Encontrados 16 documentos, a visualizar página 1 de 2
Synthesis and characterization of tungsten trioxide powders prepared from tungs...
Nogueira, HIS; Cavaleiro, AMV; Rocha, J; Trindade, T; Jesus, JDP deWO3 powders were prepared by the thermal decomposition of tungstic acids (WO3 nH2O, n ¼ 1/3, 1, 2). The tungstic acids were synthesized from WO4 2 aqueous solutions under a variety of conditions of pH, temperature and W(VI) concentrations. The thermal decomposition of the tungstic acids into WO3 was analysed by TG and DSC methods. Nano-sized WO3 powders with different morphological characteristics were obtaine...
Remanent magnetization in CoO antiferromagnetic nanoparticles
Silva, N. J. O.; Millán, A.; Palacio, F.; Martins, M.; Trindade, T.; Puente-Orench, I.; Campo, J.We report a study on the remanent magnetization Mr induced by field cooling across the ordering temperature TN in antiferromagnetic CoO nanoparticles with different sizes. The nanoparticles are composed by a structurally and magnetically ordered core and a structurally ordered and magnetically disordered shell with a thickness of about 2 nm. The ordered core has cell parameters, moments direction, and modulus s...
Resistência a antimicrobianos dependente do sistema de efluxo multidrogas em Es...
Moreira,M.A.S.; Ferreira,A.B.; Trindade,T.F.S.L.; Reis,A.L.O.; Moraes,C.A.Identificaram-se e caracterizaram-se a resistência e a multirresistência aos principais antimicrobianos usados no tratamento de mastite bovina causada por Escherichia coli. A concentração inibitória mínima (MIC) e o sistema de efluxo foram detectados pelas curvas de crescimento, com base na densidade óptica, em diferentes concentrações da droga e na presença e na ausência do desacoplador da força próton-motora ...
Surface modification of Co-doped ZnO nanocrystals and its effects on the magnet...
Pereira, A. S.; Ankiewicz, A. O.; Gehlhoff, W.; Hoffmann, A.; Pereira, S.; Trindade, T.; Grundmann, M.; Carmo, M. C.; Sobolev, N. A.A series of chemically prepared Co2+-doped ZnO colloids has been surface modified either by growing shells of ZnSe or by the in situ encapsulation in poly styrene . The surface modification effects using these two distinct chemical strategies on the magnetic properties of the nanocrystals were probed by electron paramagnetic resonance EPR . Structural characterization by means of x-ray diffraction and transmis...
Interconvertable modular framework and layered lanthanide(III)-etidronic acid c...
Shi, F. N.; Cunha-Silva, L.; Ferreira, R. A. Sá; Mafra, L.; Trindade, T.; Carlos, L. D.; Paz, F. A. Almeida; Rocha, J.POCI/QUI/58377/2004 - FEDER ; SFRH/BPD/9309/2002 (to F.-N.S.) ; SFRH/BPD/14410/2003 (to L.C.-S.) ; NoE FAME
Sistema de gestão da qualidade e ambiental na Embrapa Arroz e Feijão.
LANNA, A. C.; TRINDADE, T. B.O presente documento relata o histórico dessa mudança de filosofia institucional e mostra a interface existente entre a Gestão da Qualidade e Ambiental, para identificar e desenvolver estratégias para aplicação de modelos de planejamento integrado, que ofereçam subsídios para a sustentabilidade da empresa. ; 2007
In Situ Synthesis of Magnetite Nanoparticles in Carrageenan Gels
Daniel-da-Silva, Ana L.; Trindade, T.; Goodfellow, Brian J.; Costa, Benilde F. O.; Correia, Rui N.; Gil, Ana M.Magnetite nanoparticles have been successfully synthesized in the presence of carrageenan polysaccharides using an in situ coprecipitation method. Iron coordination to the sulfate groups of the polysaccharide was confirmed by FTIR. The polysaccharide type (κ, ι, or λ) and concentration have been varied and their effects on particle morphology and chemical stability of the resultant nanocomposite investigated. T...
In situ synthesis of magnetite nanoparticles in carrageenan gels
Daniel-da-Silva, Ana. L.; Trindade, T.; Goodfellow, Brian J.; Costa, Benilde F. O.; Correia, Rui N.; Gil, Ana M.Magnetite nanoparticles have been successfully synthesized in the presence of carrageenan polysaccharides using an in situ coprecipitation method. Iron coordination to the sulfate groups of the polysaccharide was confirmed by FTIR. The polysaccharide type ( , é, or ì) and concentration have been varied and their effects on particle morphology and chemical stability of the resultant nanocomposite investigated. T...
Layer-by-layer deposition of organically capped quantum dots
Neves, M.C.; Pereira, A.S.; Peres, M.; Kholkin, A.; Monteiro, T.; Trindade, T.Cadmium chalcogenide quantum dots (QD's) were synthesised using a single source approach while zinc oxide QD's were obtained by a colloidal technique. In both situations the dots were surface capped with tri-octylphosphine oxide (TOPO) hence leading to nanodispersed systems in organic solvents such as toluene. The organically capped QD's (CdSe, CdS and ZnO) were used as building-units to fabricate LbL (layer-by...
Nanocompósitos de matriz polimérica: estratégias de síntese de materiais híbridos
Esteves, ACC; Barros-Timmons, A; Trindade, TAssociating the well known advantages of hybrid materials to the wide potential of nanomaterials, the new and featuring class of polymer nanocomposites turned into one of the most intensively researched areas. This review highlights recent developments in the field of the synthesis of polymer based nanocomposites. Important issues related to the surface modification of fillers, in order to promote the compatibi...
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