Uv Excitation
Mostrando 13-24 de 76 artigos, teses e dissertações.
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13. 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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14. Near Infrared Emission at 1000 nm from Nanostructured Pr3+/Yb3+ Co-doped SiO2-Nb2O5 for Solar Cell Application
Energy conversion, involving UV and Vis absorption to generate near infrared (NIR) emission at 1000 nm from nanostructured Pr3+/Yb3+ co-doped SiO2-Nb2O5 for solar cell application was the main focus of this work. The synthesis, structural and optical characterization of Pr3+/Yb3+ co-doped 70SiO2-30Nb2O5 nanocomposites and planar waveguides prepared by the so
J. Braz. Chem. Soc.. Publicado em: 2015-12
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15. Enhanced biosynthesis of quercetin occurs as A photoprotective measure in Lycopersicon esculentum mill. under Acute UV-B exposure
Lycopersicon esculentum respond to UV-B by enhanced synthesis of flavonoid quercetin, a strong antioxidant that helps the plants to well acclimatize to UV-B stress. Three weeks old plants of L. esculentum were subjected to acute UV-B irradiation for 20, 40 and 60 minutes daily until 28 days and analyzed for the morphological and biochemical changes. UV-B exp
Braz. arch. biol. technol.. Publicado em: 2014-06
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16. 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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17. Obtenção e caracterização de ftalocianinas com substituintes quirais com potencial aplicação em terapia fotodinâmica / Synthesis and characterization ofphthalocyanines with chiralsubstituints with potencialfor use in Photodynamic Therapy
The main objective of this project is the synthesis and characterization of new phthalocyanines with chiral substituents to improve their photophysical and photochemical properties for use as photosensitizers in Photodynamic Therapy. Three new phthalocyanines were synthesized and characterized, one with the racemic mixture of 1-(4-bromophenyl)- ethanol, and
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/02/2012
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18. 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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19. UV dominant optical emission newly detected from radioisotopes and XRF sources
The current paper reports first and definite experimental evidence for γ-, X-, or β radiation causing UV dominant optical radiation from (1) radiochemicals such as 131I; (2) XRF sources such as Rb XRF source present as salts; and (3) metal sources such as 57Co, and Cu XRF sources. Due to low quantum yield a need arose to develop two techniques with narrow
Brazilian Journal of Physics. Publicado em: 2010-03
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20. Estudos fotoluminescentes em compostos de íons terras raras coordenados por um derivado carbazólico
[RE(czb)3(H2O)2] complexes (where RE = Eu3+, Tb3+, Gd3+; and czb = 4-(9H-carbazol-9-yl)benzoato) have been synthesized and characterized. The Gd3+ complex was used to determine the triplet state energy of the czb ligand. Photoluminescence measurements of the complexes have been carried out under UV excitation. The Tb3+ complex exhibited a strong green lumine
Química Nova. Publicado em: 2010
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21. 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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22. The involvement of nucleotide excision repair in DNA oxidative lesions in mammals cells. / Estudos de reparo de DNA por excisão de nucleotídeos em lesões oxidativas em células de mamíferos.
Para melhor entender o envolvimento do NER em lesões oxidativas averiguou-se os efeitos da foto-excitação do azul de metileno (MB) in vitro e in vivo. Verificou-se que MB e luz induzem muitos sítios sensíveis a enzima FPG em DNA plasmidial. Mostrou-se que MB é incorporado por fibroblastos humanos proficientes ou deficientes em NER (XP-A e XP-C) e gerou
Publicado em: 2008
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23. Detecção condutométrica sem contato: uma nova ferramenta para monitoramento de interações biomoleculares em microssistemas analíticos / Contactless conductivity detection: a new tool for monitoring biomolecular interactions on analytical microsystems
The study reported in this thesis shows the application of a capacitively coupled contactless conductivity detection (C4D) for monitoring biomolecular interactions on analytical microsystems. Initially, the analytical performance of the microsystems fabricated in glass, poly(dimethylsiloxane) (PDMS) and polyester-toner (PT) was investigated in order to choos
Publicado em: 2008
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24. Caracterização óptica de dispersões aquosas de nanotubos de carbono
It has been demonstrated that the electronic and optical properties of single-wall carbon nanotubes (SWNT) are strongly affected by the environment. This strong environmental effect is very relevant in analyzing the composition of carbon nanotube samples using optical techniques, especially in the case of separation experiments, where the SWNT environments a
Publicado em: 2008