1000 resultados para P-31 RMN


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A benzil-based semi-rigid dinuclear organometallic acceptor 4,4'-bistrans-Pt(PEt3)(2)(NO3)(ethynyl)]benzil (bisPt-NO3) containing a Pt-ethynyl functionality was synthesized in good yield and characterized by multinuclear NMR (H-1, P-31, and C-13), electrospray ionization mass spectrometry (ESI-MS), and single-crystal X-ray diffraction analysis of the iodide analogue bisPt-I. The stoichiometric (1:1) combination of the acceptor bisPt-NO3 separately with four different ditopic donors (L-1-L-4; L-1 = 9-ethyl-3,6-di(1H-imidazol-1-yl)-9H-carbazole, L-2 = 1,4-bis((1H-imidazol-1-yl)methyl)benzene, L-3 = 1,3-bis((1H-imidazol-1-yl)methyl)benzene and L-4 = 9,10-bis((1H-imidazol-1-yl) methyl)anthracene) yielded four 2 + 2] self-assembled metallacycles M-1-M-4 in quantitative yields, respectively. All these newly synthesized assemblies were characterized by various spectroscopic techniques (NMR, IR, ESI-MS) and their sizes/shapes were predicted through geometry optimization employing the PM6 semi-empirical method. The benzil moiety was introduced in the backbone of the acceptor bisPt-NO3 due to the interesting structural feature of long carbonyl C-C bond (similar to 1.54 angstrom), which enabled us to probe the role of conformational flexibility on size and shapes of the resulting coordination ensembles.

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This study reports a multinuclei in situ (real-time) NMR spectroscopic characterization of the electrochemical reactions of a negative Cu3P electrode toward lithium. Taking advantage of the different nuclear spin characteristics, we have obtained real-time P-31 and Li-7 NMR data for a comprehensive understanding of the electrochemical mechanism during the discharge and charge processes of a lithium battery. The large NMR chemical shift span of P-31 facilitates the observation of the chemical evolutions of different lithiated and delithiated LixCu3-xP phases, whereas the quadrupolar line features in Li-7 enable identification of asymmetric Li sites. These combined NMR data offer an unambiguous identification of four distinct LixCu3-xP phases, Cu3P, Li0.2Cu2.8P, Li2CuP, and. Li3P, and the characterization of their involvement in the electrochemical reactions. The NMR data led us to propose a delithiation process involving the intercalation of metallic Cu-0 atomic aggregates into the Li2CuP structure to form a Cu-0-Li2-xCu1-xP phase. This process might be responsible for the poor capacity retention in Cu3P lithium batteries when cycled to a low voltage.

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Resumen: El artículo examina el concepto de persona, en sus fuentes aporéticas y en el pensamiento de Santo Tomás de Aquino para, finalmente, analizar algunas de sus propiedades en orden a fundamentar una teoría de la imputación. La primera parte comienza con la consideración de los orígenes semánticos, históricos y teológicos de los términos persona e hypóstasis. Trata luego el problema teórico que este concepto implica para el pensamiento moderno, teniendo en cuenta el empobrecimiento de su Metafísica, como consecuencia del nominalismo, el principio de inmanencia y una deficiente concepción de la experiencia. Por último, se toman en consideración algunas consecuencias que dicho empobrecimiento tienen en el pensamiento contemporáneo. La segunda parte está dedicada a exponer la doctrina tomista que de un modo teóricamente definitivo dio solución, con elementos ontológicos aristotélicos, a los problemas planteados en la época Patrística. Se analiza el concepto de sustancia individual (o suppositum), que en la definición de persona opera analógicamente como género próximo, y el de naturaleza espiritual individuada, que opera como diferencia específica. Finalmente, se aportan textos del Aquinate acerca de la definición y de las diferencias conceptuales y ontológicas entre naturaleza y persona. En la tercera parte se exponen algunas propiedades, dividiéndolas en cuatro grupos de tesis: 1°) la persona como sujeto de atribución y dueña de sus proyectos vitales; 2°) como sujeto ontológicamente abierto al mundo, a los semejantes y a Dios; 3°) como sujeto consciente, libre y autónomo; 4°) el carácter ético de la persona, como sujeto de imputación y responsabilidad.

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En torno al sexenio comprendido entre las dos fechas distintivas del Bicentenario argentino, 1810 y 1816, el autor se propone una lectura histórica sobre los hombres y las ideas que rodearon a la Primera Junta de gobierno, la función propagandista del clero, el cuestionamiento por parte de dos obispos de la legitimidad de la revolución y el apoyo de un obispo patriota, el período de “interregno episcopal” y la continuidad religiosa, la obra cultural de la Junta y la celebración del Congreso de la Independencia en Tucumán. Se afirma, a partir de las fuentes, el lugar de aceptación que tuvo la IglesiaCatólica en esta época.

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Resgata pequena parte da história do anarquismo, que praticamente desapareceu do cenário político brasileiro. Utilizando o método de análise historiográfica, e compulsando os registros de sessões ocorridas, analisa a participação da Câmara dos Deputados nas políticas relacionadas à repressão dos anarquistas nas greves ocorridas em 1917. Ao final da pesquisa, chega-se à conclusão da existência de razoáveis indícios de participação da Câmara dos Deputados nas ações de repressão ao movimento anarquista.

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Discurso proferido durante a 1ª Sessão da Câmara dos Deputados na nova capital, Brasília. Considerações em torno do deslocamento do centro político brasileiro para Brasília. Apartes: Fernando Santana, Osvaldo Lima Filho, Miguel Bahury, Tristão da Cunha e Pedro Vidigal.

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International symposium on North Pacific transitional areas [pp. 1-4] [pdf, 0.8 Mb] PICES Volunteer Observing Ship (VOS) Workshop [pp. 5-7] [pdf, 0.3 Mb] Joint meeting on Causes of marine mortality of salmon [pp. 8-9] [pdf, 0.3 Mb] The state of the western North Pacific in the second half of 2001 [pp. 10-11] [pdf, 0.5 Mb] State of the eastern North Pacific in spring 2002 [pp. 12-13] [pdf. 0.4 Mb] The status of the Bering Sea in the second half of 2001 [pp. 14-15] [pdf. 0.3 Mb] PICES Workshop on “Perturbation analysis” on subarctic Pacific gyre ecosystem models [pp. 16-17] [pdf. 0.4 Mb] Status and future plans for SOLAS-Japan [pp. 18-20] [pdf. 0.5 Mb] China-Korea Joint Ocean Research Center: A bridge across the Yellow Sea to connect Chinese and Korean oceanographic institutes and scientists [pp. 21-22] [pdf. 0.3 Mb] Persistent changes in the California Current ecosystem [pp. 23-24] [pdf. 0.2 Mb] The Hokusei Maru: 53 years of research in the Pacific [pp. 25-28] [pdf. 0.5 Mb] First meeting of the CLIVAR Pacific Panel [pp. 29-30] [pdf. 0.3 Mb] Call for contributions to the North Pacific Ecosystem Status Report [p. 31] [pdf. 0.2 Mb] PICES announcements [p. 32] [pdf. 0.2 Mb]

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Cover [pdf, 0.2 Mb] The state of PICES Science - 2001 [pp. 1-2] [pdf, 0.2 Mb] Reception remarks at PICES X [pp. 3-4] [pdf, 0.3 Mb] The state of the western North Pacific in the first half of 2001 [pp. 5-7] [pdf, 0.8 Mb] The status of the Bering Sea: January - August 2001 [pp. 8-9] [pdf, 0.4 Mb] The state of the eastern Norht Pacific since spring 2001[pp. 10-11] [pdf, 0.3 Mb] 2001 SEEDS experiment in the western Norht Pacific [pp. 12-13] [pdf, 0.5 Mb] Plans for the Canadian SOLAS Iron Enrichment Experiment [pp. 14-15] [pdf,. 0.4 Mb] Photo highlights of the PICES Tenth Annual Meeting [pp. 16-17] [pdf,. 0.3 Mb] NEAR-GOOS 2001 Ocean Environment Forecasting Workshop [pp. 18-19] [pdf, 0.6 Mb] IRI/IPRC Pacific Climate-Fisheries Workshop [pp. 20-21] [pdf, 0.2 Mb] PICES North Pacific Ecosystem Status Report [p. 21] [pdf,. 0.2 Mb] U.S. GLOBEC Northeast Pacific Ocean Program [pp. 22-26] [pdf, 0.5 Mb] New PICES Committee and Program Chairmen biographies [pp. 27-29] [pdf,. 0.4 Mb] Upcoming PICES publications and meetings [p. 30] [pdf,. 0.2 Mb] North Pacific Transitional Areas Symposium [p. 31] [pdf, 0.5 Mb] Gijon Symposium and other PICES announcements [p. 32] [pdf, 0.4 Mb]

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Cover [pdf, 0.2 Mb] Climate, biodiversity and ecosystems of the North Pacific [pp. 1-2] [pdf, 0.2 Mb] The state of the western North Pacific in the second half of 2000 [pp. 3-5] [pdf, 0.8 Mb] The status of the Bering Sea: June – December 2000 [pp. 6-7] [pdf, 1.5 Mb] The state of the eastern North Pacific since autumn 2000 [p. 8] [pdf, 0.3 Mb] Korean Yellow Sea Large Marine Ecosystem Program [pp. 9-12] [pdf, 0.5 Mb] Past and ongoing Mexican ecosystem research in the northeast Pacific Ocean [pp. 13-15] [pdf, 0.3 Mb] Vera Alexander [pp. 16-19] [pdf, 1.0 Mb] North Pacific CO2 data for the new millennium [pp. 20-21] [pdf, 0.3 Mb] PICES Higher Trophic Level Modelling Workshop [pp. 22-23] [pdf, 0.4 Mb] Argo Science Team 3rd Meeting (AST-3) [pp. 24-25] [pdf, 0.3 Mb] 2001 coast ocean / salmon ecosystem event [p. 26-27] [pdf, 0.3 Mb] Shifts in zooplankton abundance and species composition off central Oregon and southwestern British Columbia [pp. 28-29] [pdf, 0.3 Mb] The CLIVAR - Pacific Workshop [p. 30] [pdf, 0.2 Mb] PICES dialogue with Mexican scientists [p. 31] [pdf, 0.2 Mb] Announcements [p. 32] [pdf, 0.2 Mb]

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Galeria dos brasileiros illustres traz retratos copiados do natural e litografados das principais figuras brasileiras da política, ciências e letras, com biografias redigidas por diversos escritos da época, por alguns dos próprios biografados ou por membros de suas famílias. Considerada a mais importante de Sisson, esta obra teve tiragem reduzida e muitos exemplares foram desmanchados por antiquários que emolduravam os retratos, vendendo-os por alto preço. Segundo Borba de Moraes, "é muito difícil encontrar-se hoje em dia um exemplar perfeito e em boas condições" e que "só muito raramente aparece um exemplar à venda."

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The local structure of Na-Al-P-O-F glasses, prepared by a novel sol-gel route, was extensively investigated by advanced solid-state NMR techniques. Al-21{F-19} rotational echo double resonance (REDOR) results indicate that the F incorporated into aluminophosphate glass is preferentially bonded to octahedral Al units and results in a significant increase in the concentration of six-coordinated aluminum. The extent of Al-F and Al-O-P connectivities are quantified consistently by analyzing Al-27{P-31} and Al-21{F-19} REDOR NMR data. Two distinct types of fluorine species were identified and characterized by various F-19{Al-27}, F-19{Na-23}, and F-19{P-31} double resonance experiments, which were able to support peak assignments to bridging (Al-F-Al, -140 ppm) and terminal (Al-F, -170 ppm) units. On the basis of the detailed quantitative dipole-dipole coupling information obtained, a comprehensive structural model for these glasses is presented, detailing the structural speciation as a function of composition.

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FSodium phosphate tellurite glasses in the system (NaPO3)(x)(TeO2)(1-x) were prepared and structurally characterized by thermal analysis, vibrational spectroscopy, X-ray photoelectron spectroscopy (XPS) and a variety of complementary solid-state nuclear magnetic resonance (NMR) techniques. Unlike the situation in other mixed-network-former glasses, the interaction between the two network formers tellurium oxide and phosphorus oxide produces no new structural units, and no sharing of the network modifier Na2O takes place. The glass structure can be regarded as a network of interlinked metaphosphate-type P(2) tetrahedral and TeO4/2 antiprismotic units. The combined interpretation of the O 1s XPS data and the P-31 solid-state NMR spectra presents clear quantitative evidence for a nonstatistical connectivity distribution. Rather the formation of homootomic P-O-P and Te-O-Te linkages is favored over mixed P-O-Te connectivities. As a consequence of this chemical segregation effect, the spatial sodium distribution is not random, as also indicated by a detailed analysis of P-31/No-23 rotational echo double-resonance (REDOR) experiments. ACHTUNGTRENUNG(TeO2)1 x were prepared and structurally characterized by thermal analysis,vibrat ional spectroscopy,X-ray photoelectron spectroscopy (XPS) and a variety of complementary solid-state nuclear magnetic resonance (NMR) techniques. Unlike the situation in other mixed-network-former glasses,the interaction between the two network formers tellurium oxide and phosphorus oxide produces no new structural units,and no sharing of the network modifier Na2O takes place. The glass structure can be regarded as a network of interlinked metaphosphate-type P(2) tetrahedral and TeO4/2 antiprismatic units. The combined interpretation of the O 1s XPS data and the 31P solid-state NMR spectra presents clear quantitative evidence for a nonstatistical connectivity distribution. Rather,the formation of homoatomic P O P and Te O Te linkages is favored over mixed P O Te connectivities. As a consequence of this chemical segregation effect,the spatial sodium distribution is not random,as also indicated by a detailed analysis of 31P/23Na rotational echo double-resonance (REDOR) experiments.