Search for dissertations about: "Gaussian beam"

Showing result 1 - 5 of 29 swedish dissertations containing the words Gaussian beam.

2. 1. Novel beam shaping and computer vision methods for laser beam welding

   Author : Yongcui Mi; Antonio Ancona; Fredrik Sikström; Isabelle Choquet; Högskolan Väst; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Laser beam welding; Beam shaping; Deformable mirror; Process monitoring; Process control; Model validation; Computer vision; Machine learning; Butt joint; T-joint.; Lasersvetsning; Beam shaping; Deformerbar spegel; Processövervakning; Processkontroll; Modellvalidering; Datorsyn; Maskininlärning; Butt joint; T-fogar;

   Abstract : Laser beam welding has been widely applied in different industrial sectors due to its unique advantages. However, there are still challenges, such as beam positioning in T-joint welding, and gap bridging in butt joint welding,especially in the case of varying gap width along a joint. READ MORE

4. 2. Propagation of some coherent and partially coherent laser beams

   Author : Yangjian Cai; Sailing He; Franco Gori; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; : dark hollow beam; elliptical Gaussian beam; flat-topped beam; twisted anisotropic Gaussian Schell-model; partial coherent; propagation; paraxial optical system; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

   Abstract : In this thesis, we investigate the propagation of some coherent and partially coherent laser beams, including a dark hollow beam (DHB), an elliptical Gaussian beam (EGB), a flat-topped beam and a twisted anisotropic Gaussian Schell-model (TAGSM) beam, through a paraxial optical system or a turbulent atmosphere. Several theoretical models are proposed to describe a DHB of circular or non-circular symmetry. READ MORE

5. 3. THz Vector Beam Measurement System for APEX Instrument SHeFI and Microwave Cryogenic Low Noise Amplifier Design

   Author : Olle Nyström; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vector measurements; mm- and submm-wave optics; LNA; radio astronomy; cryogenic amplifier; APEX; InP HEMT; Gaussian beam;

   Abstract : This licentiate thesis describes results of the author’s work on development of THz vector beam measurement system and microwave cryogenic low-noise amplifier.The first part, and the main focus, of the thesis covers the vector beam measurement system for frequency range 210-500 GHz developed to characterize/verify the cold opticsof the APEX instrument SHeFI. READ MORE

6. 4. Gaussian Beam Measurement Range for HIFI Instrument of Herschel Space Observatory

   Author : Miroslav Pantaleev; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : .... READ MORE

7. 5. Physical modelling of acoustic shallow-water communication channels

   Author : Elin Svensson; Ilkka Karasalo; Finn Jensen; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; underwater acoustics; hydroacoustics; time variability; ray tracing; Gaussian beam summation; sound propagation models; shallow water; waveguides; caustics; underwater communication; undervattensakustik; hydroakustik; tidsvariabilitet; strålgång; gaussisk strålsummation; ljudutbredningsmodeller; grunt vatten; vågledare; kaustikor; undervattenskommunikation; Acoustics; Akustik;

   Abstract : Akustiska kanaler för undervattenskommunikation är flervägskanaler där ljudet reflekteras från havets yta och botten och bryts vid ljudhastighetsförändringar. I grunt vatten är impulssvaret långt jämfört med symbolernas tidslängd i ett utskickat meddelande. READ MORE