36 resultados para pendants
Resumo:
Mononuclear copper(II) complexes of tri- and tetra-dentate tripodal ligands containing phenolic hydroxyl and benzimidazole or pyridine groups have been isolated. They are of the type (CuL(X)].nH2O, [CuL(H2O)]X.nH2O or [CuL].nH2O where X = Cl-, ClO4-, N3- or NCS- and n = 0-4. The electronic spectra of all the complexes exhibit a broad absorption band around 14000 cm-1 and the polycrystalline as well as the frozen-solution EPR spectra are axial, indicating square-based geometries. The crystal structure of [CuL(Cl)] [HL = (2-hydroxy-5-nitrobenzyl)bis(2-pyridyl-methyl)amine] revealed a square-pyramidal geometry around Cu(II). The mononuclear complex crystallises in the triclinic space group P1BAR with a = 6.938(1), b = 11.782(6), c = 12.678(3) angstrom and alpha = 114.56(3), beta = 92.70(2), gamma = 95.36(2)-degrees. The co-ordination plane is comprised of one tertiary amine and two pyridine nitrogens and a chloride ion. The phenolate ion unusually occupies the axial site, possibly due to the electron-withdrawing p-nitro group. The enhanced pi delocalisation involving the p-nitrophenolate donor elevates the E1/2 values. The spectral and electrochemical results suggest the order of donor strength as nitrophenolate < pyridine < benzimidazole in the tridentate and nitrophenolate < benzimidazole < pyridine in the tetradentate ligand complexes.
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Four novel thermally stable poly(aryl ether)s, e.g., P3F, P5F, P2A3F, and P2A5K containing ter- or pentafluorene units in the side chains for efficient blue light emission have been designed and synthesized. All the polymers show the optical properties identical to the corresponding monomers and are amorphous with higher glass transition temperature (T-g) than their monomeric Counterparts. The polymer light-emitting diodes (PLEDs) were fabricated with the device structure of ITO/(PEDOT:PSS)/polymer/Ca/Al. The incorporation of diphenylamine group to oligofluorene terminals significantly reduces the hole-injection energy barrier in PLEDs. The devices based on P2A3F and P2A5F show the luminous efficiencies of 1.2 and 2.0 cd/A at a brightness of 300 cd/m(2) with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.15, 0.13) and (0.19, 0.20), respectively. All these indicate that the high-performance light-emitting polymers can be synthesized with the traditional condensation polymerization through careful design of polymer structures.
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A PPV derivative containing bulky tetraphenylmethane side chains was synthesised. Its optical properties were examined. Compared to its parent PPV polymer, its UV-Vis absorption and PL showed less red-shift from solution to film, its PL showed much less concentration quenching effect and higher efficiency, its EL device showed 9-fold enhanced efficiency. These improvements were attributed to weakened inter-chain interaction caused by the tetraphenylmethane group.
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"Status": p. [221]-229.
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The thesis addresses the problem of Finnish Iron Age bells, pellet bells and bell pendants, previously unexplored musical artefacts from 400–1300 AD. The study, which contributes to the field of music archaeology, aims to provide a gateway to ancient soundworlds and ideas of music making. The research questions include: Where did these metal artefacts come from? How did they sound? How were they used? What did their sound mean to the people of the Iron Age? The data collected at the National Museum of Finland and at several provincial museums covers a total of 486 bells, pellet bells and bell pendants. By means of a cluster analysis, each category was divided into several subgroups. The subgroups, which all seem to have a different dating and geographical distribution, represent a spread of both local and international manufacturing traditions. According to an elemental analysis, the material varies from iron to copper-tin, copper-lead and copper-tin-lead alloys. Clappers, pellets and pebbles prove that the bells and pellet bells were indisputably instruments intended for sound production. Clusters of small bell pendants, however, probably produced sound by jingling against each other. Spectrogram plots reveal that the partials of the still audible sounds range from 1 000 to 19 850 Hz. On the basis of 129 inhumation graves, hoards, barrows and stray finds, it seems evident that the bells, pellet bells and bell pendants were fastened to dresses and horse harnesses or carried in pouches and boxes. The resulting acoustic spaces could have been employed in constructing social hierarchies, since the instruments usually appear in richly furnished graves. Furthermore, the instruments repeatedly occur with crosses, edge tools and zoomorphic pendants that in the later Finnish-Karelian culture were regarded as prophylactic amulets. In the Iron Age as well as in later folk culture, the bell sounds seem to have expressed territorial, social and cosmological boundaries.
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A tripod ligand possessing two pyridine moieties and a phenolato group as pendants forms a mononuclear complex with an axial copper(II)–phenolate co-ordination in a square-pyramidal environment.
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abstract {Proton induced X-ray emission (PIXE) technique is an effective method for the chemical composition analysis of ancient glass samples without destruction. Chemical composition of the ancient glass samples dated from the Warring States Period (770-476 B.C.) to the Six Dynasties Period (220-589 A.D.), which were unearthed in Sichuan area, was quantitatively determined by the PIXE technique. The results show that the glass Bi (disc) and the glass eye beads of the Warring States Period all belong to the PbO-BaO-SiO2 system. According to the composition and shape, we infer that these glass Bi and eye beads were made in China. Whereas, the chemical compositions of the glass ear pendants and beads of the Six Dynasties Period are varied, including K2O-CaO-SiO2, K2O-SiO2 and other glass systems. Based on the obtained results and those from literatures, some questions related to the technical propagation of the ancient Chinese glass are discussed.}
Resumo:
[ES] La reciente excavación de la cueva de Praile Aitz I (Deba) ha identificado sucesivas breves ocupaciones del Tardiglaciar. Se estudian los materiales arqueológicos más significativos del Magdaleniense Inferior recuperados sobre un suelo preparado con cantitos de caliza. En él se localizaron, además de restos industriales líticos y faunísticos que no trataremos en esta ocasión, las siguientes evidencias: una azagaya, restos de ocre y un interesante lote de colgantes (cuatro cantos rodados perforados y tres incisivos de cabra con doble perforación).
Resumo:
[ES] Durante la excavación de la cueva de Praile Aitz I (Deba, Gipuzkoa) se ha hallado una azagaya de base hendida sobre un suelo de cantos de caliza en el que se definió un contexto de habitación constituido por un hogar, escasos restos de industria y fauna, y varios colgantes. Estos materiales se atribuyen al Magdaleniense Inferior Cantábrico con fechas que se sitúan entre el 15.190 y 15.810 BP. Aprovechando este descubrimiento se realiza una revisión de ejemplares de similares características hallados en otros yacimientos cantábricos (Balmori, El Castillo) y se plantea la posible cronología magdaleniense del ejemplar de Santimamiñe.
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Homenaje a Ignacio Barandiarán Maestu / coord. por Javier Fernández Eraso, Juan Santos Yanguas
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Este trabajo ha sido realizado en el marco del Grupo de Investigación Consolidado GIC 07/21-IT.288.07.
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[ES] En algunos de los niveles del Paleolítico superior inicial de la cueva de Gatzarria (Zuberoa, País Vasco) existen documentados una buena serie de colgantes y otras manifestaciones artísticas, tanto en hueso o asta como en piedra. Por relación al registro estratigráfico, hay constancia de ellos en el Protoauriñaciense de Cjn 1, en el Auriñaciense antiguo de Cbci-Cbf y en el Auriñaciense evolucionado de Cb. La muestra más importante, tanto desde el punto de vista de la cantidad de efectivos como de la variabilidad de temas, es la correspondiente al Auriñaciense antiguo; temas que, por otra parte, han sido puestos de manifiesto en un número considerable de estaciones prehistóricas, más o menos circundantes a la cueva de Gatzarria.