Sökning: "rymdvetenskap"

Visar resultat 1 - 5 av 21 avhandlingar innehållade ordet rymdvetenskap.

  1. 1. Measurements of High-Precision Atomic Data with Applications to Astrophysics and Cosmology

    Detta är en avhandling från Lund Observatory, Lund University

    Författare :Maria Aldenius; [2007]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; atomic data; Ca; Cr; Fe; Mn; Mg; metal-poor stars; fine-structure constant; Fourier transform spectroscopy; nebulae; oscillator strengths; spectroscopy; wavelengths; Ti; Zn; Astronomy; Astronomi; Atomic and molecular physics; Atom- och molekylärfysik; rymdvetenskap; space research; cosmic chemistry; kosmisk kemi; branching fractions;

    Sammanfattning : Investigations of astrophysical spectra require accurate atomic data, such as wavelengths and transition probabilities. This thesis provides high-precision atomic data for astrophysical and cosmological applications. The measurements have been carried out using Fourier transform spectrometry on light produced in a hollow cathode light source. LÄS MER

  2. 2. Space Weather - Solar magnetic variation and its impact on Earth's atmosphere

    Detta är en avhandling från Lund Observatory, Lund University

    Författare :Fredrik Boberg; [2003]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; klimatologi; kartografi; pedology; Physical geography; marklära; geomorphology; climatology; cartography; space weather - solar magnetism - solar wind - geomagnetic activity- North Atlantic Oscillation - climate change - neural networks- wavelet analysis; Fysisk geografi; geomorfologi; Astronomy; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Fysicumarkivet A:2003:Boberg;

    Sammanfattning : A solar magnetic field is continuously being created in the solar interior. As the field evolves outward through the solar atmosphere and into the enveloping heliosphere, it causes effects on a wide range of temporal and spatial scales. LÄS MER

  3. 3. Dynamics and Atomic Processes in the Symbiotic Star AG Peg as Derived from Its Emission Line Spectrum

    Detta är en avhandling från KFS AB

    Författare :Mattias Eriksson; [2006]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomi; rymdvetenskap; kosmisk kemi; cosmic chemistry; space research; Astronomy; Atom- och molekylärfysik; Atomic and molecular physics; Symbiotic stars; Fluorescence; Atomic processes;

    Sammanfattning : The spectra of symbiotic stars are shown to frequently contain numerous fluorescence lines caused by Photo-excitation by Accidental Resonance (PAR). So far, most work involving fluorescence in stellar spectra has been assigned to the search of new PAR mechanisms, which can explain the presence of certain emission lines. LÄS MER

  4. 4. Methods of Multi-Conjugate Adaptive Optics for Astronomy

    Detta är en avhandling från Lund Observatory, Lund University

    Författare :Ralf Flicker; [2003]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Adaptive optics; anisoplanatism; laser guide stars; performance estimation; wavefront reconstruction; extremely large telescopes; optics; Electromagnetism; Elektromagnetism; acoustics; Astronomy; akustik; space research; optik; multi-conjugate; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Fysicumarkivet A:2003:Flicker;

    Sammanfattning : This work analyses several aspects of multi-conjugate adaptive optics (MCAO) for astronomy. The research ranges from fundamental and technical studies for present-day MCAO projects, to feasibility studies of high-order MCAO instruments for the extremely large telescopes (ELTs) of the future. LÄS MER

  5. 5. Solar Wind and Geomagnetic Activity - Predictions Using Neural Networks

    Detta är en avhandling från Lund Observatory, Lund University

    Författare :Hans Gleisner; [2000]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geophysics; kosmisk kemi; rymdvetenskap; magnetosphere; solar wind; space weather; geomagnetic activity; geomagnetism; ring current; auroral electrojet; neural networks; forecasting; Astronomy; space research; Astronomi; cosmic chemistry; physical oceanography; meteorology; Geofysik; fysisk oceanografi; meteorologi; Fysicumarkivet A:2000:Gleisner;

    Sammanfattning : This thesis shows how artificial neural networks (ANNs) can be applied to predict geomagnetic activity from solar-wind data. It introduces and summarizes five papers where development of ANN models are reported, and where predictions of geomagnetic activity are discussed. LÄS MER