Search for dissertations about: "point-contact"

Showing result 1 - 5 of 31 swedish dissertations containing the word point-contact.

  2. 1. Time-domain modelling of curve squeal: a fast model for one- and two-point wheel/rail contact

    Author : Ivan Zenzerovic; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; two-point contact; non-Hertzian contact; dynamics coupling; rolling contact; tangential point-contact model; Curve squeal; time domain; frictional instability;

    Abstract : Curve squeal is a type of railway noise that may arise when a railway vehicle negotiates a relatively tight curve. A single frequency, corresponding to a wheel mode, dominates the radiated sound, which makes squeal a very tonal noise. READ MORE

  4. 2. Fluctuations in Mesoscopic Constrictions

    Author : Jan Peter Hessling; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; low frequency; fluctuations; quantum; noise; 1 f-noise; superconductivity; impurity; point contact; Andreev reflection; shot noise;

    Abstract : In normal and superconducting quantum point contacts there are several sources of fluctuations. Thermally activated impurities in the vicinity of the junction cause the current (or voltage) to change with a typical frequency of the order of one Hz up to a few kHz. READ MORE

  5. 3. Collective Electron Dynamics in Mesoscopic Systems

    Author : Oleksandr Zazunov; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Andreev reflection; Josephson effect; qubit; composite fermions; Andreev levels; resonant tunneling; superconductivity; high-T c superconductors; quantum point contact; fractional quantum Hall effect;

    Abstract : This work is devoted to a theoretical investigation of collective electron dynamics in low dimensional materials and mesoscopic structures. A common feature of these studies is the focus on the properties of the low energy dynamics of conduction electrons. One class of studied materials is the high-Tc superconductor Nd2CuO4 and related compounds. READ MORE

  6. 4. Fabrication of Low-Dimensional Structures in III-V Semiconductors

    Author : Ivan Maximov; Fasta tillståndets fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; III-V semiconductors; plasma; etching; aerosol; lithography; quantum dots; quantum well wires; quantum point contact; damage; luminescence; Fysicumarkivet A:1997:Maximov; Halvledarfysik; Semiconductory physics;

    Abstract : The thesis presents studies on the processing technology and the characterization of nanometer-sized and low-dimensional structures in III-V semiconductors. Two major approaches are described: 1) the combination of aerosol technology and plasma etching for the fabrication of quantum dots (QDs) in InP-based materials and 2) the use of high-resolution electron beam lithography and plasma or wet chemical etching to make quantum well wires (QWWs) in both GaAs and InP-based structures. READ MORE

  7. 5. Noise in quantum point contacts

    Author : Jan Peter Hessling; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; noise; 1 f-noise; elementary fluctuator; quantum point contact; flicker; two level system; impurity; öow frequency;

    Abstract : .... READ MORE