14 research outputs found
Modelling of epitaxial film growth with a Ehrlich-Schwoebel barrier dependent on the step height
The formation of mounded surfaces in epitaxial growth is attributed to the
presence of barriers against interlayer diffusion in the terrace edges, known
as Ehrlich-Schwoebel (ES) barriers. We investigate a model for epitaxial growth
using a ES barrier explicitly dependent on the step height. Our model has an
intrinsic topological step barrier even in the absence of an explicit ES
barrier. We show that mounded morphologies can be obtained even for a small
barrier while a self-affine growth, consistent with the Villain-Lai-Das Sarma
equation, is observed in absence of an explicit step barrier. The mounded
surfaces are described by a super-roughness dynamical scaling characterized by
locally smooth (faceted) surfaces and a global roughness exponent .
The thin film limit is featured by surfaces with self-assembled
three-dimensional structures having an aspect ratio (height/width) that may
increase or decrease with temperature depending on the strength of step
barrier.Comment: To appear in J. Phys. Cond. Matter; 3 movies as supplementary
materia
MHD flow of an elastico-viscous fluid under periodic body acceleration
Magnetohydrodynamic (MHD) flow of blood has been studied under the influence of body acceleration. With the help of Laplace and finite
Hankel transforms, an exact solution is obtained for the unsteady
flow of blood as an electrical conducting, incompressible and
elastico-viscous fluid in the presence of a magnetic field acting
along the radius of the pipe. Analytical expressions for axial
velocity, fluid acceleration and flow rate has been obtained