Sökning: "DRIFTS"

Visar resultat 16 - 20 av 58 avhandlingar innehållade ordet DRIFTS.

  1. 16. Auroral Electric Fields From Satellite Observations and Numerical Modelling

    Författare :Tomas Karlsson; KTH; []
    Nyckelord :Satellite measurements; electric fields; ionosphere; magnetosphere; diverging electric fields; downward current region; black aurora; westward travelling surge; auroral bulge; subauroral ion drifts SAID ; subauroral electric fields SAEF ; mid-latit; TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : This thesis is about electrodynamics of thehigh-latitude/auroral region of near-Earth space. The work ismainly based on electric field measurements made by the doubleprobe instrument on the Freja satellite at altitudes ofapproximately 800-1700 km, together with measurements fromother instruments on the same satellite, and ground-basedinstrumentation. LÄS MER

  3. 17. Biochemical and spectral characterization of micro- and macroalgae

    Författare :Calle Niemi; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Algae contain many compounds which are of interest to the pharmaceutical, agricultural and food industries, among others. Despite the potential for many applications, a quick, accurate and inexpensive method for characterising algae is lacking. LÄS MER

  4. 18. Molecular analysis of lake-sediment organic matter : long-term dynamics and environmental implications in boreal lakes

    Författare :Sofia Ninnes; Richard Bindler; Xiao-Ru Wang; Christian Bigler; Hendrik Vogel; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lake sediment; Holocene; organic matter; Pyrolysis-GC MS; mid-infrared spectroscopy; boreal;

    Sammanfattning : Lake sediment organic matter is material composed of residues from plants, algae, animals, fungi and bacteria. Its molecular composition is dependent on the sources as well as secondary biotic and abiotic transformations, which combined generates a highly complex matrix. LÄS MER

  5. 19. Atomic transport in optical lattices

    Författare :Henning Hagman; Claude Dion; Daniel Comparat; Umeå universitet; []
    Nyckelord :Ultra-cold atoms; optical lattice; laser cooling; directed transport; Brownian motor; Brownian motion;

    Sammanfattning : This thesis includes both experimental and theoretical investigations of fluctuation-induced transport phenomena, presented in a series of nine papers, by studies of the dynamics of cold atoms in dissipative optical lattices. With standard laser cooling techniques about 108 cesium atoms are accumulated, cooled to a few μK, and transferred into a dissipative optical lattice. LÄS MER

  7. 20. VLF Chorus Activity Associated with Substorm Particle Injections

    Författare :Andrew Collier; KTH; []
    Nyckelord :space physics; magnetosphere; VLF waves; substorms;

    Sammanfattning : The Substorm Chorus Event (SCE) is a Very Low Frequency(VLF) radio phenomenon observed on the ground after the onsetof the substorm expansion phase. It consists of a band of VLFchorus emissions with rising upper and lower cutofffrequencies. LÄS MER