172,984 research outputs found
Le français et ses défis. Ecriture, terminologie, traduction sous la direction de Concetta Cavallini, Gabriella Serrone
No full textIl volume analizza le sfide che la lingua francese si trova ad affrontare nella sua forma scritta. La prima parte del volume utilizza un approccio più storico-culturale e ha come referente la lingua letteraria. La seconda parte utilizza un approccio più tecnico e ha come referente la lingua di specialità.Les défis du français sont l’affaire de tous ceux qui l’aiment et qui l’étudient. Le français et ses défis est un titre qui regroupe les contributions dérivant de plusieurs rencontres scientifiques qui se sont déroulées au cours de ces dernières années. La langue française, qui est au coeur des intérêts de ce volume, se trouve, en ce moment, devant un grand nombre de défis : défis externes, comme la multiculture, la globalisation linguistique avec la prédominance de l’anglais, mais aussi défis internes, comme le débat sur l’écriture inclusive ou le débat sur l’orthographe, qui ont suscité et suscitent encore des résistances. Dans ce volume sont identifiés et analysés certains de ces défis, presque tous liés à la diachronie du français, à partir du rapport entre langue française et écriture.
Ce volume représente la tentative d’explorer des frontières linguistiques, d’indiquer des pistes, et d’ouvrir la réflexion autour du français à des formes et à des contextes différents. Le souhait de partir de la forme écrite a été déterminé par le constat que la fixité provoque souvent plus de résistance aux changements et à l’évolution ; néanmoins, dans un monde qui évolue rapidement, dans un monde multiculturel, digital et globalisé, l’écrit constitue peut-être le défi le plus important
Electronic properties of Hydrogenated nanocrystalline Silicon for Photovoltaic Applications
No full textElectronic properties of Hydrogenated nanocrystalline Silicon for Photovoltaic Applications
Authors : Daniela Cavalcoli and Anna Cavallini Department of Physics, University of Bologna, viale
C. Berti-Pichat 6/II, 40127 Bologna, Italy.
Resume : Hydrogenated nanocrystalline silicon (nc-Si:H) is a promising material for photovoltaic
applications, mainly due to its higher stability with respect to amorphous silicon, nevertheless its
physical characterization has been carried out only recently, and several material properties are
still not clearly understood. The present contribution deals with the study of electrical conductivity
and below band gap spectroscopy in intrinsic and doped nc-Si:H films grown by LEPECVD (Low
Energy Plasma Enhanced Chemical Vapor Deposition). The films have been deposited using SiH4
and H2 precursor gases, at temperatures ranging from 200 to 400°C, SiH4 dilution ratios from 1%
to 50%, on several substrates: crystalline Si, glass, glass covered with ITO or ZnO. The crystal
fraction ranged from 25 to 75%, p-type and n-type doped layers were obtained by adding to the
precursor gases B2H6 and PH3, respectively. Sub-micron resolution current maps have been
obtained by conductive atomic force microscopy (C-AFM) applying a fixed voltage to a conductive
tip. The maps of the intrinsic films present a clear evidence of enhanced conduction in the
nanocrystals, while the disordered tissue surrounding the nano-grains is mostly nonconductive. In
doped films the maps show a quite similar behavior, but the spatial distribution of conductive
nanocrystals differs from the one of the intrinsic films. Surface photovoltage spectroscopy (SPS)
has been applied to intrinsic nc-Si:H films. The spectra have allowed for the determination of
defect states, energy gap and Urbach tails in the films. Several characteristics of the films were
obtained: slight n-type conductivity, optical gap around 1.5 eV, Urbach tails around 50meV and the
presence of intra-gap transitions relevant to defective states
Pierre de Brach, La Masquarade du triomphe de Diane et autres textes de théatre. Texte établi, présenté et annoté par C. Cavallini
No full textCEMS study of fracture surfaces in SAE 4340 steel
No full textConversion Mössbauer Spectroscopy (CEMS) has been applied to the study of fracture surfaces of SAE 4340 steel quenched and tempered at 200†C. This steel has a mechanically and thermally unstable low volume fraction of retained austenite (5.6 %). CEMS technique is able to detect different iron phases in layers about 100 nm thick and therefore allowed us to investigate the austenite to martensite transformation induced by the fracture process. By removing surface layers by chemical etching we were able to evaluate qualitatively the content profile of the retained austenite as a function of the depth. It was found that the content of retained austenite is zero within the experimental error down to about 150 μm beneath the surface fracture. Below this level the austenite concentration begins to increase. © 1986
Investigation of deep level defects in CdTe thin films
No full textIn the past few years, a large body of work has been dedicated to CdTe thin film semiconductors, as the electronic and optical properties of CdTe nanostructures make them desirable for photovoltaic applications. The performance of semiconductor devices is greatly influenced by the deep levels. Knowledge of parameters of deep levels present in as-grown materials and the identification of their origin is the key factor in the development of photovoltaic device performance. Photo Induced Current Transient Spectroscopy technique (PICTS) has proven to be a very powerful method for the study of deep levels enabling us to identify the type of traps, their activation energy and apparent capture cross section. In the present work, we report the effect of growth parameters and LASER irradiation intensity on the photo-electric and transport properties of CdTe thin films prepared by Close-Space Sublimation method using SiC electrical heating element. CdTe thin films were grown at three different source temperatures (630, 650 and 700 °C). The grown films were irradiated with Nd:YAG LASER and characterized by Photo-Induced Current Transient Spectroscopy, Photocurrent measurementand Current Voltage measurements. The defect levels are found to be significantly influenced by the growth temperature
« Forte avec son peuple et forte en ses chasteaux » : la Gascogne de Pierre de Brach »,
No full textPierre de Brach, poeta, drammaturgo e traduttore bordolese del Rinascimento, ci ha lasciato nei suoi scritti varie testimonianze della sua terra natale, la Gascogna. Il testo più importante è il poemetto "Voyage en Gascogne", in cui l'incidenza della descrizione reale del paesaggio si colloca sullo sfondo della tradizione della poesia bucolica e della pratica dell'ekphrasis. L'analisi di questo articolo si concentra nello studio di tale descrizione dal punto di vista storico e linguistico-retorico
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