Sökning: "e beam"

Visar resultat 21 - 25 av 333 avhandlingar innehållade orden e beam.

1. 21. Characterisation of Nickel-Based Superalloys Manufactued by Electron Beam Melting

   Författare :Annika Strondl; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEM; electron beam melting; APFIM; EBSD; XRD; DTA; nickel-based superalloys; SEM; additive manufacturing; EDS;

   Sammanfattning : Nickel-based superalloys have been manufactured by electron beam melting (EBM). EBM is an additive manufacturing process for direct production of metal parts. The part is build up by successive melting of metal powder layers in a vacuum chamber using electron beam. LÄS MER

3. 22. Optical properties of silver nanostructures prepared by electron beam lithography

   Författare :Linda K Gunnarsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nanoelectronics; surface-enhanced Raman spectroscopy; single-electron tunneling; electron-beam lithography; nanofabrication; localized surface plasmon resonance; silver nanoparticles;

   Sammanfattning : In this thesis, electron beam lithography (EBL) has been used to fabricate substrates for studies of nanoparticle optics, in particular for the investigation of noble metal nanoparticles and their tunable optical properties. The strong interaction of metal nanoparticles with light has its origin in the resonant excitation of collective oscillations of conduction electrons, so called localized surface plasmons (LSP). LÄS MER

4. 23. Studies of Tropospheric and Stratospheric Aerosol using Ion Beam Analysis

   Författare :Giorgos Papaspiropoulos; Kärnfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; atmosphere; Aerosols; troposphere; stratosphere; ion beam analysis; PIXE; impactors; particulate sulphur; chemical speciation; elemental analysis; thermography; Physics; Nuclear physics; Fysik; Metrology; Kärnfysik; physical instrumentation; Metrologi; fysisk instrumentering; Fysicumarkivet A:2001:Papaspiropoulos;

   Sammanfattning : Atmospheric aerosol particles are believed to have an impact on the radiative forcing of the earth's surface. The predicted results indicate a net cooling effect on the global climate, however there are few studies available to substantiate this and experimental data are needed. LÄS MER

5. 24. Absorbed Dose Determination and Characteristics of Degraded Electron Beams: Application to Intraoperative Radiation Therapy

   Författare :Peter Björk; Internmedicin - epidemiologi; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Clinical physics; radiology; tomography; medical instrumentation; Klinisk fysiologi; radiologi; tomografi; medicinsk instrumentering; absorbed dose distribution; output factor; stopping-power ratio; beam characteristics; Monte Carlo calculation; electron beam dosimetry; applicator system; radiation therapy; linear accelerator; intraoperative radiotherapy;

   Sammanfattning : The aim of this work was to quantify limitations of and uncertainties in commonly used dosimetric techniques for relative absorbed dose determination in degraded electron beams, such as those encountered in intraoperative radiation therapy (IORT) and small-electron-field radiotherapy. Three different detector types were investigated with regard to measurements of output factors and relative absorbed dose distributions: (1) a parallel-plate ionization chamber, (2) a p-type silicon diode detector and (3) a diamond detector. LÄS MER

7. 25. Defects in E-PBF Ti-6Al-4V and their Effect on Fatigue Behaviour : Characteristics, Distribution and Impact on Life

   Författare :Viktor Sandell; Marta-Lena Antti; Pia Åkerfeldt; Thomas Hansson; Hans Andersson; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Defects; Additive Manufacturing; Ti-6Al-4V; Probabilistic Modelling; Fatigue; Materialteknik; Engineering Materials;

   Sammanfattning : Layer by layer manufacturing (additive manufacturing, AM) of metals is emerging as an alternative to conventional subtractive manufacturing with the goal of enabling near net-shape production of complex part geometries with reduced material waste and shorter lead times. Recently this field has experienced rapid growth through industrial adaptation but has simultaneously encountered challenges. LÄS MER