Sökning: "naturvetenskap fysik atom- och molekylfysik atomfysik"

Visar resultat 1 - 5 av 132 avhandlingar innehållade orden naturvetenskap fysik atom- och molekylfysik atomfysik.

1. 1. Feature Extraction for Low-Frequency Signal Classification

   Författare :José Chilo; Thomas Lindblad; Christian Bohm; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; infrasound; seismic signals; feature extraction; wavelets; fingerprints; mining; multimodal data space; Atomic physics; Atomfysik; Electronics;

   Sammanfattning : The development of the International Monitoring System (IMS) for the verification of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) has led to a rapid revival of interest in infrasound. Furthermore, the installation of low-frequency sensors at seismic sites has increased in recent years, providing researchers with large and heterogeneous data-sets in near real-time. LÄS MER

3. 2. Guiding of highly charged ions through insulating nanocapillaries

   Författare :Hongqiang Zhang; Reinhold Schuch; Amine Cassimi; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; Atomic physics; Atomfysik; fysik; Physics;

   Sammanfattning : This thesis contains experimental work on guiding of highly charged ions through insulating nanocapillaries. We have studied the time evolution of angular distributions of transmitted ions under well defined initial conditions: already charged, as well as fully discharged nanocapillaries, by using a two-dimensional position sensitive Micro Channel Plate detector with a data acquisition system working in event mode. LÄS MER

4. 3. Time-resolved X-ray diffraction studies of phonons and phase transitions

   Författare :Ola Synnergren; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Fysik; Physics; Phase transitions; X-ray diffraction; Phonons; X-ray diffraction;

   Sammanfattning : This thesis summarizes work in which time-resolved X-ray diffraction has been used to probe crystalline materials, thereby revealing the dynamics of phonons and phase transitions. X-ray diffraction is the standard tool in investigations of structure on the atomic scale. LÄS MER

5. 4. Resonant States in Negative Ions

   Författare :Nicklas Brandefelt; John S. Briggs; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Molekylfysik; Atomfysik; Kärnfysik; Partikelfysik; Atomic and molecular physics; Atom- och molekylfysik;

   Sammanfattning : Resonant states are multiply excited states in atoms and ions that have enough energy to decay by emitting an electron. The ability to emit an electron and the strong electron correlation (which is extra strong in negative ions) makes these states both interesting and challenging from a theoretical point of view. LÄS MER

7. 5. Extreme Electron Beams and Brilliant X-rays : Generation, Manipulation and Characterization of Relativistic Electron Beams for and from Plasma-Based Accelerators

   Författare :Jonas Björklund Svensson; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; laser; plasma; wakefield; acceleration; accelerator; relativistic; electrons; x-rays; ultra-fast; betatron; laser-wakefield acceleration; plasma-wakefield acceleration; Fysicumarkivet A:2020:Björklund;

   Sammanfattning : This thesis is based on work done by the author on the development of plasma-based electron accelerators driven by ultra-intense laser pulses and dense electron bunches. Plasma based accelerators have several benefits, such as accelerating fields around 1000 times stronger than in “conventional” radio-frequency accelerators, which can allow for shrinking the overall footprint of the accelerator. LÄS MER