Sökning: "gallium"

Visar resultat 1 - 5 av 74 uppsatser innehållade ordet gallium.

  1. 1. Radiation Effects on GaN-based HEMTs for RF and Power Electronic Applications

    Master-uppsats, KTH/Tillämpad fysik

    Författare :Wilhelm Holmberg; [2023]
    Nyckelord :High Electron Mobility Transistor; HEMT; Gallium Nitride; GaN; Silicon Carbide; SiC; Proton Radiation; Galliumnitrid; GaN; Kiselkarbid; SiC; Kisel; Si; HEMT; Transistor; Protonstrålning;

    Sammanfattning : GaN-HEMTs (Gallium Nitride-based High Electron Mobility Transistors) have, thanks to the large band gap of GaN, electrical properties that are suitable for applications of high electrical voltages, high currents, and fast switching. The large band gap also gives GaN-HEMTs a high resistance to radiation. LÄS MER

  3. 2. Analysis of high-voltage low-current DC/DC converters for electrohydrodynamic pumps

    Kandidat-uppsats, Uppsala universitet/Institutionen för elektroteknik

    Författare :Sigge Axelsson; Jonas Gartner; Axel Stafström; [2023]
    Nyckelord :high-voltage; low-current; low-power; DC DC; DC-DC; high-gain; converter; electrohydrodynamic pump; EHD; transformerless converter; Royer-based converter; resonant Royer oscillator; Cockroft-Walton voltage multiplier; CWVM; voltage multiplier; series-connected positive-negative voltage multiplier; SPNVM; planar air-core transformer; planar transformer; high-freqency Royer-based converter; overcurrent protection; LT8331; gallium nitride; GaN; planar PCB-integrated transformers;

    Sammanfattning : Moving parts cause vibrations and tend to wear out. In applications where maintenance is complicated, solutions without moving parts are therefore advantageous. Electrohydrodynamic pumps are such a solution. Instead of mechanical propulsion, they use strong electric fields to induce movement in a dielectric cooling liquid. LÄS MER

  4. 3. Sputtered Transparent Contact Layers for Bifacial and Tandem Solar Cells

    Uppsats för yrkesexamina på avancerad nivå, Uppsala universitet/Solcellsteknik

    Författare :Klara Kiselman; [2022]
    Nyckelord :Solar cells; ITO; indium doped tin oxide; bifacial cell; tandem cell; transparent conductive oxides;

    Sammanfattning : A key to solar cells with lower environmental impact is higher efficiency and reduced material usages. Bifacial solar cells may have a higher efficiency as light can enter from two directions and tandem solar cells may use a larger part of the incoming solar spectrum, increasing the efficiency. LÄS MER

  5. 4. Cirkulära metallflöden i medicinteknisk utrustning

    Kandidat-uppsats, Uppsala universitet/Institutionen för geovetenskaper

    Författare :Sara Ferndahl; Frida Brännlund; Fanny Holstein-Krag; Johanna Rantala; Oscar Törsleff; Anton Virtanen; [2022]
    Nyckelord :kritiska metaller; kriticitetsmatris; kriticitet; högteknologisk medicinteknik; återvinning; upphandling; miljökrav; cirkularitet;

    Sammanfattning : I denna studie undersöktes cirkulära metallflöden i medicinteknik på Akademiska sjukhuset i Uppsala och Region Uppsala. Syftet var att kartlägga och undersöka kritiska metaller i utvald medicinteknisk utrustning. Återvinningen av metaller i utrustningen på Akademiska sjukhuset undersöktes. LÄS MER

  7. 5. Characterisation of GaN HEMTs on Different Substrates for Power Electronics Applications

    Master-uppsats, KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Författare :Hithiksha Krishna Murthy; [2022]
    Nyckelord :Gallium nitrate; High Mobility Electron Transistor; Silicon carbide; Silicon; Sapphire; substrates; power electronics;

    Sammanfattning : GaN-based High Electron Mobility Transistors (HEMT) are appealing because of their large breakdown field, high saturation velocity, and superior thermal conductivity. They work at high temperature without much degradation. HEMTs have a few drawbacks despite many positives. The cost of developing GaN HEMTs on a native substrate is high. LÄS MER