Sökning: "aperture efficiency"

Visar resultat 11 - 15 av 34 avhandlingar innehållade orden aperture efficiency.

  1. 11. Moment Method Analysis of Antennas on Cylindrical Structures by Using G2DMULT and Design of Hat Fed Reflector Antennas

    Författare :Jian Yang; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; G2DMULT; reflector antenna; paraboloid; dipole; base station antenna; screw heads; vertex plate; self impedance; G1DMULT; ring-shaped phase center; radiation efficiency; FDTD; cylindrical structures; V2D; ring-focus; moment method;

    Sammanfattning : This thesis deals with two aspects of research interest: moment method analysis of antennas on cylindrical structures by using G2DMULT, and design of hat fed reflector antennas. Both of them are two-dimensional (2D) structure problems, one being cylindrical and the other rotationally symmetric. LÄS MER

  3. 12. FtsH metalloproteases and their pseudo-proteases in the chloroplast envelope of Arabidopsis thaliana

    Författare :Laxmi S. Mishra; Christiane Funk; Magnus Wolf-Watz; Catherine de Vitry; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; Arabidopsis thaliana; AAA-ATPases; abscisic acid; chloroplast; drought; embryo-lethal; FtsH metalloprotease; intrinsic water-use efficiency WUEi ; leaf variegation; outdoor conditions; oxidative stress; plastid biogenesis; proteomics; protein import; root-associated bacterial communities seedlings; Biochemistry; biokemi; molekylärbiologi; Molecular Biology; biology; biologi;

    Sammanfattning : By cleaving peptide bonds, proteases either activate or degrade proteins and maintain protein quality control in response to various developmental stimuli and environmental factors. My work has focused on elucidating the role of the filamentation temperature sensitive protein H (FtsH) proteases. LÄS MER

  4. 13. Solar cavity receiver design for a dish-Stirling system

    Författare :Jorge Garrido Gálvez; Björn Laumert; Uwe Gampe; KTH; []
    Nyckelord :Concentrating Solar Power; Solar receiver; Solar simulator; Uncertainty analysis; Monte Carlo ray tracing; Experimental validation; Coatings; System modeling; Structural analysis; Creep damage; Thermal stress; Cavity receiver design; Energy Technology; Energiteknik;

    Sammanfattning : The growing concern for the climate change has led to an increasing research effort in renewable energy technologies in order to achieve a more sustainable electricity production. Concentrating Solar Power (CSP) is identified as a promising technology to deal with part of the future electricity production. LÄS MER

  5. 14. Dual Band Prime Focus Feed for Satellite Earth Terminals

    Författare :Yogesh Karandikar; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Reflector Antenna; Choke Horn; Eleven Feed; satellite earth terminals;

    Sammanfattning : Satellite Communication systems have been studied and developed since long. With more high frequency satellite bands coming in the market, there is a need to develop suchsystems with multi-band or wideband operation with reconfigurable antennas which can provide simultaneous transmit receive capabilities on different polarizations as well as have properties suitable to track the satellite. LÄS MER

  7. 15. Optical Design and Characterization of Solar Concentrators for Photovoltaics

    Författare :Johan Nilsson; Avdelningen för Energi och byggnadsdesign; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Stationary solar energy concentrators are a promising option for decreasing the price of photovoltaic electricity. This thesis studies stationary concentrators in PV/Thermal applications. The studied systems are parabolic troughs intended for building integration. The first chapters briefly explain the optics of solar energy concentrators. LÄS MER