Sökning: "Greens function"
Visar resultat 1 - 5 av 69 avhandlingar innehållade orden Greens function.
Sammanfattning : This work describes a new formalism for Fermionic thermal Greens functions that are discretized in imaginary time. The discretization makes the thermal Greens function periodic in imaginary (Matsubara) frequency space and requires a generalisation of the Dyson equation and Luttinger-Ward-Baym-Kadanoff functional. LÄS MER
Sammanfattning : The neutron noise, i.e. the time-variations of the neutron flux around its meanvalue, can be used for obtaining important safety parameters in a nuclear reactor,e.g. LÄS MER
Sammanfattning : The present thesis deals with the neutron noise arising in power reactor systems. Generally, it can be divided into two major parts: first, neutron noise diagnostics, or more specifically, novel methods and algorithms to monitor nuclear industrial reactors; and second, contributions to neutron noise theory as applied to power reactor systems. LÄS MER
Sammanfattning : We study the effects of local vertex corrections to the self energy of the electron gas. We find that a vertex derived from time-dependent density-functional theory can give accurate self energies without including the explicit time dependence of the exchange-correlation potential provided, however, that a proper decay at large momentum transfer (large q) is built into the vertex function. LÄS MER
5. Multiconductor transmission lines wideband modeling : A delay-rational Green’s-function-based method
Sammanfattning : The performance of variable-frequency drives (VFDs) commonly used in energy production plants can be severely affected by electromagnetic (EM) noise in the form of conducted disturbances.A VFD is composed of an inverter, a motor, and a connecting power cable. LÄS MER