Search for dissertations about: "frequency domain spectroscopy"

Showing result 21 - 25 of 48 swedish dissertations containing the words frequency domain spectroscopy.

2. 21. Ultra-fast dynamics in atoms and molecules during photoionization: from attoseconds to femtoseconds

   Author : Erik Månsson; Synkrotronljusfysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; photoelectron spectroscopy; momentum imaging; coincident detection; correlation; direct double ionization; Born–Oppenheimer approximation; high harmonics; synchrotron radiation; Fysicumarkivet A:2014:Månsson;

   Abstract : Treating the correlated behaviour of multiple particles is challenging for both theory and experiment. This thesis reports on a variety of experimental investigations aiming to advance the understanding of fundamental processes in atoms and molecules: double ionization, isomerization and dissociation. READ MORE

4. 22. On-line time domain reflectometry diagnostics of medium voltage XLPE power cables

   Author : Valentinas Dubickas; Roland Eriksson; Tord Bengtsson; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Elektroteknik;

   Abstract : Degradation of XLPE insulated power cables by water-trees is a primary cause of failure of these cables. The detection of water-trees and information about the severity of the degradation can be obtained with off-line measurement using dielectric spectroscopy. In many situations only a limited part of the cable may be degraded by the water-trees. READ MORE

5. 23. Arbitrary Waveform Impedance Spectroscopy for Characterization and Diagnostics of High Voltage Insulation

   Author : Björn Sonerud; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; insulation testing; aging; monitoring; discrete Fourier transforms; Dielectric measurements; dielectric materials;

   Abstract : In high voltage engineering the dielectric response technique is a widely used tool both for characterization of insulation materials and for diagnostics of components such as transformers and cables. Currently available techniques are not capable of measuring on-line which would be advantageous; when characterizing a material and evaluating the effect of different voltage magnitudes, waveforms and temperatures it is desirable to be able to observe the continuous development of the dielectric properties. READ MORE

6. 24. Diagnostics of stator insulatin by dielectric response and variable frequency partial discharge measurements : a study of varied low frequencies in stator insulation, with particular attention to end-winding stress-grading

   Author : Nathaniel Taylor; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Elektroteknik;

   Abstract : Stator insulation is a critical to the reliability of electrical generators and motors. It is common industrial practice to use electrical measurement of partial discharges (PD) and some form of current-voltage measurement as part of the condition assessment of stator insulation at maintenance times. READ MORE

7. 25. Radio Frequency Systems for NMR Imaging: Coil Development and Studies of Non-Thermal Biological Effects

   Author : Lars Malmgren; Lunds universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; anechoic chamber; TEM transmission cells; FDTD; circularly polarized electromagnetic fields; reduced coupling; noise matching; matching networks; low noise amplifiers; upper thoracic spine; surface coils; Nuclear magnetic resonance; magnetic resonance imaging; non-thermal biological effects; blood-brain barrier; Electronics; Elektronik;

   Abstract : This thesis concerns both design and optimization of NMR imaging systems and studies on non-thermal biological effects of electromagnetic fields. These two research fields are linked together by the fact that humans are subject to static and pulsed magnetic fields as well as to magnetic radio frequency fields (RF) during an NMR imaging investigation. READ MORE