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61.
P.S. Haddad G.E.S. Brito M.C.A. Fantini 《Journal of Sol-Gel Science and Technology》2004,30(3):173-177
The present work reports on the preparation of nickel oxi/hydroxide and gold composite nanoparticulate sols. The precursor was prepared as an alcoholic suspension of nickel oxi/hydroxide. Controlled amounts of 2,4-pentanedione (AcAc) were added to the nickel salt suspension and lead to the formation of a nickel complex. The dependence of the particle size with AcAc titration was followed by Small Angle X-Ray Scattering (SAXS). The results showed that the particle size distribution shifts towards low values with the increase in the AcAc concentration. The complex, obtained by adding an excess of the AcAc ligand, [Ni(AcAc)2]·2H2O, was identified by FTIR spectroscopy and X-ray diffraction. An AcAc specific volume was chosen in order to obtain a homogeneous sol of nickel oxi/hydroxide to which gold was added. The size distribution of the Au particles in this sol was followed by SAXS. 相似文献
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Ercules E.S. Teotonio Hermi F. Brito Hans Viertler Wagner M. Faustino Oscar L. Malta Gilberto F. de S Maria Cludia F.C. Felinto Regina H.A. Santos Marco Cremona 《Polyhedron》2006,25(18):3488-3494
Europium complexes presenting general formulas [Eu(ACIND)3(H2O)2] and [Eu(ACIND)3(TPPO)2] have been synthesized and characterized. In these formulas ACIND is stands for the ligands 2-acetyl-1,3-indandionate (AIND), 2-isovaleryl-1,3-indandionate (ISOVIND) or 2-benzyl-1,3-indandionate (BIND). The [Eu(ISOVIND)3(H2O)(EtOH)] complex was also prepared and its structure determined by single crystal X-ray analysis, showing that this complex crystallize in a monoclinic space group P21/n with the water molecules bridging through the hydrogen bond. The Eu(III) ion is eight-coordinate in a bicapped trigonal prismatic geometry defined by the oxygen donor atoms with a site of symmetry close to C2ν. Isovaleryl groups in the ISOVIND molecules in the structure are disordered over two positions of the europium complex. Carbon atoms in ethanol molecule are disordered by the thermal vibration. Photoluminescence properties of these complexes in solid state were investigated both experimentally and theoretically, suggesting an efficient ligand-to-metal intramolecular energy transfer process. 相似文献
66.
Ivn Brito Aldo Mundaca Alejandro Crdenas Matías Lpez‐Rodríguez 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(10):o606-o608
In the title disulfide, C12H8N6O2S2, all bond lengths and angles are within normal ranges, and the molecules are linked into centrosymmetric R22(20) dimers by simple C—H...N interactions. Weak intermolecular C—H...π(arene) and π–π interactions, involving the benzene CH groups and the benzene rings, and the pyridine rings, respectively, further stabilize and reinforce the crystal structure. 相似文献
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J. -C. Diels J. J. Fontaine J. C. McMichael C. Y. Wang A. Andreoni R. Cubeddu S. Cova A. Longoni W. Knox G. Mourou T. M. Nordlund C. H. Brito Cruz F. De Martini P. Mataloni E. Palange J. M. Catherall P. M. Radmore G. H. C. New A. Müller F. P. Schäler Zs. Bor B. Rácz D. Relser A. Laubereau B. Pouligny J. R. Lalanne B. Couilaud A. Ducasse C. Vaucamps D. Schubert J. Schwarz H. Wabnitz B. Wilhelmi 《Applied physics. B, Lasers and optics》1982,28(2-3):172-179
70.
The relativistic theory of elasticity is reviewed within the spherically symmetric context with a view towards the modeling
of star interiors possessing elastic properties such as the ones expected in neutron stars. Emphasis is placed on generality
in the main sections of the paper, and the results are then applied to specific examples. Along the way, a few general results
for spacetimes admitting isometries are reviewed, and their consequences are fully exploited in the case of spherical symmetry
relating them next to the the case in which the material content of the spacetime is some elastic material. Specific examples
are provided satisfying the dominant energy condition and admitting a constitutive equation, including a static two-layer
star ‘toy model’ consisting of an elastic core surrounded by a perfect fluid corresponding to the interior Schwarzschild solution
matched to the vacuum Schwarzschild solution. This paper extends and generalizes the pioneering work by Magli and Kijowski
(Gen Relat Gravit 24:139, 1992), Magli (Gen Relat Gravit 25:1277, 1993; 25:441, 1993), and complements, in a sense, that by
Karlovini and Samuelsson in their interesting series of papers (Karlovini and Samuelsson in Class Quantum Grav 20:363, 2003;
21:1559, 21:4531, 2004). 相似文献