Blar i NTNU Open på forfatter "Vullum, Per Erik"

Viser treff 41-60 av 75

    • Intermetallic Phase Layers in Cold Metal Transfer Aluminium-Steel Welds with an Al–Si–Mn Filler Alloy 

      Bergh, Tina; Ånes, Håkon Wiik; Aune, Ragnhild; Wenner, Sigurd; Holmestad, Randi; Ren, Xiaobo; Vullum, Per Erik (Peer reviewed; Journal article, 2023)

    • Lab-in-a-FIB 

      Mosberg, Aleksander Buseth (Doctoral theses at NTNU;2020:295, Doctoral thesis, 2020)
      The development of next-generation devices and technology requires micro- and nanoscale manipulation of complex functional material systems. The micro- to nanoscale experiments required to understand their function must ...

    • Large bandgap insulating superior clay nanosheets 

      Pacáková, Barbara; Vullum, Per Erik; Kirch, Alexsandro; Breu, Josef; Miranda, Caetano Rodrigues; Fossum, Jon Otto (Journal article; Peer reviewed, 2022)
      One can find conductive, semiconducting, and insulating single nanosheets with unique electronic properties that are tied to their two-dimensional (2D) structure. Here, we report on wide-bandgap 2D insulator nanosheets ...

    • Lithium bis (fluorosulfonyl) imide as electrolyte salt for high-content silicon-based anodes for Li-ion batterier 

      Asheim, Karina (Doctoral theses at NTNU;2021:413, Doctoral thesis, 2021)
      Li-ion batteries have become the superior rechargeable battery technology due to high energy density, long cycle life, safety and cost. Several materials can be used for the electrodes and the electrolyte, enabling ...

    • Magnetic domain configuration of (111)-oriented LaFeO3 epitaxial thin films 

      Hallsteinsen, Ingrid; Moreau, Magnus; Chopdekar, R.V.; Christiansen, Emil; Nord, Magnus Kristofer; Vullum, Per Erik; Grepstad, Jostein; Holmestad, Randi; Selbach, Sverre Magnus; Scholl, A; Arenholz, E; Folven, Erik; Tybell, Per Thomas Martin (Journal article; Peer reviewed, 2017)
      In antiferromagnetic spintronics control of the domains and corresponding spin axis orientation is crucial for devices. Here we investigate the antiferromagnetic axis in (111)-oriented LaFeO3/SrTiO3, which is coupled to ...

    • Methodology to Improve Strain Measurement in III–V Semiconductors Materials 

      Vatanparast, Maryam; Vullum, Per Erik; Nord, Magnus Kristofer; Reenaas, Turid Worren; Holmestad, Randi (Journal article; Peer reviewed, 2017)
      Geometric phase analysis (GPA), a fast and simple Fourier space method for strain analysis, can give useful information on accumulated strain and defect propagation in multiple layers of InAs/GaAs quantum dot (QD) materials. ...

    • Microstructural and mechanical characterisation of a second generation hybrid metal extrusion & bonding aluminium-steel butt joint 

      Bergh, Tina; Sandnes, Lise; Johnstone, Duncan Neil; Grong, Øystein; Berto, Filippo; Holmestad, Randi; Midgley, Paul Anthony; Vullum, Per Erik (Peer reviewed; Journal article, 2020)
      Hybrid metal extrusion & bonding (HYB) is a joining method that enables solid-state bonding by combining addition of aluminium filler material through continuous extrusion with pressure exerted by a rotating steel tool. ...

    • Morphology effects in MgH2 anode for lithium ion batteries 

      El-Kharbachi, Abdelouahab; Andersen, Hanne Flåten; Sørby, Magnus Helgerud; Vullum, Per Erik; Mæhlen, Jan Petter; Hauback, Bjørn (Journal article, 2017)
      In order to acquire reproducible electrodes relevant for Li ion batteries new MgH2 electrodes are successfully obtained from homogenous slurries in N-Methyl-2-Pyrrolidone “NMP” solvent. The electrodes are aimed to elucidate ...

    • Nanocrystal segmentation in scanning precession electron diffraction data 

      Bergh, Tina; Johnstone, D.N.; Crout, P; Høgås, Simon; Midgley, Paul A.; Holmestad, Randi; Vullum, Per Erik; Van Helvoort, Antonius (Journal article; Peer reviewed, 2019)
      Scanning precession electron diffraction (SPED) enables the local crystallography of materials to be probed on the nanoscale by recording a two‐dimensional precession electron diffraction (PED) pattern at every probe ...

    • Nanostructural Analysis of Co-Re/γ-Al2O3 Fischer-Tropsch Catalyst by TEM and XRD 

      Dehghan-Niri, Roya; Tsakoumis, Nikolaos E.; Voronov, Alexey; Holmen, Anders; Holmestad, Randi; Vullum, Per Erik; Borg, Øyvind; Rytter, Erling; Rønning, Magnus; Walmsley, John (Journal article; Peer reviewed, 2022)
      A rhenium promoted Fischer-Tropsch (FT) cobalt catalyst supported on γ-Al2O3 has been investigated by Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD), before and after reduction. Electron diffraction, ...

    • New insights into orthophosphoric acid assisted rapid aqueous processing of NMC622 cathodes 

      Tolchard, Julian R; Vullum, Per Erik; Arstad, Bjørnar; Wagner, Nils Peter (Peer reviewed; Journal article, 2023)
      The use of orthophosphoric acid to stabilize aqueous processing of high nickel NMC622 electrodes was assessed under rapid processing conditions, in which the active material powder was in suspension for less than 1 hour. ...

    • Nonlinear optical response and structural properties of MBE-grown Fe:ZnS films 

      Polyakov, Stanislav; Karhu, Eric Andrew; Zamiri, Reza; Moisset, Charles; Iliopoulos, Konstantinos; Vullum, Per Erik; Österberg, Ulf; Gibson, Ursula (Journal article; Peer reviewed, 2018)
      Fe-doped ZnS films of high optical quality were fabricated using vacuum vapor deposition. Preferential crystalline orientation and phase purity of the host ZnS films were increased by the addition of small amounts of Fe, ...

    • Observation of Electric-Field-Induced Structural Dislocations in a Ferroelectric Oxide 

      Evans, Donald; Småbråten, Didrik Rene; Holstad, Theodor Secanell; Vullum, Per Erik; Mosberg, Aleksander Buseth; Yan, Zewu; Bourret, Edith; Van Helvoort, Antonius; Selbach, Sverre Magnus; Meier, Dennis (Peer reviewed; Journal article, 2021)
      Dislocations are 1D topological defects with emergent electronic properties. Their low dimensionality and unique properties make them excellent candidates for innovative device concepts, ranging from dislocation-based ...

    • On intermetallic phases formed during interdiffusion between aluminium alloys and stainless steel 

      Bergh, Tina; Arbo, Siri Marthe; Hagen, Anette Brocks; Blindheim, Jørgen; Friis, Jesper; Khalid, Muhammad Zeeshan; Ringdalen, Inga Gudem; Holmestad, Randi; Westermann, Ida; Vullum, Per Erik (Peer reviewed; Journal article, 2022)
      One of the major challenges in welding of aluminium (Al) alloys and steels is the growth of brittle intermetallic phases, which depends on the thermomechanical processing history and the alloying elements. This work focuses ...

    • On the biogenicity of Fe-oxyhydroxide filaments in silicified low-temperature hydrothermal deposits: Implications for the identification of Fe-oxidizing bacteria in the rock record 

      Johannessen, Karen Cecilie; McLoughlin, Nicola; Vullum, Per Erik; Thorseth, Ingunn Hindenes (Journal article; Peer reviewed, 2019)
      Microaerophilic Fe(II)‐oxidizing bacteria produce biomineralized twisted and branched stalks, which are promising biosignatures of microbial Fe oxidation in ancient jaspers and iron formations. Extracellular Fe stalks ...

    • On Vanadium Substitution in Li2MnSiO4/C as Positive Electrode for Li-ion Batteries 

      Wagner, Nils Peter; Vullum, Per Erik; Nord, Magnus Kristofer; Svensson, Ann Mari; Vullum-Bruer, Fride (Journal article; Peer reviewed, 2016)
      Vanadium substitution is an interesting approach to manipulate the properties of the poor electronic and ionic conducting lithium transition metal orthosilicates. Especially, if incorporated on the Si site, it could alter ...

    • One-pot synthesis of highly dispersed mesoporous Cu/ZrO2 catalysts for NH3-SCR 

      Bjørkedal, Ole Håvik; Regli, Samuel K.; Nuguid, Rob Jeremiah G.; Vullum, Per Erik; Kröcher, Oliver; Ferri, Davide; Rønning, Magnus (Peer reviewed; Journal article, 2021)
      Catalysts consisting of highly dispersed copper on a mesoporous ZrO2 support were synthesised via a one-pot sol-gel synthesis and were tested for the selective catalytic reduction of NOx by NH3. The copper dispersion was ...

    • Orientation relationship between b-Si3N4 and Si in multicrystalline silicon ingots for PV applications 

      Undheim, Espen; Vullum, Per Erik; Holmestad, Randi; Arnberg, Lars; Di Sabatino Lundberg, Marisa (Journal article; Peer reviewed, 2018)
      β-Si3N4 particles are thought to be nucleation sites for silicon in multicrystalline silicon (mc-Si) ingots for PV applications. The orientation relationship (OR) between Si and β-Si3N4 has been investigated by transmission ...

    • Patterned nanomagnets - magnetic metamaterials and vortex dynamics 

      Digernes, Einar Standal (Doctoral theses at NTNU;2021:101, Doctoral thesis, 2021)
      Sustaining the rapid development of information technology will eventually require new types of devices that are smaller, faster and more power efficient. Although the transistor is, and will continue to be, tremendously ...

    • Preliminary in-situ study of FIB-assisted method for aluminium solid-state welding at the microscale 

      Celotto, Ambra; Grong, Øystein; Holmestad, Randi; Sørhaug, Jørgen A; Torgersen, Jan; Vullum, Per Erik; Berto, Filippo (Peer reviewed; Journal article, 2021)
      In situ studies allow real time monitoring and deep comprehension of phenomena. This approach has been applied to the current research for the development of a novel solid-state welding technique at the microscale. The ...