Sökning: "density fluctuations"

Visar resultat 1 - 5 av 111 avhandlingar innehållade orden density fluctuations.

1. 1. Development of an integrated neutronic/thermal-hydraulic tool for estimating fluctuations in PWRs

   Författare :Viktor Larsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Diffusion theory; Fluctuations; Neutron noise; Coupled calculations; P1 theory Analytical Nodal Method;

   Sammanfattning : Monitoring and diagnostics of a reactor core at a given state is very important for detecting potential problems and anomalies at an early stage. Several methods exist for these purposes, but the majority of them require a disruption of the plant operation, e.g. by shut-down or by perturbation of the system. LÄS MER

3. 2. Vortex fluctuations in superconductors

   Författare :Peter Olsson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Superconductor; Two dimensions; vortex; coulomb gas; XY model; Kosterlitz-Thouless transition; high-Tc.;

   Sammanfattning : The vortex fluctuations have proved to be responsible for the onset of dissipation in thin type-II superconducting Aims. There is also growing evidence that dissipation in high- temperature superconductors exhibits the same kind of two-dimensional (2D) behavior. LÄS MER

4. 3. A study of the fluctuations in atmospheric ion density

   Författare :Edward R. T. Awunor-Renner; Uppsala universitet; []
   Nyckelord :NATURAL SCIENCES; NATURVETENSKAP;

   Sammanfattning : .... LÄS MER

5. 4. 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

7. 5. Noise Aspects of some Si-based One Port Devices and Carbon Nanotubes

   Författare :Hassan Ouacha; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; etching; Schottky contacts; noise; fluctuations; generation; mobility; noise spectroscopy; recombination; p-n diodes; carbon nanotubes; thermal reaction; junction; defects; co-sputtering; irradiation; interface states; low frequency noise;

   Sammanfattning : The p-n junctions and Schottky diodes based on Si1-xGex and SiC are of great importance in modern electronic applications, such as microwave detectors and mixers. Carbon nanotubes (CNTs) have appeared recently as an attractive new class of materials with a reduced dimensionality, and proposed as building blocks for nanoelectronic technology. LÄS MER