Sökning: "Fourier"

Visar resultat 1 - 5 av 463 avhandlingar innehållade ordet Fourier.

  1. 1. Deciphering the role of genetics and circadian rhythm in cluster headache

    Författare :Carmen Fourier; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : Cluster headache (CH) is a complex neurovascular disorder with a distinct circadian attack pattern. Although many aspects of the disease’s pathophysiology remain to be elucidated, it is likely caused by a combination of different genetic and environmental risk factors. LÄS MER

  3. 2. Constructing and Commissioning HELIOS – A High Harmonic Generation Source for Pump-Probe Measurements with sub 50 fs Temporal Resolution : The Development of Experimental Equipment for Extreme Ultraviolet Spectroscopy

    Författare :Joachim A. Terschlüsen; Johan Söderström; Margaret Murnane; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Angle-resolved photoemission spectroscopy; Angle resolved photoemission spectroscopy; Angle-resolved time-of-flight; Angle resolved time of flight; ARTOF; ARPES; tr-ARPES; fs; fs resolution; Fourier transform spectrometer; Fourier-transform spectrometer; Fourier transform spectroscopy; Fourier-transform spectroscopy; FTS; gas cell; high harmonic generation; laser; liquid jet; monochromator; HELIOS; HHG; off-plane mount; off plane mount; OPA; optical parametric amplifier; PCPDTBT; pulse shaping; pump probe; pump-probe measurements; pump-probe measurements; pump-probe spectroscopy; pump-probe spectroscopy; Rowland spectrometer; time-of-flight spectrometer; time of flight spectrometer; TOF; time-resolved spectroscopy; time resolved spectroscopy; time-resolved experiments; time resolved experiments; T-MOKE; tr-PES; PES; photoelectron spectroscopy; transverse magneto optical Kerr effect; transverse magneto-optical Kerr effect; ultrafast; ultra-high vacuum; ultra high vacuum; UHV; XUV; VUV; X-rays; Permalloy; magnetization dynamic; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : This thesis presents HELIOS, an in-house laboratory for time-resolved pump-probe spectroscopy with extreme-ultraviolet (XUV) probe radiation. A wide span of pump wavelengths can be generated using commercial laser equipment while XUV probe radiation is generated via a high harmonic generation process in a noble gas delivering probe photons with energies between 20 eV and 72 eV. LÄS MER

  4. 3. Optical Frequency Comb Fourier Transform Spectroscopy

    Författare :Alexandra C. Johansson; Aleksandra Foltynowicz; Ove Axner; Jürgen Röpcke; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optical frequency comb spectroscopy; Fourier transform; molecular absorption dispersion; fysik; Physics;

    Sammanfattning : Fourier transform spectroscopy (FTS) based on optical frequency combs is an excellent spectroscopic tool as it provides broadband molecular spectra with high spectral resolution and an absolutely calibrated frequency scale. Moreover, the equidistant comb mode structure enables efficient coupling of the comb to enhancement cavities, yielding high detection sensitivity. LÄS MER

  5. 4. Leveraging Intermediate Representations for High-Performance Portable Discrete Fourier Transform Frameworks : with Application to Molecular Dynamics

    Författare :Måns Andersson; Stefano Markidis; Artur Podobas; Niclas Jansson; Ivy Bo Peng; Hartwig Anzt; KTH; []
    Nyckelord :Intermediate Representation; Discrete Fourier Transform; Fast Fourier Transform; Molecular Dynamics; Mellankod; diskret Fouriertransform; snabb Fouriertransform; Molekyldynamik;

    Sammanfattning : The Discrete Fourier Transform (DFT) and its improved formulations, the Fast Fourier Transforms (FFTs), are vital for scientists and engineers in a range of domains from signal processing to the solution of partial differential equations.  A growing trend in Scientific Computing is heterogeneous computing, where accelerators are used instead or together with CPUs. LÄS MER

  7. 5. Surface Characterization using Radiometric and Fourier Optical Methods

    Författare :Peter Hansson; Arne Roos; Mikael Sjödahl; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering physics; Radiometry; Fourier Optics; Surface Characterization; Topography; Reflectance; Color; Paper; Printing; Print quality; Gloss; Light scattering; Shape from shading; Photometric stereo; Optical motion compensation; Filtering; Wiener filter; Lamberts law; Image analysis; Image processing; Machine vision; Teknisk fysik; Engineering physics; Teknisk fysik;

    Sammanfattning : This thesis treats static and dynamic surface characterization using radiometric and Fourier optical methods. A Fourier optical method has been developed for real time image processing in paper production and printing applications. LÄS MER