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Visar resultat 1 - 5 av 56 uppsatser som matchar ovanstående sökkriterier.

  1. 1. Finding the Seeds of Supermassive Black Holes: The Direct Collapse Black Hole Scenario

    Master-uppsats, Uppsala universitet/Institutionen för fysik och astronomi

    Författare :Weihui Li; [2023]
    Nyckelord :;

    Sammanfattning : The origin of supermassive black holes (SMBHs,∼ 10^9M⊙) in the first billion years of cosmic history remains a mystery. Direct Collapse Black Holes (DCBHs,∼ 10^4M⊙) are considered one of the most promising hypotheses for the progenitor of SMBHs, as they are believed to provide a favorable starting point as massive seeds for SMBH formation. LÄS MER

  3. 2. Evaluation of pretension losses in heated screw joint

    Uppsats för yrkesexamina på avancerad nivå, Luleå tekniska universitet/Institutionen för teknikvetenskap och matematik

    Författare :Joel Svensson; [2022]
    Nyckelord :screw joint; clamping force; thermal load;

    Sammanfattning : The heated flow within the silencers of heavy transport vehicles can easily reach temperatures of hundreds of degrees Celsius. The thermal loads can cause problems for certain components on a silencer. LÄS MER

  4. 3. Fabrication and Characterization of Quantum-well Field Effect Transistor

    Master-uppsats, Lunds universitet/Fysiska institutionen; Lunds universitet/Institutionen för elektro- och informationsteknik

    Författare :Yang Fu; [2022]
    Nyckelord :quantum-well field-effect transistor; InGaAs; subthreshold swing; sheet resistance; contact resistance; electron mobility; Post Metallization Annealing; electrostatic control; Physics and Astronomy;

    Sammanfattning : The project aims to optimize the design and fabrication of InGaAs quantum-well field-effect transistor (QW-FET) by investigating transfer and output characteristics of the QW-FET. This work found a lower source/drain contact resistance solution starting with fabricating micrometer-level gate length transistors. LÄS MER

  5. 4. Phase-Contrast Imaging, Towards G2-less Grating Interferometry With Deep Silicon

    Master-uppsats, KTH/Fysik

    Författare :Rickard Brunskog; [2022]
    Nyckelord :Phase-contrast imaging; phase-contrast; CT-scanning; Computed-tomography; 1 micrometer resolution x-ray; grating-less phase-contrast imaging; Faskontraströntgen; faskontrast; CT-skanning; 1 mikrometer upplösning x-ray; gitterlös faskontrast; datortomografi;

    Sammanfattning : Conventional phase-contrast imaging entails stepping an analyser grating across the detector to resolve the interference pattern caused by the x-rays after passing through a series of gratings in a so-called Talbot-Lau interferometer. However, the analyser grating in the interferometer poses a challenge, not only due to the machinery and alignment required but also due to each exposure delivering a dose to the subject. LÄS MER

  7. 5. Submillimeter 3D surface reconstruction of concrete floors

    Uppsats för yrkesexamina på avancerad nivå, Luleå tekniska universitet/Institutionen för system- och rymdteknik

    Författare :Björn Hagström; Hampus Wallström; [2022]
    Nyckelord :Submillimeter; Structured light; Sinusoidal phase shift; Concrete; Surface reconstruction; Defocused binary pattern;

    Sammanfattning : During the creation of any concrete floor the concrete needs to be grinded down from it's very rough newly poured form to a more usable floor surface. Concrete floor grinding is very special in that the work area is often immensely large while the height difference on the surface is incredibly small, in-fact the the largest local difference of the surface from a peek to a valley during the grinding process is submillimeter and goes down to micrometer scale. LÄS MER