Sökning: "periodic boundary conditions"

Visar resultat 1 - 5 av 68 avhandlingar innehållade orden periodic boundary conditions.

  1. 1. Analysis of Conformal Antennas and Periodic Structures

    Författare :Silvia Raffaelli; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; method of moments; microstrip; corrugated surface; horn; Floquet; array; periodic; multilayer structure; finite difference time domain; dual-frequency; infinite; spectral domain analysis; conformal antenna;

    Sammanfattning : In the last decades much attention has been paid to the design of high-performance antennas. Accurate control of the radiation properties is very important in electromagnetic engineering applications. LÄS MER

  3. 2. Analysis of Planar and Circular Cylindrical Multilayer Structures with Application to Soft and Hard Surfaces

    Författare :Zvonimir Sipus; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; antennas; periodic surfaces; integral equations; approximate boundary conditions; soft and hard surfaces; Green s functions; corrugated surfaces; moment method; periodic metal strips; multilayer structures; EFIE; microstrip antennas; spectral domain analysis; group representation theory; strip scatterers;

    Sammanfattning : This thesis deals with the analysis of planar and circular cylindrical multilayer structures, such as strip-loaded dielectric layers, corrugated surfaces and microstrip antennas. In particular, we study corrugations and strip-loaded grounded dielectric slabs when they are used to realize soft and hard surfaces. LÄS MER

  4. 3. Boundary integral methods for Stokes flow : Quadrature techniques and fast Ewald methods

    Författare :Oana Marin; Anna-Karin Tornberg; Anita Layton; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; boundary integral; Stokes flow; quadrature rule; Ewald decomposition;

    Sammanfattning : Fluid phenomena dominated by viscous effects can, in many cases, be modeled by the Stokes equations. The boundary integral form of the Stokes equations reduces the number of degrees of freedom in a numerical discretization by reformulating the three-dimensional problem to two-dimensional integral equations to be discretized over the boundaries of the domain. LÄS MER

  5. 4. On the Structure and Dynamics of Polyelectrolyte Gel Systems and Gel-surfactant Complexes

    Författare :Per Johan Råsmark; Christer Elvingson; Johan Bergenholtz; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; polyelectrolyte gel; microgel; dynamic light scattering; Raman spectroscopy; periodic boundary conditions; percolation; hypersphere; Monte Carlo; Brownian dynamics; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi;

    Sammanfattning : This thesis describes the results of experimental work on polyelectrolyte gels and their interaction with oppositely charged surfactants, and presents two new algorithms applicable to the simulation of colloid and polymer systems.The model systems investigated were crosslinked poly(acrylate) (PA) and poly(styrene sulphonate) (PSS), and the surfactant was dodecyl trimethylammonium bromide (DoTAB). LÄS MER

  7. 5. Bulk-boundary correspondence and biorthogonality in non-Hermitian systems

    Författare :Elisabet Edvardsson; Emil Bergholtz; Henning Schomerus; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; non-Hermiticity; bulk-boundary correspondence; biorthogonal quantum mechanics; skin effect; Theoretical Physics; teoretisk fysik;

    Sammanfattning : In topological insulators, the bulk-boundary correspondence describes the relationship between the bulk invariant -- computed for a system with periodic boundary conditions -- and the number of topological boundary states in the corresponding system with open boundary conditions. This is a well-known property of these systems and is important for predicting how they will behave. LÄS MER