Sökning: "drift velocity"

Visar resultat 6 - 10 av 67 avhandlingar innehållade orden drift velocity.

  1. 6. Charge Transport in Single-crystalline CVD Diamond

    Författare :Markus Gabrysch; Jan Isberg; Mats Leijon; Milos Nesladek; Uppsala universitet; []
    Nyckelord :CVD diamond; wide-bandgap semiconductor; single-crystalline diamond; carrier transport; time-of-flight; drift velocity; mobility; compensation; pair-creation; electronic devices; diamond detector; diamond diode;

    Sammanfattning : Diamond is a semiconductor with many superior material properties such as high breakdown field, high saturation velocity, high carrier mobilities and the highest thermal conductivity of all materials. These extreme properties, as compared to other (wide bandgap) semiconductors, make it desirable to develop single-crystalline epitaxial diamond films for electronic device and detector applications. LÄS MER

  3. 7. Discrete Scale-Space Theory and the Scale-Space Primal Sketch

    Författare :Tony Lindeberg; Jan-Olof Eklundh; Jan. J Koenderink; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Computer vision; low-level processing; scale-space; diffusion; Gaussian filtering; discrete smoothing; primal sketch; segmentation; descriptive elements; scale detection; image structure; focus-of-attention; tuning low-level processing; blob detection; edge detection; edge focusing; histogram analysis; junction classification; perceptual grouping; texture analysis; critical points; classification of blob events; bifurcations; drift velocity; density of local extrema; multi-scale representation; digital signal processing; Computer Science; Datalogi;

    Sammanfattning : This thesis, within the subfield of computer science known as computer vision, deals with the use of scale-space analysis in early low-level processing of visual information. The main contributions comprise the following five subjects:The formulation of a scale-space theory for discrete signals. LÄS MER

  4. 8. Diamond Devices Based on Valley Polarization

    Författare :Nattakarn Suntornwipat; Jan Isberg; Markus Gabrysch; Saman Majdi; Hitoshi Umezawa; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CVD diamond; valleytronics; Negative Differential Mobility; NDM; electron polarization; Time-of-Flight; magnetotransport; carrier transport; drift velocity; valley-transistor; Transferred-Electron Oscillator; TEO; TED; Gunn diode;

    Sammanfattning : Diamond is a wide bandgap semiconductor with extreme properties such as high thermal conductivity, high breakdown field, high carrier mobilities and chemical inertness. These properties together with the possibility to synthesize high purity Single-Crystalline (SC) diamond by Chemical Vapor Deposition (CVD), make it a very interesting material and a candidate for use in power electronics and in hazardous environments. LÄS MER

  5. 9. Valley-Polarized Charge Transport in Diamond

    Författare :Nattakarn Suntornwipat; Jan Isberg; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CVD diamond; valleytronics; Negative Differential Mobility; NDM; electron polarization; Time-of-Flight; ToF; magnetotransport; carrier transport; drift velocity; Teknisk fysik med inriktning mot materialvetenskap; Engineering Science with specialization in Materials Science;

    Sammanfattning : Diamond is a wide bandgap semiconductor with extreme properties such as high thermal conductivity, high breakdown field and high carrier mobilities. These properties together with the possibility to synthesize high purity Single-Crystalline (SC) diamond by Chemical Vapor Deposition (CVD), makes it a really interesting material for electronic devices. LÄS MER

  7. 10. Plasma environment of an intermediately active comet : Evolution and dynamics observed by ESA's Rosetta spacecraft at 67P/Churyumov-Gerasimenko

    Författare :Elias Odelstad; Anders Eriksson; Andrew Coates; Uppsala universitet; []
    Nyckelord :Rosetta; comet; 67P; RPC-LAP; RPC-MIP; RPC-ICA; RPC-MAG; ROSINA-COPS; Langmuir probe; spacecraft potential; plasma; Churyumov-Gerasimenko; ion composition analyzer; diamagnetic cavity; ion velocity; electron temperature; ion-neutral drag; collisional coupling; wake effects; filamentation; electron cooling; plasma waves; hybrid waves; Bernstein waves; minimum variance; polarization; wavelet; density fluctuations; magnetic field oscillations; drift-cyclotron instability; asymmetric plasma and magnetic field enhancements; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

    Sammanfattning : The subject of this thesis is the evolution and dynamics of the plasma environment of a moderately active comet before, during and after its closest approach to the Sun. For over 2 years in 2014-2016, the European Space Agency’s Rosetta spacecraft followed the comet 67P/Churyumov-Gerasimenko at distances typically between a few tens and a few hundred kilometers from the nucleus, the longest and closest inspection of a comet ever made. LÄS MER