Search results for "Icon"
showing 10 items of 3539 documents
Redox tuning and species distribution in Maya Blue-type materials: a reassessment.
2013
Maya Blue-type specimens prepared from indigo (1 wt %) plus kaolinite, montmorillonite, palygorskite, sepiolite, and silicalite are studied. Liquid chromatography with diode array detection, ultra-performance liquid chromatography coupled with mass spectrometry, and pyrolysis-silylation gas chromatography-mass spectrometry analyses of the extracts from these specimens combined with spectral and solid-state voltammetry, electrochemical impedance spectroscopy, and scanning electrochemical microscopy techniques provide evidence for the presence of a significant amount of dehydroindigo and isatin accompanying indigo and other minority organic compounds in all samples. Solid-state electrochemist…
Abraham Bids Farewell to Hagar and Ishmael: Continuity and Variation of the Iconographic Type
2021
In traditional Christian artistic visualization, the episode of Hagar and Ishmael in the desert has given rise to various iconographic types: “The feast for the weaning of Isaac and Sara’s protests,” “Abraham bids farewell to Hagar and Ishmael,” “Hagar and Ishmael in the desert” and “Divine salvation for Hagar and Ishmael”. This study looks into the continuity and variation over time of the second of these types: “Abraham bids farewell to Hagar and Ishmael,” the one most depicted out of this entire biblical topic or episode. Since the Byzantine Octateuch in the East (11th century.) and the Canterbury Hexateuch (ca. 1025&ndash…
Myoglobin on Silica: A Case Study of the Impact of Adsorption on Protein Structure and Dynamics
2013
International audience; If protein structure and function changes upon adsorption are well documented, modification of adsorbed protein dynamics remains a blind spot, despite its importance in biological processes. The adsorption of metmyoglobin on a silica surface was studied by isotherm measurements, microcalorimetry, circular dichroïsm, and UV-visible spectroscopy to determine the thermodynamic parameters of protein adsorption and consequent structure modifications. The mean square displacement and the vibrational densities of states of the adsorbed protein were measured by elastic and inelastic neutron scattering experiments. A decrease of protein flexibility and depletion in low freque…
Post-fotografia etnografica
2021
È evidente come la nostra società tecnologica sia legata senza alcun dubbio alla diffusione delle immagini. Autori come Gottfried Boehm, John Mitchell, Hans Belting hanno indagato la natura dell'immagine ponendo le basi, negli anni Novanta, per l'idea di un pictorial turn, di una cultura totalmente dominata dalle immagini che è diventata adesso una possibilità tecnica reale su scala globale. Un nuovo statuto dell'immagine che si usa raccogliere sotto l'etichetta di iconic turner inserito nel più vasto campo visual culture studies. L'uso del termine cultura accanto a quello di visuale è indicativo dell'ampiezza del campo d'indagine che visual culture studies si prefiggono di ricercare: essi …
Introduction : formes de l'iconicité
2014
International audience; L'emploi du terme "eikon" pour désigner une forme linguistique fonctionnant comme une image est aussi ancien que la tradition linguistico-grammaticale de l'Occident. Il figure en effet pour la première fois dans le Cratyle de Platon (439a), point de départ de cette tradition. Pour Platon, qui ne distingue pas encore entre signifiant et signifié, il est raisonnable d'affirmer que le nom, dans son ensemble, et jusqu'à ses éléments phonologiques, opère comme une image de la chose signifiée, ce qui constitue du reste une bonne raison pour s'en méfier et préférer la connaissance directe des choses à celle de leurs représentations. La reprise du terme "icon" dans la pensée…
Locking Reconstruction Double Plating of Distal Humeral Fractures: How Many Screws in the Distal Ulnar Column Segment in A3 Fracture Provide Superior…
2009
Objectives: Two 90-degree configurations of locking reconstruction plates with different numbers of screws in the distal ulnar column segment of distal extra-articular humeral fractures with metaphyseal comminution (A3) were biomechanically investigated. Methods: Eight pairs of fresh-frozen human humeri were used. For paired comparison, the humeri were divided into 2 randomized groups. In both groups, double-plate osteosyntheses with locking reconstruction plates were performed in 90-degree configurations. In group 1, the posteriorly placed radial column plate exceeded the capitellum and the ulnar column plate extended into the ulnar sulcus. The ulnar plate was molded around the medial epic…
Nonlinear relaxation phenomena in metastable condensed matter systems
2016
Nonlinear relaxation phenomena in three different systems of condensed matter are investigated. (i) First, the phase dynamics in Josephson junctions is analyzed. Specifically, a superconductor-graphene-superconductor (SGS) system exhibits quantum metastable states, and the average escape time from these metastable states in the presence of Gaussian and correlated fluctuations is calculated, accounting for variations in the the noise source intensity and the bias frequency. Moreover, the transient dynamics of a long-overlap Josephson junction (JJ) subject to thermal fluctuations and non-Gaussian noise sources is investigated. Noise induced phenomena are observed, such as the noise enhanced s…
Nonequilibrium Green's function approach to strongly correlated few-electron quantum dots
2009
The effect of electron-electron scattering on the equilibrium properties of few-electron quantum dots is investigated by means of nonequilibrium Green's function theory. The ground and equilibrium states are self-consistently computed from the Matsubara (imaginary time) Green's function for the spatially inhomogeneous quantum dot system whose constituent charge carriers are treated as spin-polarized. To include correlations, the Dyson equation is solved, starting from a Hartree-Fock reference state, within a conserving (second-order) self-energy approximation where direct and exchange contributions to the electron-electron interaction are included on the same footing. We present results for…
Integrated Optical Technique for Detection of Electro-Optical Non-Linearities in Thin Films
1976
A simple method for detection of electro-optical non-linearities in thin films is presented. The method involves an easily fabricated structure and a little practice in integrated optical techniques. It is also possible to detect small induced variations of refractive index, using lower voltage with respect to those applied in a conventional Kerr cell. We have sucessfully tested our method using two different polymer materials as thin films. In both of these we have observed an induced ?n ? 3 10?5 with an electric field of 60 V/?, with a response time round about 300 nsec. The experimental values of induced ?n versus electric field fit very well a parabola, proving the quadratic behavior of…
Incoherent solitons and condensation processes
2006
International audience; We study the nonlinear interaction of partially incoherent nonlinear optical waves. We show that, in spite of the incoherence of the waves, coherent phase effects may play a relevant role during the propagation, in contrast with the usual wave turbulence description of the interaction. These nonlinear phase effects may lead the system to unexpected processes of self-organization, such as condensation, or incoherent soliton generation in instantaneous response nonlinear media. Such self-organization processes may be characterized by a reduction of the non-equilibrium entropy, which violates the Boltzmann's H-theorem of entropy growth inherent to the wave turbulence th…