17 resultados para Résistance au glissement

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Réédition d'une inscription copte peinte au plafond de l'église rupestre de Deir Abou Hennis. Le texte n'avait pas été correctement traduit ou interprété par les premiers éditeurs. Le texte se présente comme une citation de Grégoire de Nysse, et on trouve en effet à deux reprises dans son œuvre la phrase qui est traduite en copte dans l'inscription. Mais il s'agit en réalité chez Grégoire d'une citation biblique (Prov. 13, 13). L'inscription est donc bien une citation de Grégoire de Nysse, qui est elle-même une citation du livre des Proverbes.

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info:eu-repo/semantics/published

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Monolayers of octadecanethiolate on Au(1 1 1) surface were formed under electrochemical control. The influence of the formation time on the reductive desorption process was studied by cyclic voltammetry and chronoamperometry. When the formation time is increased, the reductive desorption peak observed on the voltammograms is significantly shifted in the negative direction, while the cathodic charge is only slightly affected. This behaviour is attributed to a higher degree of organisation of the monolayers for longer formation times, highlighting the role of defect sites in promoting the dissolution. A good agreement was found between our experimental chronoamperograms and theoretical models describing the dissolution process by a shrinkage mechanism. It is demonstrated that a reorganisation process takes place, consisting in the merging of small condensed domains into larger ones. This annealing phenomenon is time and potential dependent, the largest condensed domains being obtained for the longest formation times and least negative potentials. © 2008 Elsevier B.V. All rights reserved.

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The description of the monolayer formed at Au(1 1 1) by 2-mercaptobenzimidazole (MBI) under potential control has been based on electrochemical data (charge measurements) and spectroscopic information from the subtractively normalized interfacial Fourier transform infrared spectroscopy method (SNIFTIRS). From the quantitative analysis of the SNIFTIR spectra, a surface coverage Γ/Γmax was extracted for each sample potential. The evolution of the coverage with potential was in full agreement with the charge density curve. The shift of the pzc in the presence of MBI indicates that the adsorbed molecules have a nonzero component of the permanent dipole moment in the direction perpendicular to the electrode surface. Thanks to the high quality of the spectra, it was possible to determine the orientation of MBI molecules at the surface in the monolayer and submonolayer range. The angle between the C2-axis of the molecule and the direction normal to the surface is close to 64 ± 4° and its small change (<15°) with potential indicates that the orientation of the molecules is chiefly controlled by the chemical interaction between the sulphur atom and the gold surface. © 2005 Elsevier Ltd. All rights reserved.

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The behaviour of a self-assembled monolayer of 2-mercaptobenzimidazole (MBI) at the Au(111) electrode has been examined using cyclic voltammetry and in situ FTIR spectroscopy. The charge associated with the reductive desorption is pH independent while the oxidative partial redeposition charge increases when the pH is lowered. This is due to differences between the nature and the solubility of the MBI desorption product. In alkaline and neutral media MBI desorbs as the thiolate. In contrast, in acidic solutions the thiol is the desorbed product. Subtractively normalized interfacial reflection Fourier transform absorption spectroscopy (SNIFTIRS) has been applied to investigate the MBI monolayer in contact with aqueous solutions of different pH. The SNIFTIRS data are in agreement with the electrochemical results. Moreover, quantitative analysis of the IR data provided evidence that adsorbed MBI molecules assume a tilted orientation with an angle of 60±5° between the C2 axis of the molecule and the direction normal to the gold surface. © 2003 Elsevier B.V. All rights reserved.

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The adsorption of biadipate on Au(111) was studied by cyclic voltammetry and chronocoulometry. The biadipate adlayer undergoes a potential-driven phase transition. It is shown that the phase transition can be either of the first- or second-order depending on the biadipate concentration. At low surfactant concentrations, the first-order transition is characterised by a discontinuity in the charge density-potential curve and by the presence of very sharp peaks in the voltammetric response. At higher concentrations, these peaks are no longer observed but a discontinuity in the capacity curve is still noticeable, in agreement with a second-order transition. © the Owner Societies.

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info:eu-repo/semantics/published

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This paper presents a detailed analysis of Baudelaire's poem ''L'Invitation au voyage''. It aims to understand the general meaning of this poem, showing that Baudelaire's ''voyage'' comes less to an ideal paradise than to a kind of voluptuous purgatory. We associate together dimensions of the poem that are usually treated separately :biographical background, stylistic and intertextual borrowings (orientalized Holland, Goethe's Mignon, popular song and romance, Weber's music, Biblical episodes), formal structure and cognitive effects. Our method is based on Benoît de Cornulier's theory of metrics, Searle and Vanderveken's speech act theory and Marc Dominicy's theory of poetic evocation. As Dominicy's theory is quite recent, our article provides substantial summary and clarification of its main theoretical and methodological hypothesis.

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