Sökning: "Low temperature physics"

Visar resultat 6 - 10 av 450 avhandlingar innehållade orden Low temperature physics.

  1. 6. MgB2 hot-electron bolometer mixers for sub-mm wave astronomy

    Författare :Evgenii Novoselov; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; hot-electron bolometer; gain bandwidth; noise bandwidth; thin film; electron-phonon interaction; noise temperature; THz detector; conversion gain; mixer; magnesium diboride; superconductor;

    Sammanfattning : Spectroscopy and photometry in the terahertz (THz) range of remote space objects allows for a study of their chemical composition, because this range covers rotational lines from simple molecules and electron transition lines from atoms and ions. Due to high spectral resolution, THz heterodyne receivers al- low for studying dynamical properties of space objects manifested in doppler-shifted emission lines. LÄS MER

  3. 7. Thermoelectric phenomena in low-dimensional semiconductor systems

    Författare :Magnus Larsson; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; kvantmekanik; relativitet; gravitation; statistisk fysik; termodynamik; Semiconductory physics; Halvledarfysik; thermopower anomaly; thermoelectricity; thermionic couple; zone-folding; cool chip; ballistic; thermionic; Mathematical and general theoretical physics; Matematisk och allmän teoretisk fysik; thermodynamics; statistical physics; relativity; quantum mechanics; klassisk mekanik; classical mechanics;

    Sammanfattning : This thesis investigates thermoelectric effects, predominantly in low-dimensional semiconductors. Various novel phenomena are predicted, investigated and discussed. LÄS MER

  4. 8. Cryogenic InP High Electron Mobility Transistors in a Magnetic Field

    Författare :Isabel Harrysson Rodrigues; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; magnetic field; cryogenic; low noise amplifier; angular dependence; InP HEMT; geometrical magnetoresistance;

    Sammanfattning : The InGaAs-InAlAs-InP high electron mobility transistor (InP HEMT) is the preferred active device used in a cryogenic low noise amplifier (LNA) for sensitive detection of microwave signals. In this thesis it is demonstrated that the InP HEMT, when placed in a magnetic field, has a strong angular dependence in its output current. LÄS MER

  5. 9. Quantum transport and geometric integration for molecular systems

    Författare :Anders Odell; Anna Delin; Anders Niklasson; Michael Springborg; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; density functional theory; ab initio; first principles; electron transport; photoswitching; molecular dynamics; geometric integration; Condensed matter physics; Kondenserade materiens fysik; Computational physics; Beräkningsfysik;

    Sammanfattning : Molecular electronics is envisioned as a possible next step in device miniaturization. It is usually taken to mean the design and manufacturing of electronic devices and applications where organic molecules work as the fundamental functioning unit. LÄS MER

  7. 10. Membrane-based nanocalorimetry for low temperature studies with high resolution and absolute accuracy

    Författare :Stella Tagliati; Andreas Rydh; Vladimir M. Krasnov; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanocalorimetry; specific heat; membrane-based calorimeter; AC steady state; frequency dependence; thermal link conductance; thermal relaxation; GeAu thermometer; numerical simulations; fysik; Physics;

    Sammanfattning : A differential, membrane-based nanocalorimeter has been designed and constructed for thermal studies of mesoscopic samples at low temperatures. The calorimeter is intended for sample masses from mg to sub-μg and a broad temperature range from above room temperature down to the sub-K region. LÄS MER