Tesi sul tema "Transformation polymorphique"
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Doubax, Francis. "Caractérisation et modélisation de la transformation polymorphique et de l'endommagement dynamique de l'acier MARS". Toulouse 3, 1992. http://www.theses.fr/1992TOU30251.
Mabire, Catherine. "Transformation polymorphique et fusion de l'étain sous choc dans la gamme 0-100 GPa ; étude expérimentale et modélisation". Poitiers, 1999. http://www.theses.fr/1999POIT2380.
Juban, Audrey. "Transformation Induite au cours d’un Procédé Industriel (TIPI) de compression directe : transition polymorphique de la caféine et propriétés physiques des comprimés". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1144/document.
Direct compression process is widely used in the pharmaceutical industry for tablet manufacturing. This work is dedicated to the study of the polymorphic transformation induced by a direct compression process, and its impact on tablet mechanical properties. The main objective is to improve the understanding of the phase transition of caffeine Form I into Form II occurring during the direct compression process, and whether it has an impact on the tablet tensile strength. In this way, several studies have been conducted on the impact of operating conditions on the polymorphic transformation of a model active pharmaceutical ingredient (API) and on few physical properties of the tablets.The use of a compression simulator Styl’One Classique (Médel’Pharm) and a fatigue equipment (Instron®) for the manufacture of tablets, allowed studying two process parameters (compression load and compression speed) and two formulation parameters (dilution of the API and nature of the diluent). Caffeine phase transitions have been evaluated by differential scanning calorimetry (DSC). Moreover, during several months after tableting, kinetic studies were conducted in order to observe the influence of these parameters on the polymorphic transition of the anhydrous caffeine Form I into Form II in tablets during storage. Finally, the analysis of the transition mechanism of this API was performed thanks to a stretched exponential law, derived from the Johnson-Melh-Avrami model.The tensile strength of tablets (global property) was measured by a diametral compression test and their surface hardness (local property) by nanoindentation. A first predictive model for tablet tensile strength according to the caffeine content was developed. The compression cycle characteristics calculated from the data recording with the compression simulator allowed analyzing the behavior of different blends during the compression process. A second model for predicting the tensile strength was then established.Finally, results obtained for the polymorphic transition and physical properties of tablets will then be confronting
Dupont, Anthony. "Cinétiques de transformations de produits pharmaceutiques sous broyage". Electronic Thesis or Diss., Université de Lille (2022-....), 2022. https://pepite-depot.univ-lille.fr/LIBRE/EDSMRE/2022/2022ULILR020.pdf.
The objective of this thesis is to improve the understanding of the fundamental microscopic mechanisms that govern the phase transformations induced directly in the solid state by mechanical milling. In particular, three key issues have been addressed: (i) We evaluated the influence of the milling temperature on the effective amorphization rate of a crystalline material. (ii) We determined the influence of monotropic and enantiotropic characters on the mechanisms of polymorphic transformations under milling. (iii) We have shown that the polymorphic transformations under milling are not direct but involve, on the contrary, a transient amorphization mechanism. Our strategy consisted in studying these different problems through a detailed analysis of the transformation kinetics which are the direct reflection of the physical mechanisms that govern them. For this purpose, we have studied in detail the transformation kinetics of physical states of several carefully chosen compounds. These include hydrochlorothiazide, sorbitol, glycine and their mixtures. The investigations were mainly carried out by X-ray diffraction and differential scanning calorimetry (DSC). Moreover, some experimentally demonstrated transformation mechanisms could be modelled and validated by numerical simulations. In summary, all our work indicates that, in general, the transformations under milling seem to result systematically from a competition between an amorphization mechanism due to mechanical shocks and a recrystallization mechanism whose nature depends on both the milling temperature and the crystalline specificities of the material
Artigas, Alava Miguel José. "Contribution à l'étude du polymorphisme des phases MM'X (M,M' = métaux de transition, X=P, As)". Grenoble 1, 1992. http://www.theses.fr/1992GRE10133.
Khalef, Nawel. "Contributions méthodologiques et instrumentales aux études d'interaction solide-vapeur et transformations cristallines induites en recherche et développement pharmaceutique". Université Joseph Fourier (Grenoble), 2008. http://www.theses.fr/2008GRE10015.
A methodology together with an instrumental approach, consisting of thermal activity tracing due to changes of the vapour pressure to which the sample is exposed are proposed for solving various pharmaceutieal research, development and production problems. They allow carrying out stability/compatibility testing and studies of the effect ofvapour pressure upon ingredients physical stability, such as amorphous to crystalline changes and amorphous content measurements. Critical vapour pressures of the material are determined. They also allow solid surface characterizations such as sorption isotherms and surface energies assessments that take into account the surface heterogeneity and solubility of the material. Measuring principle and system validation are presented. Numerous examples offTequently encountered prob]ems while manipulating pharmaceutica] ingredients either chemically defined or not, are presented. Procedures reported in the literature, for amorphous content detennination using mierohygrostats containing saturated salt solutions and calorimetrie measurements are questioned and shown to be based upon wrong assumptions. The physicochemical phenomena underlying there limitations are exposed and experimentally shown. Alternative solutions using the approach described above are proposed and experimentally tested. This approach together with classical methods (HPLC, MNR, XRD. . . ) allows studying the stability of sodium cromoglycate in solution and as solid. Its various hydration steps and pseudopo]ymorphic changes are identified. More than a precious analytical tool, the instrument can be used to scale down and monitor processes for production conditions optimization
Desprez, Sylvain Descamps Marc. "Transformation de phases induites par broyage dans un composé moléculaire : l'indométhacine". Villeneuve d'Ascq : Université des sciences et technologies de Lille, 2007. https://iris.univ-lille1.fr/dspace/handle/1908/594.
N° d'ordre (Lille 1) : 3482. Titre provenant de la page de titre du document numérisé. Bibliogr. à la suite de chaque chapitre.
De, Gusseme Armelle. "Transformations de phases à l'état solide de matériaux pharmaceutiques : la fanansérine et la tréhalose". Lille 1, 2003. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2003/50376-2003-167.pdf.
Desprez, Sylvain. "Transformation de phases induites par broyage dans un composé moléculaire : l'indométhacine". Lille 1, 2004. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2004/50376-2004-181-182.pdf.
La nature de ces états stationnaires est le résultat de la compétition entre un processus balistique, qui dépend de l'intensité du forçage extérieur; et un processus de restauration, thermiquement activé. Cette approche théorique, initialement proposée pour décrire les évolutions des alliages métalliques sous irradiation, a été ensuite étendue au broyage mécanique. Elle semble applicable aux composés organiques, à condition de tenir compte des évolutions propres de la dynamique moléculaire dans ces matériaux, en particulier dans le domaine de la transition vitreuse. Par ailleurs, nous avons mis en évidence la possibilité de manipuler mécaniquement l'état de vieillissement du verre. Des analyses. Microstructurales suggèrent que l'on puisse générer, par broyage, des amorphes différents recristallisant dans différentes variétés polymorphiques. Une image structurale de ce po1yamorphisme, reliée' à la présence de liaisons hydrogène dans ce système, est proposée
Henri-Dubernet, Ségolène. "Etude par électrophorèse en gradient de température de la biodiversité et des dynamiques des populations lactobacilles au cours de la transformation du lait cru en "Camembert de Normandie"". Caen, 2004. http://www.theses.fr/2004CAEN2034.
Viel, Quentin. "De l'amorphe au cristal : etude d'un composé pharmaceutique chiral". Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR048/document.
During the last few decades, the field of crystal engineering has gained prominence. Along with the improvement of analytical techniques, the understanding and prediction of crystal structures become more and more accurate. The present work is dedicated to one of the borderline cases encountered that challenge the general understanding of crystallography, polymorphism, phase transition theories and chiral discrimination mechanisms. The chiral pharmaceutical drug diprophylline is one of them, at least for crystallization aspects. Both racemic and enantiopure compositions of this system at the amorphous state have been considered, to carefully study the kinetic transitions with respect to the global molecular mobility. A robust protocol has been established to investigate the molecular mobility by broadband dielectric spectroscopy covering a temperature range of more than 200 °C. The comparative dielectric study of the purified samples proved that the dynamic behaviors of a single enantiomer and of the racemic mixture are very similar; but another secondary relaxation γ was found in samples containing theophylline, the main impurity identified by chromatographic measurements. Additionally, the present study demonstrated that the crystallization from the supercooled melt occurs as a complex multistep process. It involves the homogeneous nucleation and growth of a first population, whose characteristics are highlighted, and which acts as support for the development of secondary populations constituted of metastable solid solutions with higher growth rates. Moreover, the conducted studies demonstrated that at various enantiomeric compositions, the presence of interfaces favored the heterogeneous nucleation of a more stable form
Djomani-Siawa, Doriane. "Hétérostructures allotropiques de semiconducteurs IV dans des nanofils : nouvelles opportunités more-than-Moore". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS074/document.
We have demonstrated an original way to induce a phase transformation in Si and Ge nanowires under external shear-stress. The transformation results in an unprecedented heterostructure with quasiperiodic embedded Ge-2H nanodomains distributed all along the nanowire. My thesisproject aims at understanding the mechanisms of this phase transformation and at characterizing the physical properties of the heterostructures 2H/3C in Si and Ge nanowires.We have carried out systematic structural analysis in Si- and Ge-2H/3C nanowires to evidence the key parameters of this phase transformation.The phase transformation occurs in shear bands localized along the (2-5-5) direction.The heterostructured nanowires are defined by a specific orientation relationship between the 3C and the 2H bands (both in Si and Ge nanowires)given by(1-10)3C//(-2110)2H and (110)3C//(0001)2H with the 2H bands lying mainly on (115)3C planes.The preliminary studies showed that shear-stress and the thermal budget above a threshold temperature of 350°C in Ge and 500°C in Si are mandatory for this transformation. These conditions meet the common criteria of a martensitic phase transformation. We have identified two key intrinsic parameters:the temperature and the nanowires crystallographic axis.In Si nanowires, we found that the formation of the shear bands i.e. the 2H nanodomains is related to the component of the shear-stress along the glide direction of the 3C/2H interface plane.Based on these results,the transformation could be consistent with a stress relief mechanism through the formation of (5-5-2)(1-15)3C shear bands.We have performed spatially resolved Raman measurements on single Si and Ge heterostructured nanowires to characterize their optical phonon modes.In Ge,we have detected 2 Raman bands at 288 cm⁻ ᴵ and 301 cm⁻ ᴵ attributed to the E2g and E1g + A1g + F2g modes.In Si, we have observed 3 Raman bands at 498, 515 and 520 cm⁻ ᴵ that are associated respectively to the E2g, A1g and F2g modes.Those values agree well with the literature.Moreover, we have performed Fourier Transform Infrared spectroscopy on transformed Ge nanowires to measure the optical band gap of the 2H phase.We have obtained a direct band gap of 0,58 eV attributed to the 2H phase and an indirect bandgap of 0,72 eV that might stem from the 3C phase. Those results are the first experimental data of the Ge-2H band gap.The values align well with the simulations that predict a narrow direct band gap for this structure.The 2H structure can also be achieved in bulk Si and Ge after unloading of the BC8 phase in a diamond anvil cell.The BC8 phase is unstable and convertsinto the 2H phase at room temperature in Ge or by thermal annealing in Si.In order to compare the bulk properties of the 2H phase, we have performedin-situ Raman and X-ray diffraction experiments in bulk samples by studyingvarious unloading pathways. In particular, unloading at room temperature ledto the formation of the ST12 phase or a mixture of the BC8 and ST12 phasesdepending on the unloading rate.The formation of the 2H phase is thuscomplex given its dependency on the unloading conditions and the hydrostaticconditions within the cell that are difficult to garanty. Our studies also reveala size effect. After unloading of Ge-3C nanowires, the nanostructures revertback to the 3C phase with an amorphous component detected.In addition, we have carried out in-situ band gap measurements in bulk Ge and Ge nanowires as a function of pressure.After unloading, we havemeasured optical gap values that are related to the band structure of theGe-ST12 allotrope with a direct bandgap of 0,53 eV and an indirect bandgapof 0,73 eV.Those results are consistent with the experimental values reported.The experiments on Ge nanowires showed an hysteresis behavior with theinitial value of the band gap measured after unloading.Those results clearly evidenced novel relaxation mechanisms at the nanoscale that need to be investigated
Sheng, Wang. "Étude des fonctions oncogènes du virus d'Epstein-Barr (EBV) : détermination des souches du virus impliquées dans les cancers associés à l'EBV en Afrique du Nord : étude de la transformation maligne par l'oncogène viral BARF1 dans les fibroblastes de souris et les lymphocytes B humains". Lyon 1, 2001. http://www.theses.fr/2001LYO1T038.
Snoeck, Etienne. "Phases incommensurables de la berlinite et du quartz imagees par microscopie electronique". Toulouse 3, 1986. http://www.theses.fr/1986TOU30067.
Vaills, Yann. "Contribution à l'étude des transitions de phase structurales des pérovskites CsCaCl3 et CsPbCI3 par résonance paramagnétique électronique de l'ion Gd3+". Paris 6, 1986. http://www.theses.fr/1986PA066149.
Caron, Vincent. "MECANOSYNTHESE ET VITRIFICATION A L'ETAT SOLIDE D'ALLIAGES MOLECULAIRES". Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2006. http://tel.archives-ouvertes.fr/tel-00246474.
Bouvier, Pierre. "Étude Raman des distributions de phase et de contrainte dans des couches d'oxydation d'alliages de zirconium : étude spectroscopique des effets de pression et de température sur différentes zircones nanométriques". Grenoble INPG, 2000. http://www.theses.fr/2000INPG0136.