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| Registros recuperados : 8 | |
| Registros recuperados : 8 | |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Solos. Para informações adicionais entre em contato com cnps.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Solos. |
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Data corrente: |
09/12/2008 |
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Data da última atualização: |
27/10/2021 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Circulação/Nível: |
Internacional - A |
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Autoria: |
NOVOTNY, E. H.; KNICKER, H.; MARTIN NETO, L.; AZEREDO, R. B. V.; HAYES, M. H. B. |
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Afiliação: |
ETELVINO HENRIQUE NOVOTNY, CNPS; H. Knicker, Lehrstuhl fur Bodenkunde, Technische Universitat Munchen; LADISLAU MARTIN NETO, DE/P&D; R. B. V. AZEREDO, UFF; M. H. B. HAYES, Chemical and Environmental Sciences University of Limerick. |
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Título: |
Effect of residual vanadyl ions on the spectroscopic analysis of humic acids: a multivariate approach. |
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Ano de publicação: |
2008 |
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Fonte/Imprenta: |
European Journal of Soil Science, Oxford, v. 59, n. 3, p. 439-444, Jun. 2008. |
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DOI: |
https://doi.org/10.1111/j.1365-2389.2007.00983.x |
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Idioma: |
Inglês |
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Conteúdo: |
In a study of the vanadyl (VO2þ)-humic acids system, the residual vanadyl ion suppressed fluorescence and specific electron paramagnetic resonance (EPR) and NMR signals. In the case of NMR, the proton rotating frame relaxation times (T1qH) indicate that this suppression is due to an inefficient H-C cross polarization, which is a consequence of a shortening of T1qH. Principal components analysis (PCA) facilitated the isolation of the effect of the VO2þ ion and indicated that the organic free radical signal was due to at least two paramagnetic centres and that the VO2þ ion preferentially suppressed the species whose electronic density is delocalized over O atoms (greater g-factor). additionally, the newly obtained variables (principal components ? PC) indicated that, as the result of the more intense tillage a relative increase occurred in the accumulation of: (i) recalcitrant structures; (ii) lignin and long-chain alkyl structures; and (iii) organic free radicals with smaller g-factors. |
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Palavras-Chave: |
Ácidos húmicos; Análise espectroscópica. |
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Categoria do assunto: |
P Recursos Naturais, Ciências Ambientais e da Terra |
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Marc: |
LEADER 01701naa a2200205 a 4500
001 1339740
005 2021-10-27
008 2008 bl uuuu u00u1 u #d
024 7 $ahttps://doi.org/10.1111/j.1365-2389.2007.00983.x$2DOI
100 1 $aNOVOTNY, E. H.
245 $aEffect of residual vanadyl ions on the spectroscopic analysis of humic acids$ba multivariate approach.$h[electronic resource]
260 $c2008
520 $aIn a study of the vanadyl (VO2þ)-humic acids system, the residual vanadyl ion suppressed fluorescence and specific electron paramagnetic resonance (EPR) and NMR signals. In the case of NMR, the proton rotating frame relaxation times (T1qH) indicate that this suppression is due to an inefficient H-C cross polarization, which is a consequence of a shortening of T1qH. Principal components analysis (PCA) facilitated the isolation of the effect of the VO2þ ion and indicated that the organic free radical signal was due to at least two paramagnetic centres and that the VO2þ ion preferentially suppressed the species whose electronic density is delocalized over O atoms (greater g-factor). additionally, the newly obtained variables (principal components ? PC) indicated that, as the result of the more intense tillage a relative increase occurred in the accumulation of: (i) recalcitrant structures; (ii) lignin and long-chain alkyl structures; and (iii) organic free radicals with smaller g-factors.
653 $aÁcidos húmicos
653 $aAnálise espectroscópica
700 1 $aKNICKER, H.
700 1 $aMARTIN NETO, L.
700 1 $aAZEREDO, R. B. V.
700 1 $aHAYES, M. H. B.
773 $tEuropean Journal of Soil Science, Oxford$gv. 59, n. 3, p. 439-444, Jun. 2008.
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