Sökning: "helium measurements"
Visar resultat 11 - 15 av 30 avhandlingar innehållade orden helium measurements.
11. The electronic structure of iron compounds studied by Mössbauer spectroscopy
Sammanfattning : This thesis describes Mossbauer measurements on iron compounds in the temperature range 4.2-550 Kelvin. The experimentally obtained isomer shifts and quadrupole splittings have given information about the electronic structure of the central iron atom. A large part of the thesis deals with iron compounds that are of catalytic interest. LÄS MER
12. Mössbauer studies of electron population in some iron complexes
Sammanfattning : A Mössbauer effect measuring system has been constructed. With the use of a liquid helium cryostat measurements are performed at room liquid nitrogen and liquid helium temperature. A superconducting magnet with fields up to 5 Tesla has been used in the cryostat. LÄS MER
13. Attosecond photoelectron interferometry: from wavepackets to density matrices
Sammanfattning : Through the advent of high-order harmonic generation and attosecond light pulses, photoionization dynamics has been studied on the attosecond time-scale, the intrinsic time-scale of such dynamics. When the electron leaves the atomic potential a phase shift is imprinted on the electron wavefunction. LÄS MER
14. Inside Pulsating White Dwarfs: Clues from time-resolved spectroscopy
Sammanfattning : Several analyses using time-resolved optical spectrocopy of pulsating white dwarfs are presented. The data have been put to a number of uses. First, line-of-sight velocities associated with the pulsations have been measured in three hydrogen-atmosphere white dwarfs (DAVs), bringing the total number of such measurements up to five. LÄS MER
15. A Matter of Disorder : Monte Carlo Simulations of Phase Transitions in Strongly Disordered Systems
Sammanfattning : Phase transitions and their critical scaling properties, especially in systems with disorder, are important both for our theoretical understanding of our environment, but also for their practical use in applications and materials in our everyday life. This thesis presents results from finite size scaling analysis of critical phenomena in systems with disorder, using high-precision Monte Carlo simulations and state of the art numerical methods. LÄS MER
