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 | Acesso ao texto completo restrito à biblioteca da Embrapa Milho e Sorgo. Para informações adicionais entre em contato com cnpms.biblioteca@embrapa.br. |
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Registro Completo |
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Biblioteca(s): |
Embrapa Milho e Sorgo. |
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Data corrente: |
05/03/2003 |
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Data da última atualização: |
05/06/2017 |
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Autoria: |
SANTOS, J. P. dos. |
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Afiliação: |
Embrapa Milho e Sorgo. |
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Título: |
Opção pela técnica de colheita ideal. |
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Ano de publicação: |
2002 |
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Fonte/Imprenta: |
Revista Brasileira de Agropecuária, São Paulo, v. 3, n. 17, p. 35-37, [2002]. |
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Idioma: |
Português |
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Thesagro: |
Colheita; Milho; Zea Mays. |
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Categoria do assunto: |
F Plantas e Produtos de Origem Vegetal |
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Marc: |
LEADER 00402naa a2200145 a 4500
001 1480562
005 2017-06-05
008 2002 bl uuuu u00u1 u #d
100 1 $aSANTOS, J. P. dos
245 $aOpção pela técnica de colheita ideal.
260 $c2002
650 $aColheita
650 $aMilho
650 $aZea Mays
773 $tRevista Brasileira de Agropecuária, São Paulo$gv. 3, n. 17, p. 35-37, [2002].
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Embrapa Milho e Sorgo (CNPMS) |
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Registro Completo
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Biblioteca(s): |
Embrapa Instrumentação. |
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Data corrente: |
22/12/1999 |
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Data da última atualização: |
22/12/1999 |
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Autoria: |
ASSIS, O. B. G.; CRNKOVIC, F. C.; BERNARDES FILHO, R.; AVACA, L. A. |
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Afiliação: |
EMBRAPA-CNPDIA; USP-IQSC. |
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Título: |
Roughness assessment of Ni-Co spinel type oxide electrode by atomic force microscope. |
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Ano de publicação: |
1997 |
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Fonte/Imprenta: |
In: MEETING OF THE BRAZILIAN SOCIETY FOR ELECTRON MICROSCOPY, 16., 1997, CAXAMBU. Proceedings of the 16. Meeting of the Brazilian Society for Electron Microscopy. Caxambu: Brazilian Society for Electron Microscopy, 1997. p. 76-77. Acta Microscopica, v.6, Supplement A, September 1997. |
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Idioma: |
Inglês |
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Conteúdo: |
Spinel type oxides such as NiCO2O4, are of great interest for application in electrochemical industry specially as anodes for water electrolysis and the oxygen evolution reaction. The large electrocatalytic activity of these types of materials under potentiodynamic conditions results from mechanisms of ionic transference on the solid-liquid interface and are rather dependent on the real electrode area. An increase in the geometric surface outcome an increase in the current density enhancing thus the electrolysis reaction. The roughness factor in voltametric condition, is deduced from the electrochemical peak currents normalized with respect to a flat reference electrode, as the relation (Ic(flat/Ic(rough)). Since the electrolyte medium offers differences in the ionic conductivity, and bubbles can be generate and keep attached to the electrode's surface crevices, the estimation by this method is limited and validated only in a short range of experimental conditions.An reliable way to state relative irregularities in solid surfaces is by the generation of scanning atomic force microscope (AFM) images. The AFM allows the evaluation of the surface by a direct topography assessment. In this work, the roughness of a Ni-Co base oxide electrode is evaluated as an example of the potential of the atomic force microscopy in revealing subtle details of surface. This technique when associated with appropriated software analysis, presents large advantage over chemical or two-dimensional microscopy techniques. In Figure 1 is presented a random 50 x 50 micrometers area from a central region of a NiCo2O4 polished, flat like electrode, prepared as describe in reference 3. Three intermediates analytical lines at (A), (B) and (C) were traced and the surface profiles plotted in Figure 2. These cross-sectional plots presents the actual topography along the particular line scanned. As it is possible to compare, the topographies lines show shallow corrugation and blunts increasing from the top to the bottom regions of the figure. The standard roughness values presented in the boxes of Figure 2, means the linear measurements of the lines correspondent to the surface's lenghts, since the projected straight line are 50 micrometers lenght it is possible to evaluate a proportional increase of area from a flat surface. An other possible tools is the overall roughness mapping on the figure. That is performed by processing the data from the total of the lines scanned. For the scanned regions, the RMS area is found to be 1.87 times the projected one. In Figure 3 a three dimensional projection of the region is plotted. MenosSpinel type oxides such as NiCO2O4, are of great interest for application in electrochemical industry specially as anodes for water electrolysis and the oxygen evolution reaction. The large electrocatalytic activity of these types of materials under potentiodynamic conditions results from mechanisms of ionic transference on the solid-liquid interface and are rather dependent on the real electrode area. An increase in the geometric surface outcome an increase in the current density enhancing thus the electrolysis reaction. The roughness factor in voltametric condition, is deduced from the electrochemical peak currents normalized with respect to a flat reference electrode, as the relation (Ic(flat/Ic(rough)). Since the electrolyte medium offers differences in the ionic conductivity, and bubbles can be generate and keep attached to the electrode's surface crevices, the estimation by this method is limited and validated only in a short range of experimental conditions.An reliable way to state relative irregularities in solid surfaces is by the generation of scanning atomic force microscope (AFM) images. The AFM allows the evaluation of the surface by a direct topography assessment. In this work, the roughness of a Ni-Co base oxide electrode is evaluated as an example of the potential of the atomic force microscopy in revealing subtle details of surface. This technique when associated with appropriated software analysis, presents large advantage over chemical or two-dimensional m... Mostrar Tudo |
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Palavras-Chave: |
AFM; Agricultural instrumentation; Congressos; EMBRAPA-CNPDIA; Instrumentacao agropecuaria; Microscopia de forca atomica; Technique; Tecnica. |
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Thesaurus NAL: |
atomic force microscopy. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 03626naa a2200265 a 4500
001 1027137
005 1999-12-22
008 1997 bl --- 0-- u #d
100 1 $aASSIS, O. B. G.
245 $aRoughness assessment of Ni-Co spinel type oxide electrode by atomic force microscope.
260 $c1997
520 $aSpinel type oxides such as NiCO2O4, are of great interest for application in electrochemical industry specially as anodes for water electrolysis and the oxygen evolution reaction. The large electrocatalytic activity of these types of materials under potentiodynamic conditions results from mechanisms of ionic transference on the solid-liquid interface and are rather dependent on the real electrode area. An increase in the geometric surface outcome an increase in the current density enhancing thus the electrolysis reaction. The roughness factor in voltametric condition, is deduced from the electrochemical peak currents normalized with respect to a flat reference electrode, as the relation (Ic(flat/Ic(rough)). Since the electrolyte medium offers differences in the ionic conductivity, and bubbles can be generate and keep attached to the electrode's surface crevices, the estimation by this method is limited and validated only in a short range of experimental conditions.An reliable way to state relative irregularities in solid surfaces is by the generation of scanning atomic force microscope (AFM) images. The AFM allows the evaluation of the surface by a direct topography assessment. In this work, the roughness of a Ni-Co base oxide electrode is evaluated as an example of the potential of the atomic force microscopy in revealing subtle details of surface. This technique when associated with appropriated software analysis, presents large advantage over chemical or two-dimensional microscopy techniques. In Figure 1 is presented a random 50 x 50 micrometers area from a central region of a NiCo2O4 polished, flat like electrode, prepared as describe in reference 3. Three intermediates analytical lines at (A), (B) and (C) were traced and the surface profiles plotted in Figure 2. These cross-sectional plots presents the actual topography along the particular line scanned. As it is possible to compare, the topographies lines show shallow corrugation and blunts increasing from the top to the bottom regions of the figure. The standard roughness values presented in the boxes of Figure 2, means the linear measurements of the lines correspondent to the surface's lenghts, since the projected straight line are 50 micrometers lenght it is possible to evaluate a proportional increase of area from a flat surface. An other possible tools is the overall roughness mapping on the figure. That is performed by processing the data from the total of the lines scanned. For the scanned regions, the RMS area is found to be 1.87 times the projected one. In Figure 3 a three dimensional projection of the region is plotted.
650 $aatomic force microscopy
653 $aAFM
653 $aAgricultural instrumentation
653 $aCongressos
653 $aEMBRAPA-CNPDIA
653 $aInstrumentacao agropecuaria
653 $aMicroscopia de forca atomica
653 $aTechnique
653 $aTecnica
700 1 $aCRNKOVIC, F. C.
700 1 $aBERNARDES FILHO, R.
700 1 $aAVACA, L. A.
773 $tIn: MEETING OF THE BRAZILIAN SOCIETY FOR ELECTRON MICROSCOPY, 16., 1997, CAXAMBU. Proceedings of the 16. Meeting of the Brazilian Society for Electron Microscopy. Caxambu: Brazilian Society for Electron Microscopy, 1997. p. 76-77. Acta Microscopica$gv.6, Supplement A, September 1997.
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