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Visar resultat 6 - 10 av 52 avhandlingar som matchar ovanstående sökkriterier.

1. 6. Phase Sensitive Amplifiers for Free-Space Optical Communications

   Författare :Ravikiran Kakarla; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Phase sensitive amplifier; sensitivity; optical injection locking; noisefigure;

   Sammanfattning : The demand for high data rate free-space communications is increasing due to the planned future space exploration missions. In the next few years there is a need to increase the speed by 100 times according to NASA, and this necessitates that transmission systems operate at higher carrier frequencies. LÄS MER

3. 7. Axionlike particles, quantum loops, and supernovae : The role of quantum loop corrections for astrophysical ALPs

   Författare :Eike Christoph Müller; David Marsh; Frank Wilczek; Bo Sundborg; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Theoretical Physics; teoretisk fysik;

   Sammanfattning : In this thesis the quantum field theory and astrophysical phenomenology of axionlike particles (ALPs) are studied. The effective field theory of ALPs is reviewed with a special focus on quantum loops, the renormalization group equations, and the equivalent forms of the interaction between ALPs and fermions. LÄS MER

4. 8. Off-shell, maximal supersymmetry & exceptional geometry

   Författare :Anna Karlsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Maximal supersymmetry; pure spinors; exceptional geometry; maximal supergravity; loop amplitudes; U-duality; high energy particle physics;

   Sammanfattning : Two lines of research are presented in this thesis, both with a focus on fundamental properties within the supersymmetric theories of high energy physics. The first features analyses based on the actions for maximal supersymmetric Yang–Mills theory and supergravity, provided by the pure spinor formalism. LÄS MER

5. 9. Planning in Interplace? On Time, Power and Learning in Local Activities Aiming at Social Inclusion and Sustainable Development

   Författare :Jenny Stenberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sustainable development; triggers for learning; suburban; phronesis; time; communicative planning; double-loop; social exclusion; interplace; power;

   Sammanfattning : SUBURBAN METROPOLITAN areas in Sweden built in the sixties and seventies are often considered exposed areas and are consequently involved in interventions aimed at dealing with problems such as unemployment, poverty and social exclusion. This thesis focusses on how urban planning is related to this social problem. LÄS MER

7. 10. Methods of Multi-Conjugate Adaptive Optics for Astronomy

   Författare :Ralf Flicker; Astronomi - Genomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Adaptive optics; anisoplanatism; laser guide stars; performance estimation; wavefront reconstruction; extremely large telescopes; optics; Electromagnetism; Elektromagnetism; acoustics; Astronomy; akustik; space research; optik; multi-conjugate; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Fysicumarkivet A:2003:Flicker;

   Sammanfattning : This work analyses several aspects of multi-conjugate adaptive optics (MCAO) for astronomy. The research ranges from fundamental and technical studies for present-day MCAO projects, to feasibility studies of high-order MCAO instruments for the extremely large telescopes (ELTs) of the future. LÄS MER