Germanium
Mostrando 13-24 de 55 artigos, teses e dissertações.
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13. Avaliação dos efeitos da radiação ionizante em materiais utilizados em restaurações dentárias / EVALUATION OF EFFECTS OF IONIZING RADIATION ON MATERIALS USER IN DENTAL RESTORATIONS.
This work consisted of quantitative studies of the effects caused by ionizing radiation on materials used in dental restorations (Titanium, Amalgam, Resin Composite and Glass Ionomer) aiming the deleterious effects of radiotherapy when patients with tumors in head and neck, arising when the teeth are restored within in the field of radiation. Samples were su
Publicado em: 2009
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14. Optical properties of semiconductor type II quantum dots / Propriedades opticas de pontos quanticos semicondutores tipo II
No presente trabalho apresentamos um estudo da luminescência de érbio em nanocristais de silício (nc-Si) e nanofios de óxido de zinco (nw-ZnO). Os nanocristais de silício com érbio são obtidos através do tratamento térmico de filmes finos amorfos de sub-óxidos de silício (SiOx) preparados por rf-sputtering, variando a concentração de Oxigênio e
Publicado em: 2009
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15. Efeito da concentração de irídio sobre as propriedades de catalisadores do tipo Pt-Ge-Ir/Al2O3. / Effect of concentration of iridium on the properties of type catalysts Pt-Ge-Ir/Al2O3.
The effect of iridium content on the activity, selectivity and stability of platinum, germanium and iridium supported in alumina catalysts for oil naphta catalytic reforming was studied in this work. Samples were prepared by the impregnation of the metallic salts (hexachloroplatinic acid, hexachoroiridic acid and germanium chloride) over g-alumina in order t
Publicado em: 2008
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16. Produção e caracterização de filmes finos de GeO2-PbO. / Production and characterization of thin films of GeO2-PbO.
Este trabalho apresenta a produção e a caracterização de filmes finos produzidos a partir da técnica de RF Magnetron Sputtering. Foram produzidos filmes finos sobre substrato de silício a partir de alvos vítreos de germânio de GeO2-PbO preparados com e sem os reagentes AgNO3 e Cu2O. Foi desenvolvida metodologia adequada para a obtenção de nanopart�
Publicado em: 2008
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17. Caracterização do campo de nêutrons na instalação para estudo em BNCT no Reator IEA-R1 / NEUTRON FIELD CHARACTERIZATION IN THE INSTALLATION FOR BNCT STUDY IN THE IEA R1 REACTOR.
This work aims to characterize the mixed neutron and gamma field, in the sample irradiation position, in a research installation for Boron Neutron Capture Therapy (BNCT), in the IPEN IEA-R1 reactor. The BNCT technique has been studied as a safe and selective option in the treatment of resistant cancerigenous tumors or considered non-curable by the convention
Publicado em: 2008
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18. Distribuição de radionuclídeos em um afloramento de sedimentos permianos da formação Iratí na Bacia do Paraná
The objective of this work is to study natural radionuclides in sedimentary rocks. The concentration of them reflects the origin of the sediments, the deposicional environment as well as some mineralogical characteristics of the rock matrix, and also more recent events as weathering and erosion. Using gama ray high resolution spectrometry, the profile of act
Publicado em: 2008
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19. NATURAL RADIONUCLIDES AND 137Cs IN COMMERCIALIZED EDIBLE MUSHROOMS IN SÃO PAULO-BRAZIL / Radionuclídeos naturais e 137Cs em cogumelos comestíveis comercializados em São Paulo - Brasil
Artificial and natural radionuclides are commonly found in several compartments of the earths crust. Some mushroom species have a high capacity to absorb radionuclides and toxic elements from the soil. Diet is considered as one of the main routes of radioactive contamination. Therefore, radioactivity measurements in the environment and in food are extremely
Publicado em: 2008
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20. Cristalização do germanio amorfo pelo aluminio : caracterização por espectroscopia Raman / Aluminium induced crystallization of the amorphous germanium : characterization for Raman spectroscopy
This research work studies the microscopic mechanisms leading to the low-temperature crystallization of amorphous germanium (a-Ge) films induced by aluminum. The crystallization process was studied in Al-doped samples and also in multi-layer structures possessing an Al layer sandwiched between the substrate and the a-Ge film. In the case of Al-doped samples,
Publicado em: 2007
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21. Dose de radiação ionizante decorrente do uso de fertilizantes agrícolas / Ionizing radiation dose due to the use of agricultural fertilizers
Among several agents that exist in the environment which can expose us to different risks and effects, there is the ionizing radiation whose knowledge of dose is of importance to the effective control and prevention of possible damages to human beings and to the environment. The transfer of radionuclides from fertilizers to/and soils to the foodstuffs can re
Publicado em: 2007
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22. Development of silicon-germanium films for MOS / Desenvolvimento de filmes de silicio-germanio para aplicações em dispositivos MOS
Conforme os dispositivos eletrônicos atingem dimensões nanométricas, surgem limitações que não podem ser solucionadas com os materiais empregados atualmente, como efeito de canal curto, depleção de porta, corrente de fuga e variação do Vt devido à variação estatística da dopagem. Dessa forma, novos materiais devem ser introduzidos no processo d
Publicado em: 2006
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23. Synthesis and characterization of Ge nanocrystal by LPCVD / Sintese e caracterização de nanocristais de Ge por LPCVD
In this thesis we studied the synthesis of Ge nanocrystals (NCs) by the LPCVD technique (Low Pressure Chemical Vapor Deposition). We looked for NCs with characteristics of sizes, density and uniformity of sizes that are necessary for applications in floating gate memory devices. To reach those characteristics we have optimized the process conditions. The NCs
Publicado em: 2006
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24. Automation and monitoring for refractive index profile contrrol of VAD preforms for optical fibers / Automação e monitoramento para o controle do perfil de indice de refração de preformas VAD para fibras opticas
Fabrication of preforms for special optical fiber using VAD, "Vapor-phase Axial Deposition" tecnique has been in progress at the LIQC, UNlCAMP/FEM. ln this method, the processing parameters must be accurately controlled, particularly the refractive index profile determined by the germanium doping profile, which controls de data transmission characteristics i
Publicado em: 2005