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(114) Production(s) de LE PARC R.
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A reflection anisotropy spectroscopy study of the adsorption of sulphur containing amino-acids Au(110)
Auteur(s): Le Parc R., Smith C.I., Cuquerella M.C., Williams R.L., Fernig D.G., Edwards C., Martin D.S., Weightman P.
(Article) Publié:
Langmuir, vol. 22 p.3413-3420 (2006)
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Influence of fictive temperature and composition of silica glass on anomalous elastic behaviour
Auteur(s): Le Parc R., Levelut C., Pelous Jacques, Martinez Valérie, Champagnon Bernard
(Article) Publié:
Journal Of Physics: Condensed Matter, vol. 18 p.7507 (2006)
Texte intégral en Openaccess :
Ref HAL: hal-00109721_v1
Ref Arxiv: cond-mat/0607233
DOI: 10.1088/0953-8984/188/32/001
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: In order to point out the influence of thermal history (fictive temperature) and OH content on the elastic properties of silica glass, we have performed high resolution in situ Brillouin spectra of SiO2 glass from room temperature to the supercooled liquid at 1773K across the glass transition. The well known anomalous increase of elastic modulus in the glassy state and in the supercooled liquid regime is observed. No change of slope in the elastic moduli of silica appears as a characteristic of glass transition, on the contrary to what happens in various other glasses. We show that thermal history has a weak effect on elastic moduli in the glass transition regime for silica glass. The effect of water content in silica glass is more efficient than the fictive temperature effect and gives larger changes in the amplitude of elastic modulus for the same thermal dependence. A singular decrease above 1223K is also observed in the shear moduli for hydrated samples. Different models explaining elastic properties temperature dependence in relationship with frozen-in density fluctuations or with the structure are discussed.
Commentaires: 22pages, 11 figures
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Characterisation of the glass transition in vitreous silica by temperature scanning SAXS
Auteur(s): Brüening R., Levelut C., Faivre A., Le Parc R., Simon J., Bley F., Hazemann J.L.
(Article) Publié:
-Esrf Highlight 2005, vol. 1 p.24 (2006)
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A high-temperature Raman scattering study of the phase transitions in GaPO4 and in the AlPO4-GaPO4 system
Auteur(s): Angot E., Le Parc R., Levelut C., Beaurain Marion, Armand Pascale, Cambon Olivier, Haines Julien
(Article) Publié:
Journal Of Physics: Condensed Matter, vol. 18 p.4315-4327 (2006)
Ref HAL: hal-00182371_v1
PMID 21690784
DOI: 10.1088/0953-8984/18/17/018
WoS: 000238354300022
Exporter : BibTex | endNote
22 Citations
Résumé: Al1-xGaxPO4 solid solutions (x = 0.2, 0.3, 0.38, 0.7) and the pure AlPO4 (x = 0) and GaPO4 (x = 1) end members with the α-quartz-type structure were studied by Raman scattering. An investigation as a function of composition enabled the various modes to be assigned, in particular coupled and decoupled vibrations. The tetrahedral tilting modes, which have been linked to high-temperature phase transitions to β-quartz-type forms, were found to be decoupled. In addition, it is shown that Raman spectroscopy is a powerful technique for determining the gallium content of these solid solutions. Single crystals with x = 0.2, 0.38, and 1.0 (GaPO4) were investigated at high temperature. The composition Al0.8Ga0.2PO4 was found to exhibit sequential transitions upon heating to the β-quartz and β-cristobalite forms at close to 993 K and 1073 K, respectively. Direct α-quartzβ-cristobalite transitions were observed for the two other compositions at close to 1083 K and 1253 K, respectively, upon heating. The spectra of the β-quartz and β-cristobalite forms indicate the presence of significant disorder. Back transformation to the α-quartz-type form occurred readily with a hysteresis of less than 100 K for the composition x = 0.38 and for pure GaPO4. Rapid cooling was necessary to obtain the metastable α-cristobalite form. In contrast, for Al0.80Ga0.20PO4, the α-cristobalite form was obtained even upon slow cooling.
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Density fluctuation in oxyde glasses investigated by SAXS
Auteur(s): Levelut C., Le Parc R., Faivre A., Champagnon Bernard, Brüning Ralf
Conférence invité: SAS 2006 (Kyoto, Japan, FR, 2006-07-09)
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Composes de la famille du quartz : stabilité structurale en fonction de T et P, amorphisation sous pression
Auteur(s): Le Parc R., Levelut C., Haines Julien, Cambon Olivier, Pereira Altair
Conference: 5 eme Forum technologique des hautes pressions (Monthieux, France, FR, 2006-11-06)
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Fluctuations de densité dans des verres d'oxydes étudiées par diffusion des rayons X aux petits angles
Auteur(s): Levelut C., Faivre A., Le Parc R., Champagnon Bernard, David Laurent, Simon J., Hazemann Jean-louis
(Affiches/Poster)
User's meeting Soleil (Orsay, France, FR), 2006-01-18 |