Search for dissertations about: "geometric corrections."

Showing result 1 - 5 of 7 swedish dissertations containing the words geometric corrections..

  2. 1. Enhancements in Dielectric Response Characterization of Insulation Materials

    Author : Xiangdong Xu; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; harmonic limited waveform; air reference method; contact-free electrode; geometric corrections.; frequency domain spectroscopy; Dielectric characterization;

    Abstract : The increasing demand of integrating various renewable energy recourses in power system requires extensive use of power electronic solutions, such as HVDC and FACTS, as these techniques allow energy conversion between different frequencies and serves to stabilize the network. Consequently, electric stresses other than traditional 50/60 Hz sinusoidal voltage stress are acting on high voltage insulation materials. READ MORE

  4. 2. Geometric distortions in MRI based radiotherapy and PET/MRI

    Author : Josef Lundman; Tufve Nyholm; Anne Larsson; Jörgen Olofsson; Marco Riboldi; Umeå universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Magnetic resonance imaging; MRI; PET MR; PET MRI; medical imaging; radiotherapy; geometrical distortions; MR-only; MRI-only; radiofysik; radiation physics;

    Abstract : Magnetic resonance imaging (MRI) offers high soft-tissue contrast compared to computed tomography (CT). This contrast is helpful in many cases, not least for delineating tumours for radiotherapy treatment, and has led to increasing use in radiotherapy treatment planning (RTP). READ MORE

  5. 3. Quantum mechanical models of nanomagnetism in transition metal clusters and diluted magnetic semiconductors

    Author : Olof Strandberg; Matematisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; diluted magnetic semiconductors; Mn As; Ga; transition metal clusters; magnetic anisotropy; Nanomagnetism; quantum geometric phases; Chern numbers; effective spin Hamiltonians; dimers;

    Abstract : This dissertation investigates nanomagnetism in small transition metal clusters and the diluted magnetic semiconductor (Ga,Mn)As. We derive quantum mechanical models aimed at a realistic description of the low energy physics in these systems. READ MORE

  6. 4. D-instantons and Dualities in String Theory

    Author : Christoffer Petersson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In this thesis we study non-perturbative aspects of string theory. We focus our analysis on D-instanton effects which play key roles in the context of dualities, moduli stabilization and phenomenology. READ MORE

  7. 5. New horizons in string theory : bubble babble in search of darkness

    Author : Suvendu Giri; Ulf Danielsson; Bert Vercnocke; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; String theory; black holes; dark energy; de Sitter; cosmological constant; M-theory; braneworld; anti de Sitter; Theoretical Physics; Teoretisk fysik;

    Abstract : It was discovered nearly two decades ago that we live in an accelerating universe that is dominated by dark energy. Understanding the origin of such an energy has turned out to be a very difficult open question in physics, and calls on the need for a fundamental theory like string theory. READ MORE