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Master's Dissertation
DOI
https://doi.org/10.11606/D.54.1983.tde-07042010-143424
Document
Author
Full name
João Mariz Guimarães Neto
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1983
Supervisor
Committee
Giacometti, José Alberto (President)
Oliveira, Luiz Nunes de
Wagner, Jerome
Title in Portuguese
Descargas termo-estimuladas no teflon fep-a em circuito aberto.
Keywords in Portuguese
Corrente termo estimulada
Descarga corona
Teflon fep-A
Abstract in Portuguese
Foram construídas duas montagens experimentais: Com a primeira, mediu-se o decaimento do potencial de superfície em circuito aberto, em função da temperatura; com a segunda mediu-se diretamente a corrente termo-estimulada (derivada do potencial de superfície em circuito aberto) aquecendo-se a amostra a uma taxa constante. Usando essas técnicas estudamos as propriedades de transporte e armazenamento de cargas no Teflon FEP-A, carregado com corona. Usando a segunda técnica, verificou-se que amostras descarregadas, do citado material, podem liberar portadores de cargas positivas que dão origem a uma corrente anômala, que pode interferir nas medidas de corrente termo-estimulada de amostras carregadas positivamente. Estudou-se o comportamento das curvas de corrente em amostras com e sem tratamento térmico, carregadas com corona tanto positiva como negativa. Além disto, é feita uma discussão dos resultados por nós obtidos e os publicados na literatura.
Title in English
Open-circuit TSD method in Teflon fep-A
Keywords in English
Corona discharge
Teflon fep-A
TSD
Abstract in English
Two experimental systems were constructed: with the first the surface potential could be measured, while with the second, its derivative with respect to the time (the so called open circuit current). In both cases the measurements were performed while heating previously positive or negative corona charged FEP-A Teflon 25μm samples. The results gave information about charge storage and transport properties in this material. During the work it was noticed that positive ions maybe emitted from Teflon surface. This unexpected phenomenon was followed in some detail in order to know how far it influences the usual currents. This study led us to carry measurements in previously annealed samples, whose behavior was found to differ from that of virgin samples. Our results were compared with those found in the literature.
 
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Publishing Date
2010-06-28
 
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