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Auteur Nassira Keghouche |
Documents disponibles écrits par cet auteur (4)
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Titre : Etude de l’interaction nickel-oxyde de zirconium monoclinique. : Approches experimentale et theorique. Type de document : texte imprimé Auteurs : El Hadi Boudjennad, Auteur ; Nassira Keghouche, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2016 Importance : 119 f Format : 30 cm. Note générale : 2 copies imprimées disponible Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : oxide, Ni, , mZrO2, metal/oxide interaction, VASP code, DFT-GGA.
نيكل، أكسيد، ،ZrO2تفاعل معدن-أكسيد، برنامج .
Oxyde, Ni, mZrO2, Interaction métal/oxyde, Code VASP, DFT-GGA.Index. décimale : 530 Physique Résumé : The structural and physicochemical properties of metal/oxide interface remain the subject of
experimental and theoretical studies due to their important technological application in
microelectronics, laser optics, chemistry, high-pressure physics, medicine, etc.
The present study examines the interaction between nickel and monoclinic zirconia (mZrO2).
Nickel ions are adsorbed on ZrO2 and reduced by radiolysis. After irradiation and H2
treatment at 250 °C, XRD patterns reveal the presence of ZrO2 and interfacial phase Ni7Zr2.
For the XRD spectra, of samples impregnated with Ni loads of 5% and 7.5% and calcined at
several temperatures, have showed the presence of ZrO2 and interfacial phases (NiZr2,
Ni0.99Zr0.01, NiO) beyond 550°C. While the XRD patterns, of samples impregnated with Ni
loads of 5% and reduced with hydrogen flow at 350°C, have showed only the presence of
intermetallic phases (NiZr2, Ni0.99Zr0.01) in addition to the ZrO2 support.
To estimate the shortest Ni −Zr distance, first principle density functional (DFT) calculations
are used to study the Ni−mZrO2 interaction. First, the possibility of inserting atomic nickel in
the bulk of ZrO2 is examined. Second, the effects of both insertion and adsorption on the
stable surfaces of ZrO2, such as (111) and(101) , are studied. It is shown that an increase
amount of inserted nickel, from one Ni for 4 Zr to an equivalent amount, enhances the
insertion energy and makes insertion more exothermic. This phenomenon is accompanied by
a lattice expansion (6–26%) and a reduction of symmetry. When the nickel is inserted in the
bulk, the distance Ni–Zr is equal to 2.57 Å, which is in agreement with experimental value.
Surface insertion and adsorption calculations show that nickel atoms can penetrate inside the
oxide much more easily across the surface(101) , than through the surface(111) . Theoretical
calculations show that adsorption and insertion on/in the surface processes may evolve with
the formation of Ni–Zr–O complexes.Diplôme : Doctorat en sciences En ligne : ../theses/physique/BOU6858.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10166 Etude de l’interaction nickel-oxyde de zirconium monoclinique. : Approches experimentale et theorique. [texte imprimé] / El Hadi Boudjennad, Auteur ; Nassira Keghouche, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2016 . - 119 f ; 30 cm.
2 copies imprimées disponible
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : oxide, Ni, , mZrO2, metal/oxide interaction, VASP code, DFT-GGA.
نيكل، أكسيد، ،ZrO2تفاعل معدن-أكسيد، برنامج .
Oxyde, Ni, mZrO2, Interaction métal/oxyde, Code VASP, DFT-GGA.Index. décimale : 530 Physique Résumé : The structural and physicochemical properties of metal/oxide interface remain the subject of
experimental and theoretical studies due to their important technological application in
microelectronics, laser optics, chemistry, high-pressure physics, medicine, etc.
The present study examines the interaction between nickel and monoclinic zirconia (mZrO2).
Nickel ions are adsorbed on ZrO2 and reduced by radiolysis. After irradiation and H2
treatment at 250 °C, XRD patterns reveal the presence of ZrO2 and interfacial phase Ni7Zr2.
For the XRD spectra, of samples impregnated with Ni loads of 5% and 7.5% and calcined at
several temperatures, have showed the presence of ZrO2 and interfacial phases (NiZr2,
Ni0.99Zr0.01, NiO) beyond 550°C. While the XRD patterns, of samples impregnated with Ni
loads of 5% and reduced with hydrogen flow at 350°C, have showed only the presence of
intermetallic phases (NiZr2, Ni0.99Zr0.01) in addition to the ZrO2 support.
To estimate the shortest Ni −Zr distance, first principle density functional (DFT) calculations
are used to study the Ni−mZrO2 interaction. First, the possibility of inserting atomic nickel in
the bulk of ZrO2 is examined. Second, the effects of both insertion and adsorption on the
stable surfaces of ZrO2, such as (111) and(101) , are studied. It is shown that an increase
amount of inserted nickel, from one Ni for 4 Zr to an equivalent amount, enhances the
insertion energy and makes insertion more exothermic. This phenomenon is accompanied by
a lattice expansion (6–26%) and a reduction of symmetry. When the nickel is inserted in the
bulk, the distance Ni–Zr is equal to 2.57 Å, which is in agreement with experimental value.
Surface insertion and adsorption calculations show that nickel atoms can penetrate inside the
oxide much more easily across the surface(101) , than through the surface(111) . Theoretical
calculations show that adsorption and insertion on/in the surface processes may evolve with
the formation of Ni–Zr–O complexes.Diplôme : Doctorat en sciences En ligne : ../theses/physique/BOU6858.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10166 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BOU/6858 BOU/6858 Thèse Bibliothèque principale Thèses Disponible Etude des propriétés optiques et structurales de nanoparticules de ZnS et PbS induites par radiolyse / Abdelhafid Souici
Titre : Etude des propriétés optiques et structurales de nanoparticules de ZnS et PbS induites par radiolyse Type de document : texte imprimé Auteurs : Abdelhafid Souici ; Univ. de Constantine, Éditeur scientifique ; Nassira Keghouche, Directeur de thèse Année de publication : 2009 Importance : 149 f. Note générale : 01 Disponible à la salle de recherche 02 Disponibles au magazin de la B.U.C. 01 CD Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Propriétés optiques Propriétés structurales Nanoparticules semiconductrices Radioltse Index. décimale : 530 Physique En ligne : ../theses/physique/SOU5480.pdf Permalink : index.php?lvl=notice_display&id=3425 Etude des propriétés optiques et structurales de nanoparticules de ZnS et PbS induites par radiolyse [texte imprimé] / Abdelhafid Souici ; Univ. de Constantine, Éditeur scientifique ; Nassira Keghouche, Directeur de thèse . - 2009 . - 149 f.
01 Disponible à la salle de recherche 02 Disponibles au magazin de la B.U.C. 01 CD
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Propriétés optiques Propriétés structurales Nanoparticules semiconductrices Radioltse Index. décimale : 530 Physique En ligne : ../theses/physique/SOU5480.pdf Permalink : index.php?lvl=notice_display&id=3425 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité SOU/5480 SOU/5480 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude des propriétés structurales, optiques et photocatalytiques de nanocomposites ZnS/zéolithe Y synthétisés par radiolyse. Type de document : texte imprimé Auteurs : Kamel Djebli, Auteur ; Nassira Keghouche, Directeur de thèse Mention d'édition : 01/12/2019 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 116 f. Format : 30 cm. Note générale : 1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : physique: Rayonnement et Applications méthode radiolytique photocatalyseur Nanoparticules de ZnS zéolite Y thiol Rouge Congo radiolytic method photocatalyst ZnS nanoparticles zeolite Y Congo red طريقة التحليل الإشعاعي حفاز ضوئي الجسيمات النانوية ZnSزيوليت Y ثيول الكونغو الاحمر. Index. décimale : 530 Physique Résumé :
The present study deals with würtzite ZnS nanoparticles embedded in zeolite Y, synthesized by - radiolysis. In a first step; zeolite Y (faugazite) is prepared by hydrothermal methode. In second, Zn2+ ions are fixed on the zeolite by ionic exchange. Finally, γ rays are performed on Zn-Y with thiol; which leads to the generation of ZnS-Y nanoparticles. The nanocomposites were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), UV–Visible
absorption, and photoluminescence (PL). Compared to the bulk state, ZnS nanocrystals have blue – shifted UV visible absorption, with an excitonic peak situated at around 320 nm. They display a wide photoluminescence band with seven peaks in the range of 320 to 550 nm. The increase of the irradiation dose and RSH concentration results in a growth the ZnS nanocrystals and improves their optical performances. The optical as well as the structural characterizations confirmed the nanometric size of ZnS particles (ɸ = 5-18 nm). When tested in photodegradation
of Congo red under sun light, ZnS-zeolite Y catalyst exhibited high efficiency.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/DJE7593.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11429 Etude des propriétés structurales, optiques et photocatalytiques de nanocomposites ZnS/zéolithe Y synthétisés par radiolyse. [texte imprimé] / Kamel Djebli, Auteur ; Nassira Keghouche, Directeur de thèse . - 01/12/2019 . - جامعة الإخوة منتوري قسنطينة, 2019 . - 116 f. ; 30 cm.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : physique: Rayonnement et Applications méthode radiolytique photocatalyseur Nanoparticules de ZnS zéolite Y thiol Rouge Congo radiolytic method photocatalyst ZnS nanoparticles zeolite Y Congo red طريقة التحليل الإشعاعي حفاز ضوئي الجسيمات النانوية ZnSزيوليت Y ثيول الكونغو الاحمر. Index. décimale : 530 Physique Résumé :
The present study deals with würtzite ZnS nanoparticles embedded in zeolite Y, synthesized by - radiolysis. In a first step; zeolite Y (faugazite) is prepared by hydrothermal methode. In second, Zn2+ ions are fixed on the zeolite by ionic exchange. Finally, γ rays are performed on Zn-Y with thiol; which leads to the generation of ZnS-Y nanoparticles. The nanocomposites were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), UV–Visible
absorption, and photoluminescence (PL). Compared to the bulk state, ZnS nanocrystals have blue – shifted UV visible absorption, with an excitonic peak situated at around 320 nm. They display a wide photoluminescence band with seven peaks in the range of 320 to 550 nm. The increase of the irradiation dose and RSH concentration results in a growth the ZnS nanocrystals and improves their optical performances. The optical as well as the structural characterizations confirmed the nanometric size of ZnS particles (ɸ = 5-18 nm). When tested in photodegradation
of Congo red under sun light, ZnS-zeolite Y catalyst exhibited high efficiency.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/DJE7593.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11429 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité DJE/7593 DJE/7593 Thèse Bibliothèque principale Thèses Disponible
Titre : Nanoagregats de Nickel et d’Argent : Mecanismes de formation et proprietes. Type de document : texte imprimé Auteurs : Mohamed Larbi Hioul, Auteur ; Nassira Keghouche, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 124 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : clusters agrégats nickel argent radiolyse pulsée aggregates silver pulse radiolysis لنانوجزيئات النيكل الفضة الراديوليزالنبضية Index. décimale : 530 Physique Résumé : Metallic aggregates in colloidal phases or supported aggregates attract increasing attention of researchers because of the wide range of possible applications (catalysis, environment, non-linear optics, biology and medicine). Radiolysis ranks among the most effective methods for the reduction of ions, giving the possibility of synthesis of aggregates of atoms. It is a powerful method to control the size of the particles, their location on the surface or volume. In the first part of this work, the morphological and structural properties of silver aggregates supported on silica were studied. X-ray diffraction identified the Ag6Si2O7 phase for different Ag+ ion charges as well as heat-treated samples. The FTIR spectroscopy study of Ag/SiO2 samples revealed the vibrations of Si-O-Si, Si-OH, Ag-O and Ag-SO4 bonds at the respective wave numbers 468, 810, 615 and 641 cm-1. The study of the optical properties of Ag/SiO2 nanoagreggates by UV- visible spectrophotometry showed the presence, in addition to a broadband in the visible range, three peaks in the UV domain. After reduction under hydrogen, the metal Ag phase of nanometric size was identified by XRD. In the second part, we studied, by time-resolved pulse radiolysis, nickel clusters in suspension. The formation of Ni+ ions and then those of nickel atoms was observed. The ionizing radiation generation of nickel aggregates in solution was observed for the first time live during this work.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/HIO7384.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11034 Nanoagregats de Nickel et d’Argent : Mecanismes de formation et proprietes. [texte imprimé] / Mohamed Larbi Hioul, Auteur ; Nassira Keghouche, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 124 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : clusters agrégats nickel argent radiolyse pulsée aggregates silver pulse radiolysis لنانوجزيئات النيكل الفضة الراديوليزالنبضية Index. décimale : 530 Physique Résumé : Metallic aggregates in colloidal phases or supported aggregates attract increasing attention of researchers because of the wide range of possible applications (catalysis, environment, non-linear optics, biology and medicine). Radiolysis ranks among the most effective methods for the reduction of ions, giving the possibility of synthesis of aggregates of atoms. It is a powerful method to control the size of the particles, their location on the surface or volume. In the first part of this work, the morphological and structural properties of silver aggregates supported on silica were studied. X-ray diffraction identified the Ag6Si2O7 phase for different Ag+ ion charges as well as heat-treated samples. The FTIR spectroscopy study of Ag/SiO2 samples revealed the vibrations of Si-O-Si, Si-OH, Ag-O and Ag-SO4 bonds at the respective wave numbers 468, 810, 615 and 641 cm-1. The study of the optical properties of Ag/SiO2 nanoagreggates by UV- visible spectrophotometry showed the presence, in addition to a broadband in the visible range, three peaks in the UV domain. After reduction under hydrogen, the metal Ag phase of nanometric size was identified by XRD. In the second part, we studied, by time-resolved pulse radiolysis, nickel clusters in suspension. The formation of Ni+ ions and then those of nickel atoms was observed. The ionizing radiation generation of nickel aggregates in solution was observed for the first time live during this work.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/HIO7384.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11034 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité HIO/7384 HIO/7384 Thèse Bibliothèque principale Thèses Disponible
