32,036 research outputs found
Experiments with Magnetohydrodynamically Supported Shock Layers
Shock tube experiments to determine interaction of hypersonic flow with magnetic fiel
One hundred angstrom niobium wire
Composite of fine niobium wires in copper is used to study the size and proximity effects of a superconductor in a normal matrix. The niobium rod was drawn to a 100 angstrom diameter wire on a copper tubing
Spin projection and spin current density within relativistic electronic transport calculations
A spin projection scheme is presented which allows the decomposition of the
electric conductivity into two different spin channels within fully
relativistic transport calculations that account for the impact
of spin-orbit coupling. This is demonstrated by calculations of the
spin-resolved conductivity of FeCr and CoPt disordered
alloys on the basis of the corresponding Kubo-Greenwood equation implemented
using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA)
band structure method. In addition, results for the residual resistivity of
diluted Ni-based alloys are presented that are compared to theoretical and
experimental ones that rely on Mott's two-current model for spin-polarized
systems. The application of the scheme to deal with the spin-orbit induced spin
Hall effect is discussed in addition
Competition of mixing and segregation in rotating cylinders
Using discrete element methods, we study numerically the dynamics of the size
segregation process of binary particle mixtures in three-dimensional rotating
drums, operated in the continuous flow regime. Particle rotations are included
and we focus on different volume filling fractions of the drum to study the
interplay between the competing phenomena of mixing and segregation. It is
found that segregation is best for a more than half-filled drum due to the
non-zero width of the fluidized layer. For different particle size ratios, it
is found that radial segregation occurs for any arbitrary small particle size
difference and the final amount of segregation shows a linear dependence on the
size ratio of the two particle species. To quantify the interplay between
segregation and mixing, we investigate the dynamics of the center of mass
positions for each particle component. Starting with initially separated
particle groups we find that no mixing of the component is necessary in order
to obtain a radially segregated core.Comment: 9 pages, 12 figures (EPIC/EEPIC & EPS, macros included), submitted to
Physics of Fluid
Coherent description of the intrinsic and extrinsic anomalous Hall effect in disordered alloys on an level
A coherent description of the anomalous Hall effect (AHE) is presented that
is applicable to pure as well as disordered alloy systems by treating all
sources of the AHE on equal footing. This is achieved by an implementation of
the Kubo-St\v{r}eda equation using the fully relativistic
Korringa-Kohn-Rostoker (KKR) Green's function method in combination with the
Coherent Potential Approximation (CPA) alloy theory. Applications to the pure
elemental ferromagnets bcc-Fe and fcc-Ni led to results in full accordance with
previous work. For the alloy systems fcc-FePd and
fcc-NiPd very satisfying agreement with experiment could be
achieved for the anomalous Hall conductivity (AHC) over the whole range of
concentration. To interpret these results an extension of the definition for
the intrinsic AHC is suggested. Plotting the corresponding extrinsic AHC versus
the longitudinal conductivity a linear relation is found in the dilute regimes,
that allows a detailed discussion of the role of the skew and side-jump
scattering processes.Comment: * shortened manuscript * slight rewordings * changed line style in
Fig 1 * corrected misprinted S (skewness) factor * merged Fig. 3 with Fig. 1
* new citation introduce
Ab-initio calculation of the Gilbert damping parameter via linear response formalism
A Kubo-Greenwood-like equation for the Gilbert damping parameter is
presented that is based on the linear response formalism. Its implementation
using the fully relativistic Korringa-Kohn-Rostoker (KKR) band structure method
in combination with Coherent Potential Approximation (CPA) alloy theory allows
it to be applied to a wide range of situations. This is demonstrated with
results obtained for the bcc alloy system FeCo as well as for a
series of alloys of permalloy with 5d transition metals.
To account for the thermal displacements of atoms as a scattering mechanism,
an alloy-analogy model is introduced. The corresponding calculations for Ni
correctly describe the rapid change of when small amounts of
substitutional Cu are introduced
Interpretation of x-ray-absorption dichroism experiments
A rule is derived to use x-ray magnetic circular dichroism spectra to extract the magnetic moment of the conduction-band states with j= l -1/2 separately from those with j= l + 1/2 as a function of energy. This quantity is straightforward to determine from the electronic band structure. The rule is illustrated with an application to pure iron and to the random substitutional alloy Fe_{80}CO_{20}
Incoherent pion photoproduction on the deuteron with polarization observables I: Formal expressions
Formal expressions are developed for the general five-fold differential cross
section of incoherent -photoproduction on the deuteron including beam and
target polarization. The polarization observables of the cross section are
described by various beam, target and beam-target asymmetries for polarized
photons and/or polarized deuterons. They are given as bilinear hermitean forms
in the reaction matrix elements divided by the unpolarized cross section. In
addition, the corresponding observables for the semi-exclusive reaction are also given.Comment: 11 pages, 1 figur
Recent rural radio talks.
Submitting plant specimens for disease identification. - Rose McAleer
Grading of fruit and vegetables. - E. H Rawso
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