present a computational study on the electrical behavior of the field-effect transistor based on vertical graphene-hBN- χ 3 borophene heterostructure and vertical graphene nanoribbon-hBN- χ 3 borophene nanoribbon heterostructure. We use nonequilibrium the Green function formalism along with an atomistic tight-binding (TB) model. The TB parameters are calculated by fitting tight-binding band structure and first-principle results. Also, electrical characteristics of the device, such as ION/IOFF ratio, subthreshold swing, and intrinsic gate-delay time, are investigated. We show that the increase of the hBN layer number decreases subthreshold swing and degrades the intrinsic gate-delay time....