104 research outputs found
Does the coagulation profile really matter in central venous cannulation? A review of the literature
Thickness-dependence of the electronic properties in V2O3 thin films
High quality vanadium sesquioxide V2O3 films (170-1100 {\AA}) were grown
using the pulsed laser deposition technique on (0001)-oriented sapphire
substrates, and the effects of film thickness on the lattice strain and
electronic properties were examined. X-ray diffraction indicates that there is
an in-plane compressive lattice parameter (a), close to -3.5% with respect to
the substrate and an out-of-plane tensile lattice parameter (c) . The thin film
samples display metallic character between 2-300 K, and no metal-to-insulator
transition is observed. At low temperature, the V2O3 films behave as a strongly
correlated metal, and the resistivity (\rho) follows the equation \rho =\rho_0
+ A T^2, where A is the transport coefficient in a Fermi liquid. Typical values
of A have been calculated to be 0.14 \mu\Omega cm K^{-2}, which is in agreement
with the coefficient reported for V2O3 single crystals under high pressure.
Moreover, a strong temperature-dependence of the Hall resistance confirms the
electronic correlations of these V2O3 thin films samples.Comment: 4 pages, 4 figure
Interesting magnetic properties of FeCoSi alloys
Solid solution between nonmagnetic narrow gap semiconductor FeSi and
diamagnetic semi-metal CoSi gives rise to interesting metallic alloys with
long-range helical magnetic ordering, for a wide range of intermediate
concentration. We report various interesting magnetic properties of these
alloys, including low temperature re-entrant spin-glass like behaviour and a
novel inverted magnetic hysteresis loop. Role of Dzyaloshinski-Moriya
interaction in the magnetic response of these non-centrosymmetric alloys is
discussed.Comment: 11 pages and 3 figure
A New Window of Exploration in the Mass Spectrum: Strong Lensing by Galaxy Groups in the SL2S
The existence of strong lensing systems with Einstein radii (Re) covering the
full mass spectrum, from ~1-2" (produced by galaxy scale dark matter haloes) to
>10" (produced by galaxy cluster scale haloes) have long been predicted. Many
lenses with Re around 1-2" and above 10" have been reported but very few in
between. In this article, we present a sample of 13 strong lensing systems with
Re in the range 3"- 8", i.e. systems produced by galaxy group scale dark matter
haloes, spanning a redshift range from 0.3 to 0.8. This opens a new window of
exploration in the mass spectrum, around 10^{13}- 10^{14} M_{sun}, which is a
crucial range for understanding the transition between galaxies and galaxy
clusters. Our analysis is based on multi-colour CFHTLS images complemented with
HST imaging and ground based spectroscopy. Large scale properties are derived
from both the light distribution of the elliptical galaxies group members and
weak lensing of the faint background galaxy population. On small scales, the
strong lensing analysis yields Einstein radii between 2.5" and 8". On larger
scales, the strong lenses coincide with the peak of the light distribution,
suggesting that mass is traced by light. Most of the luminosity maps have
complicated shapes, indicating that these intermediate mass structures are
dynamically young. Fitting the reduced shear with a Singular Isothermal Sphere,
we find sigma ~ 500 km/s and an upper limit of ~900 km/s for the whole sample.
The mass to light ratio for the sample is found to be M/L_i ~ 250 (solar units,
corrected for evolution), with an upper limit of 500. This can be compared to
mass to light ratios of small groups (with sigma ~ 300 km/s and galaxy clusters
with sigma > 1000 km/s, thus bridging the gap between these mass scales.Comment: A&A Accepted. Draft with Appendix images can be found at
http://www.dark-cosmology.dk/~marceau/groups_sl2s.pd
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