Publications

• Article dans une revue

Micro-Macro Correlation in Ferroelectric Materials: Depolarization Mechanism Owing Mechanical Stress

Abdelowahed Hajjaji, Mohamed Rguiti, Yahia Boughaleb, Zina Sassi, Sophie d'Astorg, Rith Ly, Christian Courtois, Gérard Moreau, Anne Leriche

Piezoelectric ceramics are commonly used in numerous piezoelectric actuators and sensors. Most ferroelectric materials behave as piezoelectric for low driving levels. The increase of electric field, temperature or stress levels leads to a depoling and results in some degradation of dielectric and…

Sensor letters, 2011, 9 (6), pp.2190-2193. ⟨10.1166/sl.2011.1792⟩. ⟨hal-04283044⟩

• Thèse

Variétés de Richardson : multiplicités et désingularisation, Richardson varieties: multiplicities and desingularization

Michaël Balan

Une variété de Richardson est l'intersection d'une variété de Schubert directe avec une variété de Schubert opposée dans une variété de drapeaux. Dans cette thèse, on s'intéresse aux singularités des variétés de Richardson. Un résultat de Kreiman et Lakshmibai donne la multiplicité d…, A Richardson variety is the intersection of a direct Schubert variety with an opposite Schubert variety inside a fiag variety. ln this thesis, we are interested in the singularities of Richardson varieties. A result of Kreiman and Lakshmibai gives the multiplicity at a T-fixed point on a Richardson…

Mathématiques [math]. Université de Valenciennes et du Hainaut-Cambrésis, 2011. Français. ⟨NNT : 2011VALE0027⟩. ⟨tel-03416030⟩

• Article dans une revue

Influence of hydrothermal synthesis conditions on BNT-based piezoceramics

Jean-François Trelcat, Sophie d'Astorg, Philippe Champagne, Christian Courtois, Mohamed Rguiti, Anne Leriche

The Bi0.5Na0.5TiO3 perovskite (BNT) is a very promising lead-free candidate for piezoelectric applications. Nevertheless a low reproducibility is commonly reported for the solid state synthesized BNT. In this work, the hydrothermal synthesis was investigated to improve the BNT ceramics…

Journal of the European Ceramic Society, 2011, 31 (11), pp.1997-2004. ⟨10.1016/j.jeurceramsoc.2011.04.025⟩. ⟨hal-04283000⟩

• Article dans une revue

Microstructure and Nanoscale Piezoelectric/Ferroelectric Properties in La 2 Ti 2 O 7 Thin Films Grown on (110)‐Oriented Doped Nb:SrTiO 3 Substrates

Zhenmian Shao, Sébastien Saitzek, Pascal Roussel, Anthony Ferri, Émilie Bruyer, Adlane Sayede, Mohamed Rguiti, Olivier Mentré, Rachel Desfeux

(00l)‐Oriented La 2 Ti 2 O 7 (LTO) thin films with monoclinic perovskite‐layer structure [a = 7.806(2) Å, b = 5.552(3) Å, c = 13.015(5) Å, β = 98.62(2)°] have been grown by a sol–gel route on conducting (110)‐oriented doped Nb:SrTiO 3 (STO) substrates. The narrow rocking curves (0.24° width for 004…

Advanced Engineering Materials, 2011, 13 (10), pp.961-969. ⟨10.1002/adem.201100105⟩. ⟨hal-04282981⟩

• Thèse

Limit behaviors of some boundary value problems with high and/or low valued parameters, Comportement limite de certains problèmes aux limites avec de grands et/ou petits paramètres

Salima Hassani

To our knowledge a systematic analysis of general systems of partial differential equations, where one parameter tends to infinity in a sub-domain that squeezes to a smooth hyper-surface of codimension 1 was not performed. In order to treat such problems, for a family of bilinear forms depending on…, A ce jour, aucune analyse systématique et générale des équations aux dérivées partielles où un paramètre tend vers l’infini dans un sous-domaine contenant une hyper-surface régulière de codimension 1 n’a été effectuée. Afin de traiter ce type de problèmes pour une famille de formes bilinéaires…

Mathematics [math]. Université de Valenciennes et du Hainaut-Cambrésis; Université Djillali Liabès (Sidi Bel-Abbès, Algérie), 2011. English. ⟨NNT : 2011VALE0015⟩. ⟨tel-03350322⟩

• Article dans une revue

Characterization of sol–gel synthesised lead-free (1−x)Na0.5Bi0.5TiO3–xBaTiO3-based ceramics

A. Chaouchi, S. Kennour, Sophie d'Astorg, Mohamed Rguiti, Christian Courtois, S. Marinel, M. Aliouat

The crystal structure, microstructure, dielectric and ferroelectric properties of (1 − x)Na0.5Bi0.5TiO3–xBaTiO3 ceramics with x = 0, 0.03, 0.05, 0.07 and 0.1 are investigated. A structural variation according to the system composition was investigated by X-ray diffraction (XRD) analyses. The…

Journal of Alloys and Compounds, 2011, 509 (37), pp.9138-9143. ⟨10.1016/j.jallcom.2011.06.085⟩. ⟨hal-02450370⟩

• Article dans une revue

Efficient 3D numerical prediction of the pressure wave generated by high-speed trains entering tunnels

David Uystepruyst, Mame William-Louis, Emmanuel Creusé, Serge Nicaise, François Monnoyer de Galland

The topic of this paper is to present a new methodology for the three-dimensional numerical simulation of the entrance of high-speed trains in a tunnel. The movement of the train is made thanks to a technique of sliding meshes and a conservative treatment of the faces between two domains. All parts…

Computers and Fluids, 2011, 47 (1), pp.165-177. ⟨10.1016/j.compfluid.2011.03.005⟩. ⟨hal-00768640⟩

• Article dans une revue

Influence of porosity on the mechanical properties of microporous β-TCP bioceramics by usual and instrumented Vickers microindentation

Arnaud Tricoteaux, E. Rguiti, Didier Chicot, L. Boilet, Michel Descamps, Anne Leriche, J. Lesage

Beta-tricalcium phosphate [Ca3(PO4)2, β-TCP] is a bioresorbable material showing an excellent biocompatibility. However, sintering of β-TCP is difficult and the material presents poor mechanical strength and a low resistance to crack-growth propagation. In this study, influence of the porosity on…

Journal of the European Ceramic Society, 2011, 31 (8), pp.1361-1369. ⟨10.1016/j.jeurceramsoc.2011.02.005⟩. ⟨hal-03577737⟩

• Article dans une revue

Modeling and characterization of piezoelectric cantilever bending sensor for energy harvesting

R. Ly, Mohamed Rguiti, Sophie d'Astorg, A. Hajjaji, Christian Courtois, Anne Leriche

The main aim of this work is to enhance the conversion of mechanical energy into electrical energy by using direct piezoelectric effect. Under the assumption of the Euler–Bernoulli Beam Theory, a piezoelectric cantilever bending of 31-effect was developed. The equations of motion for the global…

Sensors and Actuators A: Physical , 2011, 168 (1), pp.95-100. ⟨10.1016/j.sna.2011.04.020⟩. ⟨hal-04282958⟩

• Communication dans un congrès

Revisiting the Takacs-Fiksel method for stationary marked Gibbs point processes

Jean-François Coeurjolly, David Dereudre, Rémy Drouilhet, Frédéric Lavancier

SGSIA 2011 - 16th Workshop on Stochastic Geometry, Stereology and Image Analysis, Jun 2011, Sønderborg, Denmark. ⟨hal-00850679⟩