A combined theoretical and experimental study of electronic structure and optical properties of β-ZnMoO4 microcrystals

In this paper, a combined theoretical and experimental study on the electronic structure and photoluminescence (PL) properties of beta zinc molybdate (β-ZnMoO4) microcrystals synthesized by the hydrothermal method has been employed. These crystals were structurally characterized by X-ray diffraction (XRD), Rietveld refinement, Fourier transform Raman (FT-Raman) and Fourier transform infrared (FT-IR) spectroscopies. Their optical properties were investigated by ultraviolet-visible (UV-Vis) absorption spectroscopy and PL measurements. First-principles quantum mechanical calculations based on the density functional theory at the B3LYP level have been carried out. XRD patterns, Rietveld refinement, FT-Raman and FT-IR spectra showed that these crystals have a wolframite-type monoclinic structure. The Raman and IR frequencies experimental results are in reasonable agreement with theoretically calculated results. UV-Vis absorption measurements shows an optical band gap value of 3.17 eV, while the calculated band structure has a value of 3.22 eV. The density of states indicate that the main orbitals involved in the electronic structure of β-ZnMoO4 crystals are (O 2p-valence band and Mo 4d-conduction band). Finally, PL properties of β-ZnMoO4 crystals are explained by means of distortions effects in octahedral [ZnO6] and [MoO6] clusters and inhomogeneous electronic distribution into the lattice with the electron density map. © 2013 Elsevier Ltd. All rights reserved.

In vitro comparisons of casting retention on implant abutments among commercially available and experimental castor oil-containing dental luting agents

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

A theoretical and experimental study to unequivocal structural assignment of tetrahydroquinoline derivatives

The tetrahydroquinoline derivatives can be easily synthesized through Povarov reaction and have several important biological activities. This work describes a comparative study for the unequivocal assignment of molecular structure of different tetrahydroquinoline derivatives, through a complete analysis of NMR 1D and 2D NMR spectra (1H, 13C, COSY, HSQC, and HMBC), and the correlation this data with theoretical calculations of energy-minimization and chemical shift (δ), employing the theory level of DFT/B3LYP with set of the cc-pVDZ basis. For these derivatives the experimental analyses and the theoretical model adopted were sufficient to obtain a good description of its structures, and these results can be used to assign the structure of various others tetrahydroquinoline derivatives. © 2013 Springer Science+Business Media New York.

Theoretical and experimental study of the excitonic binding energy in GaAs/AlGaAs single and coupled double quantum wells

This paper discusses the theoretical and experimental results obtained for the excitonic binding energy (Eb) in a set of single and coupled double quantum wells (SQWs and CDQWs) of GaAs/AlGaAs with different Al concentrations (Al%) and inter-well barrier thicknesses. To obtain the theoretical Eb the method proposed by Mathieu, Lefebvre and Christol (MLC) was used, which is based on the idea of fractional-dimension space, together with the approach proposed by Zhao et al., which extends the MLC method for application in CDQWs. Through magnetophotoluminescence (MPL) measurements performed at 4 K with magnetic fields ranging from 0 T to 12 T, the diamagnetic shift curves were plotted and adjusted using two expressions: one appropriate to fit the curve in the range of low intensity fields and another for the range of high intensity fields, providing the experimental Eb values. The effects of increasing the Al% and the inter-well barrier thickness on E b are discussed. The Eb reduction when going from the SQW to the CDQW with 5 Å inter-well barrier is clearly observed experimentally for 35% Al concentration and this trend can be noticed even for concentrations as low as 25% and 15%, although the Eb variations in these latter cases are within the error bars. As the Zhao's approach is unable to describe this effect, the wave functions and the probability densities for electrons and holes were calculated, allowing us to explain this effect as being due to a decrease in the spatial superposition of the wave functions caused by the thin inter-well barrier. © 2013 Elsevier B.V.

Análise experimental e numérica de convecção forçada em arranjo de obstáculos dentro de canal

Pós-graduação em Engenharia Mecânica - FEIS

Estudo experimental do escoamento em cavidades retangulares: padrões de escoamento e instabilidades hidrodinâmicas na camada cisalhante

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise teórica e experimental vibro-acústica utilizando a técnica de matrizes compactas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

State-civil society partnership: issues for debate and new researches

Neste artigo analisamos a literatura de parceria entre o estado e a sociedade civil, em particular sobre a parceria entre as organizações públicas e as organizações sem fins lucrativos. Discutimos as diferentes perspectivas do conceito de parceria e objetivamos destacar algumas das principais preocupações teóricas sobre este conceito no contexto da governança. Buscamos mostrar que, em geral, o contexto histórico da parceria não tem sido incluído entre os fatores usados para explicar o seu uso no contexto da governança. Apontamos que, a despeito das análises sobre parceria que indicam que esta traz benefícios sociais, ainda existem lacunas no conhecimento que evidenciem que esta "tecnologia social" contribui efetivamente para empoderar as pessoas e os grupos sociais com menor poder de influência. A maior parte da literatura sugere que a parceria objetiva fortalecer a relação entre a população e o governo local e melhorar as possibilidades das pessoas e dos grupos sociais com menor poder de influência em participar na governança local. Entretanto, não encontramos na literatura sobre parceria evidências substantivas de que ela se direciona para modificar a estrutura de poder político. Finalmente, mostramos que não está claro se a interação entre as "pessoas comuns" e o estado, por via de um processo participativo, tem contribuído efetivamente para construir coesão social para diferentes grupos sociais. A principal contribuição do artigo é expandir o conhecimento dos fatores que influenciam (de forma positiva e negativa) o processo de parceria entre o estado e a sociedade civil para o desenvolvimento local.

Theoretical and experimental spectroscopic studies of the first highly luminescent binuclear hydrocinnamate of Eu(III), Tb(III) and Gd(III) with bidentate 2,2 '-bipyridine ligand

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Clinical manifestations and experimental studies on the spine extract of the toadfish Porichthys porosissimus

Toadfish are fish from the family Batrachoididae that are found in marine and brackish environment around the world. Among the toadfish, Porichthys genus is very common, where Porichthys porosissimus, also called Atlantic Midshipman is found in Southwest Atlantic, from Rio de Janeiro, Brazil to eastern Argentina. There was no consensus about the classification of the genus Porichthys as venomous fish because so far there are no published Studies regarding human envenomations and/or toxic activities induced in animal models. Herein, we report two conclusive envenoming in human beings caused by P porosissimus spines, with clear signs and symptoms that were very important for the development of our experimental studies. We demonstrated that the P. porosissimus spine extract, now venom, can induce nociceptive and edematogenic responses in mice as well an induction of an inflammatory response elicited by intravital microscopy and leukocyte migration. Finally, we identified in the P. porosissimus spine extract, through analysis by mass spectrometry, the presence of proteins previously detected in the venoms of other fish species and other venomous animals. We believe that based on our studies we will dismiss the non-venomous nature of this fish and clarify this issue. (C) 2014 Elsevier Ltd. All rights reserved.

Immunomodulation in human and experimental arthritis: including vitamin D, helminths and heat-shock proteins

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

The first frequency of cantilevered bars with geometric effect: a mathematical and experimental evaluation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Theoretical Analysis and Experimental Validation of the Scholte Wave Propagation in Immersed Plates for the Characterization of Viscous Fluids

This work reports the study of an attractive interfacial wave for application in ultrasonic NDE techniques for inspection and fluid characterization. This wave, called quasi-Scholte mode, is a kind of flexural wave in a plate in contact with a fluid which presents a good sensitivity to the fluid properties. In order to explore this feature, the phase velocity curve of quasi-Scholte mode is experimentally measured in a plate in contact with a viscous fluid, showing a good agreement with theory.

Avaliação da deposição e da agitação de calda em reservatórios de pulverizadores agrícolas utilizando uma análise numérica (CFD) e experimental

Pós-graduação em Engenharia Mecânica - FEB

Androgen receptors and experimental bone loss - an in vivo and in vitro study

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