Synchrotron Radiation
Mostrando 1-12 de 109 artigos, teses e dissertações.
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1. Green Synthesis of Upconverting NaYF4 and NaGdF4 Materials and Energy Levels Determination
An alternative green route using a domestic microwave oven to synthesize NaGdF4:Yb,Tm and NaYF4:Yb,Er was successfully developed. Decreasing dopants concentration increased the β-NaREF4/α-NaREF4 ratio in NaGdF4. The scanning electron microscopy (SEM) images of NaGdF4 showed particles ranging from 500 nm to 1 μm with formation of aggregates up to 100 μm,
J. Braz. Chem. Soc.. Publicado em: 2021-08
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2. Elemental Composition of Particulate Matter in the Southeastern Brazilian Ceramic Pole by Synchrotron Radiation X-ray Fluorescence Technique (SR-XRF)
In the present study, the elemental content of the particulate matter PM2.5 (particulate matter with diameters lower than 2.5 µm) and PM10 (particulate matter with diameters lower than 10 µm) of the Brazilian city of Rio Claro (SP) were analyzed by synchrotron radiation X-ray fluorescence (SR-XRF) in the Brazilian Synchrotron Light Laboratory (LNLS). A fra
J. Braz. Chem. Soc.. Publicado em: 2020-06
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3. LABORATORY INVESTIGATION OF X-RAY PHOTOLYSIS OF METHANOL ICE AND ITS IMPLICATION ON ASTROPHYSICAL ENVIRONMENTS
Methanol (CH3OH) is one of the most abundant organic molecules in astrophysical environments. It has been found in cold regions such as surfaces of comets, ices near young stellar objects and protoplanetary disks, as well as in the gas phase in different regions in space. In this work, we experimentally simulate the methanol ice and its behavior when irradia
Quím. Nova. Publicado em: 2020-05
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4. Elemental Concentration and Sulfur Chemical Speciation in the Amazonian Plant Andira surinamensis Using Synchrotron Radiation Techniques (SR-XRF, XANES), RBS and WD-XRF
The inorganic composition of the bark and leaf of a plant from the Amazon rainforest, Andira surinamensis, was determined using two non-destructive, multi-element techniques: X-ray fluorescence (XRF) and Rutherford backscattering spectrometry (RBS). XRF measurements were made using both a conventional X-ray source and synchrotron radiation. It was observed t
J. Braz. Chem. Soc.. Publicado em: 16/09/2019
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5. Análisis arqueométrico de pigmentos del sitio arqueológico Tambo Colorado por difracción de rayos X sincrotrón
ABSTRACT Despite the exceptional architecture and polychromy of archaeological site of Tambo Colorado, there has been no conservation work or in the architectural structures of raw earth, nor on the surfaces. These jobs require a proper understanding of the state of conservation of the site architecture and the analysis of the materials used. With this purpo
Matéria (Rio J.). Publicado em: 20/05/2019
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6. Local piezo-response for lead-free Ba0.9Ca0.1Ti0.9Zr0.1O3 electro-ceramic by switching spectroscopy
The purpose of this work is to determine the effective piezoelectric coefficient (d33) and the macro ferroelectric hysteresis behavior for the Ba0.9Ca0.1Ti0.9Zr0.1O3 (BCZT). The sample was prepared by the modified Pechini method and it was sintered at 1250 ºC for 5 h. The refinements of X-ray diffraction (XRD) patterns obtained by the Rietveld method sugges
Mat. Res.. Publicado em: 11/01/2018
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7. In Situ Synchrotron Radiation Measurements During Axial Strain In Hydrogen Cathodically Charged Duplex Stainless Steel SAF 2205
The objective of this work is the evaluation of hydrogen effects on the martensitic transformation and strain hardening in Duplex Stainless Steels (DSS) SAF 2205 (UNS S32205/S31803). DSS are two-phase alloys (austenite and ferrite), which are used for applications requiring high mechanical strength, in corrosive environments. Therefore, it is necessary a bet
Mat. Res.. Publicado em: 18/12/2017
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8. Ti-based BCC Alloy: Dehydrogenation Characterization Using Synchrotron and Neutron Diffraction
Dehydrogenation of a BCC alloy of composition 52Ti-12V-36Cr doped with 4 wt.% Zr7Ni10 was studied by diffraction using synchrotron and neutron radiations. In the case of synchrotron radiation dehydrogenation was imposed by raising the temperature while keeping the sample under vacuum. We found that prior to final dehydrogenation the FCC dihydride phase is be
Mat. Res.. Publicado em: 17/05/2016
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9. Study of expanded austenite formed in plasma nitrided AISI 316L samples, using synchrotron radiation diffraction
AISI 316L stainless steel samples nitrided at different conditions of temperature and time, showing different properties, such as nitrogen concentration (C N) and nitrided layer thickness, were studied. Expanded austenite (γN) diffraction peaks up to the (222) reflection were observed using suitable wavelength synchrotron radiation. XRD patterns were fitted
Mat. Res.. Publicado em: 11/11/2014
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10. Estudos de multicamadas auto-organizadas de ácidos fosfônicos por difração dispersiva em energia / Study of self-assembled multilayers of phosphonic acids by energy dispersive diffraction
Esta dissertação trata do estudo estrutural e termodinâmico de sistemas orgânicos auto-organizados utilizando diferentes técnicas de espalhamento de raios-x. Multicamadas autoorganizadas de dois tipos de moléculas de ácidos fosfônicos foram analisadas: para o OPA [Ácido octadecilfosfônico ¿ CH2(CH3)17PO(OH)2] e para o OcPA [Ácido octilfosfônico
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/02/2012
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11. Determinação de metais na bacia do rio Piracicaba usando as técnicas de Difusão em Filmes Finos por Gradiente de Concentração (DGT) e Fluorescência de Raios X Dispersiva em Energia (EDXRF) e por Reflexão Total (TXRF) / Determination of metals in Piracicaba river basin using Diffusive Gradients in Thin Films, and Energy Dispersive X-ray Fluorescence (EDXRF) and Total Reflection (TXRF) techniques
O desenvolvimento e aplicação de métodos analíticos na avaliação das concentrações de metais nas frações dissolvida e lábil na bacia do rio Piracicaba são de relevante importância para o estudo do comportamento químico-ambiental desses metais e para seu monitoramento, devido ao impacto das atividades antropogênicas nessa bacia. A técnica de d
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/09/2011
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12. Anéis de crescimento de árvores Tipuana tipu como biomonitores da poluição ambiental : quantificação pela Técnica de Fluorescência de Raios X por Reflexão Total com / Growth rings of trees Tipuana Tipu as biomonitors of environmental pollution : the quantification technique for X-ray Fluorescence Total Reflection with Synchrotron Radiation
Os metais podem ser introduzidos no ambiente naturalmente pelo intemperismo dos minerais e por fontes não naturais como fertilizantes, pesticidas, combustão de carvão e óleo, emissões veiculares, mineração, fundição, refinamento e incineração de resíduos urbanos e industriais. Atualmente muitos estudos utilizam os bioindicadores, plantas ou anima
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/08/2011