Teses / dissertações sobre o tema "Cu₂O"
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Martin, Airton Abrahao. "Preparação e caracterização de cerâmicas supercondutoras nos sistemas Y-Ba-Cu-O e Tm-Ba-Cu-O". Universidade de São Paulo, 1988. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-18122013-112538/.
Texto completo da fonteThe influence of the temperature and time in the reaction and sinterization of superconducting ceramics prepared by a solid state reaction was determined. The results clearly showed that some of its properties, such as critical temperature (Tc), magnetic susceptibility (X), resistivity (ρ), microstructure, apparent density, and porosity undergo a strong influence of the preparation conditions. Some samples in the YBa2Cu3O6.5+x and TmBa2Cu3O6.5+x systems were prepared. The ideal reaction temperature and time were 950°C for 6 hours and 925°C for 48 hours, respectively. Both annealed in O2 flow. The sample characterization was made by using X-ray diffraction, standard four probe (measures the variation of resistivity versus temperature), Bridge of Hartshorn (the variation of susceptibility versus temperature), scanning electron micrograph (microstructure analysis), and immersion method (measures the apparent density and porosity). The greatest critical temperature was approximately 94K for YBa2Cu3O6.5+x and 91K for TmBa2Cu3O6.5+x
Heffernan, Shane. "Nanostructured CU₂O solar cells". Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709220.
Texto completo da fonteSeibel, B. [Verfasser]. "Berechnungen von Röntgenabsorptionsspektren an YBa₂Cu₃O₇, PrBa₂Cu₃O₇ und Sr₂RuO₄ / B. Seibel". Karlsruhe : KIT-Bibliothek, 1997. http://d-nb.info/1108447422/34.
Texto completo da fonteSene, Abdoulaye. "Formation et fonctionnement des sites actifs des catalyseurs d'hydrogénation Cu-Zn-O et Cu-Zn-Al-O". Lille 1, 1990. http://www.theses.fr/1990LIL10166.
Texto completo da fonteBrito, Juliana Ferreira de [UNESP]. "Estudo da redução fotocatalítica e fotoeletrocatalítica de 'CO IND. 2' em meio aquoso sobre 'CU'/'CU IND. 2 'O'', 'TI' 'O IND. 2'/'PT', 'CU''NB' 'O IND. 3' - 'CU''O' e 'CU IND. 0,85''ZN IND. 0,15''NB IND. 2''O IND.6' como catalisadores para formação de metanol". Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/110841.
Texto completo da fonteO presente trabalho reporta os principais resultados obtidos na construção e caracterização de eletrodos de titânio recobertos com nanotubos de óxido de titânio modificados com nanopartículas de platina (TiO2/Pt) e eletrodos de cobre recobertos com nanopartículas de óxido de cobre (Cu/Cu2O) com vistas a sua aplicação na redução fotoeletrocatalítica de CO2 em meio aquoso e semicondutores em pó de CuNbO3-CuO, Cu0,85Zn0,15Nb2O6 e ZnNb2O6-Nb2O5 construídos e testados na redução fotocatalítica de CO2, com vistas a geração de produtos com maior valor agregado, tal como metanol. Os eletrodos TiO2/Pt e Cu/Cu2O foram construídos por meio de técnicas de eletroquímicas, enquanto que os semicondutores em pó CuNbO3-CuO, Cu0,85Zn0,15Nb2O6 e ZnNb2O6-Nb2O5 foram preparados utilizando a técnica de síntese por combustão e calcinação posterior. A redução fotoeletrocatalítica e fotocatalítica de CO2 não foi satisfatória sobre eletrodos de TiO2/Pt e semicondutor ZnNb2O6-Nb2O5, respectivamente. No entanto, o eletrodo de Cu/Cu2O apresentou grande eficiência na redução de CO2, atingindo 80% de remoção em meio de Na2CO3 0,3 mol L-1 pH 9 a +0,2 V, em solução tampão de NaHCO3/Na2CO3 0,1 mol L-1 pH 8, utilizando luz UV 125 W e potencial de +0,2 V mostrou uma reação praticamente seletiva para metanol, gerando 5,63 mmol L-1, correspondendo a 20% de conversão. Os semicondutores em pó CuNbO3-CuO e Cu0,85Zn0,15Nb2O6 também se mostraram bastante eficientes para a geração de metanol por redução de CO2 dissolvido em Na2CO3 0,1 mol L-1 pH8 utilizando luz visível de 450 W, chegando a formar 7,0 mmol L-1 e 3,2 mmol L-1 de metanol respectivamente. Os resultados obtidos neste trabalho mostram que ambas as técnicas podem ser empregadas para a redução do CO2, usando para isto os semicondutores Cu/Cu2O, CuNbO3-CuO e Cu0,85Zn0,15Nb2O6 e, poderia ser uma potencial alternativa para os problemas ambientais além de contribuir como fonte...
This present work reports the main results obtained with the construction and characterization of TiO2 nanotubes modified by platinum nanoparticle electrode (TiO2/Pt) and copper covered by copper oxide nanoparticles electrode (Cu/Cu2O) for application in the photoelectrocatalytic reduction of dissolved CO2 and CuNbO3-CuO, Cu0,85Zn0,15Nb2O6 and ZnNb2O6-Nb2O5 powders semiconductors constructed and applied in the photocatalytic reduction of dissolved CO2 for the generation of products with higher added value. The TiO2/Pt and Cu/Cu2O electrodes were prepared by electrochemical techniques, whereas the CuNbO3-CuO, Cu0,85Zn0,15Nb2O6 and ZnNb2O6-Nb2O5 powder semiconductors were prepared using the combustion synthesis technique and submitted to annealed. The CO2 reduction by photoelectrocatalysis and photocatalysis were not satisfactory when using the TiO2/Pt electrode and the ZnNb2O6-Nb2O5 semiconductor, respectively. However, the Cu/Cu2O electrode shows a high efficiency in the CO2 reduction obtaining 80% of removal in 0.3 mol L-1 Na2CO3 pH 9 and +0.2 V, and, it showed a practically selective reaction to methanol (producing 5.63 mmol L-1), corresponding to 20% of conversion at ambient of 0.1 mol L-1 NaHCO3/Na2CO3 butter solution pH 8, using UV light of 125 W and +0,2 V. The CuNbO3-CuO and Cu0,85Zn0,15Nb2O6 powder semiconductors also showed a good efficiency to the methanol formation throughout dissolved CO2 reduction in 0.1 mol L-1 Na2CO3 pH 8 using visible light of 450 W, and forming 7 mmol L-1 and 3.2 mmol L-1 of methanol, respectively. The results obtained in this work show that both techniques can be employed for the CO2 reduction, using for this the Cu/Cu2O, CuNbO3-CuO and Cu0,85Zn0,15Nb2O6 semiconductors, and it could be a potential alternative to the environmental problems and contribute as raw material source for the production of fuels, for instance.
Brito, Juliana Ferreira de. "Estudo da redução fotocatalítica e fotoeletrocatalítica de 'CO IND. 2' em meio aquoso sobre 'CU'/'CU IND. 2 'O'', 'TI' 'O IND. 2'/'PT', 'CU''NB' 'O IND. 3' - 'CU''O' e 'CU IND. 0,85''ZN IND. 0,15''NB IND. 2''O IND.6' como catalisadores para formação de metanol /". Araraquara, 2014. http://hdl.handle.net/11449/110841.
Texto completo da fonteBanca: Mário César Guerreiro
Banca: Luiz Henrique Dall'antonia
Resumo: O presente trabalho reporta os principais resultados obtidos na construção e caracterização de eletrodos de titânio recobertos com nanotubos de óxido de titânio modificados com nanopartículas de platina (TiO2/Pt) e eletrodos de cobre recobertos com nanopartículas de óxido de cobre (Cu/Cu2O) com vistas a sua aplicação na redução fotoeletrocatalítica de CO2 em meio aquoso e semicondutores em pó de CuNbO3-CuO, Cu0,85Zn0,15Nb2O6 e ZnNb2O6-Nb2O5 construídos e testados na redução fotocatalítica de CO2, com vistas a geração de produtos com maior valor agregado, tal como metanol. Os eletrodos TiO2/Pt e Cu/Cu2O foram construídos por meio de técnicas de eletroquímicas, enquanto que os semicondutores em pó CuNbO3-CuO, Cu0,85Zn0,15Nb2O6 e ZnNb2O6-Nb2O5 foram preparados utilizando a técnica de síntese por combustão e calcinação posterior. A redução fotoeletrocatalítica e fotocatalítica de CO2 não foi satisfatória sobre eletrodos de TiO2/Pt e semicondutor ZnNb2O6-Nb2O5, respectivamente. No entanto, o eletrodo de Cu/Cu2O apresentou grande eficiência na redução de CO2, atingindo 80% de remoção em meio de Na2CO3 0,3 mol L-1 pH 9 a +0,2 V, em solução tampão de NaHCO3/Na2CO3 0,1 mol L-1 pH 8, utilizando luz UV 125 W e potencial de +0,2 V mostrou uma reação praticamente seletiva para metanol, gerando 5,63 mmol L-1, correspondendo a 20% de conversão. Os semicondutores em pó CuNbO3-CuO e Cu0,85Zn0,15Nb2O6 também se mostraram bastante eficientes para a geração de metanol por redução de CO2 dissolvido em Na2CO3 0,1 mol L-1 pH8 utilizando luz visível de 450 W, chegando a formar 7,0 mmol L-1 e 3,2 mmol L-1 de metanol respectivamente. Os resultados obtidos neste trabalho mostram que ambas as técnicas podem ser empregadas para a redução do CO2, usando para isto os semicondutores Cu/Cu2O, CuNbO3-CuO e Cu0,85Zn0,15Nb2O6 e, poderia ser uma potencial alternativa para os problemas ambientais além de contribuir como fonte...
Abstract: This present work reports the main results obtained with the construction and characterization of TiO2 nanotubes modified by platinum nanoparticle electrode (TiO2/Pt) and copper covered by copper oxide nanoparticles electrode (Cu/Cu2O) for application in the photoelectrocatalytic reduction of dissolved CO2 and CuNbO3-CuO, Cu0,85Zn0,15Nb2O6 and ZnNb2O6-Nb2O5 powders semiconductors constructed and applied in the photocatalytic reduction of dissolved CO2 for the generation of products with higher added value. The TiO2/Pt and Cu/Cu2O electrodes were prepared by electrochemical techniques, whereas the CuNbO3-CuO, Cu0,85Zn0,15Nb2O6 and ZnNb2O6-Nb2O5 powder semiconductors were prepared using the combustion synthesis technique and submitted to annealed. The CO2 reduction by photoelectrocatalysis and photocatalysis were not satisfactory when using the TiO2/Pt electrode and the ZnNb2O6-Nb2O5 semiconductor, respectively. However, the Cu/Cu2O electrode shows a high efficiency in the CO2 reduction obtaining 80% of removal in 0.3 mol L-1 Na2CO3 pH 9 and +0.2 V, and, it showed a practically selective reaction to methanol (producing 5.63 mmol L-1), corresponding to 20% of conversion at ambient of 0.1 mol L-1 NaHCO3/Na2CO3 butter solution pH 8, using UV light of 125 W and +0,2 V. The CuNbO3-CuO and Cu0,85Zn0,15Nb2O6 powder semiconductors also showed a good efficiency to the methanol formation throughout dissolved CO2 reduction in 0.1 mol L-1 Na2CO3 pH 8 using visible light of 450 W, and forming 7 mmol L-1 and 3.2 mmol L-1 of methanol, respectively. The results obtained in this work show that both techniques can be employed for the CO2 reduction, using for this the Cu/Cu2O, CuNbO3-CuO and Cu0,85Zn0,15Nb2O6 semiconductors, and it could be a potential alternative to the environmental problems and contribute as raw material source for the production of fuels, for instance.
Mestre
TROUILLEUX, LIONEL. "Elaboration et etude des proprietes electriques et magnetiques de ceramiques supraconductrices texturees dans les systemes la-sr-cu-o, nd-ce-cu-o et bi-sr-ca-cu-o". Paris 11, 1991. http://www.theses.fr/1991PA112031.
Texto completo da fontePorch, Adrian. "Microwave surface impedance of YBa₂Cu₃O₇". Thesis, University of Cambridge, 1992. https://www.repository.cam.ac.uk/handle/1810/283677.
Texto completo da fonteTeruzzi, Tiziano. "Investigation of the vortex dynamics in the high-temperature superconductors Bi₂Sr₂CaCu₂O₈, YBa₂Cu₃O₇₋{delta} and YBa₂Cu₄O₈ /". Zürich, 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10361.
Texto completo da fonteSchorne, Pinto Juliano. "Etude expérimentale et modélisation thermodynamique de systèmes de delafossites à base de cuivre". Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0006.
Texto completo da fonteThis multidisciplinary thesis work was dedicated to the study of CuMO2 phases with M = {Cr and Fe} of the delafossite structural family. With the main aim of broadening knowledge and filling the gaps around the thermodynamic properties of this type of phase, an in-depth experimental study of the Cu-Fe-O and Cu-Cr-O systems was carried out. The main results obtained are: a) for the first time, a cationic non-stoichiometry for the delafossite phase of the CuFe1-yO2- type with y 0.12 has been found, b) the coordinates of the eutectic point of the Cu-Fe-O system in air were measured at 1049(3) °C for a composition x(Fe) = 0.105, c) the CuFeO2 phase is stable between 1022(2) ° C and 1070(2) ° C in air, d) an absence of solid solution with a delafossite structure CuCrO2 was observed for x (Cr) < 0.50, e) a slight solubility of chromium in CuCrO2 with a maximum value of x (Cr) = 0.524(8) was measured in this phase, f) the spinel phase CuCr2O4 was defined as stoichiometric by the invariance of the structural parameters and the chemical composition, at last g) the thermodynamic properties of the delafossite phase CuCrO2 were determined for the first time, with the selected values for this phase being: fH298(CuCrO2) = 670 800 ± 1400 J / mol, S°298(CuCrO2) = 88.89 J/mol and cp = 102.564 2.872.10-73 128 5421.5 between [298 <1300]. These results were coupled with those from the bibliography for the construction of a generic thermodynamic model describing the properties of the delafossite, liquid, and spinel phases in the quaternary Cu-Cr-Fe-O subsystems. The liquid phase was modeled by the Modified Quasichemical Model ((Cu1+,Cu2+,Cr1+,Cr2+,Cr3+,Fe1+,Fe2+,Fe3+)(O2-,Va1-)) and the binaries Cu-O and Cr-O were re-evaluated . A simplified description of the delafossite solid solution by the Compound Energy Formalism model has been proposed according to (Cu1+,Cu2+)1 [Cr3+,Fe3+,Cu2+]1 O2 (Va0,O2-)1. Finally, the Cu-Fe-O and Cu-Cr-O ternary systems have been modeled by the Calphad method with good experimental agreement. A projection for the Cu-Cr-Fe-O quaternary system has even been proposed
Raichle, Markus. "Neutron scattering studies of doped cuprates: Na 8 Cu 5 O 10 and YBa 2 Cu 3 O 6+x". [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-35797.
Texto completo da fonteDelap, Martin Richard. "Thermal conductivity studies of YBa₂Cu₃O₇₋δ". Thesis, Durham University, 1990. http://etheses.dur.ac.uk/9301/.
Texto completo da fonteCaillard, Renaud. "Synthèse, propriétés supraconductrices et thermomécaniques de céramiques texturées des systèmes Y-Ba-Cu-O et Bi-Pb-Sr-Ca-Cu-O". Caen, 2002. http://www.theses.fr/2002CAEN2016.
Texto completo da fonteGauzzi, Andrea. "Disorder and fluctuations in superconducting YBa₂Cu₃O₆.₉ films /". Lausanne, 1993. http://library.epfl.ch/theses/?nr=1184.
Texto completo da fonteLi, Qiang. "Theoretical calculation of muon site in YBa₂Cu₃O". Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29415.
Texto completo da fonteScience, Faculty of
Physics and Astronomy, Department of
Graduate
Poisl, W. Howard. "Sintering kinetics of the superconducting YBa₂Cu₃O compound". Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29752.
Texto completo da fonteApplied Science, Faculty of
Materials Engineering, Department of
Graduate
Siah, Sin Cheng. "Defect Engineering in Cuprous Oxide (Cu₂O) Solar Cells". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100143.
Texto completo da fonteCataloged from PDF version of thesis.
Includes bibliographical references (pages 105-109).
This thesis is focused on the development of a cuprous oxide (Cu₂O) thin-film (TF) solar cell that is fabricated by manufacturing-friendly methods such as electro-deposition, sputtering and atomic layer deposition. Due to its bandgap of close to 2 eV, it has the potential of being applied as top cell in a tandem configuration. Firstly, I perform bottom-up cost and price analysis to investigate the economic feasibility of TF and c-Si based tandem photovoltaic modules. Next, I investigate the formation of good ohmic back contacts on Cu₂O absorber layer and demonstrate that low contact resistivity can be achieved with a variety of metals on heavily doped Cu₂O films by forming a tunnel junction. Then, I apply synchrotron-based X-ray absorption spectroscopy (XAS) to characterize two front contact buffer materials: amorphous Zn-Sn-O (a-ZTO) and Sndoped Ga₂O₃. I elucidate a fundamental loss mechanism in the amorphous Zn-Sn-O (a-ZTO) electron-blocking layer that has origin in local structural disorder and establish the structure-process- property relationship of a-ZTO so that the front buffer layer can be optimized for photovoltaics. Then, I investigate the doping mechanism of Sn dopant atoms in TFs and single crystalline Ga₂O₃:Sn by revealing the doping mechanism so that Ga₂O₃:Sn can be optimized for photovoltaics. Lastly. I apply bulk defect engineering to manipulate the intrinsic point defect structure of Cu₂O towards improved device performance. The key results will inform the processing conditions for improving mobility and minority carrier lifetime in Cu₂O. Keywords - Earth-abundant, thin-film solar cells, tandem, defect engineering, cost modeling, synchrotron.
by Sin Cheng Siah.
Ph. D.
Gershon, Talia. "Strategies for improving solution-processed ZnO/Cu₂O photovoltaics". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610663.
Texto completo da fonteFauth, François. "Etude par diffusion neutronique des composés orientés HoBa₂Cu₃Ox (x=7, 6.2), ErBa₂Cu₃O₇ et d'un cristal Nd₁₊xBa₂₋y₋zSrzCu₃O₆.₇ /". Zürich, 1996. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11583.
Texto completo da fonteLudwig, H. [Verfasser]. "Unaxiale Druckexperimente an YBa₂Cu₃O₆₊ₓ-Einkristallen / H. Ludwig". Karlsruhe : KIT-Bibliothek, 1998. http://d-nb.info/1198220201/34.
Texto completo da fonteMarin, Andrew. "Electrical characterization of atmospherically deposited ZnO/Cu₂O photovoltaic devices". Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608206.
Texto completo da fonteWithnell, Thomas David. "Flux trapping properties of bulk RE-Ba-Cu-O superconductors". Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612195.
Texto completo da fonteSouza, Junior Edvaldo Alves de. "Filmes Cu-V-O para aplicações em catodos de microbaterias". [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277289.
Texto completo da fonteTese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
Made available in DSpace on 2018-08-05T23:58:57Z (GMT). No. of bitstreams: 1 SouzaJunior_EdvaldoAlvesde_D.pdf: 2701192 bytes, checksum: 949e8dd1afc482f52e573f2b9fbca63a (MD5) Previous issue date: 2006
Resumo: O pentóxido de vanádio é um dos compostos de intercalação mais conhecidos na área de baterias de lítio. Dada sua estrutura lamelar, íons de lítio podem ser inseridos e extraídos de forma reversível, o que torna o pentóxido de vanádio promissor para uso como catodo. No entanto, o armadilhamento de parte dos íons de lítio a cada ciclo de carga e descarga provoca a perda gradativa da capacidade. A incorporação de íons metálicos na estrutura do V2 >O5 é uma das alternativas para melhorar seu desempenho nos ciclos de carga e descarga. Por outro lado, foi demonstrado que o óxido de cobre nanoparticulado é capaz de fornecer alta capacidade de carga em processos reversíveis de inserção e extração de íons lítio. Esta tese se propõe estudar a inserção/extração de íons de lítio em filmes finos de óxidos de cobre-vanádio objetivando sua aplicação em catodos de microbaterias. Um conjunto de amostras foi obtido iniciando-se com o pentóxido de vanádio, e através de acréscimos de cobre e decréscimos de vanádio, atingindo o óxido de cobre II. Óxidos bronzes, complexos, mistos e puros foram obtidos. As amostras foram depositadas através da técnica de sputtering. Na caracterização das amostras foram utilizadas técnicas de difração de raios-X, retroespalhamento Rutherford, emissão de fotoelétrons de raios-X, absorção de raios-X (XANES) e microscopia de força atômica. A inserção de íons de lítio foi realizada através da cronopotenciometria. Cada classe de óxidos apresentou características eletroquímicas próprias. Óxidos de cobre apresentaram uma capacidade de inserção de carga quatros vezes maior que a capacidade do pentóxido de vanádio (109 µAh/cm 2-µm). Bronzes de vanádio apresentaram maior estabilidade entre todos óxidos, e melhor capacidade, quando comparado com o V2 O5. A introdução de átomos de vanádio na matriz CuO permitiu a formação de óxidos mistos com maior estabilidade eletroquímica quando comparados à filmes CuO
Abstract: In the field of lithium batteries, vanadium pentoxide is one of the most studied intercalation compound. Due to its lamellar structure, lithium ions can be reversibly inserted and extracted, and the material is a promising candidate for use as a cathode. However, trapping of part of the lithium ions in each charge/discharge cycle causes a gradative loss of capacity. The incorporation of metallic ions in the V22O5host structure is one of the alternatives to improve its cycling behavior. On the other hand, it was recently demonstrated that nanosized copper oxide is capable of providing high charge capacity in reversible lithium insertion/extraction processes. The aim of the present work is to study the insertion/extraction of lithium ions in thin films of copper-vanadium oxides for application as cathode in microbatteries. A range of samples was produced, starting from pure vanadium pentoxide. By increasing the amounts of copper and decreasing the amount of vanadium in the film, the copper oxide II composition was attained. Different classes of oxides, such as bronzes, complex oxides, mixed oxides and the pure oxides were obtained. The samples were deposited by sputtering. The characterization was performed using X-Ray diffraction, Rutherford Backscattering spectrometry, X-Ray Photoemission Spectroscopy, X-Ray Absorption Spectroscopy (mainly XANES) and Atomic Force Microscopy. The electrochemical behavior was analyzed mainly by chronopotentiometry. Each class of oxides presented distinct electrochemical properties. Copper oxide films presented an insertion capacity four times greater than the capacity of the vanadium pentoxide films (109 µAh/cm 2-µm). Vanadium bronzes presented the best stability among all of the investigated materials, and a higher capacity in comparison to vanadium pentoxide. The insertion of vanadium atoms in the CuO structure allowed the obtention of mixed oxides films with higher electrochemical stability if compared to pure CuO films
Doutorado
Superfícies e Interfaces ; Peliculas e Filamentos
Doutor em Ciências
Touron, Rivadulla José Luis. "Equilibrio termodinámico y caminos de solidificación del sistema CU-O-H-Pb". Doctoral thesis, Universitat Autònoma de Barcelona, 2001. http://hdl.handle.net/10803/3334.
Texto completo da fontePAPILLON, STEPHANE. "Etude de la production du j/psi dans les reactions p-cu, p-u, o-cu, o-u et s-u a 200 gev par nucleon". Paris 7, 1991. http://www.theses.fr/1991PA077069.
Texto completo da fonteChoi, Siyoung. "Synthesis and Magnetic Properties of ZrO2 or MgO-containing Y-Ba- Cu-O and Bi-Sr-Ca-Cu-O Superconductors prepared by self-propagating chemical decomposition /". The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487859313343754.
Texto completo da fonteMorgan, Benjamin. "Microwave surface impedance of YBa₂Cu₃O₆.₉₅ in the mixed state". Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615118.
Texto completo da fonteDerro, David Joseph. "A scanning tunneling microscopy investigation of YBa₂Cu₃O₇-[subscript x] /". Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
Texto completo da fonteKearney, Jonathan. "Cu/CeₓZr(₁₋ₓ)O₂ catalysts for solid oxide fuel cell anodes". Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/1845.
Texto completo da fonteFrison, Jean-Claude. "Cristallogenèse et caractérisations d'oxydes supraconducteurs du système Tl-Ba-Ca-Cu-O". Phd thesis, Université Sciences et Technologies - Bordeaux I, 1990. http://tel.archives-ouvertes.fr/tel-00170306.
Texto completo da fonteBradley, Alistair David. "Fabrication and characterisation of joins in melt-textured YBa₂Cu₃O₇-δ". Thesis, University of Cambridge, 2000. https://www.repository.cam.ac.uk/handle/1810/251484.
Texto completo da fonteMingard, Kenneth Philip. "Stucture and properties of sputter deposited Y-Ba-Cu-O thin films". Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276884.
Texto completo da fonteRamsay, Jonathan M. "A theoretical study of helium diffraction from the O/Cu(100) surface". Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363604.
Texto completo da fonteHarrison, Neil. "The de Haas-van Alphen effect in Y-Ba-Cu-O superconductors". Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317152.
Texto completo da fonteDaniels, Michael W. (Michael William). "Radio-frequency properties of melt-recrystallized YBa₂Cu₃O₇â[delta] fibers". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/32616.
Texto completo da fonteOn t.p., "[delta]" appears as the lower case Greek letter, in subscript. Vita.
Includes bibliographical references (p. [67]-69).
by Michael W. Daniels.
M.S.
Moya, Bonhomme Alejandro. "YBa₂CU₃O₇₋δ d.c.SQUID magnetometers : from film deposition to field imaging". Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624375.
Texto completo da fontePathak, Sandeep Kumar. "Processing, flux pinning and recycling of Y-Ba-Cu-O bulk superconductors". Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609209.
Texto completo da fonteMaritz, E. J. (Erasmus Jacobus). "Flux creep in pulsed laser deposited superconducting YBa₂Cu₃O₇ thin films". Thesis, Stellenbosch : University of Stellenbosch, 2002. http://hdl.handle.net/10019.1/6394.
Texto completo da fonteIncludes bibliography.
ENGLISH ABSTRACT: High temperature superconductivity is an important topic in contemporary solid state physics, and an area of very active research. Due to it’s potential for application in low temperature electronic devices, the material has attracted the attention of researchers in the electronic engineering and material science fields alike. Moreover, from a fundamental point of view, several questions remain unanswered, related to the origin of superconductivity of this class of materials and the nature of quantised magnetic flux present in magnetised samples. In this work, flux creep phenomena in a thin superconducting YBa₂Cu₃O₇ film deposited by pulsed laser deposition, is investigated near the critical temperature 0 ≤ Tc – T ≤ 10 K. Creep activation energy U0 and critical current density jc were determined as a function of temperature close to Tc, providing important data to a problem of high-Tc superconductivity which is still a matter of debate. In particular it is still an open question whether restoring the temperature in a creep freezing experiment in fact restores the film to it's original state before the freezing. The most important novel results concern the regime of critical fluctuations in the vicinity Tc - T < 1 K. We studied the isothermal relaxation of trapped magnetic flux, and determined that the long time decay follows a power law, where the exponent is inversely proportional to the creep activation energy. The temperature dependence of the critical current density jc(T) of the YBa₂Cu₃O₇ film close to Tc was obtained during warming runs. It was determined that jc(T) follows a square root dependence on T to high accuracy in the range 0.2 ≤ Tc – T ≤ 1.5 K. During flux creep experiments an interesting phenomenon called creep freezing related to the strong temperature dependence of the relaxation rate was observed. A pronounced slowing of relaxation with only a small drop in temperature from a starting temperature close to Tc was detected. Experiments were conducted by initiating an isothermal flux decay run. At a certain point the temperature was slightly lowered, and the flux decay stopped within experimental accuracy. When the temperature was restored to the initial value, the flux decay resumed at the previous rate before cooling. An argument based on vortex drift velocity was employed to explain the phenomenon qualitatively. During the course of this investigation, a pulsed laser deposition (PLD) system was designed and built from scratch. PLD involves the interaction of a focussed laser pulse with a multielemental solid target material. Material ablated from the target forms a fast moving plume consisting of atomic and molecular particles, directed away from the target, and towards a usually heated substrate on which the particles condense layer by layer to form a thin film. The substrate temperature and background gas are carefully controlled to be conductive to the growth of a desired phase of the multi-elemental compound. The PLD system proved to be quite versatile in the range of materials that could be deposited. It was used to deposit thin films of different materials, most notable were good quality superconducting YBa₂Cu₃O₇, thermochromic VO2, and magnetoresistive LaxCa1-xMnO3. Metallic Au and Ag layers were also successfully deposited on YBa2Cu3O7 thin films, to serve as protective coatings. The critical temperatures of the best superconducting films were 90 K as determined by resistivity measurement. The optimal deposition conditions to deposit high quality superconducting YBa₂Cu₃O₇ thin films was found to be: deposition temperature 780°C, laser energy density 2-3 J/cm2, oxygen partial pressure 0.2 mbar, and target-substrate distance 35 mm. This yields film with Tc ~ 90 K. It was found that deposition temperature plays the predominant role in determining the quality of YBa₂Cu₃O₇ thin films deposited by PLD.
AFRIKAANSE OPSOMMING: Hoë temperatuur supergeleiding is tans ’n aktuele onderwerp van vastetoestandfisika en dit is ’n gebied van baie aktiewe navorsing. Weens die potensiaal vir toepassings van hoë temperatuur supergeleiers in elektronika, het dié klas materiale die aandag van fisici and elektronici getrek. Verskeie fundamentele vraagstukke bly steeds onbeantwoord, veral met betrekking tot die oorsprong van supergeleiding in hierdie materiale en die gedrag van gekwantiseerde magnetiese vloed (“vortekse”) in gemagnetiseerde monsters. In hierdie werk word diffusie van vortekse in dun supergeleidende YBa₂Cu₃O₇ films ondersoek naby die kritieke temperatuur (0 ≤ Tc - T ≤ 10 K). Die temperatuur afhanklikheid van die diffusie aktiveringsenergie U0 en die kritieke stroomdigtheid jc word bepaal naby Tc. Dit verskaf belangrike inligting tot probleme in hoë temperatuur supergeleiding wat tans nog onbeantwoord bly. In die besonder is dit steeds ’n ope vraag of die herstel van die aanvanklike temperatuur in ’n vloedstollings eksperiment waarlik die film tot die oorspronklike toestand herstel. Die belangrikste nuwe resultate hou verband met die gebied van kritieke fluktuasies van die orde parameter in die omgewing 0 < Tc - T < 1 K. Ons het die isotermiese ontspanning van vortekse verstrik in die kristalstruktuur bestudeer, en bepaal dat die lang tydsverval ’n magsverwantskap handhaaf, waar die eksponent omgekeerd eweredig is aan U0. Die temperatuur afhanklikheid van die kritieke stroomdigtheid jc(T) van die YBa₂Cu₃O₇ film naby Tc is bepaal tydens verhittingslopies. Daar is bevind dat naby Tc, jc ’n vierkantswortel verband met T volg, tot hoë noukeurigheid in die gebied 0.2 ≤ Tc – T ≤ 1.5 K. Gedurende vorteksdiffusie eksperimente is ’n interessante verskynsel naamlik vloedstolling (“flux freezing”) waargeneem. Dit hou verband met die sterk temperatuur afhanklikheid van die vervaltempo van die magnetiese moment van ’n gemagnetiseerde film. ’n Skerp daling van die vervaltempo, weens slegs ’n klein temperatuurdaling vanaf die begin temperatuur naby Tc, is waargeneem. Gedurende eksperimente is daar aanvanklik ’n isotermiese vloedontspanning teweeg gebring. Op ’n sekere tydstip is die temperatuur effens verlaag, waarby die vloedontspanning tot stilstand gekom het binne grense van waarneming. Wanneer die temperatuur weer herstel is na die oorspronklike, het die vloedontspanning voortgegaan teen die tempo voor die temperatuurverlaging. ’n Verklaring wat gebaseer is op vorteks dryfsnelheid was aan die hand gedoen om hierdie gedrag te verklaar. ’n Groot komponent van die projek was om die dun YBa₂Cu₃O₇ films self te vervaardig. Tydens hierdie ondersoek, is ’n gepulseerde laser deposisie (“PLD”) sisteem eiehandig ontwerp en gebou. PLD behels die interaksie van ’n gefokuseerde laser puls met ’n teiken bestaande uit ’n multi-element vastestofverbinding. Materiaal wat verdamp (“ablate”) word, vorm ’n snelbewegende pluim bestaande uit atomiese en molekulêre deeltjies. Dit beweeg vanaf die teiken na ’n verhitte substraat, waarop die deeltjies kondenseer om laag vir laag ’n dun film te vorm. Die substraat temperatuur en agtergrond gas word sorgvuldig beheer om die groei van die verlangde fase van die multi-element verbinding teweeg te bring. Die PLD sisteem is baie veeldoelig ten opsigte van die verskeidenheid materiale wat suksesvol neergeslaan kan word. Dit was aangewend om verskillende materiale neer te slaan, onder andere supergeleidende YBa₂Cu₃O₇, termochromiese VO2, en magnetoresistiewe LaxCa1-xMnO3. Geleidende Au en Ag lagies is ook suksesvol neergeslaan op YBa₂Cu₃O₇ dun films, om te dien as beskermingslagies. Die kritieke temperatuur van die beste supergeleidende films was 90 K soos bepaal deur weerstandsmetings. Die optimale neerslaan toestand vir hoë kwaliteit YBa₂Cu₃O₇ dun films was: substraat temperatuur 780°C, laser energiedigtheid 2 - 3 J/cm2, suurstofdruk 0.2 mbar, en teiken-substraat afstand 35 mm. Daar is bevind dat die substraat temperatuur die deurslaggewende rol speel tydens die neerslaan proses om die kwaliteit van die supergeleidende films te bepaal.
Cheng, Show-Jye. "Cu NQR and NMR study of metal-substituted YBa Cu O and YBa Cu O". Thesis, 1995. http://hdl.handle.net/1957/34494.
Texto completo da fonteTolstova, Yulia. "Cu₂O Heterojunction Photovoltaics". Thesis, 2016. https://thesis.library.caltech.edu/9820/7/tolstova_yulia_2016_thesis.pdf.
Texto completo da fonteDarvish, Davis Solomon. "Cu₂O Substrates and Epitaxial Cu₂O/ZnO Thin Film Heterostructures for Solar Energy Conversion". Thesis, 2013. https://thesis.library.caltech.edu/7834/7/main.pdf.
Texto completo da fonteDeBenedictis, Jennifer Jean. "Resistivity in Y Ba₂Cu₃O₆₃̣₃₃:". Thesis, 2005. http://hdl.handle.net/2429/16402.
Texto completo da fonteScience, Faculty of
Physics and Astronomy, Department of
Graduate
Yu, Chueh-Yuan, e 尤玨元. "Study on Microstructure and Nanoindentation of Sputtered Cu/Cu(O) Multilayered Films". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/75258899863193714048.
Texto completo da fonte海洋大學
材料工程研究所
96
Abstract In this study, the nano-scale multilayered films with two alternating individual layers, copper (Cu) and copper oxide (CuOx) were prepared by the radio frequency sputtering system deposited on Si and stainless steel substrates. The individual layer thicknesses were 38nm, 53nm, 73nm and 82 nm. The nanoindentation results indicate the hardness increases with decreasing individual layer thickness and the modulus decreases with increasing hardness. For multilayers manufactured by depositing Cu with interruption time about 10 minutes between each Cu layer, the individual layer thicknesses were 8 nm, 28 nm and 70nm. The enhancement in hardness is not apparent with increasing number of layers or decreasing individual layer thickness. The layer structure in Cu/Cu multilayer is not observed in SIMS results, but is clearly seen in AES results for Cu/Cu2O multilayer. In XRD results, the Cu(111) and Cu2O(220) are the major components in the multilayered and samples are consistent with TEM results. For the cold rolling study, the hardness and modulus increase with increasing reduction ratios. SEM and FIB results show the distribution and size of crack and the changes of layer structure in different reduction ratios in the cold rolled samples. The cold rolling is helpful in densing film structure such as eliminations of voids, layer and grain boundary. For the micropillars, the FIB images show the micropillar diameters were in a range of 611-686 nm and the height-to-diameter aspect ratios were from 1.94:1 to 4.09:1. The stress of micropillar is ~0.4-0.5 GPa and the FIB images obtain that the micropillars were fractured interface between film and substrate.
Guan-JieChen e 陳冠捷. "Thermal Chemistry of Thiazole on Cu(100) and O/Cu(100) Surfaces". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/x4239u.
Texto completo da fonte國立成功大學
化學系
107
Temperature-programmed reaction/desorption (TPR/D), X-ray photoelectron spectroscopy (XPS) and reflection-absorption infrared spectroscopy (RAIRS), with the aid of density-functional-theory calculations, to analyze the adsorption and thermal chemistry of thiazole on Cu(100) and oxygen-precovered Cu(100). At 120 K, thiazole is predominantly adsorbed on Cu(100), via N-Cu interaction and with the aromatic ring perpendicular to the surface. At 200 K, the ring begins to rupture, and forms a small amount of sulfur atoms (S(ad)) on the surface. As the temperature further increases, C2H2(~290 K), H2(~597, 737 K) and HCN(~525 K, ~610 K, ~737 K) evolve as the reaction products. -SCHNCHCH-, -SCHCHNCH- and/or -CHNCHCH- are proposed to be the surface intermediates formed in the thiazole reaction on Cu(100). The adsorption of thiazole on O/Cu(100) at 120 K is similar to case of Cu(100). In the presence of oxygen atoms on Cu(100), thiazole also reacts on the surface and eventually generates S(ad), but the product distribution is different from that of Cu(100) with evolution of H2(~388 K, ~604 K) H2O (~438 K), C2H2 (279 K), CO (~373 K, 604 K), CO2 (~373 K, ~604 K) and N2 (~834 K). In addition to the three reaction intermediates proposed in the case of Cu(100), 〉C=C=O, NCO and another surface intermediate with C-O group are possibly formed in the thiazole reaction on O/Cu(100).
LUO, RUI-CHENG, e 羅瑞成. "Growth of Y-Ba-Cu-O and Y-Ba-Sr-Cu-O high Tc superconductor single crystals". Thesis, 1990. http://ndltd.ncl.edu.tw/handle/03656249874208581441.
Texto completo da fonteJyun-Yi, Jhuang, e 莊君毅. "Thermal Chemistry of 1H-Pyrazole on Cu(100) and O/Cu(100) Surfaces". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/41280904998465135777.
Texto completo da fonteTai-YouChen e 陳泰佑. "Thermal Chemistry of 2-Chloropyrazine on Cu(100) and O/Cu(100) Surfaces". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/87sbme.
Texto completo da fonteSheng-HsunChan e 詹昇勳. "Thermal Chemistry of 2-Chloropyrimidine on Cu(100) and O/Cu(100) Surfaces". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/r9cfd7.
Texto completo da fonteLai, Xu-Feng, e 賴許鳳. "YBaCuO-x及PrBaCuO-x薄膜光學性質之研究". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/98551077620281858508.
Texto completo da fonteSzabová, Lucie. ""Ab initio" studium rozhraní Cu-Ce-O". Master's thesis, 2009. http://www.nusl.cz/ntk/nusl-278131.
Texto completo da fonte