47 research outputs found
Deformation and Depinning of Superconducting Vortices from Artificial Defects: A Ginzburg-Landau Study
Using Ginzburg-Landau theory, we have performed detailed studies of vortices
in the presence of artificial defect arrays, for a thin film geometry. We show
that when a vortex approaches the vicinity of a defect, an abrupt transition
occurs in which the vortex core develops a ``string'' extending to the defect
boundary, while simultaneously the supercurrents and associated magnetic flux
spread out and engulf the defect. Current induced depinning of vortices is
shown to be dominated by the core string distortion in typical experimental
situations. Experimental consequences of this unusual depinning behavior are
discussed.Comment: 10 pages,9 figure
Mott Transition in An Anyon Gas
We introduce and analyze a lattice model of anyons in a periodic potential
and an external magnetic field which exhibits a transition from a Mott
insulator to a quantum Hall fluid. The transition is characterized by the anyon
statistics, , which can vary between Fermions, , and Bosons,
. For bosons the transition is in the universality class of the
classical three-dimensional XY model. Near the Fermion limit, the transition is
described by a massless Dirac theory coupled to a Chern-Simons gauge
field. Analytic calculations perturbative in , and also a large
N-expansion, show that due to gauge fluctuations, the critical properties of
the transition are dependent on the anyon statistics. Comparison with previous
calcualations at and near the Boson limit, strongly suggest that our lattice
model exhibits a fixed line of critical points, with universal critical
properties which vary continuosly and monotonically as one passes from Fermions
to Bosons. Possible relevance to experiments on the transitions between
plateaus in the fractional quantum Hall effect and the magnetic field-tuned
superconductor-insulator transition are briefly discussed.Comment: text and figures in Latex, 41 pages, UBCTP-92-28, CTP\#215
Modifications of Midfacial Soft-Tissue Thickness Among Different Skeletal Classes in Italian Children
Circulating Factors and Ultrasono-findings are Linked to Previous Atherosclerotic Burden and Recurrent Risk
Study of ?? cluster structure in 22Mg
The ??-cluster structure in the nuclei has been investigated for the perspective of nuclear structure. Contrary to the case of the 4N nuclei with N = Z, the experimental evidences of the clustering structures for the proton-rich systems are still lacking information. In order to study the interesting proton-rich 22Mg radionuclide, the 18Ne(??,??)18Ne elastic scattering will be measured at the Center for Nuclear Study Radioactive Ion Beam Separator of the University of Tokyo. By comparing the experimentally-obtained excitation function with theoretical R-matrix calculations, the resonance parameters of the 18xNe+?? system will be provided in the energy range 1MeV < Ec.m. < 12.4MeV.clos
Isolation and identification of cinnamic acid amides as antioxidants from Allium fistulosum L. and their free radical scavenging activity
Mathematical models of canine right and left atria cardiomyocytes*
The aim of this study is to build two mathematical models of canine ionic currents specific to right atria and left atria. The canine left atria mathematical model was firstly modified from the Ramirez-Nattel-Courtemanche (RNC) model using the recently available experimental data of ionic currents and was further developed based on our own experimental data. A model of right atria was then built by considering the differences between right atria and left atria. The two developed models well reproduced the experimental data on action potential morphology, the rate dependence, and action potential duration restitution. They are useful for investigating the mechanisms underlying the heterogeneity of canine regional action potentials and would help the simulation of whole heart excitation propagation and cardiac arrhythmia in the near future