Sökning: "Rajeev Ahuja"

Visar resultat 31 - 35 av 38 avhandlingar innehållade orden Rajeev Ahuja.

1. 31. First Principle Studies of Functional Materials : Spintronics, Hydrogen Storage and Cutting Tools

   Författare :Fredrik Silvearv; Ahuja Rajeev; Ali Zaoui; Uppsala universitet; []
   Nyckelord :spintronics; hydrogen storage; coating materials; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : The properties of functional materials have been studied with density functional theory. The first type of materials that have been investigated is the so called diluted magnetic semiconductors. It is a new class of materials that could offer enhanced functionality by making use of spin in addition to the charge of the electron. LÄS MER

3. 32. Designing and Tuning the Properties of Materials by Quantum Mechanical Calculations

   Författare :Jailton Souza de Almeida; Rajeev Ahuja; Patrizia Monachesi; Uppsala universitet; []
   Nyckelord :Physics; Density Functional Theory; Electronic Structure; Phase Transitions; High Pressure; Optical Properties; Dielectric Functions; Semiconductors; Metals; Fysik;

   Sammanfattning : In many materials, changes in chemical composition, pressure or temperature can induce metal to insulator transitions. It is recently observed in yttrium hydride, for example, changes from a shiny mirror (YH2) to a transparent window (YH3), which has important technological application in optical devices. LÄS MER

4. 33. Computational Studies of Hydrogen Storage Materials : Physisorbed and Chemisorbed  Systems

   Författare :Pornjuk Srepusharawoot; Rajeev Ahuja; Puru Jena; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Density functional theory; Ab initio molecular dynamics; Ab initio random structure searching; Hydrogen storage materials; Alkaline earth dicarbide; Condensed matter physics; Kondenserade materiens fysik; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : This thesis deals with first-principles calculations based on density functional theory to investigate hydrogen storage related properties in various high-surface area materials and the ground state crystal structures in alkaline earth dicarbide systems. High-surface area materials have been shown to be very promising for hydrogen storage applications owing to them containing numerous hydrogen adsorption sites and good kinetics for adsorption/desorption. LÄS MER

5. 34. Heavy Metal Compounds and Hydrogen Storage Materials from Ab Initio Calculations

   Författare :Weiwei Sun; Rajeev Ahuja; Ali Zaoui; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : In principle, most of the properties of solids can be determined by their electronic structures. So the understanding of electronic structures is essential. This thesis presents two classes of materials using ab initio method based on density functional theory. LÄS MER

7. 35. Defect Thermodynamics and Kinetics in Polyanionic Cathodes : A Theoretical Roadmap for Na-ion based Batteries and Hybrid Supercapacitors

   Författare :Teeraphat Watcharatharapong; Rajeev Ahuja; Sudip Chakraborty; Jan Isberg; Palani Balaya; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; DFT; Energy Materials; Defects; Chemical potentials; Kinetics; Hybrid supercapacitors; Na-ion batteries; Polyanionic cathodes;

   Sammanfattning : In this thesis, the framework of the density functional theory is employed to study and predict properties of polyanionic cathodes for Na-ion batteries and hybrid supercapacitors. It consists of three main parts as follows:The first part is primarily dedicated to kröhnkite-type Na2Fe(SO4)22H2O cathode. LÄS MER