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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Habilitation à Diriger des Recherches

Boudon, Vincent 09 April 2004 (has links) (PDF)
Ce rapport d'habilitation présente une synthèse des activités de recherche que j'ai menées ces huit dernières années. J'ai distingué d'une part les recherches concernant la spectroscopie rovibrationnelle dans un état électronique singulet (Partie III) et d'autre part celles concernant la spectroscopie rovibronique dans un état électronique dégénéré (Partie IV).
42

Spectroscopie des hexafluorures à nombre impair d'électrons

Boudon, Vincent 26 May 1995 (has links) (PDF)
Du point de vue théorique, un formalisme tensoriel adapté à l'étude des molécules ou ions octaédriques possédant un moment angulaire demi-entier a été développé pour la première fois. Nous avons utilisé ici la méthode des représentations projectives, plus cohérente que celle des groupes doubles. Un jeu complet de coefficients et de formules de couplage, ainsi que les programmes de calcul correspondants ont été mis au point. Ceci a tout d'abord permis l'écriture d'un modèle simple décrivant la structure électronique des hexafluorures colorés. Ensuite, un certain nombre d'applications de ce formalisme à l'étude des couplages rovibroniques pour les molécules de type XY6 dans un état électronique quatre fois dégénéré ont été examinées, en particulier concernant les opérateurs associés à l'effet Jahn-Teller dynamique. Du point de vue expérimental, nous nous sommes intéressés à IrF6, dont nous avons pu maîtriser les processus de synthèse, de purification et de conservation. Une première étude à basse résolution (absorption et diffusion Raman spontanée) a été réalisée sur cette molécule. Nous avons ensuite mis en place deux dispositifs spectroscopiques à haute résolution dans le visible (absorption saturée - testée sur une cuve à iode - et simple absorption avec multiples passages). Ceux-ci utilisent notamment un laser à colorant. Ils doivent maintenant permettre la spectroscopie de la bande visible de IrF6, afin d'en résoudre pour la première fois la structure fine rotationnelle.
43

Svensk design i MoMAs samling : en studie om samlingens samband med marknadsföringen av svensk design i USA 1930-1960 / Swedish design in MoMA´s collection : a study of the collections correlations with the marketing of Swedish design in the U.S.A. 1930-1960

Jahn, Jonatan January 2012 (has links)
Museum of Modern Art har varit mycket tongivande för historieskrivningen och definitionen av modernismen, "the international style". Svensk modernisms mest kärnfulla period 1930-1960, representeras av 55 objekt i MoMAs arkitektur och designsamling. De svenska objekten i samlingen visar på en reception av svensk design som mest inflytelserik under 1950-talet. Årtiondet är det mest välrepresenterade, till antalet objekt räknade, men ger också den mest representativa bilden av hur svensk design marknadsfördes i USA. De mest inflytelserika tillfällena för marknadsföringen av svensk design i USA under åren 1930-1960 är enligt konstprofessor Jeff Werner (Medelvägens estetik: Sverigebilder i USA), världsutställningen i Chicago 1933, världsutställningen i New York 1939 och utställningen Design in Scandinavia 1954-1957. Knappt hälften av de representerade formgivarna i MoMAs samling fanns med under marknadsföringen ,vilket kan visa på samband mellan marknadsföringen och samlingens karaktär. / Museum of Modern Art has been very influential for the historiography and definition of modernism, "the international style". Swedish modernisms most vigorous period 1930-1960, is represented by 55 items in MoMA´s Architecture and Design collection. The Swedish objects in the collection show at a reception of Swedish design as most influential during the 1950s. The decade is the most well-represented, in number of objects counted, but also gives the most representative picture of how Swedish design was marketed in the United States. The most influential opportunities for the promotion of Swedish design in the United States during the years 1930-1960 are according to art professor Jeff Werner (Medelvägens estetik: Sverigebilder i USA), the World's Fair in Chicago in 1933, the World's Fair in New York in 1939, and Exhibition Design in Scandinavia 1954-1957. Just under half of the represented designers in the MoMA collection, were included in the marketing, which can show correlations between marketing and the collection's character.
44

Oxide Thermoelectrics: The Role of Crystal Structure on Thermopower in Strongly Correlated Spinels

Sparks, Taylor David 10 August 2012 (has links)
This dissertation reports on the synthesis, structural and thermal characterization and electrical and thermal transport properties of a variety of strongly correlated spinels. General structure property relationships for electrical and thermal transport are discussed. However, the relationship between thermopower and features of the crystal structure such as spin, crystal field, anti-site disorder, and structural distortions are explored in depth. The experimental findings are reported in the context of improving existing oxide thermoelectric materials, screening for new materials or using thermopower as a unique characterization tool to determine the cation distribution in spinels. The need for improved n-type oxide thermoelectric materials has led researchers to consider mixed valence \((+3/+4)\) manganese oxides. Contrary to previous findings we report herein that the \(LiMn_2O_4\) compound reaches the relatively large n-type thermopower of \(-73 \mu V/K\) which is three times larger than the value observed in other manganese oxides, \(-25 \mu V/K\). The cause of this increase in thermopower is shown to be the absence of a Jahn-Teller distortion on the \(Mn^{3+}\) ions in \(LiMn_2O_4\). By avoiding this structural distortion the orbital degeneracy is doubled and the Koshibae et al.’s modified Heikes formula predicts a thermopower of \(-79 \mu V/K\) in good agreement with the experiment. Altering the \(Mn^{3+/4+}\) ratio via aliovalent doping did not affect the thermopower and is a second evidence of universal charge transport first reported by Kobayashi et al. The role of anti-site disorder was further examined in \(Fe_xMn_{1-x}NiCrO_4\) x=0, ½, ¾, 1 spinels but the effect on thermopower was inconclusive due to the presence of impurity phases. Next, the thermopower as a function of temperature in \(Co_3O_4\) was investigated as a means whereby the Wu and Mason’s 30 year old model for using thermopower to calculate cation distribution in spinels could be revisited. We report evidence that Wu and Mason’s original model using the standard Heikes formula and considering octahedral sites alone leads to a stoichiometrically inconsistent result at high temperatures. Alternate models are evaluated considering Koshibae et al.’s modified Heikes formula and accounting for tetrahedral site contributions. Furthermore, the effect of a possible spin state transition is considered. / Engineering and Applied Sciences
45

Laser-induced fluorescence spectroscopy of the alkoxy radicals

Liu, Jinjun 26 February 2007 (has links)
No description available.
46

De oeconomia ex natione: An Examination of the Role of Nationalism in Estonia's Transition from Socialism to Capitalism

Denson, Thomas Marvin IV 01 June 2017 (has links)
This thesis explores the role played by nationalism in Estonia's transition to capitalism in the post-Soviet era and the way it continues to impact the Estonian economy. I hypothesize that nationalism was the key factor in this transition and that nationalism has placed a disproportionate economic burden on the resident ethnic Russians. First, I examine the history of Estonian nationalism. I examine the Estonian nationalist narrative from its beginning during the Livonian Crusade, the founding of Estonian nationalist thought in the late 1800s with a German model of nationalism, the conditions of the Soviet occupation, and the role of song festivals in Estonian nationalism. Second, I give a brief overview of the economic systems of Soviet and post-Soviet Estonia. Finally, I examine the impact of nationalism on the Estonian economy. To do this, I discuss the nature of nationalist economy, the presence of an ethno-national divide between the Estonians and Russians, and the impact of nationalist policies in citizenship, education, property rights, and geographical location. I find that there is a disproportionate difference in these areas between Estonians and ethnic Russians which affect the economy. I conclude by examining the problems and potential solutions to citizenship law, the use of neoliberalism in assimilation, and proposing a framework which could be used to examine disparities between differing groups in other economies. / Master of Arts
47

MAGNETIC AND ORBITAL ORDERS COUPLED TO NEGATIVE THERMAL EXPANSION IN MOTT INSULATORS, CA2RU1-XMXO4 (M = 3D TRANSITION METAL ION)

Qi, Tongfei 01 January 2012 (has links)
Ca2RuO4 is a structurally-driven Mott insulator with a metal-insulator (MI) transition at TMI = 357K, followed by a well-separated antiferromagnetic order at TN = 110 K. Slightly substituting Ru with a 3d transition metal ion M effectively shifts TMI and induces exotic magnetic behavior below TN. Moreover, M doping for Ru produces negative thermal expansion in Ca2Ru1-xMxO4 (M = Cr, Mn, Fe or Cu); the lattice volume expands on cooling with a total volume expansion ratio reaching as high as 1%. The onset of the negative thermal expansion closely tracks TMI and TN, sharply contrasting classic negative thermal expansion that shows no relevance to electronic properties. In addition, the observed negative thermal expansion occurs near room temperature and extends over a wide temperature interval. These findings underscores new physics driven by a complex interplay between orbital, spin and lattice degrees of freedom. These materials constitute a new class of Negative Thermal Expansion (NTE) materials with novel electronic and magnetic functions.
48

Být učitelem na valašské venkovské škole v první polovině 20. století / To be a teacher at wallachian village school in the first half of the 20th century

Mikačová, Lucie January 2016 (has links)
This thesis deals with the position and everydayness of Valašsko region teachers at primary schools in the first half of 20th century. Firstly the thesis discusses the range of the Valašsko region and a diversity of its definition, then it deals with the characteristics of Valašsko education system in comparison to other regions. The situation illustrates with the example of one - class school Na Soláni. It describes Valašsko pupil, his living conditions and food. The teacher is characterized not only as an educator but also as a person with his personal interests. The last two chapters provide a probe into the fates of two teachers - Metoděj Jahn (a teacher, a writer, a folklorist) and Cyril Mach (a teacher, an organizer of social life, a promoter of tourism and a progressives). Powered by TCPDF (www.tcpdf.org)
49

Théorie des spectres rovibroniques des molécules octaédriques : Hamiltonien et moments de transition

Rey, Michaël 24 October 2002 (has links) (PDF)
Cette thèse est consacrée à l'étude des interactions rovibroniques au sein de complexes octaédriques pour lesquels l'approximation de Born-Oppenheimer n'est plus valide. Pour la première fois, un modèle rovibronique tensoriel effectif complet a été développé à partir des travaux portant sur les toupies sphériques dans un état électronique non dégénéré. Ce modèle inclut le cas de systèmes moléculaires possédant un nombre pair ou impair d'électrons et sa validité a pu être testée sur deux molécules, toutes deux octaédriques : V(CO)6 et ReF6. Pour ces deux systèmes, nous avons alors considéré quatre sous-niveaux vibroniques en interaction. Dans les deux cas, la comparaison entre les profils simulés et observés à basse résolution est satisfaisante. En parallèle, nous avons mis en place, par une approche de type algébrique, un modèle permettant le traitement d'un état électronique doublet, triplet ou quadruplet. L'effet Jahn-Teller a pu alors être rééxaminé au moyen de ce type d'approche.
50

Corrélations entre la nature des liaisons chimiques entourant un octaèdre MO6 au sein d' un réseau oxygéné de type K2NIF4 et sa distorsion : influence decelle-ci sur la transition spin faible spin fort du cobalt III et sur la stabilisation du nickel III

Byeon, Song-Ho 28 June 1991 (has links) (PDF)
Au sein d'un réseau oxygène de type K2NiF4, de formule générale (A, A')2M'0.50M0.50O4, la distorsion locale de l'octaèdre (MO6) dépend des liaisons concurrentielles (A, A')-O le long de l'axe c et M'-O dans le plan xOy. Une étude systémaique a été entreprise selon la nature des ions A, A' et M', la distorsion locale de (MO6) étant en particulier caractérisée RPE, spectroscopie IR et résonance Mössbauer. L'influence de l'environnement chimique de (MO6) a été corrélé à la transition spin faible -> spin fort dans le cas du cobalt(III) et à la stabilisation du nickel(III) à spin faible.

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