Integrability vs supersymmetry: Poisson structures of the pohlmeyer reduction

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comments on energy confinement in non-periodic structures

In this study, we investigate the possibility of mode localization occurrence in a non-periodic Pfluger's column model of a rocket with an intermediate concentrated mass at its middle point. We discuss the effects of varying the intermediate mass magnitude and its position and the resulting energy confinement for two cases. Free vibration analysis and the severity of mode localization are appraised, without decoupling the system, by considering as a solution basis the fundamental free response or dynamical solution. This allows for the reduction of the dimension of the algebraic modal equation that arises from satisfying the boundary and continuity conditions. By using the same methodology, we also consider the case of a cantilevered Pluger's column with rotational stiffness at the middle support instead of an intermediate concentrated mass. (c) 2008 Elsevier Ltd. All rights reserved.

Robust tori-like Lagrangian coherent structures

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Dynamical scaling in fractal structures in the aggregation of tetraethoxysilane-derived sonogels

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Crystal Structures of Xanthomonas Small Heat Shock Protein Provide a Structural Basis for an Active Molecular Chaperone Oligomer

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Molecular structures and vibrational frequencies for [PdX2(tdmPz)] (X = Cl-, SCN-): A DFT study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

When decisions on homologous structures cause ambiguous taxa relationships: the Neomorphinae (Aves, Cuculidae) example

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Synthesis, electrochemical behavior and X-ray crystal and molecular structures of [Fe(diene)(CO)(2)PPh3] (diene = chalcone, sorbic acid)

The compounds [Fe(ch)(CO)(2)PP3] (1) (ch = chalcone) and [Fe(sba)(CO)(2)PPh3] (2) (sba = sorbic acid) were prepared by irradiating the tetracarbonyltriphenylphosphineiron(0) complex in benzene in the presence of ch or sba. The compounds were characterized by infrared and P-31 NMR spectroscopies. Their electrochemical behavior was investigated by cyclic voltammetry and the results suggest that their oxidations occur by more than one electrochemical step, producing free ch and sba, free PPh3 and solvated Fe(III). It was observed that sba ligand contributes more effectively to the stabilization of metal center in these complexes, the X-ray crystal and molecular structures of 1 and 2 were determined; it was shown that the Fe atom adopts a distorted octahedral coordinated geometry in which three of the sites are occupied by the ch or sba ligand. The [Fe(ch)(CO)(2)PPh3] complex is a monomer and the unit cell of complex 2 contains exist two identical and crystallographically independent molecules of [Fe(sba)(CO)(2)PPh3] which are linked by short hydrogen bonds O-H . . .O (C) 2001 Published by Elsevier B.V. Ltd.

Molecular structures and vibrational frequencies for cis-[PdCl2(tmen)] and cis-[Pd(N-3)(2)(tmen)]: A DFT study

Theoretical molecular structures of the complexes cis-[PdCl2(tmen)] and cis-[Pd(N-3)(2)(tmen)] (tmen = N,N,N',N'-tetramethylethylenediamine) were investigated using B3LYP/DFT method. The calculated molecular parameters, bond distances and angles, revealed a square-planar geometry around the metallic center for both compounds with the azide being linear. The theoretical infrared spectra of C, symmetry (electronic state (1)A) of the compounds are in agreement with the experimental data. (C) 2007 Elsevier B.V. All rights reserved.

Fabrication and analysis of self-assembled photonic crystals structures

This paper presents the fabrication and analysis of a three-dimensional FCC photonic crystal (PhC) based on a self-assembly synthesis of monodispersive latex spheres. Experimental optical characterization, achieved by measurements of the specular reflectance under variable angles, indicated the clear presence of a Bragg diffraction pattern. Results are further explored by theoretical calculations based on the Finite Difference Time Domain (FDTD) method to determine the full PhC band structure.

REACTIONS OF MERCURIC ACETATE WITH PENTACARBONYLIRON IN ALCOHOLS - CRYSTAL AND MOLECULAR-STRUCTURES OF HG[FE(COOR)(CO)(4)](2) (R=CH3, C2H5)

Reactions of Hg(CH3COO)(2) with [Fe(CO)(5)] in MeOH and EtOH lead to the compounds Hg[Fe(COOR)(CO)(4)](2) (I for R = CH3 and II for R = C2H5). Crystals of I are triclinic, P (1) over bar, with a = 6.272(2), b = 6.441(3), c = 11.703(4) Angstrom, a = 92.94(3)degrees, beta = 103.77(3)degrees, gamma = 96.10(2)degrees, and Z = 1. Crystals of II are tetragonal, I4(1)/a, with a = 17.906(3) Angstrom, c = 12.756(2) Angstrom, and Z = 8. The geometry around Hg is linear for compound I and approximately linear for compound II. The Hg-Fe distances are 2.5716(8) and 2.575(4) Angstrom for compounds I and II, respectively. The geometry around the Fe in both compounds is approximately octahedral. The carboalkoxy group is cis to Hg in both compounds with Fe-C distances equal to 2.034(6) and 2.05(4) Angstrom for compounds I and II, respectively.

Synthesis and reactivity in salt metathesis reactions of trivalent [La(Tp(Me2))(2)X] (X = Cl, I) complexes: crystal structures of [La(Tp(Me2))(2)Cl] and [La(Tp(Me2))(2)(kappa(2)-pz(Me2))]

Reaction of LaX3(THF)(n) (X = Cl, 1) with two equiv. of K(Tp(Me2)) gave good yields of the bis-Tp complexes [La(Tp(Me2))(2)X] (X = Cl (1); I (3)). However, the formation of 1 and 3 is always accompanied by significant amounts of La(Tp(Me2))(2)(kappa(2)-pz(Me2)) ([pz(Me2)](-) = 3,5-dimethyl-pyrazolato) (2). The pyrazolato complex 2, which presumably arises from decomposition of the [Tp(Me2)](-) moiety during salt metathesis, was independently prepared in good yield from 1 and in situ generated [pz(Me2)](-). The solid-state structures of 1 and 2 were determined by single-crystal X-ray diffraction studies. Subsequent reactions of halogeno-Tp(Me2) complexes 1 and 3 with various alkali metal salts MR (M = Li, R = CH2SiMe3, Ph, N(SiMe3)(2); M = K, R = OAr) gave M(Tp(Me2)) as the major product. Alternatively, the mono-Tp bis(aryloxide) derivatives [Ln(Tp(Me2))(OC6H2-2,6-'Bu-4-Me)(2)] (Ln = La (4); Nd (5)) were obtained in high yields by salt metathesis of [Ln(OC6H2-2,6-'Bu-4-Me)(3)] with one equiv. of K(Tp(Me2)). (C) 2004 Elsevier Ltd. All rights reserved.