Rare Earth Complex
Mostrando 13-24 de 25 artigos, teses e dissertações.
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13. Materiais hÃbridos formados por nanofilmes moleculares depositados sobre nanofilmes metÃlicos produzidos por processo bottom-up em substratos vÃtreos para uso como parte ativa de nanodispositivos
In the present work we are investigating a hybrid systems formed by a thermally evaporated molecular nanofilm of rare earth complex over a metallic thin film obtained by a bottom-up process. To produce the new hybrid, we have deposited the photonic Eu(btfa)3bipy complex on a glassy substrate containing a silver nanostructured film formed by thermal reduction
Publicado em: 2008
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14. Petrogenese do granodiorito Fazenda Gavião : registro de uma colisão arco-continente no greenstone belt do Rio Itapicuru, Craton do São Francisco, Bahia / Petrogenesis of the Fazenda Gavião granodiorite : a record of an arc-continent collision in the Rio Itapicuru greenstone belt, São Francisco Craton, Bahia
The Rio Itapicuru greenstone belt is a gold-bearing Palaeoproterozoic volcanic-sedimentary sequence intruded by several granitic plutons in the time interval 2160-2070 Ma. The Fazenda Gavião granodiorite (FGG) is one of a set of plutons emplaced along the western boundary of the greenstone belt with the Archaean basement complex. The FGG is largely composed
Publicado em: 2008
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15. Geologia, geometalurgia, controles e gênese dos depósitos de fósforo, terras raras e titânio do complexo carbonatítico Catalão i , GO
This work describes the geological and geometallurgical characteristics of the phosphate, titanium, niobium and rare-earth elements deposits in the northeast part of the Catalão I carbonatite complex, Central Brazil. The mineralization controls were determined for magmatic, metasomatic and weathering processes. The ore types were defined on the basis of geo
Publicado em: 2008
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16. Photoluminescent Behaviour of tetrakis(b-diketonates) Complex Anions with Rare Earth Ions - Eu3+, Gd3+, Tb3+ e Tm3+ / Comportamento fotoluminescente dos ânions complexos tetrakis(-dicetonatos) de Íons terras raras - Eu3+ , Gd3+ , Tb3+ e Tm3+
Neste trabalho, os complexos tetrakis(ß-dicetonato) de terras-raras, (Q)[TR(β-dicetonato)4 ] {(Q = Li+ , Na+ , K+ , (Et3 NH)+ , (Morf)+ , (TMPip)+ e (Diciclo)+ ); (TR3+ = Eu3+ , Gd3+ , Tb+ e Tm3+ ) e (β-dicetonato = acac, dbm e tta), foram sintetizados, caracterizados e suas propriedades ópticas investigadas por meio de espectroscopia luminescent
Publicado em: 2007
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17. DEVELOPMENT OF A METHODOLOGY FOR THE SEPARATION OF EUROPIUM AND SAMARIUM FROM A MIXTURE OF RARE EARTH OXIDES BY ELECTROREDUCTION/PRECIPITATION / "Desenvolvimento de uma metodologia para a separação de Samário e Európio a partir de mistura de óxidos de Terras Raras por redução eletroquímica/ precipitação"
The rare earths (RE) were first used in 1903, when Welsbach developed a lighter that is still used today. Nowadays, the RE are employed in many different fields, as in the production of super-alloys , as catalysts for petroleum industry, in the manufacture of non-ferrous alloys, color television tubes, x-ray screens, special glasses, ceramics, computer indus
Publicado em: 2006
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18. Estudos de propriedades opticas e magneticas de manganitas
In this thesis, Raman-scattering and dc-magnetization studies on ceramic samples of RxMxMn3+s (R = rare earth; M = Ca, Sr) with Perovskite crystal structure, and X2Mn2O7(X = Tl, In, e Y) with Pyrochlore structure, are described. Some samples belonging to thefirst category present complex magnetic phenomena, among them a coexistence of distinct magnetic phase
Publicado em: 2000
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19. Litogeoquimica e controles geocronologicos da suite metamorfica algodões-choro
This thesis proposes an interpretation of the tectonic evolution of the Algodoes-Choro Metamorphic Suite (ACMS) - a paragneiss-amphibolite association intruded by granite-tonalite orthogneisses that crops out in the central region of the Ceara State, NE Brazil. The geological data support the division of this suite in the following units: 1) Algodões amphib
Publicado em: 2000
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20. O complexo mafico-ultramafico de Tijucas do Sul, correlação com o complexo de Pien, PR e considerações metalogeneticas
The study aimed primarily to assess the auriferous deposits potential of gneissic terrains of medium to high metamorphic grade, with lenticular mafic-ultramafic bodies, which outline the suture zone between the Ribeira Belt and the Luís Alves Craton, at the southern border between paraná and Santa catarina. Geological mapping at 1:25.000 scale has been car
Publicado em: 1993
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21. An introduction to the methodology of structure determination by single crystal x-ray diffraction: applications to some complexes of lanthanides and transition metals with organic ligands / Introdução aos métodos de determinação de estruturas por difração de raios-X em monocristais: aplicação a alguns complexos de lantanídeos e metais de transição com ligantes orgânicos
The crystal structure of the complexes Ln(ClO4)3.6[PONH2(C6H5)2] where Ln=Eu, La, Cu[NH2(CH3)2CCO2]2, NiBr2.4[AsO(C6H5)3].8H2O (green), NiBr2.4[AsO(C6H5)3.1,5(CH3C6H5).H2O (orange) and of the ligand PONH2(C6H5)2 have been determined by X-ray diffraction. The complexes involving lanthanide ions refined to final R factors of R(Eu)=0.125 and R(La)=0.133 and the
Publicado em: 1983
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22. A complex microbiota from snowball Earth times: Microfossils from the Neoproterozoic Kingston Peak Formation, Death Valley, USA
A thin carbonate unit associated with a Sturtian-age (≈750–700 million years ago) glaciogenic diamictite of the Neoproterozoic Kingston Peak Formation, eastern California, contains microfossil evidence of a once-thriving prokaryotic and eukaryotic microbial community (preserved in chert and carbonate). Stratiform stromatolites, oncoids, and rare columnar
The National Academy of Sciences.
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23. Terbium luminescence-lifetime heterogeneity and protein equilibrium conformational dynamics.
The fluorescence decay of the rare earth terbium when bound to the protein calmodulin changes from a simple exponential decay to a complex nonexponential decay as the temperature is lowered below 200 K. We have fit the observed decay curves by assuming that the terbium emission is a forced electric dipole transition and proteins have a distribution of contin
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24. A self-assembled, redox-responsive receptor for the selective extraction of LiCl from water
There is considerable interest in synthetic ionophores with high affinity and selectivity for Li+. But so far, compounds that selectively bind Li+ in the presence of other alkali and alkaline earth metal ions are rare and current approaches toward this goal are often accompanied with substantial synthetic efforts. Here we describe a trinuclear ruthenium meta
National Academy of Sciences.