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Dielectric Relaxation Spectroscopy of Glycerol
Stráník, Rostislav ; Liedermann, Karel (advisor)
This doctoral thesis deals with the analysis of dielectric spectra of glycerol with dielectric relaxation spectroscopy (DRS). Dielectric spectra of glycerol have been measured in the frequency range 20 Hz to 10 MHz and in the temperature range 10 K to 300 K. The observed dielectric spectra featured a typical relaxation maximum, which could be in the first approximation described by the Arrhenius equation. The activation energy of the relaxation process observed was 90 MJ/kmol. The relaxation strength as well as the shape of the relaxation peak remained in the temperature interval 180 K - 230 K (visibility of peak) almost the same, thus indicating that no change of the relaxation mechanism comes about. Much attention was in the thesis paid to the analysis of the excess component of the relaxation alfa process, in the literature commonly denoted as "excess wing". The thesis puts forward a procedure for the quantification of the magnitude of the excess wing. The excess wing magnitude thus determined turns out to increase monotonously with increasing temperature. The excess wing is here interpreted as a manifestation of a weakly-pronounced beta relaxation.
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Study of electric properties of composite
Macháček, Miroslav ; Havlíček, Svatopluk (referee) ; Polsterová, Helena (advisor)
This work deals with issues of composite materials. The general aim is to observe how the amout of filling infuence dielectric spectrum which is measured on prepared samples. For this purpose had been created variety of a samples with different percentage of filling with mica. Measured values had been compared with theoretically values, determinated using mixture formulas.
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Dielectric Relaxation Spectroscopy of Glycerol
Stráník, Rostislav ; Liedermann, Karel (advisor)
This doctoral thesis deals with the analysis of dielectric spectra of glycerol with dielectric relaxation spectroscopy (DRS). Dielectric spectra of glycerol have been measured in the frequency range 20 Hz to 10 MHz and in the temperature range 10 K to 300 K. The observed dielectric spectra featured a typical relaxation maximum, which could be in the first approximation described by the Arrhenius equation. The activation energy of the relaxation process observed was 90 MJ/kmol. The relaxation strength as well as the shape of the relaxation peak remained in the temperature interval 180 K - 230 K (visibility of peak) almost the same, thus indicating that no change of the relaxation mechanism comes about. Much attention was in the thesis paid to the analysis of the excess component of the relaxation alfa process, in the literature commonly denoted as "excess wing". The thesis puts forward a procedure for the quantification of the magnitude of the excess wing. The excess wing magnitude thus determined turns out to increase monotonously with increasing temperature. The excess wing is here interpreted as a manifestation of a weakly-pronounced beta relaxation.
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|
|
Study of electric properties of composite
Macháček, Miroslav ; Havlíček, Svatopluk (referee) ; Polsterová, Helena (advisor)
This work deals with issues of composite materials. The general aim is to observe how the amout of filling infuence dielectric spectrum which is measured on prepared samples. For this purpose had been created variety of a samples with different percentage of filling with mica. Measured values had been compared with theoretically values, determinated using mixture formulas.
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