Sökning: "vacancy clusters"

Visar resultat 1 - 5 av 15 avhandlingar innehållade orden vacancy clusters.

1. 1. 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

3. 2. Helium Filled Bubbles in Solids : Nucleation, Growth and Swelling

   Författare :Odd Runevall; Nils Sandberg; Charlotte Becquart; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Helium; Radiation Damage; DFT; molybdenum; MgO;

   Sammanfattning : When nuclear fuel, fabricated for the purpose of transmuting spent fuel is irradiated, significant amounts of He is produced from alpha particles mainly emitted when 242Cm decays into 238Pu. From irradiation experiments it is known that the presence of He in the solids alters the swelling behaviour of the material. LÄS MER

4. 3. First-principles study of the multiple He trapping in defects in vanadium and SiC

   Författare :Ruihuan Li; Levente Vitos; Anatoly Belonoshko; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : In fusion environment, large amount of helium (He) atoms are produced by transmutation along with structural damage in the structural materials, causing materials swelling and degrading of physical properties. In this thesis, using first-principles method, I examined the microscopic mechanism of He trapping in vacancies and voids in structural materials (vanadium solid and 6H–SiC composites). LÄS MER

5. 4. Influence of defects and impurities on the properties of 2D materials

   Författare :Soumyajyoti Haldar; Biplab Sanyal; Olle Eriksson; Torbjörn Björkman; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; 2D Materials; Defects on 2D materials; Impurities on 2D materials; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : Graphene, the thinnest material with a stable 2D structure, is a potential alternative for silicon-based electronics. However, zero band gap of graphene causes a poor on-off ratio of current thus making it unsuitable for logic operations. This problem prompted scientists to find other suitable 2D materials. LÄS MER

7. 5. From the Electronic Structure of Point Defects to Functional Properties of Metals and Ceramics

   Författare :David Andersson; Börje Johansson; Pavel Korzhavyi; Benjamin Burton; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; first principles; ab initio; density functional theory; Calphad; point defects; diffusion; solid electrolytes; oxygen storage materials; Material physics with surface physics; Materialfysik med ytfysik;

   Sammanfattning : Point defects are an inherent part of crystalline materials and they influence important physical and chemical properties, such as diffusion, hardness, catalytic activity and phase stability. Increased understanding of point defects enables us to tailor the defect-related properties to the application at hand. LÄS MER