Sökning: "Permittivity"

Visar resultat 21 - 25 av 90 avhandlingar innehållade ordet Permittivity.

  1. 21. Direct and Inverse Scattering of Electromagnetic Waves in Nonlinear Media

    Författare :Daniel Sjöberg; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Models for materials with nonlinear electromagnetic response are examined. Three simple physical causes for nonlinear behavior are presented: electronic polarization, molecular direction and electrostriction. LÄS MER

  3. 22. On the inception and propagation of streamers along mineral-oil/solid interfaces

    Författare :David Ariza; Marley Becerra; Olivier Lesaint; KTH; []
    Nyckelord :;

    Sammanfattning : This thesis presents an experimental study of positive and negativestreamers propagating along mineral-oil/solid interfaces under square highvoltage pulses. The thesis includes the design and construction of anexperimental setup to studying the streamers in a point-plane configurationcapable to detect streamer parameters such as velocity, length, propagationtime, emitted light and charge. LÄS MER

  4. 23. Characterization of (Ba,Sr)TiO3 thin films for multiplier applications

    Författare :Pär Rundqvist; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; BSTO; THz; triplers; powerhandling capability; multilayer structures; frequency multipliers; Ferroelectric; BST; losses; Varactor; STO;

    Sammanfattning : (Ba,Sr)TiO3 (BSTO) and SrTiO3 (STO) parallel plate ferroelectric varactors are investigated for microwave multiplier applications.STO and BSTO exhibit low losses, high permittivity and largetunability of both permittivity and losses. All films are deposited using Pulsed Laser Deposition, magnetron sputtering and E-beam evaporation. LÄS MER

  5. 24. Effective properties of heterogeneous materials with applications in electromagnetics

    Författare :Christian Engström; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; homogenization; optics; acoustics; Electromagnetism; structural parameters; anisotropic material; inverse homogenization; Bloch waves; Maxwell s equations; Elektromagnetism; optik; akustik; Inverse bounds;

    Sammanfattning : Composite materials, i.e, mixtures of two or more materials, are commonly used in industry, because they often have outstanding properties in comparison with the original materials. In many cases the inhomogeneities are on a very fine scale, which makes it difficult to perform a full numerical simulation of the material. LÄS MER

  7. 25. Evaluation of the Tactoid Formation in Clay Systems

    Författare :Maria Jansson; Beräkningskemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lera; Montmorillonit; Nano-plattor; Taktoider; Anisotropi; Grov korninga modeller; MD simuleringar; MC simuleringar; SAXS; Svälltryck; Clay; Montmorillonite; Nanoplatelets; Tactoid; Anisotropy; Coarse-grained models; MD simulations; MC simulations; SAXS; Swelling pressure;

    Sammanfattning : Clay minerals consist of anisotropic nanoplatelets where the majority of the clay minerals are highly charged, and thus, swell in aqueous solution. The structure and swelling depend on the type of clay mineral, and also on the ionic composition, and temperature. LÄS MER