Photo Excitation
Mostrando 1-12 de 22 artigos, teses e dissertações.
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1. 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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2. Emission Properties Related to Distinct Phases of Sol-Gel Dip-Coating Titanium Dioxide, and Carrier Photo-Excitation in Different Energy Ranges
Titanium dioxide (TiO2) in the form of pellets (pressed powder) and thin films are investigated, revealing the presence of distinct phases: mainly anatase and rutile. Characterization of optical, structural and electrical properties were carried out on samples submitted to different sort of thermal annealing (TA), at distinct temperatures, 500 and 1000ºC, d
Mat. Res.. Publicado em: 20/03/2017
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3. 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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4. Antilocalization effect on photo-generated carriers in semi-insulating GaAs sample
Magnetoresistance measurements were performed on an illuminated semi-insulating GaAs sample with intrinsic deep level defects. Electrical carriers were photo-generated under light excitation and positive magnetoresistance for B < 0.2 T was observed in the whole range of temperatures measured (220-315 K). Using the model developed by H. Fukuyama and K. Hoshin
Materials Research. Publicado em: 26/06/2012
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5. Estudo das propriedades opto-eletrônicas de micro-cristais de rubi / Study of opto-electronics properties of ruby micro-crystals
Films of amorphous aluminum-nitride (AlN) were prepared by conventional radio frequency sputtering of an Al+Cr target in a plasma of pure nitrogen. The Cr-to-Al relative area determines the chromium content, which stayed in the ~ 0 3.33 at.% concentration range in the present study. Film deposition was followed by thermal annealing the samples up to 1050 ºC
Publicado em: 2010
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6. 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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7. Estudo e aplicações do fenômeno de absorção de dois fótons em moléculas azo-aromáticas / Studies and applications of two-photon absorption in azo-aromatic molecules
Here we investigated fundamental and applied aspects of the two-photon absorption process in azoaromatic compounds. Azoaromatic molecules have been studied in the last few years due to their applications in optical storage devices, light modulators and surface relief gratings, processes related to the photo-isomerization mechanism. The main focus of the resu
Publicado em: 2007
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8. Espectroscopia de multicoincidencia aplicada ao estudo de moleculas
The main purpose of this thesis is to study selective photo-fragmentation processes of free molecules excited by synchrotron radiation using multi-coincidence spectros-copy. Below are summarized some original and important contributions of this work: 1) We show for the first time experimental evidences of ultrafast dissociation in water molecule after O1s ®
Publicado em: 2002
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9. Aplicações de técnicas espectroscópicas e polarográficas para caracterização e avaliação da reatividade do húmus com o herbicida atrazina. / Application of spectroscopic and polarographic methods to characterize and evaluate the reactivity between humus and atrazine.
One alternative to disposal of urban residues is recycling through composts and earthworm composts (humus production). The absence of a quality standard of these materials however brings limitations to commercial development with damage to producers and consumers. In this work was proposed a strategic parameter to be used as standard. From Electron Paramagne
Publicado em: 1999
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10. Estudo de propriedades opticas e de transporte em estruturas semicondutoras em dopagem planar
In this work we investigated semiconductor microstructures which provide the confinement of photogenerated holes. In systems obtained by periodically doping a layer of homogeneous material (M-d), this confinement is evidenced as the spacing between the dopant plans decreases and quantum limit for holes is achieved. On the other hand, as far as electrons are
Publicado em: 1993
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11. Ultra-fast excited state dynamics in green fluorescent protein: multiple states and proton transfer.
The green fluorescent protein (GFP) of the jellyfish Aequorea Victoria has attracted widespread interest since the discovery that its chromophore is generated by the autocatalytic, posttranslational cyclization and oxidation of a hexapeptide unit. This permits fusion of the DNA sequence of GFP with that of any protein whose expression or transport can then b
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12. Cold-Resistant and Cold-Sensitive Maize Lines Differ in the Phosphorylation of the Photosystem II Subunit, CP29.
The effects of low temperature on the relative contributions of the reaction center and the antenna activities to photosystem II (PSII) electron transport were estimated by chlorophyll fluorescence. The inhibition of PSII photochemistry resulted from photo-damage to the reaction center and/or a reduced probability of excitation energy trapping by the reactio