Search for dissertations about: "spectral gap"

Showing result 11 - 15 of 46 swedish dissertations containing the words spectral gap.

  2. 11. Moment Method Analysis of Antennas in Reverberation Chambers and Cylindrical Structures

    Author : Ulf Carlberg; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; antenna; spectral domain method; reverberation chamber; Ewald summation; moment method; cavity; cylindrical structure; Green s function; absorption cross section;

    Abstract : This thesis is a collection of papers using the method of moments for numerical analysis. The papers can be divided into two main groups; a study of antennas in reverberation chambers and a study of antennas in cylindrical structures.The reverberation chamber is a metal cavity for measuring antennas and other devices. READ MORE

  4. 12. Moment Method Analysis of Antennas in Reverberation Chambers and Cylindrical Structures

    Author : Ulf Carlberg; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cavity; spectral domain method; cylindrical structure; Ewald summation; Green s function; absorption cross section; moment method; reverberation chamber; antenna;

    Abstract : This thesis is a collection of papers using the method of moments for numerical analysis. The papers can be divided into two main groups; a study of antennas in reverberationchambers, and a study of antennas in cylindrical structures.The reverberation chamber is a metal cavity for measuring antennas and other devices. READ MORE

  5. 13. Leveraging HVPE for III-V/Si Integration and Mid-Infrared Photonic Device Fabrication

    Author : Axel Strömberg; Yan-Ting Sun; Sebastian Lourdudoss; Mattias Hammar; Charles Cornet; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; HVPE; III-V Si; Photovoltaics; PEC; MIR; non-linear optics; QPM; QCL; Energiteknik; Energy Technology;

    Abstract : This work covers the implementation of highly specialized epitaxial techniques enabled by the near-equilibrium hydride vapor-phase epitaxy growth process in III-V/Si integration for Si-based tandem solar cells and photoelectrochemical reactions, quasi phase matching GaP structures on GaAs substrates, and regrowth of InP:Fe on quantum cascade lasing structures.III-V/Si integration is an important topic in several fields of research with a significant one being solar energy harvesting. READ MORE

  6. 14. Investigation of Tonal Noise Sources from Centrifugal Fan using Detached Eddy Simulation

    Author : Martin Ottersten; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Computational aeroacoustics; Blade passing frequency; Centrifugal fan; Low-frequency rotation; Tonal noise.;

    Abstract : Since we spend the majority of our time indoors, heating, ventilation, and air conditioning (HVAC) systems have become a more and more important part of many people´s life. They provide a sufficient amount of airflow with the correct temperature, quality, and humidity. READ MORE

  7. 15. Higher order differential operators on graphs

    Author : Jacob Muller; Pavel Kurasov; Ram Band; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Almost periodic functions; differential operators on metric graphs; quantum graphs; estimation of eigenvalues;

    Abstract : This thesis consists of two papers, enumerated by Roman numerals. The main focus is on the spectral theory of -Laplacians. Here, an -Laplacian, for integer , refers to a metric graph equipped with a differential operator whose differential expression is the -th derivative. READ MORE