Luminescence
Mostrando 13-24 de 435 artigos, teses e dissertações.
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13. OS LANTANÍDEOS NAS REDES METALORGÂNICAS: UMA NOVA CLASSE DE MATERIAIS POROSOS
Lanthanoid organic frameworks (LOFs) stand out as an important class of functional materials. The possibility to employ a great range of metals and ligands lead to the formation of varied and highly porous structures, with diverse applications. The presence of lanthanoid ions favours the improvement of the optical, magnetic and redox properties of MOFs. This
Quím. Nova. Publicado em: 2018-06
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14. Syntheses, Experimental and Theoretical Studies on Absorption/Emission Properties of Pyrazoline-Containing Aryl/Methoxynaphthyl Substituents
5-Aryl-3-(2-methoxynaphthalen-6-yl)-1-phenylpyrazoline derivatives were synthesized starting from (E)-1-(3-aryl)-(2-methoxynaphthalen-6-yl)-prop-2-en-1-one and phenylhydrazine. The compounds were characterized by 1H and 13C nuclear magnetic resonance (NMR), elemental analyses and mass spectrometry. Some compounds showed promising luminescence properties in s
J. Braz. Chem. Soc.. Publicado em: 2018-06
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15. Effect of Dy3+ Amount on the Structural and Luminescence Properties of LaNbO4:Dy3+ Phosphor Obtained by One-Step Spray Pyrolysis Process
In this study, Dy3+-doped LaNbO4 phosphors with a blue to white emission that can be tuned by varying the activator concentration were prepared by one-step spray pyrolysis process. According to the powder X-ray diffraction results, increasing Dy3+ concentration favored the tetragonal phase. Slight changes were observed in the recorded Raman spectra as a func
J. Braz. Chem. Soc.. Publicado em: 2018-03
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16. A cathodoluminescence-assisted LA-ICP-MS study of topaz from different geological settings
ABSTRACT: In this study, the crystallization dynamics and the fingerprints of two topaz crystals from the Ouro Preto region (Brazil), two from the Eastern Brazilian Pegmatite Province (EBPP), one from the Western part of the United States (US) and one from Pakistan were characterized. The combination of scanning electron microscope-cathodoluminescence (SEM-C
Braz. J. Geol.. Publicado em: 2018-01
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17. Modulator Effect of Acetic Acid on the Morphology of Luminescent Mixed Lanthanide-Organic Frameworks
The control of the size and morphology of Metal-Organic Frameworks is a challenge that must be overcome to ensure the use of these materials in advanced applications. Mixed Lanthanide-Organic Frameworks (MLOFs) were synthesized via solvo(hydro)thermal method and then characterized by PXRD, IR, TG/DTA, SEM and PL spectroscopy. The effect of the modulator (ace
Mat. Res.. Publicado em: 30/11/2017
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18. PONTOS QUÂNTICOS AMBIENTALMENTE AMIGÁVEIS: DESTAQUE PARA O ÓXIDO DE ZINCO
Semiconductor nanocrystals with sizes in the quantum confinement regime (2-10 nm) present special physical and chemical properties. Additionally, environment-friendly quantum dots (QDs), as zinc oxide and zinc sulfide, offer many practical usages. Herein the ZnO semiconductor nanocrystals properties will be preferentially explored, such as its luminescence,
Quím. Nova. Publicado em: 2017-10
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19. Influence of the Protonatable Site in the Photo-Induced Proton-Coupled Electron Transfer between Rhenium(I) Polypyridyl Complexes and Hydroquinone
In the present work the influence of the distance of the protonatable site of different ancillary ligands to the metal center on the luminescence quenching of ReI polypyridyl complexes by hydroquinone are evaluated by means of experimental and theoretical studies. In these systems, it is expected the occurrence of proton-coupled electron transfer (PCET) reac
J. Braz. Chem. Soc.. Publicado em: 2017-09
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20. Understanding the water uptake in F-161 glass-epoxy composites using the techniques of luminescence spectroscopy and FT-NIR
Abstract This paper investigates the application of the luminescence spectroscopy technique in steady–state to study the moisture influence in glass fiber/epoxy prepreg and their laminates. The studies were monitored by intrinsic luminescence comparing the results with gravimetric analysis and near infrared with Fourier transform. Samples are cured and sub
Polímeros. Publicado em: 29/06/2017
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21. Luminescent and Magnetic Properties of Fe3O4@SiO2:phen:Eu3+
Magnetite was doped with rare earth ions (europium) to produce core-shell materials with both magnetic and luminescent properties, i.e., a magnetic Fe3O4 oxide core and a SiO2:phen:Eu3+ shell. The resulting material was analyzed by X-ray powder diffraction and transmission electron microscopy, and subjected to magnetic and luminescence emission measurements.
Mat. Res.. Publicado em: 24/06/2017
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22. Cordão Formation: loess deposits in the southern coastal plain of the state of Rio Grande do Sul, Brazil
ABSTRACT Loess consists of silt-dominated sediments that cover ~10% of the Earth's surface. In southern South America it occurs in Argentina, Bolivia, Paraguay and Uruguay, and its presence in southern Brazil was never studied in detail. Here is proposed a new lithostratigraphic unit, Cordão Formation, consisting of loess deposits in the southern Brazilian
An. Acad. Bras. Ciênc.. Publicado em: 2016-12
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23. INTERACTION OF CHALCONES WITH CT-DNA BY SPECTROPHOTOMETRIC ANALYSIS AND THEORETICALSIMULATIONS
Chalcones are open chain molecules precursors of flavonoids and isoflavonoids, found spread in edible plants. Because they are easily accessible trough Claisen Shmidt condensation, a great variety of derivatives are available. They have also shown potential in pharmacological and biological applications. It is known that chalcone derivatives display a role i
Quím. Nova. Publicado em: 2016-09
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24. Datação de sedimentos brasileiros por luminescência opticamente estimulada e termoluminescência isotérmica do quartzo: do Holoceno tardio ao Plioceno?
RESUMO: O desenvolvimento da datação de sedimentos por luminescência opticamente estimulada (optically stimulated luminescence, OSL) proporcionou considerável avanço na geocronologia do Quaternário. A datação por OSL constitui técnica bem estabelecida para determinar idades de deposição de sedimentos com algumas dezenas de anos até poucas cente
Braz. J. Geol.. Publicado em: 2016-06