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Les temps de declin de la luminescence de KCl:Ga('+), KBr:In('+), KI:Sn('2+), KI:Tl('+) ont ete mesures dans la region de temperature 3.3-300K; l'analyse des resultats permet d'obtenir des renseignements detailles sur la surface d'energie potentielle adiabatique de l'etat excite relaxe. / Une etude des temps de declin sous champ magnetique est presentee; les resultats sont interpretes a l'aide de la theorie des perturbations en premier ordre a l'interieur d'un modele ou le couplage electron-reseau (effet Jahn-Teller) domine le couplage spin-orbite. A basse temperature, la probabilite de transition radiative varie lineairement avec le carre du champ magnetique; la presence de composantes independantes du champ dans le signal de declin de luminescence permet la determination de la symetrie de l'etat excite relaxe. La valeur du parametre g (facteur de Lande) de l'etat excite est obtenue de l'analyse des donnees. / On a pu ainsi attribuer une nouvelle bande d'emission de KI:Sn('2+) a un dimere d'ions Sn('2+) accompagne de lacunes cationiques stabilisatrices. De meme, l'origine de la bande A(,x) de KI:Tl('+) a ete attribuee a un minimum de symetrie trigonale sur la surface d'energie potentielle adiabatique de l'etat excite relaxe.

Nickel molybdenum oxide catalysts with different chemical compositions have been synthesized and tested for the oxidative dehydrogenation of n-hexane. The co-precipitation method was used for the synthesis and several methods were used to characterize these catalysts. These include inductively-coupled plasma optical emission spectroscopy, Raman spectroscopy, infrared spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, temperature programmed reduction, temperature programmed desorption, X-ray photo-electron spectroscopy and X-ray diffraction spectroscopy techniques as well as the Brauner-Emmet-Teller technique for surface area determination. The phase composition of the catalysts was largely dependent on the chemical composition. Catalyst testing on n-hexane feed was done with a fixed bed continuous flow reactor and experiments were performed with feed/air ratios above and below the flammability limit. Varied reaction conditions were used for the catalytic testing. Prior to the catalytic testing, blank experiments were performed. Analysis of the products were done both online and offline in conjunction with gas chromatography employing FID and TCD detectors. The influence of the catalyst on the conversion of n-hexane and selectivity to dehydrogenation products is reported. Products observed were the carbon oxides (CO and CO2), isomers of hexene (1-hexene, 2-hexene and 3-hexene), cyclic C6 products (cyclohexene and benzene), cracked products: alkanes/alkenes (propane/ene, butane/ene) and oxygenates (ethanal, acetic acid and propanoic acid). B-NiMoO4 was most selective to the hexenes, especially, 1-hexene and a reaction scheme is proposed. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2009.

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Thesis (PhD)--University of South Australia, 2003.

Bibliography: leaves 239-248. / viii, 248 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Shows that the normalised Fourier/Hartley spectral data can be used for imaging when the seismic source wavelet is unknown. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1998

Thesis (Ph. D.)--Case Western Reserve University, 2008. / [School of Medicine] Department of Bochemistry. Includes bibliographical references.