Sökning: "point defect"

Visar resultat 16 - 20 av 93 avhandlingar innehållade orden point defect.

1. 16. Time-resolved optical characterisation of defect-rich semiconductors

   Författare :Andreas Gaarder; KTH; []
   Nyckelord :;

   Sammanfattning : This thesis explores carrier trapping and recombination indefect-rich semiconductors, and methods for materialcharacterisation. Optimal manufacturing parameters areestablished for materials to be used in the ultrafast devicesneeded for future telecommunication applications. LÄS MER

3. 17. Squat Detection in Railway Switches & Crossings Using Point Machine Vibration

   Författare :Yang Zuo; Matti Rantatalo; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Drift och underhållsteknik; Operation and Maintenance;

   Sammanfattning : Railway switches and crossings (S&Cs) are among the most important high-value components in a railway network and a single failure of such an asset could result in severe network disturbance, huge economical loss, and even severe accidents. Therefore, potential defects need to be detected at an early stage and the status of the S&C must be monitored to prevent such consequences. LÄS MER

4. 18. Thermodynamic and kinetic properties of Fe-Cr and TiC-ZrC alloys from Density Functional Theory

   Författare :Vsevolod Razumovskiy; Pavel Korzhavyi; Andrei Ruban; Malin Selleby; Sergei Dudarev; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ab initio; first principles; point defects; vacancy clusters; alloys; steels; iron; carbides; diffusion; phase diagram; density functional theory; elastic constants; elastic properties; thermodynamic modelling;

   Sammanfattning : The complete and accurate thermodynamic and kinetic description of any systemis crucialfor understanding and predicting its properties. A particular interest is in systemsthat are used for some practical applications and have to be constantly improved usingmodification of their composition and structure. LÄS MER

5. 19. On the defective origin of conductive and structural properties of oxides: insights from first principles

   Författare :Anders Lindman; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; point defects; thermodynamic modeling; proton conductors; oxyhydrides; density-functional theory; BaZrO3; polarons; grain boundaries; space charges; oxides;

   Sammanfattning : Oxides are versatile materials with applications in many different research fields; especially those related to clean energy technologies, such as fuel cells, batteries and solar panels. Many functional properties of these materials derive from lattice imperfections, or defects, and a lot of effort has been put into fine tuning these materials by modifying their structure on the atomic scale. LÄS MER

7. 20. Capacitance transient measurements on point defects in silicon and silicol carbide

   Författare :Hanne Kortegaard Nielsen; Anders Hallén; F. Damie Auret; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electronics; Elektronik; Electronics; Elektronik;

   Sammanfattning : Electrically active point defects in semiconductor materials are important because they strongly affect material properties like effective doping concentration and charge carrier lifetimes. This thesis presents results on point defects introduced by ion implantation in silicon and silicon carbide. LÄS MER