Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol
Ano de defesa: | 2018 |
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Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | , , , , |
Tipo de documento: | Tese |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Universidade Federal de Goiás
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Programa de Pós-Graduação: |
Programa de Pós-graduação em Química (IQ)
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Departamento: |
Instituto de Química - IQ (RG)
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País: |
Brasil
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Palavras-chave em Português: | |
Palavras-chave em Inglês: | |
Área do conhecimento CNPq: | |
Link de acesso: | http://repositorio.bc.ufg.br/tede/handle/tede/8894 |
Resumo: | n this study we investigated the structural, optical band-gap, and magnetic properties of CoFe2-xYxO4 ) nanoparticles (NPs) synthesized using a combustion reaction method without the need for subsequent heat treatment or the calcing process. The particle size measured from X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images confirms the nanostructural character in the range of 16–36 nm. The optical band-gap (Eg) values increase with the Y3+ ion concentration being 3.30 and 3.58 eV for x = 0,00 and x = 0,04, respectively. The presence of yttrium in the cobalt ferrite (Y-doped cobalt ferrite) structure affects the magnetic properties. For instance, the saturation magnetization, MS and remanent magnetization, Mr, decrease from 69 emu.g-1 to 33 and 28 to 12 emu.g-1 for x = 0,00 and x = 0.04, respectively. On the other hand the coercivity, Hc, increases from 1100 to 1900 Oe for x = 0,00 and x = 0,04 at room temperature. Also we found that MS, Mr, and Hc decreased with increasing temperature up to 773 K. The cubic magnetocrystalline constant, K1, determined by using the ‘‘law of approach’’ (LA) to saturation decreases with Y3+ ion concentration and temperature. K1 values for x = 0,00 (x = 0,04) were 3,3 x 106 erg.cm-3 (2,0 x 106 erg.cm-3) e 0,4 x 106 erg.cm-3 (0,3 x 106 erg.cm-3) at 300 K and 773 K, respectively. The results were discussed in terms of inter-particle interactions induced by thermal fluctuations, and Co2+ ion distribution over tetrahedral and octahedral sites of the spinel structure due to Y3+ ion substitution. Also, in the present work, zinc oxide (ZnO) nanoparticles were prepared by the polyol method which consist of zinc acetate acetate and sodium acetate in propylene glycol solution with control over the hydrolysis reaction time and subjecting to the variation of reaction parameters, as ratio of hydrolysis (th) and ratio of acetate (ta). It was observed that the reaction time of the hydrolysis and the addition of ions had a strong effect on the morphology and size of the ZnO particles. For example, transmission electron microscopy (TEM) images revealed that the ZnO samples were synthesized for short time of RH (10 min) and long time (300 min) in small rods and in elongated rod forms, respectively. On the other hand, using only zinc acetate reagent, as the ZnO samples crystallized into a coarse spherical shape. These differences can be attributed to the polarization of the acetate and the propylene glycol, i.e., the greater amount of deficits present in the preferred growth solution of the ZnO crystals. In addition, the HR time does not change changes in the optical band gap. For example, values controlled by the Kubelka-Munk model decreased from 3.31 eV to 3.28 eV for the short HR time and the long HR time, respectively. This can be explained in terms of defects and is due to the change in particle sizes. X-ray diffraction patterns (XRDs) revealed that all the units crystallized the typical wurtzite structure of ZnO. However, the relative intensity of the diffraction peak (002) of the ZnO samples was synthesized with zinc acetate and was higher than the sensations from zinc acetate as sodium acetate. That is, an indication of direction should be directed toward the preferential growth of the crystals. Therefore, the morphology of the ZnO samples can be adapted using the polyol method, just as the physical properties are important for some technological applications. |
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Franco Júnior, Adolfohttp://lattes.cnpq.br/0187547195548392Franco Júnior, AdolfoPessoa, Márcio SolinoAraújo, Olacir AlvesLima, Emília Celma de OliveiraSartoratto, Patrícia Pommé Confessorihttp://lattes.cnpq.br/3930238965441986Alves, Thiago Eduardo Pereira2018-09-20T11:36:11Z2018-07-18ALVES, Thiago Eduardo Pereira. Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol. 2018. 156 f. Tese (Doutorado em Química) - Universidade Federal de Goiás, Goiânia, 2018.http://repositorio.bc.ufg.br/tede/handle/tede/8894n this study we investigated the structural, optical band-gap, and magnetic properties of CoFe2-xYxO4 ) nanoparticles (NPs) synthesized using a combustion reaction method without the need for subsequent heat treatment or the calcing process. The particle size measured from X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images confirms the nanostructural character in the range of 16–36 nm. The optical band-gap (Eg) values increase with the Y3+ ion concentration being 3.30 and 3.58 eV for x = 0,00 and x = 0,04, respectively. The presence of yttrium in the cobalt ferrite (Y-doped cobalt ferrite) structure affects the magnetic properties. For instance, the saturation magnetization, MS and remanent magnetization, Mr, decrease from 69 emu.g-1 to 33 and 28 to 12 emu.g-1 for x = 0,00 and x = 0.04, respectively. On the other hand the coercivity, Hc, increases from 1100 to 1900 Oe for x = 0,00 and x = 0,04 at room temperature. Also we found that MS, Mr, and Hc decreased with increasing temperature up to 773 K. The cubic magnetocrystalline constant, K1, determined by using the ‘‘law of approach’’ (LA) to saturation decreases with Y3+ ion concentration and temperature. K1 values for x = 0,00 (x = 0,04) were 3,3 x 106 erg.cm-3 (2,0 x 106 erg.cm-3) e 0,4 x 106 erg.cm-3 (0,3 x 106 erg.cm-3) at 300 K and 773 K, respectively. The results were discussed in terms of inter-particle interactions induced by thermal fluctuations, and Co2+ ion distribution over tetrahedral and octahedral sites of the spinel structure due to Y3+ ion substitution. Also, in the present work, zinc oxide (ZnO) nanoparticles were prepared by the polyol method which consist of zinc acetate acetate and sodium acetate in propylene glycol solution with control over the hydrolysis reaction time and subjecting to the variation of reaction parameters, as ratio of hydrolysis (th) and ratio of acetate (ta). It was observed that the reaction time of the hydrolysis and the addition of ions had a strong effect on the morphology and size of the ZnO particles. For example, transmission electron microscopy (TEM) images revealed that the ZnO samples were synthesized for short time of RH (10 min) and long time (300 min) in small rods and in elongated rod forms, respectively. On the other hand, using only zinc acetate reagent, as the ZnO samples crystallized into a coarse spherical shape. These differences can be attributed to the polarization of the acetate and the propylene glycol, i.e., the greater amount of deficits present in the preferred growth solution of the ZnO crystals. In addition, the HR time does not change changes in the optical band gap. For example, values controlled by the Kubelka-Munk model decreased from 3.31 eV to 3.28 eV for the short HR time and the long HR time, respectively. This can be explained in terms of defects and is due to the change in particle sizes. X-ray diffraction patterns (XRDs) revealed that all the units crystallized the typical wurtzite structure of ZnO. However, the relative intensity of the diffraction peak (002) of the ZnO samples was synthesized with zinc acetate and was higher than the sensations from zinc acetate as sodium acetate. That is, an indication of direction should be directed toward the preferential growth of the crystals. Therefore, the morphology of the ZnO samples can be adapted using the polyol method, just as the physical properties are important for some technological applications.Neste trabalho, foram investigadas as propriedades estruturais, ópticas e magnéticas de nanopartículas de CoFe2-xYxO4 ) sintetizadas pelo método de reação de combustão sem tratamento térmico subsequente ou o processo de calcinação. Os tamanhos de partícula medidos a partir de padrões de difração de raios X (DRX) e imagens de microscopia eletrônica de transmissão (MET) confirmam nanoestruturas na faixa de 16-36 nm. Os valores de bandas ópticas (Eg) aumentam com a concentração de íons Y+3 sendo 3,30 e 3,58 eV para x = 0,00 e x = 0,04, respectivamente. A dopagem com ítrio na ferrita de cobalto afeta as propriedades magnéticas. Por exemplo, a magnetização de saturação (MS) e a magnetização remanescente (Mr), diminuem de 69 emu.g-1 para 33 e 28 para 12 emu.g-1 para x = 0,00 e x = 0,04, respectivamente. Por outro lado, a coercividade (HC), aumenta de 1100 para 1900 Oe para x = 0,00 e x = 0,04 à temperatura ambiente. Também foidescoberto que MS, Mr e HC diminuem com o aumento da temperatura até 773 K. A constante de anisotropia magnetocristalina (K1), determinada usando a lei de approach para magnetizações próximas à saturação diminuem com a concentração do íon Y3 + e com a temperatura. Os valores de K1 para x = 0,00 e (x = 0,04) foram 3,3 x 106 erg.cm-3 (2,0 x 106 erg.cm-3) e 0,4 x 106 erg.cm-3 (0,3 x 106 erg.cm-3) a 300 K e 773 K, respectivamente. Os resultados foram discutidos em termos de interações entre partículas induzidas por flutuações térmicas e distribuição dos íons Co2+ nos sítios tetraédricos e octaédricos da estrutura espinélio, principalmente devido à substituição iônica pelo Y3+. Também neste trabalho preparou-se nanopartículas de óxido de zinco (ZnO) pelo método do poliol utilizando acetato de zinco e acetato de sódio em solução de propileno glicol com controle sobre o tempo de reação da hidrólise (RH) e submetendo à variação de parâmetros reacionais, como razão de hidrólise (th) e razão de contra íons acetatos (ta). Observou-se que o tempo de reação da hidrólise e a adição de íons acetato tiveram um forte efeito na morfologia e tamanho das partículas de ZnO. Por exemplo, imagens de microscopia eletrônica de transmissão (MET) revelaram que as amostras de ZnO sintetizadas por tempo curto de RH (10 min) e tempo de RH longo (300 min) cristalizaram em pequenos bastões e em formas de bastões alongados, respectivamente. Por outro lado, utilizando apenas reagente de acetato de zinco, as amostras de ZnO cristalizaram numa forma aproximadamente esférica. Essas diferenças podem ser atribuídas à relação da polarização do acetato e do propileno glicol, isto é, a maior quantidade de acetato presente na solução afeta o crescimento preferencial orientado dos cristais de ZnO. Além disso, o tempo de RH causou alterações no gap de banda óptica (Eg) das amostras. Por exemplo, os valores determinados pelo modelo de Kubelka-Munk diminuíram de 3,31 eV para 3,28 eV para os tempos, curto e longo de RH, respectivamente. Isto pode ser explicado em termos de defeitos estruturais e principalmente devido à diferença entre os tamanhos de partículas. Os padrões de difração de raios X (DRX) revelaram que todas as amostras cristalizaram na estrutura típica de wurtzita de ZnO. Contudo, a intensidade relativa do pico de difração (002) das amostras de ZnO sintetizadas apenas com acetato de zinco foi superior àqueles sintetizados utilizando tanto acetato de zinco como acetato de sódio. Isto indica de que o eixo c deve ser a direção de crescimento preferencial dos cristais. Portanto, a morfologia das amostras de ZnO pode ser adaptada usando o método poliol, assim as propriedades físicas que são importantes para algumas aplicações tecnológicas, poderiam ser controladas.Submitted by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-09-19T15:25:10Z No. of bitstreams: 2 Tese - Thiago Eduardo Pereira Alves - 2018.pdf: 6446029 bytes, checksum: 608f540fa5df66d012459688ced998d9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-09-20T11:36:11Z (GMT) No. of bitstreams: 2 Tese - Thiago Eduardo Pereira Alves - 2018.pdf: 6446029 bytes, checksum: 608f540fa5df66d012459688ced998d9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Made available in DSpace on 2018-09-20T11:36:11Z (GMT). No. of bitstreams: 2 Tese - Thiago Eduardo Pereira Alves - 2018.pdf: 6446029 bytes, checksum: 608f540fa5df66d012459688ced998d9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-07-18Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESapplication/pdfporUniversidade Federal de GoiásPrograma de Pós-graduação em Química (IQ)UFGBrasilInstituto de Química - IQ (RG)http://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessNanomagnetismoCoFe2O4ZnOReação de combustãoMétodo poliolNanomagnetismCombustion reactionPolyol methodCIENCIAS EXATAS E DA TERRA::QUIMICASíntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliolSynthesis, characterization and study of the magnetic and optical properties of nanoparticulated oxides: CoFe2-xYxO4 produced by combustion reaction and ZnO developed by the polyol methodinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesis663693921325415158600600600600782606674374119727815717003253031171952075167498588264571reponame:Repositório Institucional da UFGinstname:Universidade Federal de Goiás (UFG)instacron:UFGLICENSElicense.txtlicense.txttext/plain; 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dc.title.eng.fl_str_mv |
Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol |
dc.title.alternative.eng.fl_str_mv |
Synthesis, characterization and study of the magnetic and optical properties of nanoparticulated oxides: CoFe2-xYxO4 produced by combustion reaction and ZnO developed by the polyol method |
title |
Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol |
spellingShingle |
Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol Alves, Thiago Eduardo Pereira Nanomagnetismo CoFe2O4 ZnO Reação de combustão Método poliol Nanomagnetism Combustion reaction Polyol method CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol |
title_full |
Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol |
title_fullStr |
Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol |
title_full_unstemmed |
Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol |
title_sort |
Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol |
author |
Alves, Thiago Eduardo Pereira |
author_facet |
Alves, Thiago Eduardo Pereira |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
Franco Júnior, Adolfo |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/0187547195548392 |
dc.contributor.referee1.fl_str_mv |
Franco Júnior, Adolfo |
dc.contributor.referee2.fl_str_mv |
Pessoa, Márcio Solino |
dc.contributor.referee3.fl_str_mv |
Araújo, Olacir Alves |
dc.contributor.referee4.fl_str_mv |
Lima, Emília Celma de Oliveira |
dc.contributor.referee5.fl_str_mv |
Sartoratto, Patrícia Pommé Confessori |
dc.contributor.authorLattes.fl_str_mv |
http://lattes.cnpq.br/3930238965441986 |
dc.contributor.author.fl_str_mv |
Alves, Thiago Eduardo Pereira |
contributor_str_mv |
Franco Júnior, Adolfo Franco Júnior, Adolfo Pessoa, Márcio Solino Araújo, Olacir Alves Lima, Emília Celma de Oliveira Sartoratto, Patrícia Pommé Confessori |
dc.subject.por.fl_str_mv |
Nanomagnetismo CoFe2O4 ZnO Reação de combustão Método poliol |
topic |
Nanomagnetismo CoFe2O4 ZnO Reação de combustão Método poliol Nanomagnetism Combustion reaction Polyol method CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.eng.fl_str_mv |
Nanomagnetism Combustion reaction Polyol method |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
n this study we investigated the structural, optical band-gap, and magnetic properties of CoFe2-xYxO4 ) nanoparticles (NPs) synthesized using a combustion reaction method without the need for subsequent heat treatment or the calcing process. The particle size measured from X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images confirms the nanostructural character in the range of 16–36 nm. The optical band-gap (Eg) values increase with the Y3+ ion concentration being 3.30 and 3.58 eV for x = 0,00 and x = 0,04, respectively. The presence of yttrium in the cobalt ferrite (Y-doped cobalt ferrite) structure affects the magnetic properties. For instance, the saturation magnetization, MS and remanent magnetization, Mr, decrease from 69 emu.g-1 to 33 and 28 to 12 emu.g-1 for x = 0,00 and x = 0.04, respectively. On the other hand the coercivity, Hc, increases from 1100 to 1900 Oe for x = 0,00 and x = 0,04 at room temperature. Also we found that MS, Mr, and Hc decreased with increasing temperature up to 773 K. The cubic magnetocrystalline constant, K1, determined by using the ‘‘law of approach’’ (LA) to saturation decreases with Y3+ ion concentration and temperature. K1 values for x = 0,00 (x = 0,04) were 3,3 x 106 erg.cm-3 (2,0 x 106 erg.cm-3) e 0,4 x 106 erg.cm-3 (0,3 x 106 erg.cm-3) at 300 K and 773 K, respectively. The results were discussed in terms of inter-particle interactions induced by thermal fluctuations, and Co2+ ion distribution over tetrahedral and octahedral sites of the spinel structure due to Y3+ ion substitution. Also, in the present work, zinc oxide (ZnO) nanoparticles were prepared by the polyol method which consist of zinc acetate acetate and sodium acetate in propylene glycol solution with control over the hydrolysis reaction time and subjecting to the variation of reaction parameters, as ratio of hydrolysis (th) and ratio of acetate (ta). It was observed that the reaction time of the hydrolysis and the addition of ions had a strong effect on the morphology and size of the ZnO particles. For example, transmission electron microscopy (TEM) images revealed that the ZnO samples were synthesized for short time of RH (10 min) and long time (300 min) in small rods and in elongated rod forms, respectively. On the other hand, using only zinc acetate reagent, as the ZnO samples crystallized into a coarse spherical shape. These differences can be attributed to the polarization of the acetate and the propylene glycol, i.e., the greater amount of deficits present in the preferred growth solution of the ZnO crystals. In addition, the HR time does not change changes in the optical band gap. For example, values controlled by the Kubelka-Munk model decreased from 3.31 eV to 3.28 eV for the short HR time and the long HR time, respectively. This can be explained in terms of defects and is due to the change in particle sizes. X-ray diffraction patterns (XRDs) revealed that all the units crystallized the typical wurtzite structure of ZnO. However, the relative intensity of the diffraction peak (002) of the ZnO samples was synthesized with zinc acetate and was higher than the sensations from zinc acetate as sodium acetate. That is, an indication of direction should be directed toward the preferential growth of the crystals. Therefore, the morphology of the ZnO samples can be adapted using the polyol method, just as the physical properties are important for some technological applications. |
publishDate |
2018 |
dc.date.accessioned.fl_str_mv |
2018-09-20T11:36:11Z |
dc.date.issued.fl_str_mv |
2018-07-18 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
ALVES, Thiago Eduardo Pereira. Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol. 2018. 156 f. Tese (Doutorado em Química) - Universidade Federal de Goiás, Goiânia, 2018. |
dc.identifier.uri.fl_str_mv |
http://repositorio.bc.ufg.br/tede/handle/tede/8894 |
identifier_str_mv |
ALVES, Thiago Eduardo Pereira. Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol. 2018. 156 f. Tese (Doutorado em Química) - Universidade Federal de Goiás, Goiânia, 2018. |
url |
http://repositorio.bc.ufg.br/tede/handle/tede/8894 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.relation.program.fl_str_mv |
663693921325415158 |
dc.relation.confidence.fl_str_mv |
600 600 600 600 |
dc.relation.department.fl_str_mv |
7826066743741197278 |
dc.relation.cnpq.fl_str_mv |
1571700325303117195 |
dc.relation.sponsorship.fl_str_mv |
2075167498588264571 |
dc.rights.driver.fl_str_mv |
http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
http://creativecommons.org/licenses/by-nc-nd/4.0/ |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal de Goiás |
dc.publisher.program.fl_str_mv |
Programa de Pós-graduação em Química (IQ) |
dc.publisher.initials.fl_str_mv |
UFG |
dc.publisher.country.fl_str_mv |
Brasil |
dc.publisher.department.fl_str_mv |
Instituto de Química - IQ (RG) |
publisher.none.fl_str_mv |
Universidade Federal de Goiás |
dc.source.none.fl_str_mv |
reponame:Repositório Institucional da UFG instname:Universidade Federal de Goiás (UFG) instacron:UFG |
instname_str |
Universidade Federal de Goiás (UFG) |
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UFG |
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UFG |
reponame_str |
Repositório Institucional da UFG |
collection |
Repositório Institucional da UFG |
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