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Applications of Earth's Field NMR to porous systems and polymer gels [Elektronische Ressource] / Maarten Veevaete


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Fachbereich 1(Physik/Elektro- und Informationstechnik)Applications of Earth’s Field NMRto porous systems and polymer gelsMaarten VeevaeteGutachter: Prof. Dr. J. Bleck-NeuhausDr. habil. F. StallmachEingereicht am 06.10.2008Tag des mu¨ndliches Kolloqiums: 09.12.2008Dissertation zur Erlangung des Gradeseines Doktors der Naturwissenschaften (Dr. rer. nat.)AbstractIn this work, NMR relaxometry in the Earth’s magnetic field is used to characterize poroussystems and polymer gels. The used instrument is a home built Earth’s field NMR (EFNMR)device (Goedecke [1993]) that is slightly modified for those applications. The EFNMR device isequipped with some unique features such as first order gradiometer polarization and detectioncoils, shimming coils and a shielding box that make it possible to directly derive the relaxationtimes from the Free Induction Decay (FID) signal inside a laboratory building with a signalto noise ratio of about 100. The strength of the Earth’s magnetic field is about 50 μT,corresponding with Larmor frequencies of about 2 kHz. The experimental setup applying themeasurement method of Packard and Varian [1954] using pre-polarization, compensates forthe inherent low signal to noise ratio of NMR in the Earth’s magnetic field. By the use ofthe field-cycling technique, the EFNMR device is also capable of measuring the longitudinalrelaxation time at frequencies from 3 kHz up to 3 MHz.



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Published 01 January 2008
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Language English
Document size 3 MB