Sökning: "wave equations"
Visar resultat 1 - 5 av 218 avhandlingar innehållade orden wave equations.
1. Geometric Methods for some Nonlinear Wave Equations
Sammanfattning : A number of results related to the geometric interpretation of some dispersive nonlinear wave equations are presented. It is first described how some well-known shallow water equations arise geometrically as Euler equations for the geodesic flow on the Virasoro group endowed with certain right-invariant metrics. LÄS MER
2. Wave Propagation in Structural Elements - Direct and Inverse Problems in the Time Domain
Sammanfattning : The subject of this thesis is direct and inverse wave propagation problems in structural elements. The considered structures are beams, plates and rods. The models for the beams and the plates are based on linear theory, while the rods are assumed to be nonlinear. The greater part of the work concerns the Timoshenko beam. LÄS MER
3. Three-wave mixing in Josephson travelling-wave parametric amplifiers
Sammanfattning : This work explores possibilities of building a wide-band, quantum-limited low-noise amplifier by means of three-wave mixing (3WM) in different kinds of Josephson travelling-wave parametric amplifiers (TWPAs). We extend the theory of the continuous three-mode model to include any number of up-converted modes in the small frequency limit where the frequency dispersion is close to linear. LÄS MER
4. Scattering on the Timoshenko Beam. Direct and Inverse Problems in the Time Domain
Sammanfattning : This thesis concerns the use of time domain methods for treating direct and inverse scattering problems for flexural waves on beams. The Timoshenko equation is used throughout to describe the behaviour of such waves. LÄS MER
5. Wave Splitting in Direct and Inverse Scattering Problems
Sammanfattning : The focus of this thesis is on the use of wave splitting in electromagnetic direct and inverse scattering problems. Wave splitting offers a decomposition of wave fields into appropriate input and output wave constituents. LÄS MER