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Visar resultat 1 - 5 av 38 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Total-energy calculations with the effective-medium theory

    Författare :Uno Yxklinten; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; oxygen; subsurface site; total-energy calculations; force-dipole tensor; effective-medium theory; elastic properties; hydrogen; chemisorption; three-fold site; magnesium; adsorbate; aluminium;

    Sammanfattning : .... LÄS MER

  3. 2. Elastic scattering on polarised protons at medium energies

    Författare :Sverker Almehed; Partikel- och kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : [abstract missing].... LÄS MER

  4. 3. Thin Layers in Elastic Wave Propagation -Effective Modelling and Diffraction

    Författare :Peter Bövik; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Geometrical Theory of Diffraction; elastic wave scattering; shear waves; Wienr-Hopf method; L-TV waves; applications;

    Sammanfattning : In the present thesis, the interest is focussed on the problem of effective modelling of thin interface layers for applications in elastic wave scattering. The layers are considered to be thin compared with wavelengths involved and it is shown that when all effects to lowest order in the layer thickness are included, we get boundary conditions (BCs) which have a number of nice features, including the one of implying that no scattering occurs when the layer has material parameters identical to the ones in the matrix medium. LÄS MER

  5. 4. Guided Elastic Waves along Periodically Corrugated Structures

    Författare :Ahmed M. A. El-Bahrawy; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : The present thesis consider time-harmonic surface and guided elastic waves propagating along periodically corrugated structures. The problems discussed deal with various configurations where the surfaces are sinusoidally - singly or doubly - periodic, and the interest is focused on investigating the roots of the dispersion relations and in particular the stopband and cross-over resonances. LÄS MER

  7. 5. Elastic and acoustic characterisation of porous layered system

    Författare :Rémi Guastavino; Peter Göransson; Henry Rice; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Acoustics; Akustik;

    Sammanfattning : For an accurate prediction of the low and medium frequency surface vibration and sound radiation behaviour of porous layered systems, there is a need to improve the means of estimating their elastic and acoustic properties. The underlying reasons for this are many and of varying origin, one prominent being a poor knowledge of the geometric anisotropy of the cell microstructure in the manufactured porous materials. LÄS MER