Sökning: "paraxial"

Visar resultat 1 - 5 av 11 avhandlingar innehållade ordet paraxial.

1. 1. Developmental origin and molecular regulation of vascular smooth muscle cells

   Författare :Per Wasteson; Göteborgs universitet; []
   Nyckelord :smooth muscle cell; aorta; cell origin; lateral plate mesoderm; paraxial mesoderm; lipoma preferred partner; serum response factor; neointimal hyperplasia; angiotensin II; platelet-derived growth factor-B;

   Sammanfattning : Several pathologies of the vascular system have been suggested to be dependent on the smooth muscle cells (SMCs) that build up the vessel wall. Aortic SMCs have been proposed to derive from lateral plate mesoderm. LÄS MER

3. 2. Analysis and Design of Conformal Array Antennas

   Författare :Patrik Persson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Conformal antennas; conformal arrays; UTD; high frequency method; MoM; hybrid method; mutual coupling; singly curved surface; doubly curved surface; geodesics; dielectric covered circular cylinder; non-paraxial region. paraxial region; waveguide fed; Electrical engineering; Elektroteknik;

   Sammanfattning : Today there is a great need for communication between people and even between things, using systems onboard e.g. aircraft, cars, ships and satellites. As a consequence, these communications needs require antennas mounted on or integrated in the surfaces of different vehicles or platforms, i. LÄS MER

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

   Författare :Yangjian Cai; Sailing He; Franco Gori; KTH; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

5. 4. Nonlinear Propagation of Optical Pulses and Beams

   Författare :Magnus Karlsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; self-phase modulation; optical wave breaking; paraxial-ray approximation; stimulated Raman scattering; nonlinear Schrödinger equation; optical collapse; modulational instability; higher-order dispersion; optical fibers; saturable nonlinearity; Kerr-nonlinearity; self-trapping; group-velocity dispersion; optical solitons; self-focusing;

   Sammanfattning : The propagation of optical beams and pulses under the influence of nonlinear effects is characterized by a rich variety of phenomena and many potentially important applications. We analyse two main topics in this context: nonlinear beam propagation, and nonlinear pulse propagation in optical fibers. LÄS MER

7. 5. Simulation of Electro-Optic Modulators by a Time-Domain Beam-Propagation Method

   Författare :Elin Solberg; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; time-domain beam-propagation method; finite element method; tensor products; computational electromagnetics; photonics; electro-optic modulators; finite element method;

   Sammanfattning : Electro-optic modulators (EOMs) are components which convert electric signals to optical ones. They are needed, e.g., at the transmitter end of fiber-optic communication systems and in time-stretch analog-to-digital converters. LÄS MER