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Search Results: 1 - 10 of 167674 matches for " E. Drouard "
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Le participant observateur dans l'intervention humaine
Hervé Drouard
m@gm@ , 2003,
Abstract: Tout homme est donc participant et observateur de sa vie et du monde pour exister, survivre, grandir. Dans le même mouvement, il observe les faits et les apprécie (là encore le mot a gardé sa double signification avec ses connotations morales et plut t négatives: on n'aime guère recevoir des "observations"). Mais il y a des degrés, des modalités, des orientations, des inclinations, des choix. La société valorise aujourd'hui, soi-disant pour l'efficacité! la curiosité productive, super-orientée, le savant ignare et sans conscience morale. Je prétends qu'il est temps de rétablir chaque homme dans sa dignité de praticien-chercheur-enseignant dans tous les domaines de sa vie et particulièrement dans cette partie essentielle qu'est le métier, la profession.
L'osservatore partecipante e l'intervento sociale
Hervé Drouard
m@gm@ , 2003,
Abstract: Ogni uomo è dunque partecipante e osservatore della sua vita e del mondo per esistere, sopravvivere, crescere. Nello stesso movimento, osserva i fatti e li valuta (la parola ha conservato anche il suo duplice significato con le sue connotazioni morali e piuttosto negative: non amiamo per niente ricevere delle "osservazioni"). Ma ci sono dei livelli, delle modalità, degli orientamenti, delle inclinazioni, delle scelte. La società oggi valorizza, a suo dire per l'efficienza! la curiosità feconda, super orientata, l'inconsapevole erudito e senza coscienza morale. Io pretendo che sia giunto il tempo di ristabilire ogni uomo nella sua dignità d'esperto-ricercatore-insegnante in tutti gli ambiti della sua vita e particolarmente in questa parte essenziale che è il mestiere, la professione.
Crispy in the french breakfast
Alain Drouard
Anthropology of Food , 2003,
Abstract: Bien qu’il y ait eu du croquant et du croustillant dans l’alimentation des Fran ais avant l’époque contemporaine (pain, gateaux, fruits frais ou secs) sa place a augmenté récemment à la suite des changements intervenus dans le petit déjeuner. Le but de cet article est d’analyser historiquement la pénétration et la diffusion du croquant et du croustillant dans le petit déjeuner fran ais. Celle ci s’est faite d’abord dans les villes sous l’influence de modèles étrangers et principalement Anglo-Saxons qui font une place importante au croustillant. Les partisans des nouveaux petits déjeuners à base de lait, de céréales et de fruits ne cherchaient pas seulement à promouvoir le végétarisme mais aussi à lutter contre la dégénérescence qui mena ait à leurs yeux la société moderne. Après avoir rappelé la naissance du petit déjeuner fran ais, on étudiera le r le des modèles étrangers dans l’évolution de la consommation d’aliments croustillants. Though crispy items were present in French food before the contemporary period (what with bread, cakes, fresh or dried fruits), they have recently played a more important part as breakfast underwent a series of changes. The aim of this article is to make an historical analysis of the emergence and spread of crispy food in the French breakfast. The influence of foreign and more especially Anglo-Saxon models contributed to increasing its importance. Those who advocated these new breakfasts at the beginning of the XXth century were convinced to fight also against “degeneracy” which they thought was a threat to modern society. I shall first briefly explain how the French breakfast was born, then I shall focus on the influence and impact of foreign models.
Absorbing photonic crystals for thin film photovoltaics
O. El Daif,E. Drouard,G. Gomard,X. Meng,A. Kaminski,A. Fave,M. Lemiti,E. Garcia Caurel,P. Roca i Cabarrocas,S. Ahn,H. Jeon,C. Seassal
Physics , 2010, DOI: 10.1117/12.854035
Abstract: The absorption of thin hydrogenated amorphous silicon layers can be efficiently enhanced through a controlled periodic patterning. Light is trapped through coupling with photonic Bloch modes of the periodic structures, which act as an absorbing planar photonic crystal. We theoretically demonstrate this absorption enhancement through one or two dimensional patterning, and show the experimental feasibility through large area holographic patterning. Numerical simulations show over 50% absorption enhancement over the part of the solar spectrum comprised between 380 and 750nm. It is experimentally confirmed by optical measurements performed on planar photonic crystals fabricated by laser holography and reactive ion etching.
Micrometer-Thin Crystalline-Silicon Solar Cells Integrating Numerically Optimized 2-D Photonic Crystals
V. Depauw,X. Meng,O. El Daif,G. Gomard,L. Lalouat,E. Drouard,C. Trompoukis,A. Fave,C. Seassal,I. Gordon
Physics , 2013, DOI: 10.1109/JPHOTOV.2013.2286521
Abstract: A 2-D photonic crystal was integrated experimentally into a thin-film crystalline-silicon solar cell of 1-{\mu}m thickness, after numerical optimization maximizing light absorption in the active material. The photonic crystal boosted the short-circuit current of the cell, but it also damaged its open-circuit voltage and fill factor, which led to an overall decrease in performances. Comparisons between modeled and actual optical behaviors of the cell, and between ideal and actual morphologies, show the global robustness of the nanostructure to experimental deviations, but its particular sensitivity to the conformality of the top coatings and the spread in pattern dimensions, which should not be neglected in the optical model. As for the electrical behavior, the measured internal quantum efficiency shows the strong parasitic absorptions from the transparent conductive oxide and from the back-reflector, as well as the negative impact of the nanopattern on surface passivation. Our exemplifying case, thus, illustrates and experimentally confirms two recommendations for future integration of surface nanostructures for light trapping purposes: 1) the necessity to optimize absorption not for the total stack but for the single active material, and 2) the necessity to avoid damage to the active material by pattern etching.
Modal approach for tailoring the absorption in a photonic crystal membrane
Romain Peretti,Guillaume Gomard,Christian Seassal,Xavier Letartre,Emmanuel Drouard
Physics , 2013, DOI: 10.1063/1.4730443
Abstract: In this paper, we propose a method for tailoring the absorption in a photonic crystal membrane. For that purpose, we first applied Time Domain Coupled Mode Theory to such a subwavelength membrane and demonstrated that 100% resonant absorption can be reached even for a symmetric membrane, if degenerate modes are involved. Design rules were then derived from this model in order to tune the absorption. Subsequently, Finite Difference Time Domain simulations were used as a proof of concept and carried out on a low absorbing material (extinction coefficient=10-2) with a high refractive index corresponding to the optical indices of amorphous silicon at around 720 nm. In doing so, 85% resonant absorption was obtained, which is significantly higher than the commonly reported 50% maximum value. Those results were finally analyzed and confronted to theory so as to extend our method to other materials, configurations and applications.
On the reflection of Alfvén waves and its implication for Earth's core modeling
Nathana?l Schaeffer,Dominique Jault,Philippe Cardin,Marie Drouard
Physics , 2011, DOI: 10.1111/j.1365-246X.2012.05611.x
Abstract: Alfv\'en waves propagate in electrically conducting fluids in the presence of a magnetic field. Their reflection properties depend on the ratio between the kinematic viscosity and the magnetic diffusivity of the fluid, also known as the magnetic Prandtl number Pm. In the special case Pm=1, there is no reflection on an insulating, no-slip boundary, and the wave energy is entirely dissipated in the boundary layer. We investigate the consequences of this remarkable behaviour for the numerical modeling of torsional Alfv\'en waves (also known as torsional oscillations), which represent a special class of Alfv\'en waves, in rapidly rotating spherical shells. They consist of geostrophic motions and are thought to exist in the fluid cores of planets with internal magnetic field. In the geophysical limit Pm << 1, these waves are reflected at the core equator, where they are entirely absorbed for Pm=1. Our numerical calculations show that the reflection coefficient at the equator of these waves remains below 0.2 for Pm > 0.3, which is the range of values for which geodynamo numerical models operate. As a result, geodynamo models with no-slip boundary conditions cannot exhibit torsional oscillation normal modes.
Absorption enhancement in photonic crystal thin films by pseudo disordered perturbations
Romain Peretti,Guillaume Gomard,Lo?c Lalouat,Christian Seassal,Emmanuel Drouard
Physics , 2014, DOI: 10.1557/opl.2014.123
Abstract: The effects resulting from the introduction of a controlled perturbation in a single pattern membrane on its absorption are first studied and then analyzed on the basis of band folding considerations. The interest of this approach for photovoltaic applications is finally demonstrated by overcoming the integrated absorption of an optimized single pattern membrane through the introduction of a proper pseudo disordered perturbation.
Absorption control in pseudodisordered photonic-crystal thin film
Romain Peretti,Guillaume Gomard,Lo?c Lalouat,Christian Seassal,Emmanuel Drouard
Physics , 2013, DOI: 10.1103/PhysRevA.88.053835
Abstract: The positive effects of various perturbations introduced in a bidimensional photonic-crystal patterned membrane on its integrated absorption are investigated numerically and theoretically. Two phenomena responsible for the enhanced absorption observed are identified: an increase of the spectral density of modes, obtained thanks to folding mechanisms in the reciprocal lattice, and a better coupling of the modes with the incident light. By introducing a proper pseudodisordered pattern, we show that those two effects can be exploited so as to overcome the integrated absorption obtained for an optimized and single pattern unit cell photonic crystal.
Collapse of the N=28 shell closure in $^{42}$Si
B. Bastin,S. Grévy,D. Sohler,O. Sorlin,Zs. Dombrádi,N. L. Achouri,J. C. Angélique,F. Azaiez,D. Baiborodin,R. Borcea,C. Bourgeois,A. Buta,A. Bürger,R. Chapman,J. C. Dalouzy,Z. Dlouhy,A. Drouard,Z. Elekes,S. Franchoo,S. Iacob,B. Laurent,M. Lazar,X. Liang,E. Liénard,J. Mrazek,L. Nalpas,F. Negoita,N. A. Orr,Y. Penionzhkevich,Zs. Podolyák,F. Pougheon,P. Roussel-Chomaz,M. G. Saint-Laurent,M. Stanoiu,I. Stefan,F. Nowacki,A. Poves
Physics , 2007, DOI: 10.1103/PhysRevLett.99.022503
Abstract: The energies of the excited states in very neutron-rich $^{42}$Si and $^{41,43}$P have been measured using in-beam $\gamma$-ray spectroscopy from the fragmentation of secondary beams of $^{42,44}$S at 39 A.MeV. The low 2$^+$ energy of $^{42}$Si, 770(19) keV, together with the level schemes of $^{41,43}$P provide evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that $^{42}$Si is best described as a well deformed oblate rotor.
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