Magnetic Metals
Mostrando 13-24 de 59 artigos, teses e dissertações.
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13. Avaliação de métodos de extração para a determinação de cromo e níquel em formulações farmacêuticas e em matérias-primas usadas na fabricação de medicamentos à base de cefalexina e ciprofloxacino
This paper reports the evaluation of extraction strategies for the treatment of medicine samples to determine chromium and nickel by GFAAS. Different approaches for extraction were evaluated and the most efficient involved magnetic stirring. The metals were quantitatively extracted by stirring 0.20 g samples with 25 mL of 2.0 mol L-1 HCl solution for 60 min.
Quím. Nova. Publicado em: 2012
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14. Separation and characterization of asphaltenic subfractions
The structure of the various asphaltenic subfractions found in crude oil was evaluated. For this purpose, C5 asphaltenes were extracted from an asphaltic residue using n-pentane as the flocculant solvent. The different subfractions were isolated from the C5 asphaltenes by the difference in solubility in different solvents. These were characterized by infrare
Quím. Nova. Publicado em: 2012
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15. Estudos da dinâmica estrutural da proteína ligante de cálcio S100A12 humana e da lisozima T4 / Structural dynamics studies of human calcium binding protein S100A12 and T4 lysozyme
The work presented here was conceived with two main objectives. The first one, more general, involved the implementation of a new methodology for the study of conformational changes in proteins, i.e., its structural dynamics. The technique of Site-directed Spin Labeling combined with Electronic Paramagnetic Resonance (SDSL-EPR) are the pillars of this new me
Publicado em: 2011
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16. Quitosana modificada quimicamente atraves de cloretos organicos e o uso como fonte em remoção cationica / Chitosan chemically modified with organic chlorides and the use as source in cationic removal
The biopolymer chitosan was submitted to a series of reactions, with the purpose to explore the free amino group reactivity polymeric chain through reactions involving organic chlorides and primary amines compounds. Isophthaloyl dichloride and cyanuric chloride were used in the modifications, following by reactions with ethylenediamine or diethylenetriamine.
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/04/2010
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17. Complexes of 4-chlorophenoxyacetates of Nd(III), Gd(III) and Ho(III)
The complexes of 4-chlorophenoxyacetates of Nd(III), Gd(III) and Ho(III) have been synthesized as polycrystalline hydrated solids, and characterized by elemental analysis, spectroscopy, magnetic studies and also by X-ray diffraction and thermogravimetric measurements. The analysed complexes have the following colours: violet for Nd(III), white for Gd(III) an
Eclética Química. Publicado em: 2010
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18. The physico-chemical properties of 2-methoxyphenoxyacetates of Mn(II), Co(II), Ni(II) and Cu(II)
The complexes of 2-methoxyhenoxyacetates of Mn(II), Co(II), Ni(II) and Cu(II)with the general formula: M(C9H9O4)3·4H2O, where M(II) = Mn, Co, Ni and Cu have been synthesized and characterized by elemental analysis, IR spectroscopy, magnetic and thermogravimetric studies and also X-ray diffraction measurements. The complexes have colours typical for M(II) io
Eclética Química. Publicado em: 2010
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19. Investigation of structural, electronic and magnetica properties of Ca2-xLaxFelrO6, Sr2-xLaxFelrO6 e TbMnO3 oxides / Investigação as propriedades estruturais, eletronicas e magneticas dos oxidos Ca2-xLaxFelrO6, Sr2-xLaxFelrO6 e TbMnO3
For many decades the transition metal oxides are subject of great scientific interest because of the wide variety of interesting physical properties and their potential technological applications. More recently, for example, oxides of transition metals with multiferroic properties have been considered as potential magneto-electronic devices. Many transition
Publicado em: 2010
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20. APLICAÇÃO DA AMOSTRAGEM DIRETA-GF AAS PARA A DETERMINAÇÃO DE ELEMENTOS TRAÇO EM METÉRIAS-PRIMAS PARA A PRODUÇÃO DE POLIURETANOS
Polymeric diphenylmethane diisocyanate (PMDI) and diphenylthane dianiline (MDA) are importante raw materials in the manufacture of polyurethanes. These products have wide application in various fields such as medicine, catalysis and electronics. Actually, considerable interest has been given for the presence of metal contaminants in raw materials for the pro
Publicado em: 2010
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21. Ruido no transporte eletronico em sistemas mesoscopicos / Noise in the electronic transport in mesoscopic systems
This dissertation describes the fundamental caracteristics of mesoscopic conductors, and the origins and properties of the sources of noise in conductors. Firstly, we describe the noise through different methods and emphasize the properties of each kind of noise. In the following, we present the scattering approach for coherent phase conductors, which allows
Publicado em: 2009
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22. Funcionalization of mesoporous silica with 2-bezothiazolethiol and 3-mercaptopropyltrimetoxysilane for electronalytical application / Funcionalização de sílicas mesoporosas com benzotiazol-2-tiol e 3-mercaptopropiltrimetoxisilano para aplicações em eletroanalítica
Mesoporous silicas were functionalised by immobilisation of organic substances covalently bonded to the silanol groups on the silica surface. SBA-15 nanostructured silica was functionalised by post-synthesis with 2-benzothiazolethiol and silica films modified with 3-mercaptopropyltrimethoxysilane were obtained by direct functionalisation. The characterizatio
Publicado em: 2009
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23. The physico-chemical properties of 4-chlorophenoxyacetates of Mn(II), Co(II), Ni(II) and Cu(II)
The complexes of 4-chlorophenoxyacetates of Mn(II), Co(II), Ni(II) and Cu(II) have been synthesized as polycrystalline solids, and characterized by elemental analysis, spectroscopy, magnetic studies and also by X-ray diffraction and thermogravimetric measurements. The analysed complexes have the following colours: pink for Co(II), green for Ni(II), blue for
Eclética Química. Publicado em: 2008
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24. Comparison of some properties of 2,3 - and 3,4 - dimethoxybenzoates of Cu(II), Co(II) and Nd(III)
The physicochemical properties of 2,4-, and 3,4- dimethoxybenzoates of Cu(II), Co(II) and Nd(III) were studied and compared to observe the -OCH3 substituent positions in benzene ring on the character of complexes. The analysed compounds are crystalline hydrated or anhydrous salts with colours depending on the kind of central ions: blue for Cu(II), pink for C
Eclética Química. Publicado em: 2008