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Visar resultat 1 - 5 av 28 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Nanofluidic Scattering Microscopy for Single Particle Catalysis

    Författare :Björn Altenburger; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; label-free methods; Platinum; Nanofluidics; Single nanoparticle catalysis; Particle trapping; Hydrogen Peroxide decomposition; Colloidal particles; Dark field microscopy;

    Sammanfattning : Heterogeneous catalysis concerns material formulations – catalysts – that can assist a chemical reaction by improving its rate or selectivity, by lowering activation barriers and altering the energy landscape. The core of catalysts are often tiny metal particles that provide a large reaction surface at a small volume, as well as low coordination sites whose type and abundance depends on particle size and shape. LÄS MER

  2. 2. Transmission Electron Microscopy of Graphene and Hydrated Biomaterial Nanostructures : Novel Techniques and Analysis

    Författare :Sultan Akhtar; Klaus Leifer; Hilborn Jöns; Stefano Rubino; Marco Cantoni; Uppsala universitet; []
    Nyckelord :Graphene flakes; magnetic beads DNA coils; hydrated biomaterials; transmission electron microscopy; focused ion beam scanning electron microscopy; bright-field dark-field imaging; high resolution imaging; electron diffraction and cryogenic temperatures; Materialvetenskap; Materials Science;

    Sammanfattning : Transmission Electron Microscopy (TEM) on light element materials and soft matters is problematic due to electron irradiation damage and low contrast. In this doctoral thesis techniques were developed to address some of those issues and successfully characterize these materials at high resolution. LÄS MER

  3. 3. Nanofluidics as a tool for parallelized single nanoparticle characterization: Fluorescence single nanoparticle catalysis and size determination through 1D Brownian motion

    Författare :Sune Levin; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; dark field microscopy; single nanoparticle catalysis; heterogenous catalysis; particle tracking; Brownian motion; fluorescence microscopy; nanofluidics;

    Sammanfattning : Nanoparticles exist widely in nature and are objects of study in many scientific disciplines due to their high performance in a wide range of applications. With modern techniques that facilitate creating and shaping of nanoparticles into ever more complex shapes and compositions, characterization of particle properties is essential. LÄS MER

  4. 4. Transient State Fluorescence Microscopy - method development and biological applications : Exploiting the dark states of fluorophores to measure oxygen concentrations, redox state, Förster resonance energy transfer and membrane viscosity

    Författare :Thiemo Spielmann; Jerker Widengren; Karsten König; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Transient States imaging TRAST ; Triplet State imaging; fluorescence microscopy; modulated excitation; triplet state; radical state; trans-cis isomerisation;

    Sammanfattning : Due to their long lifetime, triplet, redox and other transient states of fluorophores are highly sensitive to the micro-environment. Imaging their spatial distribution in biological samples can therefore help answer interesting questions about the metabolism, molecular interactions and dynamics in living cells. LÄS MER

  5. 5. Studies of Molecular Interactions with Single Nanoparticles: Combining in Situ Plasmonic Nanospectroscopy with Transmission Electron Microscopy

    Författare :Sara Nilsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; oxidation; plasmonic nanospectroscopy; heterogeneous catalysis; localized surface plasmon resonance sensing; grain boundary; transmission electron microscopy; single nanoparticle; palladium hydride; dark-field scattering spectroscopy;

    Sammanfattning : The cyclic methanol and hydrogen economies are two viable options in the strive for clean energy production. Industrial methanol synthesis is conducted over copper (Cu)-based catalysts. However, Cu is prone to oxidation, which leads to Cu catalyst deactivation. LÄS MER