Sökning: "Niobium Nb"

Visar resultat 1 - 5 av 16 avhandlingar innehållade orden Niobium Nb.

1. 1. Antenna Integrated Superconducting Mixers

   Författare :Hans Ekström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tapered slotline antenna; mixer; double dipole antenna; superconducting; hot electron; receiver; Niobium; bolometer; trilayer junction; edge junction; Niobium Nitride; SIS;

   Sammanfattning : This thesis investigates the prospects of some different superconducting mixers integrated with planar antennas for the millimeter and submillimeter regime. Two kinds of Superconductor/Insulator/Superconductor (SIS) tunnel junctions for use in mixers have been fabricated; Nb/PbBi edge junctions and Nb trilayer junctions. LÄS MER

3. 2. Structural investigation of Nb-based layer sulfides

   Författare :Alexander Grippa; Sven Lidin; Pedro Berastegui; Carlos Otero Díaz; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nb-based sulfides; misfit layered; structure determination; electron diffraction; Chemistry; Kemi;

   Sammanfattning : In this work we have investigated the intercalation of electron-donors between NbS2 slabs in Nb-based layer sulfides.Two series of Sr substituted Nb-based misfit sulfides belonging to the 1.5Q/1H and 1Q/1H series of misfit layer compounds have been synthesised. LÄS MER

4. 3. Charging Effects in Niobium Nanostructures

   Författare :Torsten Henning; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Three types of metallic nanostructures comprising niobium were investigated experimentally; in all three types, electric transport at very low temperatures was governed by Coulomb blockade effects. 1. LÄS MER

5. 4. 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

7. 5. Weldability of Cast Superalloys - Effect of homogenization heat treatments on hot cracking susceptibility of cast Alloy 718, ATI® 718Plus®, and Haynes® 282®

   Författare :Sukhdeep Singh; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hot ductility; Segregation; Homogenization; Boron; Gleeble; Welding; Nickel-based superalloys; Varestraint; Hot cracking; Hot isostatic pressing; Niobium;

   Sammanfattning : Precipitation hardened Ni- and Ni–Fe-based superalloys are used in high-temperature sections of aero engines owing to their superior mechanical properties compared to those of the other alloys. However, their better mechanical performance is accompanied by its own challenges during the manufacturing process. LÄS MER