Sökning: "Elektromagnetism"

Visar resultat 6 - 10 av 28 avhandlingar innehållade ordet Elektromagnetism.

1. 6. Methods of Multi-Conjugate Adaptive Optics for Astronomy

   Författare :Ralf Flicker; Astronomi - Genomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Adaptive optics; anisoplanatism; laser guide stars; performance estimation; wavefront reconstruction; extremely large telescopes; optics; Electromagnetism; Elektromagnetism; acoustics; Astronomy; akustik; space research; optik; multi-conjugate; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Fysicumarkivet A:2003:Flicker;

   Sammanfattning : This work analyses several aspects of multi-conjugate adaptive optics (MCAO) for astronomy. The research ranges from fundamental and technical studies for present-day MCAO projects, to feasibility studies of high-order MCAO instruments for the extremely large telescopes (ELTs) of the future. LÄS MER

3. 7. Extremely Large Telescopes Optical Design and Wavefront Correction

   Författare :Alexander Gontcharov; Astronomi - Genomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; akustik; optik; Adaptive Optics; Extremely Large Telescopes; optical design methods; wavefront correction methods.; Electromagnetism; optics; Elektromagnetism; acoustics; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi;

   Sammanfattning : An overview of the state of art within optical design of large astronomical telescopes is given. Recent advances within the field are presented. The importance of new computer-controlled mirror-polishing methods is emphasized. LÄS MER

4. 8. Energy Transfer Patterns in Photosynthetic Antenna System of Purple Bacteria

   Författare :Susan Hess; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; optics; Electromagnetism; mykologi; virologi; bakteriologi; photosynthesis; Mikrobiologi; Picosecond and femtosecond spectroscopy; energy transfer; purple bacteria.; Microbiology; bacteriology; mycology; virology; acoustics; Elektromagnetism; optik; akustik; Fysicumarkivet A:1997:Hess;

   Sammanfattning : Steady state and time-resolved absorption and fluorescence spectroscopy have been used to investigated the energy transfer in photosynthetic purple bacteria. Picosecond light pulses were used in measurements of Rb. LÄS MER

5. 9. Attosecond Optical and Electronic Wave Packets

   Författare :Per Johnsson; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; optik; acoustics; optics; Electromagnetism; Ionization Dynamics; Electron Wave Packet Interferometry; Electron Wave Packet Control; Pulse Characterization; High-Order Harmonics; Attosecond Pulse Trains; Atom- och molekylärfysik; Atomic and molecular physics; akustik; Elektromagnetism;

   Sammanfattning : When a low-frequency laser pulse is focused to a high intensity in a gas, the electric field of the laser may become comparable to, or even exceed, the electric field between the electrons and the nucleus in the atom. Under such conditions, through a process known as high-order harmonic generation, bursts of extreme ultraviolet radiation may be emitted, with durations in the attosecond domain (1 as = 10^{-18} s), which is the time-scale of electronic processes. LÄS MER

7. 10. A Novel Signal Model and Estimation Method for Acoustic Doppler Current Meters

   Författare :Thomas L Lagö; Teknisk akustik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Doppler Profiler; Acoustic Doppler; Gaussian Backscattering Model; ADCM; ADCP; The Symmiktos Method; Estimation; Doppler; Current; MPCA.; Technological sciences; Teknik; Electromagnetism; optics; acoustics; Elektromagnetism; optik; akustik;

   Sammanfattning : This thesis deals with the process of estimating underwater current from the backscattering signal transmitted from an ultrasonic transducer. The narrowband sinusoidal burst signal is Doppler-shifted due to the current, and this information is converted into current. LÄS MER