909 research outputs found
La Formation de Jupille, nouvelle formation dans le Dévonien inférieur de la Haute-Ardenne (Belgique)
The Jupille Formation, new formation in the lower Devonian of the High-Ardenne (Belgium). A new formation named Jupille is proposed to better characterize in the High-Ardenne area the rocks interbedded between the La Roche (or Villé if La Roche is missing) and Pèrnelle Formations, at the transition between the Pragian/Emsian stages (Lower Devonian). This formation is made up of series of grey, blue grey or greenish grey sandstone layers interbedded in blue grey siltstones and slates similar to those of the La Roche Formation. Locally, the sandstones grades to quartzites. Tool marks, current ripples, lenticular and oblique or hummocky cross-stratifications and load casts (pseudonodules) are present in the sandstone layers
Microfaciès d’une lentille biohermale a la limite Eifelien/Givetien (‘Fondry Des Chiens’, Nismes, bord sud du synclinorium de Dinant)
Microfacies of a biohermal lens at the Eifelian.Givetian transition (‘Fondry des Chiens’, Nismes, southern border of the Dinant Synclinorium). The biohermal lens of the ‘Fondry des Chiens’ belongs to the Eifelian-Givetian transition beds near Nismes (southern flank of the Dinant basin). The lens is 64 m thick and composed of a stromatopore-coral framestone. It is overlain by restricted lagoonal algal and cyanophycean facies near the emersion, and overlies Udoteacean and coral-bryozoan coverstones forming the flanks of two other unexposed lenses. Two crinoidal soles stabilized by syntaxial cementation constitute the substratum of these lenses. The reefal sedimentation is regressive. The log is based on the succession of 10 carbonate microfacies (MF1-10, standard sequence). The deepest microfacies (MF1) is open marine at the upper limit of the storm waves and the dysphotic-euphotic boundary. The shallowest sediments were partly emerged (lagoonal sediments, MF10). The exposed reefal lens (rudstones and framestones, MF6-7) and the flanks (grainstones, floatstones and coverstones, MF3-4-5) of the two other lenses are preserved due to early isopachous intergranular cement in the original cavities of the framestones or ‘intramicritic’ (replacement of the matrix) cementation in the floatstones and coverstones. The similarity of the facies and their algal content suggest that the sedimentary model proposed at Wellin is applicable at Nismes. Sequential analysis points to a three steps regressive evolution of the sedimentation probably related to a discontinuous subidence. The sequences have similar thicknesses (sixty or so meters) and grade from the dysphotic-euphotic boundary estimated here around twenty meters deep to emersion. As for Wellin, the subsidence is thus much more important than the eustatic regression
Rejection of randomly coinciding events in LiMoO scintillating bolometers using light detectors based on the Neganov-Luke effect
Random coincidences of nuclear events can be one of the main background
sources in low-temperature calorimetric experiments looking for neutrinoless
double-beta decay, especially in those searches based on scintillating
bolometers embedding the promising double-beta candidate Mo, because of
the relatively short half-life of the two-neutrino double-beta decay of this
nucleus. We show in this work that randomly coinciding events of the
two-neutrino double decay of Mo in enriched LiMoO
detectors can be effectively discriminated by pulse-shape analysis in the light
channel if the scintillating bolometer is provided with a Neganov-Luke light
detector, which can improve the signal-to-noise ratio by a large factor,
assumed here at the level of on the basis of preliminary
experimental results obtained with these devices. The achieved pile-up
rejection efficiency results in a very low contribution, of the order of counts/(keVkgy), to the background counting rate
in the region of interest for a large volume ( cm)
LiMoO detector. This background level is very encouraging in
view of a possible use of the LiMoO solution for a bolometric
tonne-scale next-generation experiment as that proposed in the CUPID project
Generative adversarial networks: an overview
Generative adversarial networks (GANs) provide a way to learn deep representations without extensively annotated training data. They achieve this by deriving backpropagation signals through a competitive process involving a pair of networks. The representations that can be learned by GANs may be used in a variety of applications, including image synthesis, semantic image editing, style transfer, image superresolution, and classification. The aim of this review article is to provide an overview of GANs for the signal processing community, drawing on familiar analogies and concepts where possible. In addition to identifying different methods for training and constructing GANs, we also point to remaining challenges in their theory and application
Electron glass effects in amorphous NbSi films
We report on non equilibrium field effect in insulating amorphous NbSi thin
films having different Nb contents and thicknesses. The hallmark of an electron
glass, namely the logarithmic growth of a memory dip in conductance versus gate
voltage curves, is observed in all the films after a cooling from room
temperature to 4.2 K. A very rich phenomenology is demonstrated. While the
memory dip width is found to strongly vary with the film parameters, as was
also observed in amorphous indium oxide films, screening lengths and
temperature dependence of the dynamics are closer to what is observed in
granular Al films. Our results demonstrate that the differentiation between
continuous and discontinuous systems is not relevant to understand the
discrepancies reported between various systems in the electron glass features.
We suggest instead that they are not of fundamental nature and stem from
differences in the protocols used and in the electrical inhomogeneity length
scales within each material.Comment: Submission SciPos
Nernst effect as a probe of superconducting fluctuations in disordered thin films
In amorphous superconducting thin films of and ,
a finite Nernst coefficient can be detected in a wide range of temperature and
magnetic field. Due to the negligible contribution of normal quasi-particles,
superconducting fluctuations easily dominate the Nernst response in the entire
range of study. In the vicinity of the critical temperature and in the
zero-field limit, the magnitude of the signal is in quantitative agreement with
what is theoretically expected for the Gaussian fluctuations of the
superconducting order parameter. Even at higher temperatures and finite
magnetic field, the Nernst coefficient is set by the size of superconducting
fluctuations. The Nernst coefficient emerges as a direct probe of the ghost
critical field, the normal-state mirror of the upper critical field. Moreover,
upon leaving the normal state with fluctuating Cooper pairs, we show that the
temperature evolution of the Nernst coefficient is different whether the system
enters a vortex solid, a vortex liquid or a phase-fluctuating superconducting
regime.Comment: Submitted to New. J. Phys. for a focus issue on "Superconductors with
Exotic Symmetries
Defect detection and characterisation in composite materials using active IR thermography coupled with SVD analysis and thermal quadrupole modeling
Abstract In t his s tudy, a ctive i nfrared t hermography is us ed t o det ect and c haracterize def ects i n c arbon/epoxy c omposite plates. Defects are polymeric discs inserted between plies at different depths of the sample. The thermal excitation consists in a f inite t ime s tep us ing h alogen l amps. The t ransient t hermal m odeling pr ovides a one-dimensional analytical s olution through thermal quadrupoles. Finally an inversion procedure is carried out to estimate modeling unknown parameters, especially the depth and thermal resistance of the defect
Proceedings of the third French-Ukrainian workshop on the instrumentation developments for HEP
The reports collected in these proceedings have been presented in the third
French-Ukrainian workshop on the instrumentation developments for high-energy
physics held at LAL, Orsay on October 15-16. The workshop was conducted in the
scope of the IDEATE International Associated Laboratory (LIA). Joint
developments between French and Ukrainian laboratories and universities as well
as new proposals have been discussed. The main topics of the papers presented
in the Proceedings are developments for accelerator and beam monitoring,
detector developments, joint developments for large-scale high-energy and
astroparticle physics projects, medical applications.Comment: 3rd French-Ukrainian workshop on the instrumentation developments for
High Energy Physics, October 15-16, 2015, LAL, Orsay, France, 94 page
Spectral Properties of Quasiparticle Excitations Induced by Magnetic Moments in Superconductors
The consequences of localized, classical magnetic moments in superconductors
are explored and their effect on the spectral properties of the intragap bound
states is studied. Above a critical moment, a localized quasiparticle
excitation in an s-wave superconductor is spontaneously created near a magnetic
impurity, inducing a zero-temperature quantum transition. In this transition,
the spin quantum number of the ground state changes from zero to 1/2, while the
total charge remains the same. In contrast, the spin-unpolarized ground state
of a d-wave superconductor is found to be stable for any value of the magnetic
moment when the normal-state energy spectrum possesses particle-hole symmetry.
The effect of impurity scattering on the quasiparticle states is interpreted in
the spirit of relevant symmetries of the clean superconductor. The results
obtained by the non-self-consistent (T matrix) and the self-consistent
mean-field approximations are compared and qualitative agreement between the
two schemes is found in the regime where the coherence length is longer than
the Fermi length.Comment: to appear in Phys. Rev. B55, May 1st (1997
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