Now showing items 1716-1735 of 1739

    • Walker Breakdown in Magnon-Induced Ferromagnetic Domain Wall Motion 

      Risinggård, Vetle Meland (Master thesis, 2015)
      We derive for the first time the collective coordinate equations for magnon-driven domain wall motion in ferromagnets from the Landau-Lifshitz-Gilbert equation. By performing a consistent calculation to second order we are ...
    • Water waves with compactly supported vorticity: A functional-analytic approach to bifurcation theory and the mathematical theory of traveling water waves 

      Varholm, Kristoffer (Master thesis, 2014)
      We study the mathematical theory of water waves. Local bifurcation theory is also discussed, including the Crandall-Rabinowitz theorem; an abstract theorem used to establish the presence of bifurcation points in the zero ...
    • Watt-level Kerr-Lens Mode-Locked Cr:ZnS Laser at 2.4 μm 

      Tolstik, Nikolai; Sorokin, E; Sorokina, Irina T (Chapter, 2013)
      Power scaling of Kerr-lens mode-locked Cr:ZnS femtosecond oscillator allows reaching 1 W output power and pulse energies over 8 nJ. Soliton and chirped-pulse regimes result in 68 fs and 0.8-2 ps pulses, respectively.
    • Wave Propagation Along a Thin Wire Antenna Placed in a Horizontally Layered Medium 

      Wei, Yingkang; Holter, Bengt; Simonsen, Ingve; Husby, Karsten; Kuhnle, Jacob; Norum, Lars Einar (Conference object, 2010)
    • Wave scattering and transmission from penetrable self-affine surfaces 

      Hansen, Ole Martin (Master thesis, 2009)
    • Wave scattering theory applied to inversion and design 

      Nesse, Torstein (Doctoral theses at NTNU;2018:310, Doctoral thesis, 2018)
      The scattering of waves from objects can be used as a tool for both characterization and manipulation. The way waves interact and scatter from objects can give us information about their structure and composition. Additionally, ...
    • Wavelength conversion and supercontinuum generation in silicon optical fibers 

      Peacock, Anna; Campling, Joseph; Runge, Antoine; Ren, Haonan; Shen, Li; Aktas, Ozan; Horak, Peter; Healy, Noel; Gibson, Ursula; Ballato, John (Journal article, 2018)
      This paper describes the state of the art in wavelength conversion and supercontinuum generation using glass-clad silicon core optical fibers. Such semiconductor fibers have enjoyed considerable attention due to their ...
    • Waves Propagating on Fluids with Piecewise Constant Vorticity 

      Toften, Ståle (Master thesis, 2015)
      The purpose of this study was to find the dispersion relation for waves on an arbitrary current velocity profile approximated by N linear layers. Using a Stokes expansion to first order in the steepness parameter ka the ...
    • What causes the mid-winter cooling? 

      Fritsch, Frauke Ruth Lotte (Master thesis, 2016)
      This thesis investigated the influence and conditions of vertical propagation of planetary waves on the mid-winter cooling in the southern hemispheric polar meso- sphere. MERRA zonal wind data was used to extract planetary ...
    • Winds and tides in the mid-latitude southern hemisphere upper mesosphere recorded with the Falkland Islands SuperDARN radar 

      Hibbins, Robert; Freeman, Mervyn P.; Milan, Steve E.; Ruohoniemi, J. M. (Journal article; Peer reviewed, 2011)
      Meteor wind data from the first year of operation of the Falkland Islands SuperDARN radar (52 S, 59 W) are used to characterize the atmospheric tides and background winds in the upper mesosphere above the South Atlantic. ...
    • X-ray Diffraction and Tomography Studies of Functional Organic Fibres 

      Esmaeili, Morteza (Doktoravhandlinger ved NTNU, 1503-8181; 2013:74, Doctoral thesis, 2013)
      Structural characterisations of materials belong to the primary interests of basic and applied research, since they provide insights into the interactions of molecules and atoms, establish correlations with desired properties ...
    • X-ray nanoscopy of a bulk heterojunction 

      Patil, Nilesh; Skjønsfjell, Eirik Torbjørn Bakken; Van den Brande, Niko; Chavez Panduro, Elvia Anabela; Claessens, Raf; Guizar-Sicairos, Manuel; Van Mele, Bruno; Breiby, Dag Werner (Journal article; Peer reviewed, 2016)
      Optimizing the morphology of bulk heterojunctions is known to significantly improve the photovoltaic performance of organic solar cells, but available quantitative imaging techniques are few and have severe limitations. ...
    • X-ray Scattering Study of Nanostructured GaSb Surfaces 

      Døli, Ellen (Master thesis, 2013)
      In this thesis the surface structure of a sample consisting of slightly tilted, denselypacked Gallium-Antimonide (GaSb) nanocones, self-assembled through Ion Beam Sputtering(IBS) is investigated with a selection of X-ray ...
    • X-ray Studies of Capture, Storage and Release of CO2 

      Rustenberg, Karin Hveding (Master thesis, 2012)
      We show experimentally that CO2 intercalates into the interlayer spaceof the synthetic smectite clay Li-fluorohectorite (LiFh). The intercalationoccurs for a range of conditions in terms of pressure (5 bar to 20 bar) ...
    • X-ray Studies of Carbon Dioxide Intercalation in Na-Fluorohectorite Clay at Near-Ambient Conditions 

      Hemmen, Henrik; Rolseth, Erlend G.; Fonseca, Davi de Miranda; Hansen, Elisabeth Lindbo; Fossum, Jon Otto; Plivelic, T (Journal article, 2012)
      We show experimentally that gaseous CO2 intercalates into the interlayer space of the synthetic smectite clay Na-fluorohectorite at conditions not too far from ambient. The mean interlayer repetition distance of the clay ...
    • XPS and GDOES characterization of porous coating enriched with copper and calcium obtained on tantalum via plasma electrolytic oxidation 

      Rokosz, Krzysztof; Hryniewicz, Tadeusz; Chapon, Patrick; Raaen, Steinar; Sandim, Hugo Ricardo Zschommler (Peer reviewed; Journal article, 2016)
      XPS and GDOES characterizations of porous coatings on tantalum after Plasma Electrolytic Oxidation (PEO) at 450 V for 3 minutes in electrolyte containing concentrated (85%) phosphoric acid with calcium nitrate and copper ...
    • Yb-Doped Fiber Lasers Operating in the Range of 1147-1200 nm 

      Dvoyrin, Vladislav; Medvedkov, OI; Sorokina, Irina T (Chapter, 2012)
      Pump source brightness and heat production per unit fiber length were found to be the critical parameters for the realized and investigated Yb-doped fiber lasers operating in the range of 1147-1200 nm.
    • Yb-Tm energy transfer in Y-codoped fibers 

      Klimentov, Dmitry; Sorokina, Irina T; Dvoyrin, Vladislav; Halder, Arindam; paul, mukul; Das, Shyamal; Bhadra, Shyamal; Pal, Mrinmay (Chapter, 2013)
      Experimental investigation of Yb-Tm energy transfer process in Yb/Tm-doped fibers with Y-codoping provided a fairly high energy transfer efficiency of 50 %, making lasers based on these glass fibers attractive for diode-pumping ...
    • YDFL Operating in 1150-1200-nm Spectral Domain 

      Dvoyrin, Vladislav; Medvedkov, OI; Sorokina, Irina T (Journal article; Peer reviewed, 2013)
      A family of high-power Yb-doped fiber lasers operated in the range of 1150–1180 nm with output powers of up to 35 W and optical efficiencies up to 60% is realized. Operation at 1200 nm is also demonstrated. Amplified ...
    • Zernike phase contrast in high-energy x-ray transmission microscopy based on refractive optics 

      Falch, Ken Vidar; Lyubormiskiy, Mikhail; Casari, Daniele; Snigirev, Anatoly; Snigireva, Irina; Detlefs, Carsten; Di Michiel, Marco; Lyatun, Ivan; Mathiesen, Ragnvald (Journal article; Peer reviewed, 2018)
      The current work represents the first implementation of Zernike phase contrast for compound refractive lens based x-ray microscopy, and also the first successful Zernike phase contrast experiment at photon energies above ...