Sökning: "pulse"

Visar resultat 16 - 20 av 877 avhandlingar innehållade ordet pulse.

1. 16. Nonlinear Pulse Propagation in Optical Fibres

   Författare :Anders Berntson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Pulse propagation in optical fibre communication systems is affected by the fibre nonlinearity even at relatively low power levels (.... LÄS MER

3. 17. Attosecond Wave Packet Metrology

   Författare :Marko Swoboda; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Molecular dissociation; Electron wave packets; Pulse characterization; Two-color harmonic generation; Attosecond pulse trains; Single attosecond pulses; Resonant two-photon ionization; Fysicumarkivet A:2010:Swoboda;

   Sammanfattning : Attosecond pulses allow the study of electrons on their natural timescale. They are created from the interaction of atoms with ultrashort, intense laser pulses whose electric field approaches the strength of inner-atomic electric fields. This thesis presents experiments around the generation, characterization and application of attosecond pulses. LÄS MER

4. 18. 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

5. 19. Pulse oximetry: Evaluation of a potential tool for early detection of critical congenital heart disease

   Författare :Anne de-Wahl Granelli; Göteborgs universitet; []
   Nyckelord :pulse oximetry; duct-dependent; newborn screening; congenital heart disease; perfusion index;

   Sammanfattning : Background: About one third of newborns with life-threatening congenital heart disease leave newborn nurseries without the problem being recognized, and risk death or serious damage from circulatory collapse. The main aim of this thesis has been to evaluate if routine newborn screening with pulse oximetry could improve early in-hospital detection of newborns with duct-dependent circulation (DDC). LÄS MER

7. 20. Short-Pulse Photofragmentation and Fluorescence-based Diagnostics - Development and Applications

   Författare :Malin Jonsson; Förbränningsfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hydroxyl radical OH ; Short-pulse excitation; Photofragmentation; Combustion diagnostics; Laser-induced fluorescence; Hydrogen peroxides; Collisional quenching; Fysicumarkivet A:2015:Jonsson;

   Sammanfattning : The work presented in the thesis covers the use of laser-induced fluorescence (LIF) and photofragmentation laser-induced fluorescence (PFLIF) with short laser pulses to determine species concentrations in different combustion environments. To attain quantitative species concentrations using LIF investigations of the influence of collisional quenching on the fluorescence signal strength is of vital importance, which can be done by measuring the fluorescence lifetime. LÄS MER