Search for dissertations about: "beam collapse"

Showing result 1 - 5 of 11 swedish dissertations containing the words beam collapse.

  2. 1. Nonlinear Theory of Partially Coherent Optical Waves

    Author : Tobias Hansson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Nonlinear optics; partial coherence; beam collapse; saturable logarithmic media; soliton interaction; dressing method; parabolic beams; Wigner transform; invariants; modulational instability;

    Abstract : Nonlinear effects arise in optics as a consequence of the medium properties being modified by the presence of light. Of particular interest are situations where the effect of the nonlinearity can be described by an intensity dependent refractive index and the subsequent interplay with dispersion and diffraction. READ MORE

  4. 2. Nonlinear Propagation of Optical Pulses and Beams

    Author : Magnus Karlsson; Chalmers tekniska högskola; []
    Keywords : 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;

    Abstract : 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. READ MORE

  5. 3. Development and application of corotational finite elements for the analysis of steel structures in fire

    Author : Luca Possidente; Jean-Marc Battini; Nicola Tondini; Paulo Vila Real; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Thermomechanical finite element; Shell element; 3D beam element; Steel structures; Buckling; Fire Safety Engineering; Structural Engineering and Bridges; Bro- och stålbyggnad;

    Abstract : The ignition and the propagation of a fire inside a building may lead to global or local structural collapse, especially in steel framed structures. Indeed, steel structures are particularly vulnerable to thermal attack because of a high value of steel conductivity and of the small thickness that characterise the cross-sections. READ MORE

  6. 4. Stiffness of reverse channel connections at room and elevated temperatures

    Author : Tim Heistermann; Darko Beg; Luleå tekniska universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Steel Structures; Stålbyggnad;

    Abstract : A frame structure exposed to fire undergoes two types of changes due to the resulting temperature fields. The first is the thermal expansion of the structural members and the second is the degradation of the material strength and stiffness as temperature rises. READ MORE

  7. 5. Nanofabrication of Diffractive Soft X-ray Optics

    Author : Magnus Lindblom; Hans M. Hertz; Erik H. Anderson; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Nanofabrication; Zone plate; x-ray; diffractive x-ray optics; x-ray microscopy; Optics; Optik; Physics; Fysik;

    Abstract : This thesis summarizes the present status of the nanofabrication of diffractive optics, i.e. zone plates, and test objects for soft x-ray microscopy at KTH. The emphasis is on new and improved fabrication processes for nickel and germanium zone plates. READ MORE