Sökning: "gap geometry"

Visar resultat 1 - 5 av 105 avhandlingar innehållade orden gap geometry.

  1. 1. Nonspherical black holes and spacetime reconstructions

    Författare :Eric Staffas; Mattias Dahl; Jan Metzger; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Sammanfattning : This thesis consists of three papers in mathematical general relativity. The first paper concerns inverse problems and reconstruction of spacetimes from boundary data. We consider boundary data in the form of broken geodesics with different causal types, which have the physical interpretation of relativistic fireworks. LÄS MER

  3. 2. Technology and properties of InP-based photonic crystal structures and devices

    Författare :Naeem Shahid; Srinivasan Anand; Rob W. vad der Heijden; KTH; []
    Nyckelord :Integrated optics materials; Photonic crystals; Planar waveguides; Dispersion; Band-gap; Mode-gap; mini-stopband; InP; Nanostructure fabrication; dry etching; mass transport; material reflow; reliability; SRA - ICT; SRA - Informations- och kommunikationsteknik;

    Sammanfattning : Photonic crystals (PhCs) are periodic dielectric structures that exhibit a photonic band gap; a range of wavelengths for which light propagation is forbidden. 2D PhCs exhibit most of the properties as their three dimension counterparts with a compatibility with standard semiconductor processing techniques such as epitaxial growth, electron beam lithography, Plasma deposition/etching and electromechanical lapping/polishing. LÄS MER

  4. 3. Gap Waveguide Technology for Millimeter Wave Applications and Integration with Antennas

    Författare :Elena Pucci; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Array Antennas.; Microstrip Lines; Micromachining; Artificial Magnetic Conductors; Millimeter Waves; Waveguide Resonators; Packaging of Microwave Components; Gap Waveguides; Losses;

    Sammanfattning : The increasing advance of short range wireless communications requiring high data rates and the lack of available spectrum have driven researchers and industry to move towards higher frequencies, in particular to the millimeter wave range. The opening of this wide portion of free spectrum has risen a large interest in developing mm-wave communication systems for commercial applications. LÄS MER

  5. 4. EM Design for New Ultra Wide Band Technologies: Eleven Feed Baluns, Bowtie Antennas and Gap Waveguides

    Författare :Syed Hasan Raza Zaidi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ultra-wideband; Eleven feed; gap waveguide; baluns; Multiport feeding network; power divider; ring hybrid.; packaging;

    Sammanfattning : UWB (ultra wideband), depending on the application requirement, is usually referred to more than 500 MHz bandwidth for radio/wireless applications. Here in this thesis it is also used to denote extremely wideband antennas and components of several octaves bandwidth, particularly for high frequency applications. LÄS MER

  7. 5. An inductive gap measurement method for square butt joints

    Författare :Edvard Svenman; Anna-Karin Christiansson; Anna Runnemalm; Johan Carlsson; Högskolan Väst; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Eddy current; Seam tracking; Measurement; Laser beam welding; gap geometry; Production Technology; Produktionsteknik; Manufacturing and materials engineering; Produktions- och materialteknik;

    Sammanfattning : A recent method in aero engine production is to fabricate components from smaller pieces, rather than machining them from large castings. This has made laser beam welding popular, offering high precision with low heat input and distortion, but also high productivity. LÄS MER