Sökning: "Permittivity"

Visar resultat 31 - 35 av 90 avhandlingar innehållade ordet Permittivity.

1. 31. Ferroelectric Thin Films on Si-substrate for Tunable Microwave Applications

   Författare :Saeed Abadei; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Phase shifter; BaxSr1-xTiO3; Tunable microwave device; Ferroelectric Varactor; Paraelectric; Filter; Na0.5K0.5NbO3; Integrated ferroelectric device; SrTiO3; Ferroelectric;

   Sammanfattning : The thesis presents the development of microwave tunable devices based onferroelectric thin films. The main tasks in this work are the fabrication, optimization, andintegration of ferroelectric thin film into Si-MMIC. LÄS MER

3. 32. Meso-scale modelling of composites and semi-crystalline polymers

   Författare :Fritjof Nilsson; Mikael Hedenqvist; Ulf Gedde; Hans Ågren; Göran Grimvall; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; semi-crystalline polymers; simulations; diffusion; electrostatics; Materials science; Teknisk materialvetenskap; Applied mathematics; Tillämpad matematik; Polymer chemistry; Polymerkemi;

   Sammanfattning : This thesis covers the first few steps of a multi-scale computer simulation strategy for predicting physical properties of complex polymers like composites and semi-crystalline polymers. Meso-scale simulations of crystallization and solvent diffusion in polyethylene as well as simulations examining the geometrical impact on the effective permittivity of composites have been performed. LÄS MER

4. 33. Diagnosis of Moisture in Transformer Insulation - Application of frequency domain spectroscopy

   Författare :Chandima Ekanayake; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; moisture content; diagnostic methods; modelling; polarisation depolarisation currents PDC ; frequency domain spectroscopy FDS ; dielectric response measurements; Oil-impregnated pressboard paper insulation; Karl Fischer titration KFT ; conductivity; ageing;

   Sammanfattning : This thesis presents application of dielectric response measurements for identifying condition of high voltage insulation in power transformers. Results of such measurements, incorporated with different modelling techniques, allow to estimate moisture content in solid part of transformer insulation. LÄS MER

5. 34. Optics of Conducting Polymer Thin Films and Nanostructures

   Författare :Shangzhi Chen; Magnus Jonsson; Vanya Darakchieva; William Barnes; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Intrinsically conducting polymers forms a category of doped conjugated polymers that can conduct electricity. Since their discovery in the late 1970s, they have been widely applied in many fields, ranging from optoelectronic devices to biosensors. The most common type of conducting polymers is poly(3,4-ethylenedioxythiophene), or PEDOT. LÄS MER

7. 35. Analysis of Industrial Microwave Ovens

   Författare :Magnus Sundberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; source model; heat transfer; moment method; finite difference time domain; TM applicator; GMT; edge diffraction; thermal simulation; MMP; FDTD; generalized multipole technique; cost function; MM; optimization; magnetron; simulated annealing; multiple multipole program; microwave heating; edge overheating; TE applicator; tunnel-oven; applicator;

   Sammanfattning : This thesis deals with the analysis and design of microwave ovens used in the food industry. Such analysis is desirable in order to optimize the performance of the ovens and to reduce the time and expenses of developing new or improved ovens. LÄS MER