Sökning: "surface segregation"

Visar resultat 6 - 10 av 87 avhandlingar innehållade orden surface segregation.

1. 6. Pd-nanoalloys for hydrogen sensing: Multiscale modeling of thermodynamic and optical properties

   Författare :Pernilla Ekborg-Tanner; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Pd-alloys; hydrogen sensing; surface segregation; nanoplasmonics; nanoalloys;

   Sammanfattning : Hydrogen sensing based on Pd nanoalloys has shown great promise in the past decades and could potentially be part of a solution that enables a safe future hydrogen economy. There are, however, remaining challenges related to, e.g., long-term stability and a need for further optimization of these systems. LÄS MER

3. 7. Free Metal Clusters Studied by Photoelectron Spectroscopy

   Författare :Tomas Andersson; Olle Björneholm; Maxim Tchaplyguine; Paolo Piseri; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; clusters; nanoparticles; electronic structure; photoelectron spectroscopy; synchrotron radiation; surface segregation; nanoalloys; size-dependence; metallicity; plasmons; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : Clusters are aggregates of a finite number of atoms or molecules. In the present work, free clusters out of metallic parent materials have been created and studied by synchrotron radiation-based photoelectron spectroscopy. The clusters have been formed and studied in a beam and the electronic structure of the clusters has been investigated. LÄS MER

4. 8. Environmentally Friendly Plasticizers for PVC : Improved Material Properties and Long-term Performance Through Plasticizer Design

   Författare :Annika Lindström; Minna Hakkaraninen; Anders Södergård; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; poly butylene adipate ; poly vinyl chloride ; plasticizers; miscibility; mechanical properties; surface segregation; migration; degradation products; Polymer chemistry; Polymerkemi;

   Sammanfattning : Linear and branched poly(butylene adipate) polyesters with number-average molecular weights ranging from 700 to 10 000 g/mol, and degrees of branching ranging from very low to hyperbranched were solution cast with PVC to study the effects of chemical structure, molecular weight, end-group functionality, and chain architecture on plasticizing efficiency and durability. Miscibility was evaluated by the existence of a single glass transition temperature and a shift of the carbonyl group absorption band. LÄS MER

5. 9. Mechanical properties of semi-solid Al castings : Role of stirring

   Författare :Qing Zhang; Anders E.W. Jarfors; Stefan Jonsson; Tomas Liljenfors; Arne K. Dahle; Johan Ahlström; Jönköping University; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rheometal™ process; aluminum alloys; stirring; segregation; porosity; oxides; ductility; fatigue performance; melt quality;

   Sammanfattning : Aluminum castings have been widely used in the automotive industry to reduce the vehicle's weight. However, the existence of casting defects significantly limits its application. The most common and detrimental defects in aluminum castings are porosity and oxides. LÄS MER

7. 10. Microstructure and properties of welds in the lean duplex stainless steel LDX 2101

   Författare :Elin M. Westin; John Ågren; Hannu Hänninen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Duplex stainless steel; welding; HAZ; nitrogen; manganese; microstructure; austenite formation; phase balance; precipitates; element distribution; segregation; depletion; solidification; pitting corrosion resistance; solidification; element loss; evaporation; deposition; weld oxide; thermo-mechanical simulation; thermodynamic modelling; EPMA; XPS; post-weld cleaning; pickling; Metallurgical process and manufacturing engineering; Metallurgisk process- och produktionsteknik;

   Sammanfattning : Duplex stainless steels can be very attractive alternatives to austenitic grades due to their almost double strength at equal pitting corrosion resistance. When welding, the duplex alloys normally require addition of filler metal, while the commodity austenitic grades can often be welded autogenously. LÄS MER