1,654 research outputs found
CO2 lidar system for atmospheric studies
A lidar facility using a TEA CO2 laser source is being developed at the ENEA Laboratories for Atmospheric Studies. The different subsystems and the proposed experimental activities are described
Effect of proton irradiation on the normal state low-energy excitations of Ba(FeRh)As superconductors
We present a \asnmr Nuclear Magnetic Resonance (NMR) and resistivity study of
the effect of 5.5 MeV proton irradiation on the optimal electron doped (
0.068) and overdoped ( 0.107) Ba(FeRh)As iron based
superconductors. While the proton induced defects only mildly suppress the
critical temperature and increase residual resistivity in both compositions,
sizable broadening of the NMR spectra was observed in all the irradiated
samples at low temperature. The effect is significantly stronger in the
optimally doped sample where the Curie Weiss temperature dependence of the line
width suggests the onset of ferromagnetic correlations coexisting with
superconductivity at the nanoscale. 1/T measurements revealed that the
energy barrier characterizing the low energy spin fluctuations of these
compounds is enhanced upon proton irradiation, suggesting that the defects are
likely slowing down the fluctuations between ( and (,0) nematic
ground states.Comment: 9 pages, 9 figure
Development of MOST, a fast simulation model for optimisation of floating offshore wind turbines in Simscape Multibody
Screening magnetic fields by a superconducting disk: a simple model
We introduce a simple approach to evaluate the magnetic field distribution
around superconducting samples, based on the London equations; the elementary
variable is the vector potential. This procedure has no adjustable parameters,
only the sample geometry and the London length, , determine the
solution. The calculated field reproduces quantitatively the measured induction
field above MgB disks of different diameters, at 20K and for applied fields
lower than 0.4T. The model can be applied if the flux line penetration inside
the sample can be neglected when calculating the induction field distribution
outside the superconductor. Finally we show on a cup-shape geometry how one can
design a magnetic shield satisfying a specific constraint
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