Sökning: "wave propagators"

Hittade 4 avhandlingar innehållade orden wave propagators.

  1. 1. Scattering on the Timoshenko Beam. Direct and Inverse Problems in the Time Domain

    Författare :Dag V. J. Billger; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; integro-differential equations; wave splitting; transient wave propagation; viscoelastic damping; wave propagators; inverse problems; scattering operators; Timoshenko beam; non-uniform beams; imbedding;

    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

  3. 2. Transient waves in nonstationary media : with applications to lightning and nonlinear media

    Författare :Ingegerd Åberg; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lightning; Klein-Gordon; nonlinear; characteristics; wave splitting; imbedding; sources; propagators; Green functions; direct and inverse scattering; Nonstationary; transient; high-frequency switching; Kerr.; Technological sciences; Teknik;

    Sammanfattning : Propagation of transient waves in nonstationary, inhomogeneous, dispersive, stratified media is considered. Waves originating from sources exterior to the scatterer as well as from internal sources are treated. Algorithms are developed and illustrated by computations of wave phenomena in stationary, nonstationary and weakly nonlinear media. LÄS MER

  4. 3. Propagation of singularities for pseudo-differential operators and generalized Schrödinger propagators

    Författare :Karoline Johansson; Joachim Toft; Anders Olofsson; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Banach spaces; Fourier; Generalized time-dependent Schrödinger equation; Micro-local; Modulation spaces; Non-tangential convergence; Pseudo-differential operators; Regularity; Wave-front sets; Banachrum; Fourier; Generaliserad tidsberoende Schrödinger ekvation; Icke-tangentiell konvergens; Mikrolokal; Modulationsrum; Pseudodifferentialoperatorer; Regularitet; Vågfrontsmängder; Mathematical analysis; Analys; Mathematics; Matematik;

    Sammanfattning : In this thesis we discuss different types of regularity for distributions which appear in the theory of pseudo-differential operators and partial differential equations. Partial differential equations often appear in science and technology. LÄS MER

  5. 4. BRST and Topological Gauge Theories

    Författare :Niclas Sandström; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gauge theory; BRST-quantization; topological field theory; BV-quantization; almost product structure APS ; superfield formulation;

    Sammanfattning : In this thesis, the BRST-quantization of gauge theories is discussed. A detailed analysis of the BRST-quantization on inner product spaces is performed for a class of abelian models, including reparametrization invariant ones. General rules how to obtain physical wave functions and propagators are proposed. LÄS MER