1,353 research outputs found
Specific heat evidence for two-gap superconductivity in ternary-iron silicide LuFeSi
We report low-temperature specific heat studies on single-crystalline
ternary-iron silicide superconductor LuFeSi with = 6.1 K
down to . We confirm a reduced normalized jump in specific heat at
, and find that the specific heat divided by temperature shows
sudden drop at and goes to zero with further decreasing
temperature. These results indicate the presence of two distinct
superconducting gaps in LuFeSi, similar to a typical two-gap
superconductor MgB. We also report Hall coefficients, band structure
calculation, and the anisotropy of upper critical fields for
LuFeSi, which support the anisotropic multiband nature and
reinforce the existence of two superconducting gaps in
LuFeSi.Comment: 5 pages, 5 figure
Disorder-sensitive superconductivity in the iron silicide LuFeSi studied by the Lu-site substitutions
We studied effect of non-magnetic and magnetic impurities on
superconductivity in LuFeSi by small amount substitution of the Lu
site, which investigated structural, magnetic, and electrical properties of
non-magnetic (LuSc)FeSi,
(LuY)FeSi, and magnetic
(LuDy)FeSi. The rapid depression of by
non-magnetic impurities in accordance with the increase of residual resistivity
reveals the strong pair breaking dominated by disorder. We provide compelling
evidence for the sign reversal of the superconducting order parameter in
LuFeSi.Comment: 4 pages, 5 figure
Semiótica y Teatro
Viene fornito neU'articolo il modello della comunicazione teatrale, mediante un confronto con la comunicazione narrativa. In sostanza, la comunicazione teatrale é perpendicolare a quella che si svolge tra i personaggi in scena (che infatti usano i pronomi IO/TU come se fossero soggetti autonomi, mentre il rapporto tra emitiente e ricevente del testo é occultato); invece la comunicazione narrativa collega orizzontalmente 1'emitiente e il ricevente, trasmettendo il testo tramite un narratore implÃcito o esplicito, che designa i personaggi con la terza persona. E'solo con la mediazone di questa terza persona che viene comunicato talora, attraverso i discorsi diretti, il dialogo IO/TU dei personaggi. The article deals with the model of theatre communication and compares it with narrative communication model. Substancially, theatre communication is perpendicular to the one of the characters on the scene (in fact characters use the pronouns I/YOU as if they were autonomous subjects, while the relationshÃp between the addressee of the text is concealed). On the other hand of narrative communication horizontally connects the addresser and the addressee by transferring the text through an implicit narrator who indicates the characters with the third person that sometimes the dialogue I/YOU of the characters is delivered through direct speaches
The Finite Field Kakeya Problem
A Besicovitch set in AG(n,q) is a set of points containing a line in every
direction. The Kakeya problem is to determine the minimal size of such a set.
We solve the Kakeya problem in the plane, and substantially improve the known
bounds for n greater than 4.Comment: 13 page
Extinction efficiencies of coated absorbing aerosols measured by cavity ring down aerosol spectrometry
International audienceIn this study, we measure the extinction efficiency at 532 nm of absorbing aerosol particles coated with a non-absorbing solid and liquid organic shell with coating thickness varying between 5 and 100 nm using cavity ring down aerosol spectrometry. For this purpose, we use nigrosin, an organic black dye, as a model absorbing core and two non-absorbing organic substances as shells, glutaric acid (GA) and Di-Ethyl-Hexyl-Sebacate (DEHS). The measured behavior of the coated particles is consistent with Mie calculations of core-shell particles. Errors between measured and calculated values for nigrosin coated with GA and DEHS are between 0.5% and 10.5% and between 0.5% and 9%, respectively. However, it is evident that the calculations are in better agreement with the measured results for thinner coatings. Possible reasons for these discrepancies are discussed
Shear-induced quench of long-range correlations in a liquid mixture
A static correlation function of concentration fluctuations in a (dilute)
binary liquid mixture subjected to both a concentration gradient and uniform
shear flow is investigated within the framework of fluctuating hydrodynamics.
It is shown that a well-known long-range correlation at
large wave numbers crosses over to a weaker divergent one for wave numbers
satisfying , while an asymptotic shear-controlled
power-law dependence is confirmed at much smaller wave numbers given by , where , , and are the
mass concentration, the rate of the shear, the mass diffusivity and the
kinematic viscosity of the mixture, respectively. The result will provide for
the first time the possibility to observe the shear-induced suppression of a
long-range correlation experimentally by using, for example, a low-angle light
scattering technique.Comment: 8pages, 2figure
Surfaces containing a family of plane curves not forming a fibration
We complete the classification of smooth surfaces swept out by a
1-dimensional family of plane curves that do not form a fibration. As a
consequence, we characterize manifolds swept out by a 1-dimensional family of
hypersurfaces that do not form a fibration.Comment: Author's post-print, final version published online in Collect. Mat
Free-energy transition in a gas of non-interacting nonlinear wave-particles
We investigate the dynamics of a gas of non-interacting particle-like soliton
waves, demonstrating that phase transitions originate from their collective
behavior. This is predicted by solving exactly the nonlinear equations and by
employing methods of the statistical mechanics of chaos. In particular, we show
that a suitable free energy undergoes a metamorphosis as the input excitation
is increased, thereby developing a first order phase transition whose
measurable manifestation is the formation of shock waves. This demonstrates
that even the simplest phase-space dynamics, involving independent (uncoupled)
degrees of freedom, can sustain critical phenomena.Comment: 4 pages, 3 figure
- …