426 research outputs found
A theoretical analysis on highly spin-polarized transport of iron nitride Fe_4N
In order to propose a ferromagnet exhibiting highly spin-polarized transport,
we theoretically analyzed the spin polarization ratio of the conductivity of
the bulk FeN with a perovskite type structure, in which N is located at the
body center position of fcc-Fe. The spin polarization ratio is defined by , with being the conductivity at zero
temperature of the up spin (down spin). The conductivity is obtained by using
the Kubo formula and the Slater-Koster tight binding model, where parameters
are determined from the least-square fitting of the dispersion curves by the
tight binding model to those by the first principles calculation. In the
vicinity of the Fermi energy, takes almost 1.0, indicating perfectly
spin-polarized transport. In addition, by comparing FeN to fcc-Fe
(FeN) in the ferromagnetic state with the equilibrium lattice constant
of FeN, it is shown that the non-magnetic atom N plays an important role in
increasing .Comment: 4 pages, 2 figures, accepted for publication in Phys. Rev.
Finite-element analysis of high Reynolds number flow past a circular cylinder
AbstractRecently we developed a new upwind finite-element scheme for the incompressible Navier-Stokes equations. In this paper we apply the scheme to a problem of high Reynolds number flows past a circular cylinder and discuss the effect of the subdivision of the boundary layer upon flow patterns and drag coefficients
Local structures and structural phase change in Ni-Zr-Nb glassy alloys composed of Ni5Zr5Nb3 icosahedral clusters
Convergence analysis of the interface for interfacial transport phenomena
In this paper we are concerned with the convergence analysis of the interface for interfacial transport phenomena such as incompressible immiscible two-fluid flows. Some convergence results for the interface are shown by the regularized Heaviside function. In order to validate our convergence results, numerical examples are presented with an original test problem having non-trivial but explicit interface
Streett Automata Model Checking of Higher-Order Recursion Schemes
We propose a practical algorithm for Streett automata model checking of higher-order recursion schemes (HORS), which checks whether the tree generated by a given HORS is accepted by a given Streett automaton. The Streett automata model checking of HORS is useful in the context of liveness verification of higher-order functional programs. The previous approach to Streett automata model checking converted Streett automata to parity automata and then invoked a parity tree automata model checker. We show through experiments that our direct approach outperforms the previous approach. Besides being able to directly deal with Streett automata, our algorithm is the first practical Streett or parity automata model checking algorithm that runs in time polynomial in the size of HORS, assuming that the other parameters are fixed. Previous practical fixed-parameter polynomial time algorithms for HORS could only deal with the class of trivial tree automata. We have confirmed through experiments that (a parity automata version of) our model checker outperforms previous parity automata model checkers for HORS
Elastic precursor of the transformation from glycolipid-nanotube to -vesicle
By the combination of optical tweezer manipulation and digital video
microscopy, the flexural rigidity of single glycolipid "nano" tubes has been
measured below the transition temperature at which the lipid tubules are
transformed into vesicles. Consequently, we have found a clear reduction of the
rigidity obviously before the transition as temperature increasing. Further
experiments of infrared spectroscopy (FT-IR) and differential scanning
calorimetry (DSC) have suggested a microscopic change of the tube walls,
synchronizing with the precursory softening of the nanotubes.Comment: 9 pages, 6 figure
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