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Dissertations / Theses on the topic 'Activation energies'

Author: Grafiati
Published: 4 June 2021
Last updated: 27 July 2025

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1

Marinaro, Damián. "A study into the effects of fission-fragment damage on activation energies in AG/B12223 tapes." Access electronically, 2003. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20040413.125335/index.html.

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2

Chick, Michael D. "Feasibility of the Use of Neutron Activation Analysis Techniques in an Underwater Environment." TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1744.

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Elements when bombarded with neutrons emit a gamma ray that is characteristic of the isotope that underwent a neutron induced nuclear reaction; this is known as neutron activation. The characteristic gamma energy of an isotope can then be detected and recorded. One can then analyze the gamma energies captured and determine the elemental makeup of the sample. This form of analysis can be used in an underwater environment making it potentially a valuable tool for agencies tasked with maritime security of ports and waterways, or clean-up operations. This thesis will focus on the feasibility of ne
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3

Cai, Yu. "Theory for Fundamental Reactions in Fuel Cells." Case Western Reserve University School of Graduate Studies / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=case1120759456.

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4

Perreault, Luke J. "Activation Energies of Kerogen in the Eagle Ford Shale Estimated from Rock Eval Pyrolysis Data| Comparison of Methods Using Single and Multiple Heating Rates." Thesis, University of Louisiana at Lafayette, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10615395.

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<p> Source rock kinetics have become increasingly important when defining kerogen maturity and building basin models. Recent studies have suggested that the activation energies (E<sub>a</sub>) needed for these applications can be obtained using one-run open-system pyrolysis with a single heating rate and a fixed frequency factor (A). This method is thought to be faster and cheaper than using multiple heating rates with a varying frequency factor. In this study both methods were used to find the E<sub>a</sub> of seven organic-rich samples from the Eagle Ford Shale. Activation energies for the m
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5

Bevillon, Emile. "Etude théorique du matériau BaSnO₃, en tant que conducteur protonique pour électrolytes de piles à combustible." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2009. http://www.theses.fr/2009ECAP0039/document.

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Les travaux effectués ont consisté en une étude théorique du matériau BaSnO3 en tant que matériau conducteur protonique pour électrolytes de piles à combustible. Ces matériaux sont obtenus après un dopage aliovalent préalable qui génère des lacunes d'oxygène sur le sous-réseau d'oxygène du matériau. Ce matériau, placé en milieu humide va s'hydrater, c'est à dire que des molécules d'eau vont se dissocier au sein du matériau. La propriété principale souhaitée pour de tels matériaux est la conductivité protonique. Celle-ci dépend du nombre de porteurs de charges (les hydrogènes ou protons apporté
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6

Slančík, Tomáš. "Experimentální analýza vlivu chloridových solí v poli neutronů různých energií." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400595.

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Master’s thesis focuses on the history and current progress in research of molten salt reactors around the world, with an emphasis placed on the properties of molten salts and the problems associated with their use. In relation to the practical part, one chapter is devoted to the creation of input file in the MCNP software. The practical part deals with neutron activation analysis of graphite prism experiment, which is filled with powder NaCl salt. This experiment is focused on the effect of salt on neutron flux with different energy levels. The whole problem was also simulated in the MCNP env
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7

Zeman, Vojtěch. "Kinetika fotochromních reakcí v tenkých polymerních filmech." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216218.

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The thesis is aimed to the study of spiropyrane behavior in polymeric matrix of poly(N-vinylkarbazole) (PVK) and poly[2-methoxy-5-(3´,7´-dimethyloctyloxy)-1,4-fenylenvinylene)] (MDMO-PPV). The photochromic transformation of spiropyrane to its isomeric merocyanine form (SPMC) was studied by absorption and emission spectroscopy. It was found, that photochromic reaction is markedly dependent on the environment. In the PVK polymer, which don’t absorb in the visible region, a high yield of photochromic reaction was achieved. Both, absorption and emission spectrums were observed for this system. Fro
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8

MARTINS, FERNANDO P. G. "Medida do espectro de energia dos neutrons no núcleo do reator IPEN/MB-01." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11485.

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Made available in DSpace on 2014-10-09T12:52:25Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:01:35Z (GMT). No. of bitstreams: 0<br>Dissertação (Mestrado)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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9

Ríos, Quiroga Luis Carlos [UNESP]. "Avaliação da relação entre a energia de ativação e a energia útil para diferentes misturas de etanol e gasolina aplicados a motores de ignição por centelha." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/146676.

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Submitted by LUIS CARLOS RIOS QUIROGA null (lcriosq@gmail.com) on 2016-12-12T00:09:20Z No. of bitstreams: 1 Tese Luis Carlos Rios 2016.pdf: 5350341 bytes, checksum: 21d3aaff1b9c7c11beb35ad9586d6956 (MD5)<br>Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-13T12:02:23Z (GMT) No. of bitstreams: 1 quiroga_lcr_dr_guara.pdf: 5350341 bytes, checksum: 21d3aaff1b9c7c11beb35ad9586d6956 (MD5)<br>Made available in DSpace on 2016-12-13T12:02:23Z (GMT). No. of bitstreams: 1 quiroga_lcr_dr_guara.pdf: 5350341 bytes, checksum: 21d3aaff1b9c7c11beb35ad9586d695
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10

Kopecký, Jan. "Určení kinetických parametrů reakcí pomocí DSC měření." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378413.

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The master thesis deals with DSC measurments a calculation of kinetic parameters. In the theoretical part, iron alotropy is briefly described, followed by a description of the DSC analysis itself. The thesis also includes division and derivation of isoconversional methods for calculating the activation energy. In the experimental part, a series of measurments is perfomed on pure iron prepared by Cold Spray method. In the paper the influence of deformation on the Curie temperature of the magnetic transformation in -Fe and transformation > is investigated. The activation energy is calculated f
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11

Leiva, Cecilia Rocío Morales. "O emprego da termogravimetria na determinação da energia de ativação no processo de combustão de óleos combustíveis." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-30092005-094638/.

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Neste trabalho, determinou-se a energia de ativação (Ea) no processo de combustão de três óleos combustíveis cedidos pela Petrobrás–Cenpes e denominados por A, B e C. Empregou-se análise termogravimétrica (TG) utilizando um sistema Shimadzu 51H e, para todas as amostras observaram-se três regiões oxidativas distintas identificadas como, oxidação à baixa temperatura (LTO), depósito de combustível (FD) e oxidação à alta temperatura (HTO). As energias de ativação foram determinadas como uma função do grau de conversão ('alfa') e temperatura na região LTO e utilizando-se dois métodos cinéticos, de
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12

Aquino, Fl?via de Medeiros. "S?ntese, caracteriza??o e cin?tica da decomposi??o t?rmica dos materiais cer?micos PrMO3 (M = Ni ou Co)." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12690.

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Made available in DSpace on 2014-12-17T14:06:54Z (GMT). No. of bitstreams: 1 FlaviaMA_DISSERT.pdf: 2525916 bytes, checksum: e66ea09a8c50d8b220412e1d5685d5d1 (MD5) Previous issue date: 2010-03-11<br>Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior<br>In this work have been studied the preparation, characterization and kinetic study of decomposition of the polymerizing agent used in the synthesis under non-isothermal condition ceramics PrMO3 of general formula (M = Co and Ni). These materials were obtained starting from the respective metal nitrates, as a cations source, and making
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13

Khoury, Antonio. "Parametres caracteristiques d'une photopile : etude experimentale, influence de la temperature." Perpignan, 1987. http://www.theses.fr/1987PERP0026.

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Etude de la determination des parametres caracterisant une photopile afin de proposer des methodes pratiques de mesure et d'en fixer les limites d'utilisation. Toutes les methodes connues pour mesurer la resistance serie d'une cellule ont ete utilisees et on montre que les ecarts importants observes proviennent de l'absence d'un controle precis de la temperature. On montre la necessite de determiner, ensemble le facteur de qualite et le courant inverse des cellules. Determination de la variation des parametres avec la temperature les mecanismes de transport des changes sont alors consideres
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14

Nogueira, Paulo Alberto. "Influência da temperatura na dinâmica oscilatória de um sistema químico homogêneo aberto." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-16092011-155351/.

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As reações químicas genericamente referidas como reações de Belousov-Zhabotinsky (BZ) têm sido bastante utilizadas como paradigmas de complexidade em sistemas químicos homogêneos. Apesar dos avanços consideráveis realizados no estudo de tais sistemas, aspectos como o papel do fluxo de reagentes e da temperatura na dinâmica oscilatória ainda são pouco entendidos. O presente trabalho consiste na investigação experimental do efeito destes dois parâmetros em duas variantes da reação de BZ. Após alguns testes iniciais com o sistema bromato/hipofosfito-acetona/manganês-ferroína, a maioria dos experi
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15

Martins, Fernando Prat Gonçalves. "Medida do espectro de energia dos nêutrons no núcleo do Reator IPEN/MB-01." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/85/85133/tde-14052012-110606/.

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Este trabalho apresenta a medida do espectro de energia dos nêutrons no núcleo do Reator IPEN/MB-01. Para tal, foram inseridos detectores de ativação na forma de diminutas folhas metálicas no núcleo do reator, na região moderadora, utilizando um dispositivo articulado que permite que as folhas fiquem posicionadas na posição central do núcleo do reator, garantindo que todas as folhas sejam irradiadas na mesma posição. Os detectores de ativação foram selecionados de forma a cobrir grande parte do espectro de energia dos nêutrons no Reator, para tanto foram utilizadas folhas de Au197, Mg24, Ti48,
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16

NUNES, BEATRIZ G. "Determinação exerimental de razões espectrais e do espectro de energia dos nêutrons no combustível do reator nuclear IPEN/MB-01." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10069.

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Made available in DSpace on 2014-10-09T12:34:24Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:09:44Z (GMT). No. of bitstreams: 0<br>Dissertação (Mestrado)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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17

Barros, João Lúcio de. "Biocoque de eucalipto como fonte de energia renovável para uso siderúrgico /." Sorocaba, 2019. http://hdl.handle.net/11449/190651.

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Orientador: Leandro Cardoso de Morais<br>Resumo: O Brasil se destaca na produção do ferro e aço, e principalmente na utilização de fontes renováveis como insumos energéticos para sua produção. O biocoque possui potencial para utilização de biomassas como insumos energéticos em alto fornos, em substituição aos tradicionais combustíveis fósseis, carvão e coque, porém, ainda é um material pouco conhecido cientificamente. O objetivo foi encontrar os parâmetros adequados para a produção, em escala laboratorial, do biocoque de casca e serragem da madeira de eucalipto. Também verificar suas principai
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18

Šlaičiūnaitė, Ilona. "Srovės pernešimo mechanizmai plonose oksido plėvelėse." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2007. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20070816_170904-16078.

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Šiame darbe buvo tirtas srovės pernešimo mechanizmas plonose oksido plėvelėse,t.y. SiO-Al, Al-SiO2-Al, Al-Al2O3-Al ir p/Si-Ta2O5-Al. Tuo tiklu buvo eksperimentiškai išmatuotos srovės stiprio temperatūrinės priklausomybės, esant įvairių įtampų vertėms, taip pat voltamperinės charakteristikos plačiame temperatūrų intervale ir nustatytas barjero aukščio (aktyvacijos energijos) kitimas nuo įtampos ir temperatūros. Eksperimentiniai rezultatai lyginami su teorinėmis elektronų tunelinių šuolių tikimybės priklausomybėmis nuo elektrinio lauko stiprio ir temperatūros.<br>The conduction mechanisms in SiO
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19

Míka, Petr. "Dynamická viskozita elektroizolačních kapalin." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220241.

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This work deals with persepective environmentally friendly electroinsulating liquids. Important properties of currently used electroinsulating liquids are listed. Physical nature of viscosity of liquids and its temperature dependance are described and methods of its measuring are listed. Also temperature dependance of density is described from physical point of view. Measurement of density and of temperature dependance of viscosity of chosen vegetable and mineral oils was performed. On the basis of this measurement was calulated the activation energy of these samples. Two methods of dynamic vi
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20

Castro, Mauricio de. "ESTUDO COMPARATIVO DA ATIVAÇÃO MECÂNICA POR MOINHOS DE ALTA ENERGIA E CARACTERIZAÇÃO DOS PRODUTOS OBTIDOS DURANTE REAÇÃO DE REDUÇÃO DO ÓXIDO DE CROMO POR ALUMÍNIO." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2015. http://tede2.uepg.br/jspui/handle/prefix/1470.

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Made available in DSpace on 2017-07-21T20:43:47Z (GMT). No. of bitstreams: 1 Mauricio Castro.pdf: 5841824 bytes, checksum: 35f8699394396800943abee89ca868ba (MD5) Previous issue date: 2015-01-30<br>Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná<br>This study aims to compare the supply capacity of power each of the three main types of high-energy mills: The "SPEX", Planetary and "Attritor" mills. The system used was chromium oxide with metallic aluminum, both are powders. The reduction reaction of chromium oxide with aluminum in the milling does not occur ins
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21

Laraqi, Najib. "Etude du comportement thermique d'un polymere en cours de degradation." Paris 6, 1987. http://www.theses.fr/1987PA066469.

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L'etude la degradation thermique du polymethacrylate de methyle avant inflammation est traitee par voie experimentale et par differentes approches numeriques. Ce travail concerne la reponse thermique et massique de ce materiau a des flux de chaleur constants. Le modele traduit parfaitement les evolutions des temperatures et des masses degrades
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22

Conconi, Charles Corrêa. "Avaliação físico-química e o potencial de desempenho do farnesano, biodiesel de soja, diesel fóssil e suas misturas por meio da energia de ativação e da correlação com as emissões em motores diesel." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18147/tde-26092016-184640/.

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Nos últimos anos o principal desafio da humanidade foi a substituição total ou parcial dos combustíveis fósseis que são responsáveis pelas mudanças climáticas e contribuem para a formação dos gases do efeito estufa. Como alternativa, os combustíveis renováveis - denominados biocombustíveis - têm se tornado uma alternativa viável. Este trabalho investigou o comportamento térmico e a energia de ativação de dois biocombustíveis (farnesano e biodiesel de soja) e suas misturas com diesel fóssil. Além disso, foram feitos estudos comparativos de comportamento térmico e energia de ativação entre todos
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23

Planche, Marie-France. "Etude des mécanismes de vieillissement du polymère conducteur polypyrrole et améliorations possibles." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10239.

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Le polypyrrole, synthetise par voie chimique, est d'une elaboration facile et presente de nombreuses applications potentielles. Dans ce travail, sa synthese a ete optimisee de facon a obtenir un polymere de conductivite elevee et de bonne stabilite. En outre, cette etude a permis une meilleure comprehension des mecanismes reactionnels de la synthese chimique. Cependant, le principal probleme pour la plupart des applications reste la degradation ambiante de ce materiau. La modelisation obtenue de la perte de conductivite dans le temps, en temperature, est caracteristique d'un mecanisme de condu
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24

Leverd, François. "Contribution à l'étude de la catalyse des polyestérifications par les dérives organiques des métaux de transition." Paris 6, 1986. http://www.theses.fr/1986PA066267.

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Synthèse d'alcoolates doubles bimétalliques dont l'activité catalytique potentielle, ainsi que celle d'autres dérivés métalliques est comparée à celle de Ti(Or)::(4) et Zr(Or)::(4). Mécanisme d'estérification et polyestérification (polyadipate de decanediyle-1,10)
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25

Peres, Luciano Donizeti Pantano [UNESP]. "Avaliação de propriedades mecânicas de peças pré-moldadas submetidas à cura térmica pelo método da maturidade: estudo de caso." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/94559.

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Made available in DSpace on 2014-06-11T19:27:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-04-26Bitstream added on 2014-06-13T20:55:56Z : No. of bitstreams: 1 peres_ldp_me_ilha.pdf: 2857785 bytes, checksum: b65c61234cf2091abda94892d39a8f54 (MD5)<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>O Método da Maturidade é um ensaio não-destrutivo utilizado para avaliação das propriedades do concreto que estejam relacionadas ao desenvolvimento do grau de hidratação do material, a partir do seu histórico de temperaturas. O presente trabalho apresenta a aplicação dos
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26

Planer, Jakub. "Ab-initio výpočty elektronických a strukturních vlastností olovo-zirkonátu-titanátu (PZT)." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-319928.

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This work is focused on Density Functional Theory (DFT) calculations of oxygen vacancy diffusion barriers in mixed perovskite lead zirconate titanate and its pure counterparts. We found out that barrier heights are different in lead titanate and lead zirconate caused by the different localization of the excess electrons due to the oxygen vacancy formation. Diffusion barriers were also determined for titanium-rich mixed phases and compared to experimental values. This work contributes to clarify unusually low experimentally measured diffusion coefficients in PZT. We found out that the induced v
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27

Pokam, Kuisseu Pauline Sylvia. "Détachement des substrats ultra-minces des matériaux semi-conducteurs par implantation d’hydrogène à hautes énergies pour les applications photovoltaïques et électroniques." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2035/document.

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Cette thèse a été motivée par l’étude d’un procédé innovant de production de substrats ultra-minces (d’épaisseur variant de 15 μm à 70 μm), basé sur l’implantation d’hydrogène à haute énergie, dans notre cas comprise entre 1MeV et 2.5MeV. Une telle implantation suivie d’un traitement thermique approprié, conduit au détachement d’un film mince autoporté, appelé « substrat ultra-mince ». L’intérêt de ce procédé de détachement est purement économique, car il ne génère presque aucune perte de matière première. Nous l’avons particulièrement utilisé pour produire des substrats ultra-minces de silici
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Rosell-Laclau, Eliette. "Addition d'éléments de transition dans les alliages Al-Ni précurseurs des catalyseurs de nickel de Ranay." Grenoble INPG, 1994. http://www.theses.fr/1994INPG0071.

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Cette etude concerne l'influence d'elements d'addition (titane, fer et chrome) dans les alliages precurseurs al-ni, des catalyseurs de nickel de raney. Deux aspects principaux ont ete developpes lors de ce travail. La premiere partie traite de l'effet du dopant sur la reactivite des phases al#3ni et al#3ni#2 vis-a-vis de l'extraction d'aluminium par attaque alcaline. L'attaque de al#3ni par propagation d'un front plan, a permis de mettre en evidence un processus d'attaque identique que ce soit sans dopant ou en presence de titane ou de chrome. Une energie d'activation de 60 kj/mol a ete determ
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29

Kleider, Jean-Paul. "Etude des centres profonds du silicium amorphe hydrogène a-Si:H par des mesures d'admittances de diodes Schottky : caractérisation d'interfaces SI::(X)-N::(1-X):H/A-SI:H sur des structures MIS." Paris 6, 1987. http://www.theses.fr/1987PA066015.

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DDétermination des caractéristiques du silicium amorphe hydrogène par mesure et analyse des admittances de diodes Schottky fournies sur ce matériau: densité d'états en-dessous et au niveau de fermi avec section de capture efficace des électrons et énergie d'activation du matériel.
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Madouri, Ali. "Heterodiffusion du manganese dans la wuestite : fe1-y o::(-)." Paris 7, 1987. http://www.theses.fr/1987PA077285.

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Les coefficients de diffusion de mn dans feo sont mesures en fonction de la temperature (700**(o)c-1100**(o)c) pour quatre valeurs du rapport r=pco::(2)(pco (r=0,7; 1,0; 1,8; 2,5). Les coefficients de diffusion du manganese sont systematiquement plus eleves que les coefficients d'autodiffusion du fer pris dans la litterature (chen et peterson, 1973) a cause de l'energie d'activation de d::(mn) plus faible que celle de d::(fe). Les resultats de diffusion d'interpretent en termes d'interactions attractives entre les lacunes et les atomes de manganese
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31

Cazzitti, Anne. "Etude de la phase amorphe de polyamides plastifies par spectroscopie micromecanique thermostimulee." Toulouse 3, 1988. http://www.theses.fr/1988TOU30007.

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Etude par fluage thermostimule de l'influence des parametres chimiques et physiques sur la structure de la phase amorphe de polyamides. Etude de la plastification des polyamides 11 et 12. Influence de la mise en oeuvre sur l'evolution des proprietes mecaniques de polyamides plastifies
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32

Santos, Liane Ferreira dos [UNESP]. "A influência do patamar de cura térmica sobre a resistência dos concretos auto-adensáveis elaborados com diferentes tipos de cimento: avaliação pelo método da maturidade." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/94478.

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Made available in DSpace on 2014-06-11T19:27:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-26Bitstream added on 2014-06-13T20:16:15Z : No. of bitstreams: 1 santos_lf_me_ilha.pdf: 6137370 bytes, checksum: 5de758f11cce6406d87fe87638a96bb5 (MD5)<br>O concreto auto-adensável (CAA) é um material que representa um dos maiores avanços na tecnologia do concreto das últimas décadas. O desenvolvimento do CAA propiciou eficiência e melhora nas condições de trabalho em canteiro de obras e na indústria de pré-moldados. Do ponto de vista reológico, o CAA é uma mistura fluida que proporciona
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Oliveira, Aline Ara?jo Alves de. "Estudo cin?tico da degrada??o t?rmica e catal?tica de petr?leo pesado usando Al-MCM-41." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17781.

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Made available in DSpace on 2014-12-17T15:42:27Z (GMT). No. of bitstreams: 1 AlineAAO_TESE.pdf: 3075922 bytes, checksum: bd3bdc6aafacdcbe05784c0fbe751097 (MD5) Previous issue date: 2013-08-09<br>The mesoporous nanostructured materials have been studied for application in the oil industry, in particular Al-MCM-41, due to the surface area around 800 to 1.000 m2 g-1 and, pore diameters ranging from 2 to 10 nm, suitable for catalysis to large molecules such as heavy oil. The MCM-41 has been synthesized by hydrothermal method, on which aluminum was added, in the ratio Si/Al equal to 50, to increa
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Souza, Michelle Carvalho de. "Estudo da cinética de secagem e análise da farinha de yacon (Smallanthus sonchifolius)." Universidade Federal do Espírito Santo, 2013. http://repositorio.ufes.br/handle/10/5763.

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Made available in DSpace on 2016-12-23T13:50:03Z (GMT). No. of bitstreams: 1 Michelle Carvalho de Souza.pdf: 1066706 bytes, checksum: 3c78ec62d0a1683cf0df485633effc39 (MD5) Previous issue date: 2013-08-21<br>O yacon é um tubérculo de origem andina, e seu consumo tem se disseminado pelos demais países devido as suas características de alimento funcional. Os benefícios advindos do yacon são devido à presença dos FOS (frutooligossacarídeos), que são carboidratos não digeríveis pelo organismo humano, que atuam como fibra e são fermentados pelas bactérias intestinais, produzindo compostos benéfic
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35

Gadaud, Pascal. "Etude par frottement interieur haute temperature des defauts structuraux dans le silicium monocristallin." Poitiers, 1987. http://www.theses.fr/1987POIT2273.

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Des experiences de frottement interne haute temperature en basse frequence ont ete realisees sur le silicium nonocristallin deforme. Plusieurs effets de relaxation ont ete relies a differents comportements des dislocations en correlation avec les parametres structuraux. L'interpretation de ces relaxations a permis de preciser les energies des mecanismes elementaires de glissement et le role du dopant, propres a la structure covalente
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36

Hamet, Jean-François. "Etude de bicristaux de silicium par spectroscopie capacitive, influence des traitementsthermiques et des impuretes." Caen, 1989. http://www.theses.fr/1989CAEN2001.

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Etude des proprietes electriques des joints de grain par dlts, tscap et egalement par des mesures de recombinaison ebic. L'activite electrique des joints est liee a la presence de precipites a caractere metallique le long des joints
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37

De, la Rosa Figueroa Aida. "Etude de la mobilité moléculaire dans la phase amorphe de polymères vinyliques à groupements latéraux polaires." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10064.

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Cette these presente une etude comparative de la mobilite moleculaire en dessous de la transition vitreuse dans la phase amorphe du poly(alcool vinylique) (pva) et du poly(alcool allylique) (paa). Elle comprend une partie experimentale et une partie de simulation moleculaire. Dans une premiere partie, les relaxations secondaires des deux polymeres sont caracterisees par spectrometries mecanique et dielectrique, a l'etat sec ou hydrate. Ces polymeres presentent des similarites dans la position, l'energie d'activation et la sensibilite aux solvants polaires des relaxations secondaires des polysa
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38

Belkacem, Sihem. "Recherche de forme par relaxation dynamique des structures reticulees spatiales autocontraintes." Toulouse 3, 1987. http://www.theses.fr/1987TOU30146.

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39

Castro, Kesia Kelly Vieira de. "Degrada??o t?rmica e catal?tica do res?duo atmosf?rico de petr?leo (RAT), utilizando materiais nanoestruturados do tipo SBA-15." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17783.

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Made available in DSpace on 2014-12-17T15:42:27Z (GMT). No. of bitstreams: 1 KesiaKVC_TESE.pdf: 1888403 bytes, checksum: 628d99fa0e77dc19c5054fa5d201217e (MD5) Previous issue date: 2013-04-17<br>In this work were synthesized and characterized the materials mesoporous SBA-15 and Al- SBA-15, Si / Al = 25, 50 and 75, discovered by researchers at the University of California- Santa Barbara, USA, with pore diameters ranging from 2 to 30 nm and wall thickness from 3.1 to 6.4 nm, making these promising materials in the field of catalysis, particularly for petroleum refining (catalytic cracking), as
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40

WEHREY-AUGUSTIN, FABIENNE. "Oxydo-reduction du neptunium dans les melanges phosphate tributylique-dodecane." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13007.

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Etude des reactions de dismutation et d'oxydation (parhno::(3)) de np(v) dans les melanges tbp-dodecane. La dismutation de np(v) en milieu perchlorique est une reaction d'ordre 2 par rapport a np. Cinetique et energie d'activation de la reaction
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41

Ohm, Thorsten. "Effet tunnel quantique de l'aimantation dans un aimant moleculaire, Fe8." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10187.

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Nous avons étudié les retournements d'aimantation par effet tunnel quantique dans des aimants moléculaires. Nos expériences montrent clairement l'effet tunnel quantique dans l'aimant moléculaire Fe8. Ce système se compose d'un ensemble d'aimants nanoscopiques identiques et orientes parallèlement. Chacune des molécules porte un spin s = 10. Les mesures de relaxation sont faites en utilisant des magnétomètres à squid aux performances uniques. Ces magnétomètres permettent des mesures de haute sensibilité en champ fort, jusqu'a 8 tesla, et aux très basses températures (>50 mK). A haute température
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42

Hamou, Ahmed. "Relaxation et cristallisation d'alliages chalcogènes vitreux riches en sélenium : influence de la coordination de l'élément d'addition." Rouen, 1993. http://www.theses.fr/1993ROUES001.

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Le but du travail présenté dans cette thèse est de chercher à partir de matériaux modèles, des grandeurs ou des méthodes pouvant caractériser la structure d'un verre. Dans une première partie, nous justifierons le choix des alliages étudiés (Se, Se-As, Se-Bi et Se-Ge). Puis nous présenterons leurs structures cristallines et vitreuses, enfin nous donnerons un bref aperçu des méthodes expérimentales utilisées pour la fabrication et le contrôle des échantillons. La deuxième partie est consacrée aux résultats expérimentaux. Par les études de la relaxation et la cristallisation des alliages étudiés
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43

Ocampo, Juan. "Etude des phénomènes d'interface dans la glace : adsorption, croissance des clathrates et désordre protonique : [thèse en partie soutenue sur un ensemble de travaux]." Grenoble 1, 1988. http://www.theses.fr/1988GRE10087.

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Etude depuis l'etat amorphe a 77 k jusqu'a l'etat hexagonal pres du point de fusion de l'evolution structurale et dynamique de la surface de la glace en contact ou non avec des gaz (he, kr, ar, n::(2), co::(2), nc::(4)h::(10)) ou des solides (sio::(2), pvc, h::(2)so::(4)). Approche thermodynamique (adsorption de gaz), cinetique (frittage et croissance de clathrates) et spectroscopique (rmn des protons). Mecanisme de reconstruction de la surface depuis l'adsorption jusqu'a la clathration, en tenant compte des coefficients de diffusion et des energies d'activation mesurees. Existence d'une couch
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44

Mambou, Josiane. "Dopage au bore à partir de la phase vapeur : étude comparative des couches minces polycristallines et monocristallines de diamant." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10055.

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Le diamant est un semi-conducteur tres prometteur pour les applications electroniques a haute temperature et de forte puissance. Neanmoins, pour optimiser les performances des dispositifs electroniques actuels, il est indispensable de mieux connaitre et de minimiser la concentration des defauts residuels qui limitent l'efficacite du dopage. Pour cela, nous avons elabore des couches minces de diamant dopees au bore, et etudie l'influence de l'incorporation de bore sur les proprietes du diamant et sur les defauts natifs. La caracterisation des couches s'est faite par differentes techniques : mic
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45

Santos, Zilvam Melo dos. "Estudos das intera??es de quitosana/CTAB/C12E8." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17775.

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Made available in DSpace on 2014-12-17T15:42:26Z (GMT). No. of bitstreams: 1 ZilvamMS_TESE_reduzido.pdf: 9108618 bytes, checksum: 613dad3fd1a359dce84e2af73b067934 (MD5) Previous issue date: 2013-02-22<br>Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior<br>Surfactant-polymer interactions are widely used when required rheological properties for specific applications, such as the production of fluids for oil exploration. Studies of the interactions of chitosan with cationic surfactants has attracted attention by being able to cause changes in rheological parameters of the systems mak
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46

Itawi, Ahmad. "Dispositifs photoniques hybrides sur Silicium comportant des guides nano-structurés : conception, fabrication et caractérisation." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112363/document.

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Le contexte de cette thèse couvre les dispositifs photoniques hybrides III-V sur silicium. L’étude porte sur l’intégration par collage de matériau à base d'InP sur le silicium, puis la conception d’un guide optique comportant une nanostructuration qui permettra la sélection en longueur d’onde dans un laser DFB hybride. Enfin, on étudie les étapes technologiques de fabrication d’un laser hybride injecté électriquement fonctionnant dans le domaine spectral 1.55µm, et on caractérise les dispositifs. Pour associer les matériaux III-V sur Si, nous avons développé le collage sans couche intermédiair
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47

Widmer, Johannes. "Charge transport and energy levels in organic semiconductors." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-154918.

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Organic semiconductors are a new key technology for large-area and flexible thin-film electronics. They are deposited as thin films (sub-nanometer to micrometer) on large-area substrates. The technologically most advanced applications are organic light emitting diodes (OLEDs) and organic photovoltaics (OPV). For the improvement of performance and efficiency, correct modeling of the electronic processes in the devices is essential. Reliable characterization and validation of the electronic properties of the materials is simultaneously required for the successful optimization of devices. Further
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48

Khan, Abdul Kareem. "Electrostaticanalisys the Ras active site." Doctoral thesis, Universitat Pompeu Fabra, 2009. http://hdl.handle.net/10803/7161.

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La preorganització electrostàtica del centre actiu s'ha postulat com el mecanisme genèric de l'acció dels enzims. Així, alguns residus "estratègics" es disposarien per catalitzar reaccions interaccionant en una forma més forta amb l'estat de transició, baixant d'aquesta manera el valor de l'energia dactivació &#61508;g cat. S'ha proposat que aquesta preorientació electrostática s'hauria de poder mostrar analitzant l'estabilitat electrostàtica de residus individuals en el centre actiu.<br/>Ras es una proteïna essencial de senyalització i actúa com un interruptor cel.lular. Les característiques
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49

Wang, Wei-Chyn, and 王偉銓. "Theoretical Calculation of Activation Energies of SN2 Reactions in the Cleaving of Silyl Ether." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/19870616036636860079.

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50

Gong, Yu-Ting, and 龔玉婷. "Study of the activation energies for the carbonization of metal–organic frameworks using Raman spectroscopy." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/h9m2q4.

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碩士<br>中原大學<br>化學研究所<br>103<br>This study explored the reaction rates of the carbonization process of metal-organic frameworks using Raman spectroscopy. The metal-organic frameworks of MIL-100(Al), MIL-53(Al), MIL-69(Al), DUT-4(Al), and CYCU-4(Al) of the same metal center series were selected. These metal-organic frameworks have different molecular structures. MIL-100 is of cage-like porous structure, while other metal-organic frameworks are of diamond-shaped porous structure. The pore and specific surface areas, as well as the ligand types, are different. Raman spectroscopy was used to measure
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