Sökning: "transition metals"

Visar resultat 31 - 35 av 229 avhandlingar innehållade orden transition metals.

1. 31. Ab initio simulations of core level spectra : Towards an atomistic understanding of the dye-sensitized solar cell

   Författare :Ida Josefsson; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; multiconfigurational quantum chemistry; CASSCF calculations; core-level spectroscopy; x-ray photoelectron spectroscopy; x-ray absorption; resonant x-ray scattering; dye solar cells; transition metals; kemisk fysik; Chemical Physics;

   Sammanfattning : The main focus of this thesis is ab initio modeling of core level spectra with a high-level quantum chemical description both of the chemical interactions and of local atomic multiplet effects. In particular, the combination of calculations and synchrotron-based core-level spectroscopy aims at understanding the local structure of the electronic valence in transition metal complexes, and the details of the solvation mechanisms of electrolyte solutions, systems relevant for the dye-sensitized solar cell. LÄS MER

3. 32. Modelling of radiation damage and positron annihilation in metallic materials

   Författare :Qigui Yang; Pär Olsson; Bernardo Barbiellini; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Radiation damage; First-principles; Positron annihilation spectroscopy; Cu precipitation; Two-component density functional theory; Tungsten; Transition metals; Kärnenergiteknik; Nuclear Engineering; Physics; Fysik;

   Sammanfattning : The radiation damage is one of the key concerns in the research of materials used in radiation environments. In this thesis, we theoretically investigate the radiation damage phenomenon by focusing on two important topics: the defect production and evolution, and the defect characterization. The first part aims at two aspects. LÄS MER

4. 33. Magnetism in Transition Metal Systems : Interplay between structure, dimensionality and electron correlation

   Författare :Samara Keshavarz Hedayati; Yaroslav Kvashnin; Patrik Thunström; Olle Eriksson; Tamio Oguchi; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : In this thesis, an ab initio study of electronic structures and magnetic properties of transition metal systems has been presented, covering bulk, interface and surface geometries. Among them are Fe, Co, Ni, CaMnO3, Co2MnSi, a ferromagnetic Heusler alloy, as well as double-perovskites oxides such as Sr3(Fe1.25Ni0.75)O6 and Nd2NiMnO6. LÄS MER

5. 34. Slurry Hydrotreatment of Biomass Materials over Metal Sulfide-based Supported and Unsupported Catalysts

   Författare :You Wayne Cheah; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Hydrotreatment; Kraft lignin; Transition metals; Slurry hydrocracking; Propylguaiacol; Advanced biofuels; MoS2; Reaction network; Pyrolysis oil; Unsupported TMS;

   Sammanfattning : The scarcity of fossil feedstocks and the deterioration of the current global climate condition have prompted the search for reliable alternatives for fossil fuel replacement. Biomass feedstocks are abundant, carbon-rich, and renewable bioresources that can be used to produce renewable bio-oils that can fill the gap left by fossil-derived oils. LÄS MER

7. 35. Al-Si Cast Alloys - Microstructure and Mechanical Properties at Ambient and Elevated Temperatures

   Författare :Mohammadreza Zamani; Salem Seifeddine; Anders Jarfors; Franco Bonollo; Jönköping University; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aluminium cast alloys; eutectic modification; microstructural scale effect; transition metals; room and elevated temperatures tensile properties; physically-based constitutive model.;

   Sammanfattning : Swedish industry is a global leader in development and manufacture of automotive and aviation components where the usage of aluminium products is remarkable. In addition to manufacturing aluminium components, casting enables low-cost and low-emission production of complex geometry components with a range of sizes. LÄS MER