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See detailElectrostatic coupling of MEMS structures: transient simulations and dynamic pull-in
Rochus, Véronique ULg; Rixen, Daniel J.; Golinval, Jean-Claude ULg

in Nonlinear Analysis (2005), 63

In micro-electromechanical systems (MEMS), coupling of structures through electrostatic forces is a primordial phenomenon. Simulating the dynamics of MEMS and taking into account such strong coupling ... [more ▼]

In micro-electromechanical systems (MEMS), coupling of structures through electrostatic forces is a primordial phenomenon. Simulating the dynamics of MEMS and taking into account such strong coupling effects allows one to predict dynamical performance and stability, and is therefore an essential issue in the design of highly effective and reliable devices. Analysis techniques for such systems require special attention in order to provide to the designer accurate and fast tools.We propose a finite element approach (FEM) that properly handles the strong electromechanical coupling in MEMS. In the simulation example of a micro-bridge, we show that such simulation techniques can reveal complex dynamical behaviors of MEMS such as dynamic pull-in. [less ▲]

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See detailElectrostatic hierarchical co-assembly in aqueous solutions of two oppositevely charged double hydrophilic diblock copolymers
Voets, Ilja K.; de Keizer, Arie; Leermakers, Frans A. M. et al

in European Polymer Journal (2009), 45(10), 2913-2925

The formation of spherical micelles in aqueous solutions of poly(N-methyl-2-vinyl pyridinium iodide)-block-poly(ethylene oxide), P2MVP-b-PEO and poly(acrylic acid)-block-poly(vinyl alcohol), PAA-b-PVOH ... [more ▼]

The formation of spherical micelles in aqueous solutions of poly(N-methyl-2-vinyl pyridinium iodide)-block-poly(ethylene oxide), P2MVP-b-PEO and poly(acrylic acid)-block-poly(vinyl alcohol), PAA-b-PVOH has been investigated with light scattering-titrations, dynamic and static light scattering, and 1H 2D Nuclear Overhauser Effect Spectroscopy. Complex coacervate core micelles, also called PIC micelles, block ionomer complexes, and interpolyelectrolyte complexes, are formed in thermodynamic equilibrium under charge neutral conditions (pH 8, 1 mM NaNO3, T = 25 °C) through electrostatic interaction between the core-forming P2MVP and PAA blocks. 2D 1H NOESY NMR experiments show no cross-correlations between PEO and PVOH blocks, indicating their segregation in the micellar corona. Self-consistent field calculations support the conclusion that these C3Ms are likely to resemble a ‘patched micelle’; that is, micelles featuring a ‘spheres-on-sphere’ morphology. [less ▲]

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See detailElectrostatic potential maps at the quantum chemistry level of the active sites of the serine peptidases, α-chymotrypsin and subtilisin
Lamotte-Brasseur, Josette; Dive, Georges ULg; Dehareng, Dominique ULg et al

in Journal of Theoretical Biology (1990), 145(2), 183-98

The electronic properties of the active-sites of the structurally unrelated serine peptidases, alpha-chymotrypsin and subtilisin, have been expressed in the form of three-dimensional electrostatic ... [more ▼]

The electronic properties of the active-sites of the structurally unrelated serine peptidases, alpha-chymotrypsin and subtilisin, have been expressed in the form of three-dimensional electrostatic potential maps derived from integrals calculated at the quantum chemistry level. As a consequence of the asymmetrical distribution of the secondary structures that occur within a 7 A sphere around the serine of the catalytic triad, the active sites are highly polarized entities and exhibit large dipole moments. One part of the active sites generates a nucleophilic suction-pump. Its isocontour at -10 kcal mol-1 defines an impressive, negatively-charged volume which bears a narrow channel in the immediate vicinity of the active-site serine 195 in alpha-chymotrypsin or 221 in subtilisin. In native alpha-chymotrypsin, there is a perfect complementation between this nucleophilic suction-pump and the positively-charged electrophilic hole that is generated by the backbone NH of Ser 195 and Gly 193. In subtilisin, generation of the complementing electrophilic hole requires binding of a carbonyl donor ligand and may be achieved by rotation of the side-chain amide of Asn 155 towards the backbone NH of Ser 221. Small variations in the atomic co-ordinates of alpha-chymotrypsin used for the calculations, the presence of water molecules in its active site and the occurrence of point mutations in the amino acid sequence of subtilisin have little effects on the shape and characteristics of the electrostatic potential. [less ▲]

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See detailElectrostatic Simulation using XFEM for Conductor and Dielectric Interfaces
Rochus, Véronique ULg; Rixen, Daniel; Van Miegroet, Laurent ULg et al

in International Journal for Numerical Methods in Engineering (2011), 85(10), 12071226

ManyMicro-Electro-Mechanical Systems (e.g. RF-switches, micro-resonators and micro-rotors) involve mechanical structures moving in an electrostatic field. For this type of problems, it is required to ... [more ▼]

ManyMicro-Electro-Mechanical Systems (e.g. RF-switches, micro-resonators and micro-rotors) involve mechanical structures moving in an electrostatic field. For this type of problems, it is required to evaluate accurately the electrostatic forces acting on the devices. Extended Finite Element (X-FEM) approaches can easily handle moving boundaries and interfaces in the electrostatic domain and seem therefore very suitable to model Micro-Electro-Mechanical Systems. In this study we investigate different X-FEM techniques to solve the electrostatic problem when the electrostatic domain is bounded by a conducting material. Preliminary studies in one-dimension have shown that one can obtain good results in the computation of electrostatic potential using X-FEM. In this paper the extension of these preliminary studies to 2D problem is presented. In particular a new type of enrichment functions is proposed in order to treat accurately Dirichlet boundary conditions on the interface. [less ▲]

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See detailElectrostimulation du muscle dénervé (Questions-réponses)
Vanderthommen, Marc ULg

in Correspondances en Nerf & Muscle (2006), 1(3-4), 31-32

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See detailElectrostriction at the LaAlO3/SrTiO3 Interface
Cancellieri, C.; Fontaine, Denis ULg; Gariglio, S. et al

in Physical Review Letters (2011), 107

We present a direct comparison between experimental data and ab initio calculations for the electrostrictive effect in the polar LaAlO3 layer grown on SrTiO3 substrates. From the structural data, a ... [more ▼]

We present a direct comparison between experimental data and ab initio calculations for the electrostrictive effect in the polar LaAlO3 layer grown on SrTiO3 substrates. From the structural data, a complete screening of the LaAlO3 dipole field is observed for film thicknesses between 6 and 20 uc. For thinner films, an expansion of the c axis of 2% matching the theoretical predictions for an electrostrictive effect is observed experimentally. [less ▲]

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See detailElectrosynthesis of polyacrylic/polypyrrole composites : formation of polypyrrole wires
Jérôme, Christine ULg; Labaye, David; Bodart, Isabelle et al

in Synthetic Metals (1999), 101(1-3), 3-4

A new preparation method is reported for the synthesis of conducting polypyrrole nanowires. This two-step all-electrochemical method consists in the cathodic grafting of a thin polyacrylate film on a ... [more ▼]

A new preparation method is reported for the synthesis of conducting polypyrrole nanowires. This two-step all-electrochemical method consists in the cathodic grafting of a thin polyacrylate film on a carbon electrode, which is then used as an anode for the electropolymerization of pyrrole. Scanning electron microscopy shows the formation of polypyrrole wires (diameter ~600 nm lenght ~300 µm) growing through holes in the polyacrylate precoating. The effect of the experimental conditions, such as nature of the grafted polymer, solvent, and electrode, on the wire formation is discussed. [less ▲]

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See detailElectrothérapie. Electrostimulation.
Crepon, F.; DOUBRERE, J. F.; Vanderthommen, Marc ULg et al

in Encyclopédie médico-chirurgicale (EMC) (2007)

Detailed reference viewed: 168 (7 ULg)
See detail« Élégie funèbre pour Drévicius », « À Richard Bartholinus » [traduction de textes latins de Dantiscus]
Pietquin, Paul ULg

in Polet, Jean-Claude (Ed.) Patrimoine littéraire européen. 7 : Etablissement des genres et retour du tragique : 1515-1616 (1995)

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See detailThe ELEKTRA project: Towards a new learning experience
Kickmeier-Rust, M; Schwarz, D; Albert, Dietrich et al

in Pohl, M; Holzinger, A; Motschnig, R (Eds.) et al M3 – Interdisciplinary aspects on digital media & education (2006, November 23)

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See detailThe ELEKTRA project: Towards a new learning experience
Kickmeier-Rust, M. D.; Schwarz, D.; Albert, D. et al

in Pohl, Margit; Holzinger, A.; Motschnig, R. (Eds.) et al M3 – Interdisciplinary aspects on digital media & education (2006)

Digital game-based learning is a hot topic of research and development. Since the advent of computer and video games, educators were inherently interested in utilizing the beneficial aspects of computer ... [more ▼]

Digital game-based learning is a hot topic of research and development. Since the advent of computer and video games, educators were inherently interested in utilizing the beneficial aspects of computer games for educational purposes. These factors are primarily the intrinsic motivation of games, immersive environments, engaging stories, and an artful balance between challenges and continuously growing abilities. Proponents of computer games delivered a large number of empirical investigations revealing that games may foster the development of abilities and competencies. Besides the advantageous aspects of computer games, a variety of problems were reported by researchers. Due to the high costs of professional game development, many educational games are technologically poor and cannot compete with entertainment games in terms of visual design, possibilities for interactions, or storytelling. Moreover, many current educational games do not incorporate a sound psychological, pedagogical, or didactic background; instead they are focusing on transmission or rehearsal of isolated facts or skills. Finally, such games lack the ability to adapt to individual competencies failing to balance challenge and abilities regarding knowledge or skills. The ELEKTRA project, introduced in this article, aims for addressing these problems relying on an interdisciplinary approach of cognitive science, neuroscience, pedagogy, game design, and game development. The project will develop an adventure game that can keep up with commercial games and that focuses on primarily curriculum-related educational purposes by incorporating a sound psychological and pedagogical framework. Moreover, the project will prove the outcomes of research and development by a comprehensive game demonstrator. [less ▲]

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See detailElektraRed, NetVocList et LinguaProLio : 3 recettes de vitamines pour dynamiser la langue
Thiry, Bernard ULg

in Les Cahiers de la Recherche en UER-Langues de HEC-ULg (2008), 2

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See detailElektraRed, NetVocList et LinguaProLio : trois recettes de vitamines pour dynamiser la langue
Thiry, Bernard ULg

in Langage et l'Homme (Le) : Recherches Pluridisciplinaires sur le Langage (2008), XXXXIII(2), 109-128

L'apprentissage des langues est un phénomène complexe, notamment parce que son succès dépend du degré de correspondance entre les convictions et attitudes de toute une génération d’étudiants, d’une part ... [more ▼]

L'apprentissage des langues est un phénomène complexe, notamment parce que son succès dépend du degré de correspondance entre les convictions et attitudes de toute une génération d’étudiants, d’une part, et de professeurs, d’autre part. Quand ses résultats se révèlent décevants, force est alors d'interroger les méthodologies et les outils mis en oeuvre. C'est ce que tente de faire le présent article en proposant des solutions alternatives : trois « recettes de vitamines » pour dynamiser la langue. [less ▲]

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See detailElektronenspectroscopie: een analysetechniek voor het bestuderen van oppervlakken.
Locht, Robert ULg; Delwiche, Jacques ULg

in Chemisch Weekblad (1973), 69(30/31), 21-23

The shift of electron binding energies can be measured by ESCA (Electron Spectroscopy for Chemical Analysis). This phenomenon is the basis of important data for structural analysis.

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See detailL'élément d'extranéité au sein des faits générateurs de la demande et la règle de conflit comme règle de droit
Boularbah, Hakim ULg

in J. Linsmeau et M. Storme : Le rôle respectif du juge et des parties dans le procès civil (1999)

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See detailElément de coque à géométrie de révolution
Debongnie, Jean-François ULg

Report (1974)

The first par of this report is focused on the formulation of the conical shell element in SAMCEF. In chapter 2, benchmark applications of this element in statics are discussed. Chapter 3 is devoted to ... [more ▼]

The first par of this report is focused on the formulation of the conical shell element in SAMCEF. In chapter 2, benchmark applications of this element in statics are discussed. Chapter 3 is devoted to numerical tests in modal analysis. [less ▲]

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See detailElement Diffusion in the Solar Interior
Thoul, Anne ULg; Bahcall, J.N.; Loeb, A.

Poster (1992, December)

We study the diffusion of helium and other heavy elements in the solar interior, using the flow equations developed by Burgers (1969) for a multi-component fluid. The set of equations is solved exactly ... [more ▼]

We study the diffusion of helium and other heavy elements in the solar interior, using the flow equations developed by Burgers (1969) for a multi-component fluid. The set of equations is solved exactly, including the residual heat flow terms. No approximation is made about the relative concentrations and no restriction is placed on the number of elements considered. For helium diffusion, we compare our results with those obtained by Bahcall and Loeb (1990) using a simplified treatment with heat flows neglected. We find that the inclusion of the residual heat flow terms leads to a significant increase in the helium diffusion velocity. However, we also find that the temperature and charge-dependence of the Coulomb logarithm has the opposite effect, leading to a decrease in the helium diffusion velocity. By coincidence, the two effects partially cancel each other out throughout most of the solar interior. Our complete treatment of element diffusion could be directly incorporated in a standard stellar evolution code, but, for convenience, we also give simple analytical fits of our numerical results. Burgers, J.M. 1969, Flow equations for composite gases(Academic Press, New York). Bahcall, J.N., and Loeb, A. 1990, Ap.J.,360, 267. [less ▲]

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See detailELEMENT DIFFUSION IN THE SOLAR INTERIOR
Thoul, Anne ULg; BAHCALL, J. N.; LOEB, A.

in Astrophysical Journal (1994), 421(2), 828-842

We study the diffusion of helium and other heavy elements in the solar interior by solving exactly the set of flow equations developed by Burgers for a multicomponent fluid, including the residual heat ... [more ▼]

We study the diffusion of helium and other heavy elements in the solar interior by solving exactly the set of flow equations developed by Burgers for a multicomponent fluid, including the residual heat-flow terms. No approximation is made concerning the relative concentrations, and no restriction is placed on the number of elements considered. We give improved diffusion velocities for hydrogen, helium, oxygen, and iron, in the analytic form derived previously by Bahcall & Loeb. These expressions for the diffusion velocities are simple to program in stellar evolution codes and are expected to be accurate to similar to 15%. We find that the inclusion of the residual heat flow terms leads to an increase in the hydrogen diffusion velocity. We compare our numerical results-with those obtained analytically by Bahcall & Loeb using a simplified treatment, as well as with those derived numerically by Michaud & Proffitt. We find that for conditions characteristic of the Sun, the results of Bahcall & Loeb for the hydrogen diffusion velocity are smaller than our more accurate numerical results by similar to 30%, except very near the center where the error becomes larger. The Michaud & Proffitt results differ from the numerical results derived here by less than or similar to 15%. Our complete treatment of element diffusion can be directly incorporated in a standard stellar evolution code by means of an exportable subroutine, but, for convenience, we also give simple analytical fits to our numerical results. [less ▲]

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See detailUn élément Epontilles pour LBR5-Report R&D5
Rigo, Philippe ULg

Report (2003)

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