Search for dissertations about: "Electric polarization"

Showing result 16 - 20 of 67 swedish dissertations containing the words Electric polarization.

2. 16. Electrical Characterization of Partial Discharge Resistant Enamel Insulation

   Author : Tuan Anh Hoang; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Enamel wire insulation; dipolar polarization; charge injection; charge transport; chromium oxide; dc conductivity; partial discharge; twisted pair.; dielectric permittivity;

   Abstract : Adjustable speed drives for rotating machines have become increasingly popular as they provide possibilities of smooth and accurate process control as well as for energy savings. In such systems, due to the fact that the voltage applied at terminals of motor windings is no longer purely sinusoidal but characterized by a high content of harmonics, the appearing electrical and thermal stresses yield premature failures of the winding insulation, mainly because of an increased partial discharge (PD) activity. READ MORE

4. 17. Impact of carrier localization on recombination in InGaN quantum wells with nonbasal crystallographic orientations

   Author : Ruslan Ivanov; Saulius Marcinkevičius; Nicolas Grandjean; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; InGaN; quantum well; semipolar; nonpolar; near-field microscopy; carrier localization; carrier transport; optical polarization; Fysik; Physics;

   Abstract : The modern InGaN technology demonstrates high efficiencies only in the blue spectral region and low current operation modes. The growth of InGaN quantum wells (QWs) on nonbasal crystallographic planes (NBP) has potential to deliver high-power blue and green light emitting diodes and lasers. READ MORE

5. 18. Surface potential dynamics on insulating polymers for HVDC applications

   Author : Shahid Alam; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric spectroscopy; silicone rubber; intrinsic conduction; surface potential decay; activation energy; electric conductivity; HVDC insulation;

   Abstract : The use of high voltage direct current (HVDC) technology in power transmission systems is continuously expanding. Nowadays, HVDC transmissions operate at voltages up to 800 kV and higher levels are being developed. READ MORE

6. 19. Sample Handling Techniques in Biological and Environmental Applications Emphasizing Biomolecular Recognition and MALDI-TOF MS

   Author : Patrik Önnerfjord; Reumatologi och molekylär skelettbiologi; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; protein identification; microchip IMER; microdispensing; MALDI-TOF MS; fluorescence polarization; flow immunoassay; pesticide immunoassays; phenol biosensor; restricted access media; SPE; Analytical chemistry; Analytisk kemi;

   Abstract : The use of restricted access media and other stationary phases for clean-up and trace enrichment of environmental samples coupled on-line to liquid chromatography using diode array detection as well as thermospray MS is described. This on-line configuration was compared with commercially available ELISAs for the determination of triazines in complex matrices, showing superior precision and accuracy with the chromatographic method. READ MORE

7. 20. P-type and polarization doping of GaN in hot-wall MOCVD

   Author : Alexis Papamichail; Vanya Darakchieva; Anelia Kakanakova-Gueorguieva; Jr-Tai Chen; Zhaoxia Bi; Linköpings universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : The devolopment of group-III nitride semiconductor technology continues to expand rapidly over the last two decades. The indium nitride (InN), gallium nitride (GaN) and aluminum nitride (AlN) compounds and their alloys are direct bandgap semiconductors with a wide bandgap range, spanning from infrared(IR) to deep-ultraviolet (UV), enabling their utilization in optoelectronic industry. READ MORE