Thermoluminescence
Mostrando 25-36 de 50 artigos, teses e dissertações.
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25. Centros de cor, centros paramagnéticos e centros de luminescência dependentes de defeitos pontuais em zirconita / Color center, paramagnetic center and luminescence center due the defect point in zircon
In the present work the investigation of some properties of Thermoluminescence (TL), Electronic Paramagnetic Resonance (EPR) and Optical Absorption (OA) of two samples of zircon (of brown color) from Minas Gerais, but the unknown exact origin, were carried out. The glow curves of thermoluminescence emission have shown the presence of 4 TL peaks at 140, 215,
Publicado em: 2005
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26. Thermal and sctructural properties of the CaB4O7-CaB2O4 system viewing the development of thermoluminescent dosimeter / Propriedades térmicas e estruturais do sistema CaB4O7-CaB2O4 visando o desenvolvimento de dosímetro termoluminescente
Borate glasses containing modified oxides have been studied on account of their effective atomic number close to that of the human tissue, what makes them interesting materials for the development of the thermoluminescent dosimeters. The purpose of this work was to study the thermal and structure properties of the xCaB4O7-(100-x)CaB2O4 system with x ranging
Publicado em: 2005
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27. Dosimetria gama e concentração de 222Rn em ambientes de trabalho fechados da cidade de São Paulo / Gamma dosimetry and 222Rn concentration in indoor workplaces of São Paulo
In this work we present the evaluation of the ambient gamma dose rates and the concentration of 222Rn in the air of 16 rooms of radiotherapy centers and 15 places of seven subway stations in the city of São Paulo. The places included in this study were indoor places with continuous permanence of workers. The deepest working places of the subway stations in
Publicado em: 2005
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28. Panorama das exposições médicas em radiologia convencional no Estado de São Paulo / Overview of the medical exposures in coventional radiology in the State of São Paulo
Patients dosimetry, associated with the assessment of the performance of the radiological equipment and of the series of procedures employed in the accomplishment of the examinations, plays fundamental role in the radiation protection system of medical exposures. Therefore, a large-scale survey of absorbed doses was carried out in health services localized i
Publicado em: 2005
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29. Upper Pleistocene deposits of the Comprida Island (São Paulo State) dated by thermoluminescence method
As formações Cananéia (Pleistoceno superior) e Ilha Comprida (Holoceno), aflorantes na Ilha Comprida (SP), foram mapeadas com base em critérios geomorfológicos e litológicos. Uma amostra da Formação Cananéia, coletada na ilha homônima em frente à Ilha Comprida, apresentou idade superior ao alcance do método convencional de radiocarbono. Deste mod
Anais da Academia Brasileira de Ciências. Publicado em: 2003-03
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30. Laser sintering and characterization of the compounds Bi4Ti3O12 and Bi4Ge3O12 / "Sinterização a laser e caracterização física dos compostos Bi4Ti3O12 e Bi4Ge3O12"
The goals of this work were the implantation and optimization of the laser sintering technique for ceramic bodies, the kinetic study of the process and the evaluation of the physical properties of the laser sintered compounds Bi4Ti3O12 and Bi4Ge3O12, compared to ceramics sintered in conventional furnace. The choice of the materials was based on their potenti
Publicado em: 2003
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31. Efeito da radiação UV e gama nas propriedades de absorção óptica, de ressonância paramagnética eletrônica e de termoluminescência na kunzita / Effect of UV and gamma radiation on the properties of optical absorption, electron paramagnetic resonance and thermoluminescence in kunzite
O espodumênio (LiAl Si IND 2 O IND 6) de cor lilás, chamado kunzita, encontrado no Estado de Minas Gerais, foi investigado no presente trabalho. A análise de fluorescência de raios-X revelou, além das componentes básicas Si 0 IND 2, Al IND 2 O IND 3 e Li IND 2O, várias impurezas, sendo Mn e Fe as principais. Para comparação com o material natural, u
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/02/2002
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32. Desvendando a cor e a termoluminescência do topázio: um estudo dos defeitos e processos termicamente e opticamente estimulados no cristal natural / Unraveling the color of topaz and thermoluminescence: a study of defects and thermally and optically stimulated processes in natural crystal
O topázio [Al2SiO4(F,OH)2] é mais freqüentemente encontrado na natureza na forma incolor, a partir do qual gemas azuis vêm sendo produzidas comercialmente através da aplicação de radiação ionizante seguida de tratamentos térmicos. O topázio também exibe termoluminescência (ou luminescência termicamente estimulada) relativamente intensa, que é
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/06/2001
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33. Implementação de Grandezas Operacionais na Monitoração Individual e de Área / Implementation of new operational quantities in the Individual and area monitoring
Operational quantities have been implemented to be applied in individual and area routine monitoring against external radiation exposure. This procedure is based on the use of an ideal combination of thermoluminescent detectors inside a monitor: two pellets of CaF2, one covered by a lead filter of (0,50 ± 0,05) mm and another one without filter and one TLD-
Publicado em: 2000
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34. Charge accumulation and photochemistry in leaves studied by thermoluminescence and delayed light emission
A major breakthrough in our understanding of how plants oxidize water to molecular O2 was the discovery by P. Joliot and co-workers that the O2 yield per flash, in a series of light flashes, oscillates with a periodicity of 4. This led to the concept by B. Kok and co-workers that these reactions involve accumulation of four positive charges in independent �
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35. High CO2 concentration alleviates the block in photosynthetic electron transport in an ndhB-inactivated mutant of Synechococcus sp. PCC 7942.
The high-concentration CO2-requiring mutant N5 of Synechococcus sp. PCC 7942 was obtained by the insertion of a kanamycin-resistant gene at the EcoRI site, 12.4 kb upstream of rbc. The mutant is unable to accumulate inorganic carbon internally and exhibits very low apparent photosynthetic affinity for inorganic carbon but a photosynthetic Vmax similar to tha
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36. Changes in the Redox Potential of Primary and Secondary Electron-Accepting Quinones in Photosystem II Confer Increased Resistance to Photoinhibition in Low-Temperature-Acclimated Arabidopsis1
Exposure of control (non-hardened) Arabidopsis leaves for 2 h at high irradiance at 5°C resulted in a 55% decrease in photosystem II (PSII) photochemical efficiency as indicated by Fv/Fm. In contrast, cold-acclimated leaves exposed to the same conditions showed only a 22% decrease in Fv/Fm. Thermoluminescence was used to assess the possible role(s) of
The American Society for Plant Biologists.