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Visar resultat 1 - 5 av 7 uppsatser som matchar ovanstående sökkriterier.

  1. 1. Quantum Optical Description of High-order Harmonic Generation

    Master-uppsats, Lunds universitet/Atomfysik; Lunds universitet/Fysiska institutionen

    Författare :Isabel Moreno; [2024]
    Nyckelord :Physics and Astronomy;

    Sammanfattning : High-order Harmonic Generation (HHG) is a highly non-linear process in which an atom interacts with a strong laser field. The laser field lowers the atomic potential barrier allowing bound electrons to escape into the continuum through tunnel ionization, propagate, and, with some probability, recombine with the parent ion. LÄS MER

  3. 2. Focal Spot Optimization Using Spatial Light Modulation and a Phase Retrieval Algorithm

    Master-uppsats, Lunds universitet/Atomfysik; Lunds universitet/Fysiska institutionen

    Författare :Robert Petersen; [2023]
    Nyckelord :Spatial Light Modulation; Phase Retrieval Algorithm; Focal Spot Optimization; Adaptive Optics; Wavefront Sensing; Lasers; Physics and Astronomy; Technology and Engineering;

    Sammanfattning : Aberrations to the wavefront of a laser beam reduce the quality of the focal spot and are generally undesired. This project is aimed at determining the aberrations of laser beams by using a phase retrieval algorithm and to show that it is possible to correct the aberrations with a spatial light modulator to optimize the focal spot. LÄS MER

  4. 3. NH Planetary-Scale Circulation in Troposphere and Stratosphere: A Spectral and Dynamical Perspective

    Master-uppsats, Uppsala universitet/Luft-, vatten- och landskapslära

    Författare :Michael Konrad Schutte; [2023]
    Nyckelord :jet stream; Rossby waves; polar vortex; spectral analysis; dynamic systems theory; sudden stratospheric warmings; strong polar vortex events; jetström; Rossbyvågor; polär virvel; spektralanalys; dynamisk systemteori; plötsliga stratosfäriska uppvärmingar; starka polvortexhändelser;

    Sammanfattning : Dynamic Systems Theory (DST) and spectral analysis are employed to study the tropospheric jet stream and the stratospheric polar vortex. The objective is to investigate the relationship between Rossby wave activity and inverse persistence and dimensionality of geopotential height at 250 hPa and 10 hPa, as these two dynamical indicators are expected to show a characteristic behavior of Rossby wave harmonics. LÄS MER

  5. 4. Exploiting the Overtones in Online Localization of Sound Sources

    Master-uppsats, Lunds universitet/Matematisk statistik

    Författare :David Sundström; [2022]
    Nyckelord :Multi-pitch estimation; localization; block sparsity; sparse recursive least squares; online estimation; ADMM; adaptive dictionary; Mathematics and Statistics;

    Sammanfattning : Localization of multiple sound sources from a microphone array is a challenging task that has been a research topic for decades. The challenges stem from the diversity of acoustic contexts due to reverberation and disturbances. LÄS MER

  7. 5. Contrastive Multimodal Image Representations for Deformable Image Registration

    Master-uppsats, Uppsala universitet/Institutionen för informationsteknologi

    Författare :Love Nordling; [2022]
    Nyckelord :;

    Sammanfattning : Image registration is the process of finding correspondences between images of the same or of similar scenes. Multimodal image registration is the specific case where the images are captured with different imaging systems. LÄS MER