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Visar resultat 1 - 5 av 27 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Statistical Investigations ofthe Emission Processes in Gamma-ray Bursts

    Författare :Zeynep Acuner; Felix Ryde; Judith Racusin; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gamma-ray bursts; Atomic; Subatomic and Astrophysics; Atomär fysik; subatomär fysik och astrofysik;

    Sammanfattning : Physical emission mechanisms responsible for gamma-ray bursts (GRBs) remain elusive to this day, 50 years after their discovery. Although there are well studied physical models, their power to explain the observed data is a matter of debate. LÄS MER

  3. 2. Experimental Studies of the Neutron Deficient Atomic Nuclei 94Ru, 95Rh and 172Pt via their Electromagnetic Properties : Du som saknar dator/datorvana kan kontakta Pär Olsson, [email protected] för information

    Författare :Aysegul Ertoprak; Bo Cederwall; Paul Garrett; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atomic; Subatomic and Astrophysics; Atomär fysik; subatomär fysik och astrofysik;

    Sammanfattning : This thesis reports new results obtained from studies of the neutron deficient atomic nuclei 94Ru, 95Rh and 172Pt using two different experimental set-ups. In the first part, lifetimes of highly excited states in nuclei near the N=50 closed-shell (94Ru and 95Rh) were deduced from an analysis of the Doppler broadened transition lineshapes measured following the 58Ni(40Ca,4p) and 58Ni(40Ca,3p) fusion-evaporation reactions at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator complex situated in Caen, France. 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. The effect of surface steps and oxides on the catalytic activity on model Pd and Rh catalysts

    Författare :Chu Zhang; Synkrotronljusfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Surface X-ray diffraction SXRD ; X-ray photonelectron spectroscopy; Catalytic activity; Oxide; Single Crystal surface; surface structure; vicinal surface; CO oxidation; stepped surface; Fysicumarkivet A:2018:Zhang;

    Sammanfattning : A catalyst is a substance that can speed up the rate of a chemical reaction without itself being consumed. Catalysts are crucial for chemical production industries, where about 90% of all chemicals are produced using catalysts. LÄS MER

  7. 5. The short, excited life of tellurium : Lifetime analysis of excited states in the Te midshell region

    Författare :Ebba Ahlgren Cederlöf; Ayse Nyberg; Torbjörn Bäck; Johan Nyberg; Matthias Weiszflog; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gamma spectroscopy; lifetime measurement; lifetime; shell model; RDDS; DDCM; nuclear physics; nuclear structure; gamma spektroskopi; livstidsmätningar; livstid; skalmodellen; RDDS; DDCM; kärnfysik; kärnstruktur; Atomic; Subatomic and Astrophysics; Atomär fysik; subatomär fysik och astrofysik;

    Sammanfattning : In this licentiate thesis, lifetimes of low lying excited states in the midshell region of tellurium isotopes are discussed. The nuclear lifetimes are interesting properties to study, since they are inversely proportional to the transition probabilities, which contain information on the underlying structure of the nucleus. LÄS MER