Sökning: "x-ray"

Visar resultat 21 - 25 av 2239 avhandlingar innehållade ordet x-ray.

1. 21. Ultrafast spin dynamics at the nanoscale : using coherent X-ray and terahertz radiation

   Författare :Nanna Zhou Hagström; Stefano Bonetti; Stefan Eisebitt; Ferran Macià Bros; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; XFEL; small-angle X-ray scattering; X-ray holography; ultrafast magnetism; symmetry-breaking; magnetic domains; terahertz; magnetic field enhancement; metamaterial; time-resolved magneto-optical microscope; Physics; fysik;

   Sammanfattning : The field of ultrafast magnetism is driven by the growing need for faster and more efficient magnetic data storage, which comprises the vast majority of the digital information worldwide. However, after more than two decades of intense research, the understanding of the fundamental physical processes governing the transfer of angular momentum necessary for magnetic switching, is still lacking, partially hampered by the appropriate experimental tools. LÄS MER

3. 22. Liquid-Jet-Target Microfocus X-Ray Sources : Electron Guns, Optics and Phase-Contrast Imaging

   Författare :Tomi Tuohimaa; Hans M. Hertz; Stephen Wilkins; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electron-impact; x-ray; brightness; liquid-jet-target; phase-contrast imaging; Engineering physics; Teknisk fysik;

   Sammanfattning : This Thesis describes the development of an electron-impact microfocus x-ray source and its application for phase-contrast imaging. The source is based on a novel, liquid-jet target concept. Stable and continuous operation can be achieved at substantially higher electron-beam power densities than conventional solid target based systems. LÄS MER

4. 23. X-ray and neutron μCT of biomedical samples: from image acquisition to quantification

   Författare :Niccoló Peruzzi; Lund Medicinsk strålningsfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; x-ray imaging; neutron imaging; μCT; synchrotron radiation; x-ray phase-contrast; nanoholotomography; x-ray elemental mapping; biomedical applications; virtual histology; biodegradable implants; Mg-alloys; enteric nervous system; peripheral neuropathy; gastroenteric dysmotility; Fysicumarkivet A:2021:Peruzzi;

   Sammanfattning : Even though the validity of x-ray computed tomography in the analysis of biomedical samples is nowadays undisputed, the more recent imaging techniques and more advanced instruments (such as synchrotrons) are still relatively unknown to many medical doctors that could benefit from them.The doctoral work presented in this thesis joins a collective effort from the imaging community to demonstrate potential applications of advanced x-ray and neutron imaging methods to preclinical medical research, with the hope of contributing to reach a “critical mass” in the medical community and in the public opinion as well. LÄS MER

5. 24. Ultrafast Coherent X-ray Diffractive Nanoimaging

   Författare :Filipe R. N. C. Maia; Janos Hajdu; David van der Spoel; Keith Nugent; Uppsala universitet; []
   Nyckelord :XFEL; Phasing; Image Reconstruction; Single Particle Imaging; Ultrafast Diffraction; X-ray diffraction; Coherent Diffractive Imaging; CXDI;

   Sammanfattning : X-ray lasers are creating unprecedented research opportunities in physics,chemistry and biology. The peak brightness of these lasers exceeds presentsynchrotrons by 1010, the coherence degeneracy parameters exceedsynchrotrons by 109, and the time resolution is 105 times better. LÄS MER

7. 25. X-ray scattering and spectroscopy of supercooled water and ice

   Författare :Jonas A. Sellberg; Anders Nilsson; Lars G. M. Pettersson; Thomas Loerting; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; supercooled water; ice; x-ray scattering; x-ray spectroscopy; free-electron laser; kemisk fysik; Chemical Physics;

   Sammanfattning : This thesis presents experimental studies of water and ice at near-atmospheric pressures using intense x-rays only accessible at synchrotrons and free-electron lasers. In particular, it focuses on the deeply supercooled, metastable state and its implications on ice nucleation. LÄS MER