Search for dissertations about: "diffraction wave"

Showing result 1 - 5 of 51 swedish dissertations containing the words diffraction wave.

2. 1. Thin Layers in Elastic Wave Propagation -Effective Modelling and Diffraction

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

   Abstract : 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. READ MORE

4. 2. Elastic Wave Scattering by Cracks - Interfacial Forces and High Frequency Diffraction

   Author : Gert Persson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ultrasonic testing; Wiener-Hopf calculations; Geometrical Theory of Diffraction; edge diffracted body waves; PEDGE; two-dimensional diffraction; geometrical elastodynamic waves;

   Abstract : This thesis treats elastic wave scattering by cracks with interfacial forces. The results are of practical interest in ultrasonic testing and includes development of numerical methods used to predict such testing. First the canonical problem of two-dimensional (2-D) diffraction from a semi-infinite crack is solved. READ MORE

5. 3. Time-Resolved Diffraction Studies of Structural Dynamics in Solids

   Author : Xiaocui Wang; Atomfysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Time-resolved X-ray diffraction; phonons; photo-acoustic transducer; electron diffusion; pressure wave; non-thermal melting; Fysicumarkivet A:2019:Wang;

   Abstract : Studies of the structural dynamics of solids can improve our understanding of atomic motion in materials, and may thus help in the manufacture of new devices or the development of materials with novel structures and properties. Ultrashort laser pulses, a few tens of femtoseconds long, can deliver high energies (mJ–kJ). READ MORE

6. 4. Time-Resolved X-ray Diffraction Studies of Laser-Induced Dynamics in Solids

   Author : Åsa Bengtsson; Atomfysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Time-resolved X-ray diffraction; ultrafast; phonons; pressure wave; Non-thermal melting; Fysicumarkivet A:2022:Bengtsson;

   Abstract : X-ray diffraction is an invaluable tool in the field of structural dynamics. In the work described in this thesis, time-resolved X-ray diffraction experiments were carried out to investigate ultrafast lattice dynamics. READ MORE

7. 5. Acoustic, Thermal and Non-thermal Dynamics in Condensed Matter Studied by Time-Resolved X-ray Diffraction

   Author : Carl Ekström; Atomfysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; X-ray diffraction; Time-resolved; Ultrafast; Non-thermal melting; Thermal conductivity; Pressure wave; Opto-acoustic transducer; Fysicumarkivet A:2020:Ekström;

   Abstract : The method of using short laser and X-ray pulses to investigate dynamics in materials (pump-probe) has been used for several decades. This thesis presents work that was carried out using these sources of light to reveal acoustic, thermal and non-thermal dynamics. READ MORE