Ultraviolet Excitation
Mostrando 1-12 de 40 artigos, teses e dissertações.
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1. Carbon Dots from Pilosocereus gounellei for Fluorimetric Determination of Tannin in Tea Using a Flow-Batch System
In this study, xiquexique (Pilosocereus gounellei) native endemic cactus from the Brazilian semiarid was used for the first time as a natural carbon source (“green precursor”) for the synthesis of highly fluorescent carbon dots (CDs). These CDs were successfully used to develop a fast, low-cost, eco-friendly fluorescence method for the determination of t
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. A novel fluorescence sensor for the detection of chloride ion in artificial sweat and environmental water with nitrogen-doped graphene quantum dots
A new fluorescent detection route for chloride ion was designed with Nitrogen-doped graphene quantum dots (N-GQDs), which were prepared by a traditional hydrothermal method with citric acid as carbon source and urea as nitrogen source. The prepared N-GQDs solution was light yellow, and the freeze-dried solid was black. It emitted blue light under ultraviolet
Química Nova. Publicado em: 2022
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3. Preparation of Fluorescent Carbon-Based Dots from Waste Tire Pyrolysis
The pyrolysis of waste tire has been proposed as an alternative route to its recycling producing residual oils that can be used as fuels. In this work, a physicochemical process to obtain carbon-based dots (CBD) from carbon black (CBL) derivatives of tires is described. For this, the CBL was treated with different acids to produce CBL1 and CBL2 particles sus
J. Braz. Chem. Soc.. Publicado em: 2020-11
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4. Synthesis and Characterization of Nb2O5:La3+,Eu3+ Phosphors Obtained by the Non-Hydrolytic Sol-Gel Process
The phosphor-converted light-emitting diode technique is an important solid-state illumination strategy. Sulfide-based materials are the most often employed red phosphors, but they are chemically unstable and present lower efficiency in comparison to the blue and green phosphors. Therefore, it is important to find a new red phosphor source that can emit inte
J. Braz. Chem. Soc.. Publicado em: 2015-12
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5. Electrospinning Preparation and Photoluminescence Properties of Y3Al5O12:Eu3+ Nanobelts
Novel structures of Y3Al5O12: Eu3+ (denoted as YAG: Eu3+ for short) nanobelts were fabricated by calcination of the electrospun PVP/[Y(NO3)3+Eu(NO3)3+Al(NO3)3] composite nanobelts. X-ray powder diffraction (XRD) analysis showed that YAG: Eu3+ nanobelts were cubic in structure with space group Ia3d. Fourier transform infrared spectroscopy (FTIR) analysis mani
Mat. Res.. Publicado em: 2015-04
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6. Photo-Induced conductivity of heterojunction GaAs/Rare-Earth doped SnO2
Rare-earth doped (Eu3+ or Ce3+) thin layers of tin dioxide (SnO2) are deposited by the sol-gel-dip-coating technique, along with gallium arsenide (GaAs) films, deposited by the resistive evaporation technique. The as-built heterojunction has potential application in optoelectronic devices, because it may combine the emission from the rare-earth-doped transpa
Mat. Res.. Publicado em: 23/04/2013
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7. Espectroscopia ultrarrápida do polímero semicondutor luminescente MEH-PPV com excitação no ultravioleta / Ultrafast spectroscopy of the luminescent semiconducting polymer MEH-PPV with ultraviolet excitation
The optoelectronics industry is currently undergoing a transition period in which inorganic materials are being replaced by organic materials, oligomers and polymers, in the fabrication of some types of devices. However, factors such as low efficiency and low lifetime prevent polymer based devices on entering the market definitely. The solution of these issu
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/08/2012
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8. Estudo da emissão por fluorescência de ultravioleta na quantificação de um inibidor de corrosão do tipo sal de amônio quaternário em água
Quaternary ammonium salts are the corrosion inhibitors most frequently used by the oil industry. In this study, the ultraviolet fluorescence technique was evaluated for the analysis of a quaternary ammonium salt in water as a corrosion inhibitor. The comparison with standard salt showed that an alkyl aryl quaternary ammonium salt is the main fluorophore, wit
Química Nova. Publicado em: 2012
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9. Study of the photoluminescent properties of MgTiO3 powder and thin films obtained by the polimeric precursor method / Estudo das propriedades fotoluminescentes de pós e filmes finos de MgTiO3 obtidos pelo método dos precursores poliméricos
In this study, MgTiO3 (MTO) powders and thin films that crystallize in a perovskite ilmenite crystalline structure were obtained and characterized. MTO were synthesized by the polymeric precursor method (PPM), which allows obtaining structurally ordered and disordered structures. In addiction, the photoluminescent properties were investigated as a function o
Publicado em: 2011
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10. Ordem-desordem: uma avaliação estrutural do Ba(ZrxTi1-x)O3 / Order-disorder: an evaluation structural of Ba(ZrxTi1x)O3
This work have as aim, the synthesis of ceramic powders of Ba(ZrxTi1x)O3 (x = 0, 0.25, 0.50, 0.75 and 1) by the polymeric precursor method and investigate the degree of structural order-disorder of these systems by different characterization techniques, such as: thermogravimetric analysis (TA), differential thermal analysis (DTA), X-ray diffraction (XRD), Ra
Publicado em: 2009
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11. Photoluminescence excited in the ultraviolet in conjugated polymers / "Fotoluminescência excitada no ultravioleta em polímeros conjugados"
Os polímeros conjugados luminescentes são materiais com grande potencial tecnológico, mas apesar de estudados desde a década de 80, algumas de suas propriedades óticas ainda não foram totalmente entendidas. Por exemplo, ainda persistem dúvidas quanto à natureza das suas excitações primárias. Nesse sentido foi feito um estudo da fotoluminescência
Publicado em: 2007
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12. Fluorescência óptica no diagnóstico de lesões teciduais / Optical fluorescence in tissue injury diagnosis
The fluorescence spectroscopy is a conventionally used method, in the study of materials for the compound determination in function to the characteristic emission bands. The same principle can be used to determine the presence of fluorescent agents in biological tissues, which can be useful in the diagnosis, and for a better direction in the treatment of tis
Publicado em: 2005