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Visar resultat 11 - 15 av 559 avhandlingar som matchar ovanstående sökkriterier.
11. Spectral and Temporal Studies of Gamma-Ray Bursts
Sammanfattning : Gamma-ray bursts (GRBs) are sporadic flashes of light observed primarily in the gamma-ray band. Being the brightest explosions in the Universe since its birth, they are at present also the furthest astronomical sources detected. LÄS MER
12. Radio waves in the ionosphere : Propagation, generation and detection
Sammanfattning : We discuss various topics concerning the propagation, generation, and detec-tionof high-frequency (HF) radio waves in the Earth's ionosphere. With re-gardsto propagation, we derive a full wave Hamiltonian and a polarization evo-lutionequation for electromagnetic waves in a cold, stratified magnetoplasma. LÄS MER
13. Thermophysical Modelling and Mechanical Stability of Cometary Nuclei
Sammanfattning : Comets are the most primordial and least evolved bodies in the Solar System. As such, they are unique sources of information regarding the early history of the Solar System. However, little is known about cometary nuclei since they are very difficult to observe due to the obscuring coma. LÄS MER
14. The faintest stars : A study of white, red and brown dwarfs
Sammanfattning : The local space density of the faintest stars, including M dwarfs, white dwarfs and brown dwarfs has been studied by two different methods.By using dark nebulae as opaque outer screens, the luminosity functions of M dwarfs and white dwarfs were studied as volume-limited and dynamically unbiassed foreground samples. LÄS MER
15. On the Abundances of Li, Be and O in Metal-Poor Stars in the Galaxy
Sammanfattning : Stellar atmospheres constitute excellent environments to study the chemical evolution of our Galaxy. The chemical composition of these atmospheres reflects the composition of the gas from where these stars were born. LÄS MER