Sökning: "direction fields"

Visar resultat 26 - 30 av 145 avhandlingar innehållade orden direction fields.

  1. 26. On Some Properties and Applications of Patterned Ferromagnetic Thin Films

    Författare :Pierre E. Roy; Peter Svedlindh; Per Nordblad; Jeffrey McCord; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; micromagnetics; vortex; spin dynamics; domains; MFM; microwave; patterned; permalloy; Materialvetenskap; Materials science; Teknisk materialvetenskap;

    Sammanfattning : A microwave reflection method has been used to measure the spin excitations corresponding to the translational mode of magnetic vortices in samples containing either one or two vortices. Experimental findings are complemented by micromagnetic simulations. One-vortex systems are investigated in micron-sized circular and elliptical cylinders. LÄS MER

  3. 27. Coherent Far-Infrared Mode Pumping in Ballistic Electron Channels

    Författare :Ola Tageman; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The influence of a high frequency electromagnetic field on transport properties of ballistic electron channels is investigated theoretically. We are primarily concerned with submicron-width channels formed by split-gate depletion of a two-dimensional electron gas at a GaAs/AlGaAs heterostructure interface. LÄS MER

  4. 28. On the Modelling of Fracture Using Strong Discontinuities

    Författare :Martin Fagerström; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fracture; strong discontinuity; material forces; finite deformations; FEM;

    Sammanfattning : The major concern of this work is the constitutive and numerical modelling of fracture,based on strong discontinuity formulations. More particularly, an extended finiteelement approach is used, where the total displacement is separated in two mutuallyindependent fields, representing the continuous and discontinuous displacement respectively. LÄS MER

  5. 29. Numerical modelling of fluid flow and particle transport in rough rock fracture during shear

    Författare :Tomofumi Koyama; Lahru Jing; Auli Niemi; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; single rock fracture; coupled stress-flow test; shear displacement; fluid flow; particle; Geoengineering; Geoteknik;

    Sammanfattning : The effects of different shearing processes and sample sizes on the fluid flow anisotropy and its impact on particle transport process in rough rock fractures are significant factors that need to be considered in the performance and safety assessments of underground nuclear waste repositories. The subjects, however, have not been adequately investigated previously in either laboratory experiments or numerical modeling. LÄS MER

  7. 30. Development and Applications of a Laser-Wakefield X-ray Source

    Författare :Isabel Gallardo Gonzalez; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; laser-wakefield acceleration; betatron radiation; ionization-induced trapping; direct laser acceleration; laser-wakefield merging; warm dense matter; phase-contrast imaging; Fysicumarkivet A:2018:Gallardo;

    Sammanfattning : In laser-wakefield acceleration (LWFA), a femtosecond laser pulse is tightly focused in a gas to intensities exceeding 1018 W/cm2 . The laser radiation ionizes the medium and excites a plasma wave that travels behind the laser pulse. LÄS MER