Search for dissertations about: "line spectra"
Showing result 1 - 5 of 130 swedish dissertations containing the words line spectra.
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1. Sparse Modeling of Grouped Line Spectra
Abstract : This licentiate thesis focuses on clustered parametric models for estimation of line spectra, when the spectral content of a signal source is assumed to exhibit some form of grouping. Different from previous parametric approaches, which generally require explicit knowledge of the model orders, this thesis exploits sparse modeling, where the orders are implicitly chosen. READ MORE
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2. Advances in Stellar Astrophysics from Laboratory Spectroscopy
Abstract : Investigation of astrophysical plasmas, such as stellar atmospheres, require both knowledge of atomic structure and data. We present laboratory instruments, techniques and tools for acquisition of the data required to derive important atomic parameters such as, wavelengths, oscillator strengths and line profiles. READ MORE
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3. Atomic Processes in Stellar Atmospheres : Inelastic Collisions and Effects on Late-type Spectra
Abstract : Chemical abundances as measured from stellar spectral lines are often subject to uncertainties due to lack of accurate data for inelastic collisions, which is needed for non-local thermodynamic equilibrium (non-LTE) modelling. For cool stars, understanding of collision processes with electrons and hydrogen atoms is required to achieve high precision measurements. READ MORE
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4. On problems and benefits associated with line structure in stellar spectra
Abstract : [abstract missing].... READ MORE
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5. Atomic Influences in Stellar Spectroscopy
Abstract : This thesis is a description of how knowledge of atomic physics can be used in a stellar spectrum analysis. Stellar investigations are spectroscopically performed based on wavelengths, intensities and spectral line structure. READ MORE