Avancerad sökning

Visar resultat 1 - 5 av 17 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Fast wave heating and current drive in tokamaks

   Författare :Martin Laxåback; Torbjörn Hellsten; Raymond Koch; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Tokamak; JET; ITER; thermonuclear fusion; fast wave; heating; current drive; ion cyclotron resonance; polychromatic; finite orbit widths; RF-induced transport; neutral beam injection; fusion born alpha particles; magnetosonic eigenmodes; parasitic absorption; modelling; weighted Monte Carlo scheme; Fysik; Physics; Fysik;

   Sammanfattning : This thesis concerns heating and current drive in tokamak plasmas using the fast magnetosonic wave in the ion cyclotron range of frequencies. Fast wave heating is a versatile heating method for thermonuclear fusion plasmas and can provide both ion and electron heating and non-inductive current drive. LÄS MER

3. 2. Impact of Tissue Characteristics on Radio-Frequency Lesioning and Navigation in the Brain : Simulation, experimental and clinical studies

   Författare :Johannes Johansson; Karin Wårdell; Hans von Holst; Linköpings universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Brain; Radio frequency ablation; Finite element method; Monte Carlo simulation; light reflectance; Radiological research; Radiologisk forskning;

   Sammanfattning : Radio-Frequency (RF) lesioning, or RF ablation, is a method that uses high frequency currents for thermal coagulation of pathological tissue or signal pathways. The current is delivered from an electrode, which also contains a temperature sensor permitting control of the current at a desired target temperature. In the brain, RF lesioning can e.g. LÄS MER

4. 3. Thermocoagulation in Deep Brain Structures : Modelling, simulation and experimental study of radio-frequency lesioning

   Författare :Johannes Johansson; Karin Wårdel; Stefan Andersson-Engels; Linköpings universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Neurosurgery; Radiofrequency ablation; Finite element method; Blood perfusion; Cerebrospinal fluid; Free convection; Neurosurgery; Neurokirurgi;

   Sammanfattning : Radio-frequency (RF) lesioning is a method utilising high frequency currents for thermal coagulation of pathological tissue or signal pathways. The current is delivered from an electrode with a temperature sensor, permitting control of the current at a desired target temperature. In the brain RF-lesioning can e.g. LÄS MER

5. 4. Neutron Spectroscopy Studies of Heating Effects in Fusion Plasmas

   Författare :Hans Henriksson; Jan Källne; Joaquín Sánchez; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nuclear physics; neutron emission spectroscopy; diagnostic; fusion research; plasma heating; Kärnfysik; Nuclear physics; Kärnfysik; Applied Nuclear Physics; tillämpad kärnfysik;

   Sammanfattning : High power fusion plasmas produced in the world’s largest facility for magnetic confinement experiments (JET), have been studied using the neutron emission measured with the magnetic proton recoil (MPR) spectrometer. The MPR has been used to observe plasmas since 1996 including those of deuterium-tritium leading to several fusion records and corresponding observational achievements of neutron emission spectroscopy. LÄS MER

7. 5. GaN-based HEMTs for Cryogenic Low-Noise Applications

   Författare :Mohamed Aniss Mebarki; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cryogenic temperatures; superconductivity; RFI; High Electron Mobility Transistor HEMT ; Low Noise Amplifier LNA ; Niobium Nb ; Radio-astronomy; Gallium Nitride GaN ; high frequency;

   Sammanfattning : Radio-astronomy deals with signals and radiations of extremely weak intensity. Also, it requires robust and rugged technologies able to sustain and prevent the Radio Frequency Interferences (RFI). LÄS MER