Sökning: "echo"
Visar resultat 16 - 20 av 191 avhandlingar innehållade ordet echo.
16. Quantum Optics and Quantum Information Processing in Rare-Earth-Ion-Doped Crystals
Sammanfattning : In this thesis, aspects of the use of cryogenically cooled rare-earth-ion-doped crystals in the fields of quantum optics and quantum information processing are addressed. The experiments and theoretical considerations referred to in this thesis are based on the coherent transient interaction between light and the ions in the crystals. LÄS MER
17. Optical Memories and Processing in Time- and Frequency Domain
Sammanfattning : Spectral hole burning and photon echoes are the techniques for frequency-selective optical memories, which have the potential to increase areal data storage density by a factor 10**7. They also have the capability to perform in-memory data processing. LÄS MER
18. Towards Efficient Quantum Memories in Rare-Earth-Ion-Doped Solids
Sammanfattning : This thesis describes experiments aimed at developing a key component in applications such as quantum networks and long-distance quantum communication systems: quantum memories. Quantum memories for light using photon-echo and coherent rephrasing techniques have been developed. The work is carried out on rare-earth-ion-doped inorganic crystals. LÄS MER
19. Lamb wave evaluation of concrete plates
Sammanfattning : This thesis is about the application of Lamb waves for non-destructive evaluation of plate-like concrete structures under one-sided access test condition using a portable equipment consisting of an accelerometer and impact hammer. With this type of equipment and based on array signal processing, the impact-echo (IE) method can be extended with measurements of surface waves; this extension allows an evaluation with Lamb waves. LÄS MER
20. Fetal echo doppler for early detection of congenital heart block
Sammanfattning : Background: Fetal echo Doppler methods detecting prolonged atrioventricular (AV) time intervals, a mechanical PR interval corresponding to the electrical PR interval in ECG, have been proposed for surveillance of pregnancies at risk of complete congenital heart block (CCHB). The aim of this thesis was; to validate these Doppler methods by comparing AV time intervals from left ventricular inflow (MV), inflow and aortic outflow (MV-Ao) and superior vena cava and aortic flow (SVC-Ao) with ECG in newborns (Paper I); to investigate the significance of mechanical components in AV time prolongation (Paper II); to evaluate the diagnostic precision in a target population (Paper III) and to verify childhood outcome of fetuses, exposed to maternal anti- SSA/Ro antibodies (SSA),(Paper IV). LÄS MER