19,749 research outputs found
Crystal field effects on spin pumping
"Spin pumping" is the injection of spin angular momentum by a time-dependent
magnetization into an adjacent normal metal proportional to the spin mixing
conductance. We study the role of electrostatic interactions in the form of
crystal fields on the pumped spin currents generated by insulators with
exchange-coupled local moments at the interface to a metal. The crystal field
is shown to render the spin currents anisotropic, which implies that the spin
mixing conductance of insulator|normal metal bilayers depends on crystal cut
and orientation. We interpret the interface "effective field" (imaginary part
of the spin mixing conductance) in terms of the coherent motion of the
equilibrium spin density induced by proximity in the normal metal.Comment: 8 pages+, 7 figure
Voltage control of interface rare-earth magnetic moments
The large spin orbit interaction in rare earth atoms implies a strong
coupling between their charge and spin degrees of freedom. We formulate the
coupling between voltage and the local magnetic moments of rare earth atoms
with partially filled 4f shell at the interface between an insulator and a
metal. The rare earth-mediated torques allow power-efficient control of
spintronic devices by electric field-induced ferromagnetic resonance and
magnetization switching
Glossinidae
One zebu bull of 365 kg live weight was treated along the back line with 36 mL
of fipronil as a pour-on formulation. Long-lasting mortalities of Glossina
palpalis gambiensis were recorded despite exposure to sunlight and regular
rinsing with 50 L of water during the following 5 months. Significantly higher
mortalities were still observed even 140, 170 and 190 days after treatment
following their triple releases or triple feeding of caged tsetse on the
treated bull. Mortalities of 70, 80 and 44 %, respectively, were recorded
after 15 days of observation. This contrasted with the mortalities of control
flies that were released in the presence of the untreated bull or fed in cages
on the animal, amounting to 20 and twice 10 % after 170 and 190 days. The
feeding successes of the released or caged flies were higher than 95 % and did
not differ between control and experimental groups, indicating no repulsive or
irritant effects of fipronil. The findings of this study are discussed,
particularly in view of the potential of fipronil as an effective means for
tsetse control
The use of ERTS-1 multispectral imagery for crop identification in a semi-arid climate
Crop identification using multispectral satellite imagery and multivariate pattern recognition was used to identify wheat accurately in Greeley County, Kansas. A classification accuracy of 97 percent was found for wheat and the wheat estimate in hectares was within 5 percent of the USDA's Statistical Reporting Service estimate for 1973. The multispectral response of cotton and sorghum in Texas was not unique enough to distinguish between them nor to separate them from other cultivated crops
Critical curves in conformally invariant statistical systems
We consider critical curves -- conformally invariant curves that appear at
critical points of two-dimensional statistical mechanical systems. We show how
to describe these curves in terms of the Coulomb gas formalism of conformal
field theory (CFT). We also provide links between this description and the
stochastic (Schramm-) Loewner evolution (SLE). The connection appears in the
long-time limit of stochastic evolution of various SLE observables related to
CFT primary fields. We show how the multifractal spectrum of harmonic measure
and other fractal characteristics of critical curves can be obtained.Comment: Published versio
Recommended from our members
Estimating Boat-Wake-Induced Levee Erosion using Sediment Suspension Measurements
LERW as an example of off-critical SLEs
Two dimensional loop erased random walk (LERW) is a random curve, whose
continuum limit is known to be a Schramm-Loewner evolution (SLE) with parameter
kappa=2. In this article we study ``off-critical loop erased random walks'',
loop erasures of random walks penalized by their number of steps. On one hand
we are able to identify counterparts for some LERW observables in terms of
symplectic fermions (c=-2), thus making further steps towards a field theoretic
description of LERWs. On the other hand, we show that it is possible to
understand the Loewner driving function of the continuum limit of off-critical
LERWs, thus providing an example of application of SLE-like techniques to
models near their critical point. Such a description is bound to be quite
complicated because outside the critical point one has a finite correlation
length and therefore no conformal invariance. However, the example here shows
the question need not be intractable. We will present the results with emphasis
on general features that can be expected to be true in other off-critical
models.Comment: 45 pages, 2 figure
- …