Publications

• Article dans une revue

EXPLICIT FORMULAS FOR CALCULATING THE NORMAL FORM OF ZERO-HOPF BIFURCATION IN A CLASS OF NEUTRAL DIFFERENTIAL EQUATIONS

Houssem Achouri, Chaouki Aouiti

Journal of Mathematical Sciences, 2024, ⟨10.1007/s10958-024-07400-w⟩. ⟨hal-04951733⟩

• Pré-publication, Document de travail

SPECTRUM ANALYSIS OF THE UNDERLYING OPERATOR FOR A 2D PIEZOELECTRIC BEAM WITH MAGNETIC EFFECT ON AN ANNULAR DOMAIN

Virginie Régnier, Mohammad Akil

The aim is to determine the eigenvalues of locally coupled equations modelling a 2D piezoelectric beam with magnetic effect with only one local viscous damping on an annular domain without geometric conditions. The eigenvalues are proved to lie in a vertical band defined explicitly in terms of the…

2024. ⟨hal-04715844⟩

• Article dans une revue

Control of the preferentially orientated growth of Sr2TiSi2O8 crystals in a SrO – TiO2 – SiO2 – Al2O3 – K2O parent glass

Oussama Zwein, Marie-Sophie Renoirt, Maurice Gonon, Nicolas Preux, Sandra Abdelouhab, Rıdvan Yildiz, Marc Duquennoy

A polar glass-ceramic containing Sr-fresnoite Sr2TiSi2O8 (STS) as single crystalline phase was developed through the controlled crystallization of a parent glass composition containing SrO, TiO2, SiO2, K2O, and Al2O3. The objective of this work is to obtain a piezoelectric substrate exhibiting a…

Journal of Non-Crystalline Solids, 2024, 641, pp.123132. ⟨10.1016/j.jnoncrysol.2024.123132⟩. ⟨hal-04664713⟩

• Article dans une revue

Advanced Refinement of Geopolymer Composites for Enhanced 3D Printing via In-Depth Rheological Insights

Abrar Gasmi, Christine Pélegris, Ralph Davidovits, Mohamed Guessasma, Hugues Tortajada, Florian Jean

The advancement of 3D printing technology has been remarkable, yet the quality of printed prototypes heavily relies on the rheological behavior of the materials used. This study focuses on optimizing geopolymer-based composite formulas to achieve high-quality 3D printing, with particular attention…

Ceramics, 2024, 7 (4), pp.1316-1339. ⟨10.3390/ceramics7040087⟩. ⟨hal-04717760⟩

• Pré-publication, Document de travail

Diagnostic checking of periodic vector autoregressive time series models with dependent errors

Yacouba Boubacar Mainassara, Eugen Ursu

<div><p>In this article, we study the asymptotic behaviour of the residual autocorrelations for periodic vector autoregressive time series models (PVAR henceforth) with uncorrelated but dependent innovations (i.e., weak PVAR). We then deduce the asymptotic distribution of the Ljung-Box-…

2024. ⟨hal-04711375⟩

• Poster de conférence

Impact Of Substrate And Post-Annealing Temperatures On The Refractive Index And Crystallinity Of Lead-Free BCTZ Thin Films, Impact du substrat et des températures de recuit post-dépôt sur l'indice de réfraction et la cristallinité des couches minces sans plomb de BCTZ

Yusuf Kerem Bostan, F Jean, Fahrettin Sarcan, E Hut, A Erol, D Remiens, J Teng, E Dogheche

In this study, we investigated the effects of substrate temperature and post-annealing treatment (P.A.T.) on the refractive index of lead-free Ba₀.₈₅Ca₀.₁₅Ti₀.₉Zr₀.₁O₃ (BCTZ) thin films synthesized by magnetron RF sputtering. Our results indicate that both the in-situ substrate temperature and the…, Dans cette étude, nous avons étudié les effets de la température du substrat et du traitement de recuit post-dépôt (P.A.T.) sur l’indice de réfraction des couches minces sans plomb de Ba₀.₈₅Ca₀.₁₅Ti₀.₉Zr₀.₁O₃ (BCTZ) synthétisées par pulvérisation magnétron RF. Nos résultats indiquent que la…

2D Ferroelectrics and Their Perspectives for Neural Networks, Sep 2024, Antibes (06160), France. ⟨hal-05030065⟩

• Thèse

Submanifolds of the nearly Kähler SL(2,R) x SL(2,R), Sous-variétés du nearly Kähler SL(2,R) x SL(2,R)

Mateo Anarella

A strict nearly Kähler manifold is an almost Hermitian manifold for which thecovariant derivative of the almost complex structure is non-degenerate and skewsymmetric. Strict nearly Kähler manifolds are quite rare. In six dimensions,there are only four homogeneous strict nearly Kähler manifolds: S6…, Le but de cette thèse est d’élargir la compréhension de la variété presque kählerienne SL(2,R) × SL(2,R) et de ses sous-variétés. Les variétés presquekähleriennes sont une relaxation riemannienne de la définition de variété Kähler : une variété presque hermitienne (M, g, J) est presque kählerienne…, Een strikte nagenoeg-Kählervariëteit is een bijna-Hermitische variëteit waarvoor de covariante afgeleide van de bijna-complexe structuur niet-ontaard en scheefsymmetrisch is. Dergelijke variëteiten zijn vrij zeldzaam. In dimensie zes zijn er slechts vier homogene strikte nagenoeg-Kählervariëteiten…

Differential Geometry [math.DG]. Université Polytechnique Hauts-de-France; Katholieke Universiteit Leuven (Brabant flamand, Belgique ; 1970-..), 2024. English. ⟨NNT : 2024UPHF0024⟩. ⟨tel-04791049⟩

• Article dans une revue

Insights into the nature of Zr-species in MFI-type Zr-metallosilicates by using bulk and surface techniques

Bakytzhan Yeskendir, Izabela Kurzydym, Pardis Simon, Nicolas Nuns, Maya Marinova, Herve Vezin, Christian Courtois, Yannick Lorgouilloux, Izabela Czekaj, Jean-François Paul, Sebastien Royer, Jean-Philippe Dacquin, Jérémy Dhainaut

The purpose of this study is to prepare Zr-metallosilicates with MFI-type framework via direct hydrothermal approach, by varying Si and Zr precursors. First, a set of routine characterization techniques was applied to confirm the presence of the targeted structure as well as their intrinsic…

Microporous and Mesoporous Materials, 2024, Microporous and Mesoporous Materials, 378, pp.113261. ⟨10.1016/j.micromeso.2024.113261⟩. ⟨hal-04676205⟩

• Pré-publication, Document de travail

Block-Additive Gaussian Processes under Monotonicity Constraints

Mathis Deronzier, Andrés F. López-Lopera, François Bachoc, O Roustant, Jérémy Rohmer

We generalize the additive constrained Gaussian process framework to handle interactions between input variables while enforcing monotonicity constraints everywhere on the input space. The block-additive structure of the model is particularly suitable in the presence of interactions, while…

2024. ⟨hal-04654255⟩

• Thèse

Stability of some hyperbolic systems with different types of controls under weak geometric conditions, Stabilité de certains systèmes hyperboliques avec différents types de contrôles dans des conditions géométriques faibles

Farah Trad

The purpose of this thesis is to investigate the stabilization of certain second order evolution equations. First, we focus on studying the stabilization of locally weakly coupled second order evolution equations of hyperbolic type, characterized by direct damping in only one of the two equations.…, Le but de cette thèse est d'étudier la stabilisation de certaines équations d'évolution du second ordre. Tout d’abord, nous nous concentrons sur l’étude de la stabilisation d’équations d’évolution du second ordre de type hyperbolique localement faiblement couplées, caractérisées par un…

Mathematics [math]. Université Polytechnique Hauts-de-France; Institut national des sciences appliquées Hauts-de-France, 2024. English. ⟨NNT : 2024UPHF0015⟩. ⟨tel-04693104⟩