Endre søk
Begrens søket
567891011 351 - 400 of 4448
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 351.
    Boden, Andreas
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Pennacchietti, Francesca
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Al-Kadhimi, Staffan
    Uriati, Eleonora
    Testa, Ilaria
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    A versatile tool to predict and validate RESOLFT images based on photoswitching, labelling, and optical propertiesManuskript (preprint) (Annet vitenskapelig)
  • 352.
    Bodén, Andreas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH Royal Institute of Technology.
    3D super-resolution microscopy of living cells using reversibly switchable fluorophores2021Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Traditional optical microscopy techniques are limited in spatial resolution due to the wave nature of light. This means that neighboring objects separated by a distance smaller than about 200 nm cannot be distinguished. Super‑resolution microscopy techniques overcome this limitation by utilizing specific light-matter interactions of fluorescent labels to encode finer spatial detail into the recorded data. Regrettably, current super‑resolution approaches often increase the complexity of sample preparation as well as the energy, time, and invasiveness of the imaging scheme compared to conventional imaging techniques. This makes many of these techniques ill‑suited for imaging the dynamics of living cells. Since many biological studies rely on highly spatially resolved data containing three‑dimensional and temporally dynamic information, developing super‑resolution techniques toward the goal of acquiring such data is vital. With this work, we take several important steps in this direction by utilizing reversibly switchable fluorescence proteins (RSFPs) together with new illumination patterns that allow for a parallelized data acquisition scheme. Even low intensity illumination patterns can induce photo‑switching of the RSFPs and generate specific patterns of fluorescent emission that carry high‑resolution spatial information in all three dimensions. By using RSFPs in a parallelized acquisition scheme, temporally extended recordings can be acquired with low illumination intensities and at high speed. In addition to the imaging schemes, we present a theoretical framework for modelling the impact that RSFP properties on image formation and show how different imaging parameters affect the final image quality. We predict and explore the effect of labelling density and photobleaching on single and timelapse recordings, taking into consideration the stochasticity of labelling and fluorophore fatigue. We also present a new family of red‑shifted RSFPs that can be imaged without the need for near‑UV illumination, allowing even less invasive live‑cell imaging. This work aims to not only provide new tools for imaging, but also to contribute to a better understanding of the underlying concepts and to facilitate future developments of super-resolution microscopy for bio-imaging applications.

    Fulltekst (pdf)
    fulltext
  • 353.
    Bodén, Andreas
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Moreno, Xavier Casas
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik.
    Cooper, Benjamin K.
    Calico Life Sci LLC, San Francisco, CA 94080 USA..
    York, Andrew G.
    Calico Life Sci LLC, San Francisco, CA 94080 USA..
    Testa, Ilaria
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Predicting resolution and image quality in RESOLFT and other point scanning microscopes [Invited]2020Inngår i: Biomedical Optics Express, E-ISSN 2156-7085, Vol. 11, nr 5, s. 2313-2327Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The performance of fluorescence microscopy and nanoscopy is often discussed by the effective point spread function and the optical transfer function. However, due to the complexity of the fluorophore properties such as photobleaching or other forms of photoswitching, which introduce a variance in photon emission, it is not trivial to choose optimal imaging parameters and to predict the spatial resolution. In this paper, we analytically derive a theoretical framework for estimating the achievable resolution of a microscope depending on parameters such as photoswitching, labeling densities, exposure time and sampling. We developed a numerical simulation software to analyze the impact of reversibly switchable probes in RESOLFT imaging.

  • 354.
    Bodén, Andreas
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Pennacchietti, Francesca
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Coceano, Giovanna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Damenti, Martina
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Ratz, M.
    Testa, Ilaria
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Volumetric live cell imaging with three-dimensional parallelized RESOLFT microscopy2021Inngår i: Nature Biotechnology, ISSN 1087-0156, E-ISSN 1546-1696, Vol. 39, nr 5, s. 609-618Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Elucidating the volumetric architecture of organelles and molecules inside cells requires microscopy methods with a sufficiently high spatial resolution in all three dimensions. Current methods are limited by insufficient resolving power along the optical axis, long recording times and photobleaching when applied to live cell imaging. Here, we present a 3D, parallelized, reversible, saturable/switchable optical fluorescence transition (3D pRESOLFT) microscope capable of delivering sub-80-nm 3D resolution in whole living cells. We achieved rapid (1-2 Hz) acquisition of large fields of view (similar to 40 x 40 mu m(2)) by highly parallelized image acquisition with an interference pattern that creates an array of 3D-confined and equally spaced intensity minima. This allowed us to reversibly turn switchable fluorescent proteins to dark states, leading to a targeted 3D confinement of fluorescence. We visualized the 3D organization and dynamics of organelles in living cells and volumetric structural alterations of synapses during plasticity in cultured hippocampal neurons.

  • 355.
    Bogoni, Antonella
    et al.
    Scuola Super Sant Anna, I-56127 Pisa, Italy..
    Mecozzi, Antonio
    Univ Aquila, Dept Phys & Chem Sci, I-67100 Laquila, Italy..
    Okonkwo, Chigo M.
    Eindhoven Univ Technol, NL-5612 AZ Eindhoven, Netherlands..
    Plant, David V.
    McGill Univ, Dept Elect & Comp Engn, Montreal, PQ, Canada..
    Saitoh, Kunimasa
    Hokkaido Univ, Elect Engn, Sapporo, Hokkaido 0600814, Japan.;Hokkaido Univ, Grad Sch Engn, Sapporo, Hokkaido 0600814, Japan.;Hokkaido Univ, Grad Sch Informat Sci & Technol, Sapporo, Hokkaido 0600814, Japan..
    Wosinska, Lena
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik. KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Liu, Gordon Ning
    Huawei Technol Co Ltd, Shenzhen 518129, Peoples R China..
    Umbach, Andreas
    AUCCEPT Consulting GmbH, D-14055 Berlin, Germany..
    Charlet, Gabriel
    Huawei Paris Res Ctr, F-75002 Paris, France..
    Gaudino, Roberto
    Politecn Torino, Dipartimento Elettron & Telecomunicaz, I-10129 Turin, Italy..
    Foreword to the Special Issue on the 44th European Conference on Optical Communication (ECOC 2018)2019Inngår i: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 37, nr 5, s. 1450-1455Artikkel i tidsskrift (Annet vitenskapelig)
  • 356.
    Bokhari, Ramiz Ahmed
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Confocal Imaging and Analysis of Quantum Dots on living Cells2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 357. Bolanos, Western
    et al.
    Carvajal, Joan J.
    Mateos, Xavier
    Cinta Pujol, Maria
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Lifante, Gines
    Aguilo, Magdalena
    Diaz, Francesc
    Epitaxial layers of KY1-x-yGdxLuy(WO4)(2) doped with Er3+ and Tm3+ for planar waveguide lasers2010Inngår i: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 32, nr 3, s. 469-474Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Here we show the results we obtained in the fabrication of planar wave guide lasers based on monoclinic double tungstates doped with Er3+ and Tm3+. We have successfully introduced these ions into the lattice matched KY0.59Gd0.19Lu0.22(WO4)(2) epitaxial layers grown on KY(WO4)(2) substrates without loss of optical quality and keeping a high refractive index contrast between the epitaxial layer and the substrate. We characterized the waveguiding properties of these epitaxial layers at lambda = 632.8 nm by dark modes spectroscopy, and we showed that these waveguides can support several TE and TM modes. Spectroscopic characterization of the active lanthanide ions in these crystals is also presented.

  • 358. Bolaños, W.
    et al.
    Carvajal, J.J.
    Mateos, X.
    Pujol, M.C.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Aguiló, M.
    Díaz, F.
    Fabrication and characterization of epitaxial layers of the KY1-x-yGdxLuy(WO4)2 system for waveguide lasers2009Konferansepaper (Fagfellevurdert)
  • 359. Bollampalli, V. P.
    et al.
    Harumi Yamashiro, L.
    Feng, X.
    Bierschenk, D.
    Gao, Y.
    Blom, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Henriques-Normark, B.
    Nylén, S.
    Rothfuchs, A. G.
    BCG Skin Infection Triggers IL-1R-MyD88-Dependent Migration of EpCAMlow CD11bhigh Skin Dendritic cells to Draining Lymph Node During CD4+ T-Cell Priming2015Inngår i: PLoS Pathogens, ISSN 1553-7366, E-ISSN 1553-7374, Vol. 11, nr 10, artikkel-id e1005206Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The transport of antigen from the periphery to the draining lymph node (DLN) is critical for T-cell priming but remains poorly studied during infection with Mycobacterium bovis Bacille Calmette-Guérin (BCG). To address this we employed a mouse model to track the traffic of Dendritic cells (DCs) and mycobacteria from the BCG inoculation site in the skin to the DLN. Detection of BCG in the DLN was concomitant with the priming of antigen-specific CD4+ T cells at that site. We found EpCAMlow CD11bhigh migratory skin DCs to be mobilized during the transport of BCG to the DLN. Migratory skin DCs distributed to the T-cell area of the LN, co-localized with BCG and were found in close apposition to antigen-specific CD4+ T cells. Consequently, blockade of skin DC traffic into DLN dramatically reduced mycobacterial entry into DLN and muted T-cell priming. Interestingly, DC and mycobacterial entry into the DLN was dependent on IL-1R-I, MyD88, TNFR-I and IL-12p40. In addition, we found using DC adoptive transfers that the requirement for MyD88 in BCG-triggered migration was not restricted to the migrating DC itself and that hematopoietic expression of MyD88 was needed in part for full-fledged migration. Our observations thus identify a population of DCs that contribute towards the priming of CD4+ T cells to BCG infection by transporting bacilli into the DLN in an IL-1R-MyD88-dependent manner and reveal both DC-intrinsic and -extrinsic requirements for MyD88 in DC migration.

  • 360. Bollampalli, V. P.
    et al.
    Yamashiro, L. H.
    Feng, X.
    Bierschenk, D.
    Gao, Y.
    Blom, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Henriques-Normark, B.
    Nylen, S.
    Rothfuchs, A. G.
    BCG skin infection triggers IL-1R-MyD88-dependent migration of EpCAM(low) CD11b(high) skin dendritic cells to draining lymph node during CD4(+) T-cell priming2016Inngår i: European Journal of Immunology, ISSN 0014-2980, E-ISSN 1521-4141, Vol. 46, s. 790-790Artikkel i tidsskrift (Annet vitenskapelig)
  • 361.
    Bondarenko, Artem
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Nonlinear dynamics of strongly-bound magnetic vortex pairs2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This work is a study of nonlinear phenomena in vertically stacked pairs of magnetic vortices. New dynamic regimes are uncovered with a decrease in the inter-vortex separation to below the lateral vortex-core size. These include linear, non-linear, and chaos dynamics of the coupled vortex cores, as well as core-core coupling/decoupling driven by resonant microwave fields. In addition to the direct advantages gained from the favorable symmetry of the system, which includes the fringing flux closure, new ways of exciting and controlling the motion of the vortex cores are shown. The dynamics of the vortex stack show promising improvements over those of a single vortex, in particular the characteristic speed of operation can be increased by an order of magnitude. The system therefore is viewed to have the potential for applications in data storage and oscillators.

    A combination of experimental, analytical, and numerical methods is used. A theoretical framework based on the quasiparticle Thiele-equation approach, extended to thermally driven dynamics by using the Monte Carlo method, is constructed and extensively tested experimentally and numerically. In-depth micromagnetic simulations are performed and show consistency with the results obtained analytically, both successfully validated against the measured data collected in a series of experiments on spin vortex pairs. Among these are microwave spectroscopy, transient dynamics, thermal decay, and pinning spectroscopy measurements.

    In particular, it is shown that the nonlinear frequency response of a two-vortex system exhibits a fold-over and an isolated rotational core-core resonance. A parametric inter-modal interaction is shown to induce hybrid dynamic regimes of the vortex-core oscillation when the system is subject to high excitation amplitudes.

    An intrinsic bi-stability of the core positions in the structure is found and investigated as a candidate for a memory element. The bi-stability is pronounced at lower temperatures. The rates of thermal switching were investigated in order to find the optimum operating DC-bias conditions.

    It is found that parametric interactions play a big role in the otherwise frustrated dynamics of essentially a 1D system. The parameters of the short excitation pulses for switching between the core-core states are optimized to achieve switching probabilities of over 90% in the experiment, with the pulses only a few nanoseconds long.

    Vortex pairs are demonstrated to be sensitive to the presence of defects in the ferromagnetic layers of the nanostructure. It is shown that the key factor in this sensitivity lies in the vortex' flux closure. Binding of a core-core pair to a defect is observed experimentally. A model is developed to describe the changes in the dynamical characteristics of the defect-pinned vortex pair. The capabilities of the model for characterizing magnetic and morphological defects in nanostructures are demonstrated.

    Fulltekst (pdf)
    Bondarenko-thesis
  • 362.
    Bondarenko, Artem
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Holmgren, Erik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Koop, Björn C.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Descamps, Thomas
    KTH.
    Ivanov, B. A.
    Korenivski, Vladislav
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Stochastic dynamics of strongly-bound magnetic vortex pairs2017Inngår i: AIP Advances, E-ISSN 2158-3226, Vol. 7, nr 5, artikkel-id 056007Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate that strongly-bound spin-vortex pairs exhibit pronounced stochastic behaviour. Such dynamics is due to collective magnetization states originating from purely dipolar interactions between the vortices. The resulting thermal noise exhibits telegraph-like behaviour, with random switching between different oscillation regimes observable at room temperature. The noise in the system is further studied by varying the external field and observing the related changes in the frequency of switching and the probability for different magnetic states and regimes. Monte Carlo simulations are used to replicate and explain the experimental observations.

  • 363.
    Bondarenko, Artem
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Holmgren, Erik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Li, Zhong Wei
    Ivanov, B. A.
    Institute of Magnetism, National Academy of Science, 03142 Kiev, Ukraine; National University of Science and Technology “MISiS”, Moscow 119049, Russian Federation..
    Korenivski, Vladislav
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Chaotic dynamics in spin-vortex pairs2019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, artikkel-id 054402Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on spin-vortex pair dynamics measured at temperatures low enough to suppress stochastic core motion, thereby uncovering the highly nonlinear intrinsic dynamics of the system. Our analysis shows that the decoupling of the two vortex cores is resonant and can be enhanced by dynamic chaos. We detail the regions of the relevant parameter space, in which the various mechanisms of the resonant core-core dynamics are activated. We show that the presence of chaos can reduce the thermally induced spread in the decoupling time by up to two orders of magnitude.

  • 364.
    Bondarenko, Vasyl
    et al.
    Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
    Chen, Qiang
    Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
    Singewald, Kevin
    Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
    Haloi, Nandan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Tillman, Tommy S.
    Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
    Howard, Rebecca
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Lindahl, Erik
    KTH, Centra, SeRC - Swedish e-Science Research Centre. KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik.
    Xu, Yan
    Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States; Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States; Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
    Tang, Pei
    Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States; Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
    Structural Elucidation of Ivermectin Binding to α7nAChR and the Induced Channel Desensitization2023Inngår i: ACS Chemical Neuroscience, E-ISSN 1948-7193, Vol. 14, nr 6, s. 1156-1165Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The α7 nicotinic acetylcholine receptor (α7nAChR) mediates signaling in the central nervous system and cholinergic anti-inflammatory pathways. Ivermectin is a positive allosteric modulator of a full-length α7nAChR and an agonist of the α7nAChR construct containing transmembrane (TMD) and intracellular (ICD) domains, but structural insights of the binding have not previously been determined. Here, combining nuclear magnetic resonance as a primary experimental tool with Rosetta comparative modeling and molecular dynamics simulations, we have revealed details of ivermectin binding to the α7nAChR TMD + ICD and corresponding structural changes in an ivermectin-induced desensitized state. Ivermectin binding was stabilized predominantly by hydrophobic interactions from interfacial residues between adjacent subunits near the extracellular end of the TMD, where the inter-subunit gap was substantially expanded in comparison to the apo structure. The ion-permeation pathway showed a profile distinctly different from the resting-state profile but similar to profiles of desensitized α7nAChR. The ICD also exhibited structural changes, including reorientation of the MX and h3 helices relative to the channel axis. The resulting structures of the α7nAChR TMD + ICD in complex with ivermectin provide opportunities for discovering new modulators of therapeutic potential and exploring the structural basis of cytoplasmic signaling under different α7nAChR functional states.

  • 365.
    Bondarenko, Vasyl
    et al.
    Univ Pittsburgh, Dept Anesthesiol & Perioperat Med, Pittsburgh, PA 15260 USA..
    Wells, Marta M.
    Univ Pittsburgh, Dept Anesthesiol & Perioperat Med, Pittsburgh, PA 15260 USA..
    Chen, Qiang
    Univ Pittsburgh, Dept Anesthesiol & Perioperat Med, Pittsburgh, PA 15260 USA..
    Tillman, Tommy S.
    Univ Pittsburgh, Dept Anesthesiol & Perioperat Med, Pittsburgh, PA 15260 USA..
    Singewald, Kevin
    Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA..
    Lawless, Matthew J.
    Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA..
    Caporoso, Joel
    Univ Pittsburgh, Dept Anesthesiol & Perioperat Med, Pittsburgh, PA 15260 USA..
    Brandon, Nicole
    Univ Pittsburgh, Dept Anesthesiol & Perioperat Med, Pittsburgh, PA 15260 USA..
    Coleman, Jonathan A.
    Univ Pittsburgh, Dept Struct Biol, Pittsburgh, PA 15260 USA..
    Saxena, Sunil
    Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA..
    Lindahl, Erik
    KTH, Centra, SeRC - Swedish e-Science Research Centre. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Stockholm Univ, Dept Biochem & Biophys, Sci Life Lab, Solna, Sweden..
    Xu, Yan
    Univ Pittsburgh, Dept Anesthesiol & Perioperat Med, Pittsburgh, PA 15260 USA.;Univ Pittsburgh, Dept Struct Biol, Pittsburgh, PA 15260 USA.;Univ Pittsburgh, Dept Pharmacol & Chem Biol, Pittsburgh, PA 15260 USA.;Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA..
    Tang, Pei
    Univ Pittsburgh, Dept Anesthesiol & Perioperat Med, Pittsburgh, PA 15260 USA.;Univ Pittsburgh, Dept Pharmacol & Chem Biol, Pittsburgh, PA 15260 USA.;Univ Pittsburgh, Dept Computat & Syst Biol, Pittsburgh, PA 15260 USA..
    Structures of highly flexible intracellular domain of human alpha 7 nicotinic acetylcholine receptor2022Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 13, nr 1, artikkel-id 793Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The intracellular domain (ICD) of Cys-loop receptors mediates diverse functions. To date, no structure of a full-length ICD is available due to challenges stemming from its dynamic nature. Here, combining nuclear magnetic resonance (NMR) and electron spin resonance experiments with Rosetta computations, we determine full-length ICD structures of the human alpha 7 nicotinic acetylcholine receptor in a resting state. We show that similar to 57% of the ICD residues are in highly flexible regions, primarily in a large loop (loop L) with the most mobile segment spanning similar to 50 angstrom from the central channel axis. Loop L is anchored onto the MA helix and virtually forms two smaller loops, thereby increasing its stability. Previously known motifs for cytoplasmic binding, regulation, and signaling are found in both the helices and disordered flexible regions, supporting the essential role of the ICD conformational plasticity in orchestrating a broad range of biological processes.

  • 366.
    Bora, Tanujjal
    et al.
    Asian Inst Technol, Sch Engn & Technol, Ind Syst Engn, Nanotechnol, POB 4, Klongluang 12120, Pathumthani, Thailand..
    Dutta, Joydeep
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Plasmonic Photocatalyst Design: Metal-Semiconductor Junction Affecting Photocatalytic Efficiency2019Inngår i: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 19, nr 1, s. 383-388Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Silver-zinc oxide nanorods (Ag-ZnO NRs) and gold-zinc oxide nanorods (Au-ZnO NRs) plasmonic photocatalysts were fabricated by the deposition of Ag and Au nanoparticles on ZnO NRs. The photocatalysts were studied with electron microscopy, energy dispersive spectroscopy (EDS), UV-vis optical absorption and photoluminescence spectroscopy. The effect of type of metals on the ZnO surface on its photocatalytic activity under ultra violet (UV) as well as visible light excitation are investigated and their contribution towards enhanced photo-generated charge separation in terms of the type of junction (Ohmic or Schottky) the metal forms with the semiconductor are explained.

  • 367.
    Borg, Malin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Ghattas, Elias
    KTH, Skolan för teknik och hälsa (STH). KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Syla, Ardian
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Graphical User Interface for Intermodulation Atomic Force Microscopyok.2011Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    In atomic force microscopy (AFM) a cantilever, with a sharp tip attached

    to its free end, is scanned over a surface. Forces from the surface aect

    the tip causing cantilever deection, which is registered by a detector. This

    information is then used to create a topographical image of the surface on

    nanoscale. We were a part of a project that developed a new type of AFM,

    namely intermodulation atomic force microscopy (IMAFM). It is based on

    dynamic AFM, but instead of one drive frequency, two or more frequencies

    are used. This generates more information from the sample. Our part in this

    project was to improve the software already in use. This will facilitate future

    simulations and experiments; and also utilize the available information in a

    new way.

    Fulltekst (pdf)
    Kandidatexamensjobb, Malin Borg, Elias Ghattas, Ardian Syla
  • 368.
    Borgani, Riccardo
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Probing nonlinear electrical properties at the nanoscale: Studies in multifrequency AFM2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Nanostructured materials promise great advances in diverse and active research fields such as energy harvesting and storage, corrosion prevention and high-density memories. Electrical characterization at the nanometer scale is key to understanding and optimizing the performance of these materials, and therefore central to the progress of nanotechnology. One of the most versatile tools for this purpose is the atomic force microscope (AFM), thanks to its ability to image surfaces with high spatial resolution.

    In this thesis we present several multifrequency techniques for AFM. Intermodulation electrostatic force microscopy (ImEFM) measures the potential of a surface with low noise and high spatial resolution. In contrast to traditionally available methods, ImEFM does not use a feedback-controlled bias to measure the surface potential, and is therefore suitable to measurements in liquid environments. Removing feedback allows the applied bias to be used for investigating charge injection and extraction on nanocomposite materials. Intermodulation conductive AFM (ImCFM) measures the current-voltage characteristic of a sample at every point of an AFM image. ImCFM is able to separate the galvanic and displacement contributions to the measured current, improving the measurement speed by four orders of magnitude compared to previously available methods. We finally demonstrate an alternative approach to pump-probe spectroscopy, which allows the AFM to measure electrical charge dynamics with a time resolution approaching the nanosecond range.

    These techniques are based on intermodulation spectroscopy, and they demonstrate the power and flexibility of measuring and analyzing nonlinear response in the frequency domain. The nonlinearity of the tip-surface force is used to concentrate response in a narrow band around the resonance of the AFM cantilever, where force measurement sensitivity is at the thermal limit. In this narrow band, we perform coherent measurements at multiple frequencies by exploiting the stability of a single reference oscillation. The power of the multifrequency approach is nicely demonstrated in a general method for measuring and compensating background forces, i.e. long-range linear forces that act on the body of the AFM probe. This compensation is necessary to reveal the the true force between the surface and the AFM tip. We show the effect of the compensation on soft polymer materials, where the background forces are typically strongest.

    Fulltekst (pdf)
    fulltext
  • 369.
    Borgani, Riccardo
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Sensing photo-induced surface charges on OrganicPhoto-Voltaic materials using Atomic Force Microscopy2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 370.
    Borgani, Riccardo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Forchheimer, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Bergqvist, Jonas
    Thorén, Per-Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Inganas, Olle
    Haviland, David B.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Intermodulation electrostatic force microscopy for imaging surface photo-voltage2014Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 105, nr 14, s. 143113-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate an alternative to Kelvin Probe Force Microscopy for imaging surface potential. The open-loop, single-pass technique applies a low-frequency AC voltage to the atomic force microscopy tip while driving the cantilever near its resonance frequency. Frequency mixing due to the nonlinear capacitance gives intermodulation products of the two drive frequencies near the cantilever resonance, where they are measured with high signal to noise ratio. Analysis of this intermodulation response allows for quantitative reconstruction of the contact potential difference. We derive the theory of the method, validate it with numerical simulation and a control experiment, and we demonstrate its utility for fast imaging of the surface photo-voltage on an organic photovoltaic material.

  • 371.
    Borgani, Riccardo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Gilzad Kohan, Mojtaba
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, 97187 Luleå, Sweden.
    Vomiero, Alberto
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, 97187 Luleå, Sweden.
    Haviland, David B.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Fast multifrequency measurement of nonlinear conductanceManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Low noise measurement of small currents in nanometer-scale junctions is of central importance to the characterization of novel high-performance devices and materials for applications ranging from energy harvesting and energy conversion to topological materials for quantum computers. The high resistance of these junctions and the stray capacitance of their measurement leads impose speed limitations (tens of seconds) on the traditional methods of measuring their nonlinear conductance, making detailed investigations of change with external fields or maps of variation over a surface impractical, if not impossible. Here we demonstrate fast (milliseconds) reconstruction of nonlinear current-voltage characteristics from phase-coherent multifrequency lock-in data using the inverse Fourier transform. The measurement technique allows for separation of the galvanic and displacement currents in the junction and easy cancellation of parasitic displacement current due to the measurement leads. We use the method to reveal nanometer-scale variations in the electrical transport properties of organic photovoltaic and semiconducting thin films. The method has broad applicability and its wide-spread implementation promises advancement in high-speed and high-resolution characterization for nanotechnology.

  • 372.
    Borgani, Riccardo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Haviland, David B.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Intermodulation spectroscopy as an alternative to pump-probe for the measurement of fast dynamics at the nanometer scaleManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    We present an alternative approach to pump-probe spectroscopy for measuring fast charge dynamics with an atomic force microscope (AFM). Our approach is based on coherent multifrequency lock-in measurement of the intermodulation between a mechanical drive and an optical or electrical excitation. In response to the excitation, the charge dynamics of the sample is reconstructed by fitting a theoretical model to the measured frequency spectrum of the electrostatic force near resonance of the AFM cantilever. We discuss the time resolution, which in theory is limited only by the measurement time, but in practice is of order one nanosecond for standard cantilevers and imaging speeds. We verify the method with simulations and demonstrate it with a control experiment, achieving a time resolution of 20 ns in ambient conditions, limited by thermal noise.

  • 373.
    Borgani, Riccardo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Haviland, David B.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Intermodulation spectroscopy as an alternative to pump-probe for the measurement of fast dynamics at the nanometer scale2019Inngår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 90, nr 1, artikkel-id 013705Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present an alternative approach to pump-probe spectroscopy for measuring fast charge dynamics with an atomic force microscope (AFM). Our approach is based on coherent multifrequency lock-in measurement of the intermodulation between a mechanical drive and an optical or electrical excitation. In response to the excitation, the charge dynamics of the sample is reconstructed by fitting a theoretical model to the measured frequency spectrum of the electrostatic force near resonance of the AFM cantilever. We discuss the time resolution, which in theory is limited only by the measurement time, but in practice is of order 1 ns for standard cantilevers and imaging speeds. We verify the method with simulations and demonstrate it with a control experiment, achieving a time resolution of 30 ns in ambient conditions, limited by thermal noise.

  • 374.
    Borgani, Riccardo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Kohan, Mojtaba Gilzad
    Lulea Univ Technol, Dept Engn Sci & Math, SE-97187 Lulea, Sweden..
    Vomiero, Alberto
    Lulea Univ Technol, Dept Engn Sci & Math, SE-97187 Lulea, Sweden..
    Haviland, David B.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Fast Multifrequency Measurement of Nonlinear Conductance2019Inngår i: Physical Review Applied, E-ISSN 2331-7019, Vol. 11, nr 4, artikkel-id 044062Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe a phase-coherent multifrequency lock-in measurement technique that uses the inverse Fourier transform to reconstruct the nonlinear current-voltage characteristic of a nanoscale junction. The method provides separation of the galvanic and displacement currents in the junction and easy cancellation of the parasitic displacement current from the measurement leads. These two features allow us to overcome traditional limitations imposed by the low conductance of the junction and the high capacitance of the leads, thus providing an increase in measurement speed of several orders of magnitude. We demonstrate the method in the context of conductive atomic force microscopy, acquiring current-voltage characteristics at every pixel while scanning at standard imaging speed.

  • 375.
    Borgani, Riccardo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Pallon, Love
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Gedde, Ulf W.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Haviland, David
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Local Charge Injection and Extraction on Surface-Modified Al2O3Nanoparticles in LDPE2016Inngår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 16, nr 9, s. 5934-5937, artikkel-id 10.1021/acs.nanolett.6b02920Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We use a recently developed scanning probe technique to image with high spatial resolution the injection and extraction of charge around individual surface-modified aluminum oxide nanoparticles embedded in a low-density polyethylene (LDPE) matrix. We find that the experimental results are consistent with a simple band structure model where localized electronic states are available in the band gap (trap states) in the vicinity of the nanoparticles. This work offers experimental support to a previously proposed mechanism for enhanced insulating properties of nanocomposite LDPE and provides a powerful experimental tool to further investigate such properties.

  • 376.
    Borgani, Riccardo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Thorén, Per-Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Forchheimer, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Dobryden, Illia
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Sah, Si Mohamed
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Haviland, David B.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Background-Force Compensation in Dynamic Atomic Force Microscopy2017Inngår i: Physical Review Applied, E-ISSN 2331-7019, Vol. 7, nr 6, artikkel-id 064018Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background forces are linear long-range interactions of the cantilever body with its surroundings that must be compensated for in order to reveal tip-surface force, the quantity of interest for determining material properties in atomic force microscopy. We provide a mathematical derivation of a method to compensate for background forces, apply it to experimental data, and discuss how to include background forces in simulation. Our method, based on linear-response theory in the frequency domain, provides a general way of measuring and compensating for any background force and it can be readily applied to different force reconstruction methods in dynamic AFM.

  • 377.
    Borisov, Vladislav
    et al.
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Kvashnin, Yaroslav O.
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Ntallis, Nikolaos
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Thonig, Danny
    Örebro Univ, Sch Sci & Technol, SE-70182 Örebro, Sweden..
    Thunström, Patrik
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Pereiro, Manuel
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Bergman, Anders
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Sjöqvist, Erik
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Delin, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik. KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Nordström, Lars
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Eriksson, Olle
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden.;Örebro Univ, Sch Sci & Technol, SE-70182 Örebro, Sweden..
    Heisenberg and anisotropic exchange interactions in magnetic materials with correlated electronic structure and significant spin-orbit coupling2021Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 103, nr 17, artikkel-id 174422Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Dzyaloshinskii-Moriya (DM) interaction, as well as symmetric anisotropic exchange, are important ingredients for stabilizing topologically nontrivial magnetic textures, such as, e.g., skyrmions, merons, and hopfions. These types of textures are currently in focus from a fundamental science perspective and they are also discussed in the context of future spintronics information technology. While the theoretical understanding of the Heisenberg exchange interactions is well developed, it is still a challenge to access, from first principles theory, the DM interaction as well as the symmetric anisotropic exchange, which both require a fully-relativistic treatment of the electronic structure, in magnetic systems where substantial electron-electron correlations are present. Here, we present results of a theoretical framework which allows to compute these interactions in any given system and demonstrate its performance for several selected cases, for both bulk and low-dimensional systems. We address several representative cases, including the bulk systems CoPt and FePt, the B20 compounds MnSi and FeGe as well as the low-dimensional transition metal bilayers Co/Pt(111) andMn/W(001). The effect of electron-electron correlations is analyzed using dynamical mean-field theory on the level of the spin-polarized T -matrix + fluctuating exchange (SPTF) approximation, as regards the strength and character of the isotropic (Heisenberg) and anisotropic (DM) interactions in relation to the underlying electronic structure. Our method can be combined with more advanced techniques for treating correlations, e.g., quantum Monte Carlo and exact diagonalization methods for the impurity solver of dynamical mean-field theory. We find that correlation-induced changes of the DM interaction can be rather significant, with up to fivefold modifications in the most distinctive case.

  • 378.
    Borisov, Vladislav
    et al.
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Xu, Qichen
    KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Ntallis, Nikolaos
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Clulow, Rebecca
    Uppsala Univ, Dept Chem, Box 538, SE-75121 Uppsala, Sweden..
    Shtender, Vitalii
    Uppsala Univ, Dept Chem, Box 538, SE-75121 Uppsala, Sweden..
    Cedervall, Johan
    Stockholm Univ, Dept Mat & Environm Chem, SE-10691 Stockholm, Sweden..
    Sahlberg, Martin
    Uppsala Univ, Dept Chem, Box 538, SE-75121 Uppsala, Sweden..
    Wikfeldt, Kjartan Thor
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Centra, Parallelldatorcentrum, PDC.
    Thonig, Danny
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden.;Örebro Univ, Sch Sci & Technol, SE-70182 Örebro, Sweden..
    Pereiro, Manuel
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Bergman, Anders
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Delin, Anna
    KTH, Centra, SeRC - Swedish e-Science Research Centre. KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Eriksson, Olle
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden.;Örebro Univ, Sch Sci & Technol, SE-70182 Örebro, Sweden..
    Tuning skyrmions in B20 compounds by 4d and 5d doping2022Inngår i: Physical Review Materials, E-ISSN 2475-9953, Vol. 6, nr 8, artikkel-id 084401Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Skyrmion stabilization in novel magnetic systems with the B20 crystal structure is reported here, primarily based on theoretical results. The focus is on the effect of alloying on the 3d sublattice of the B20 structure by substitution of heavier 4d and 5d elements, with the ambition to tune the spin-orbit coupling and its influence on magnetic interactions. State-of-the-art methods based on density functional theory are used to calculate both isotropic and anisotropic exchange interactions. Significant enhancement of the Dzyaloshinskii-Moriya interaction is reported for 5d-doped FeSi and CoSi, accompanied by a large modification of the spin stiffness and spiralization. Micromagnetic simulations coupled to atomistic spin-dynamics and ab initio magnetic interactions reveal the spin-spiral nature of the magnetic ground state and field-induced skyrmions for all these systems. Especially small skyrmions similar to 50 nm are predicted for Co0.75Os0.25Si, compared to similar to 148 nm for Fe0.75Co0.25Si. Convex-hull analysis suggests that all B20 compounds considered here are structurally stable at elevated temperatures and should be possible to synthesize. This prediction is confirmed experimentally by synthesis and structural analysis of the Ru-doped CoSi systems discussed here, both in powder and in single-crystal forms.

  • 379.
    Borlenghi, Simone
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Boman, Magnus
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Programvaruteknik och datorsystem, SCS. RISE SICS, Electrum 229, SE-16429 Kista, Sweden..
    Delin, Anna
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik. KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Modeling reservoir computing with the discrete nonlinear Schrodinger equation2018Inngår i: Physical review. E, ISSN 2470-0045, E-ISSN 2470-0053, Vol. 98, nr 5, artikkel-id 052101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We formulate, using the discrete nonlinear Schrodinger equation (DNLS), a general approach to encode and process information based on reservoir computing. Reservoir computing is a promising avenue for realizing neuromorphic computing devices. In such computing systems, training is performed only at the output level by adjusting the output from the reservoir with respect to a target signal. In our formulation, the reservoir can be an arbitrary physical system, driven out of thermal equilibrium by an external driving. The DNLS is a general oscillator model with broad application in physics, and we argue that our approach is completely general and does not depend on the physical realization of the reservoir. The driving, which encodes the object to be recognized, acts as a thermodynamic force, one for each node in the reservoir. Currents associated with these thermodynamic forces in turn encode the output signal from the reservoir. As an example, we consider numerically the problem of supervised learning for pattern recognition, using as a reservoir a network of nonlinear oscillators.

  • 380.
    Borlenghi, Simone
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Delin, Anna
    KTH, Centra, SeRC - Swedish e-Science Research Centre. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Stochastic Thermodynamics of Oscillators' Networks2018Inngår i: Entropy, E-ISSN 1099-4300, Vol. 20, nr 12, artikkel-id 992Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We apply the stochastic thermodynamics formalism to describe the dynamics of systems of complex Langevin and Fokker-Planck equations. We provide in particular a simple and general recipe to calculate thermodynamical currents, dissipated and propagating heat for networks of nonlinear oscillators. By using the Hodge decomposition of thermodynamical forces and fluxes, we derive a formula for entropy production that generalises the notion of non-potential forces and makes transparent the breaking of detailed balance and of time reversal symmetry for states arbitrarily far from equilibrium. Our formalism is then applied to describe the off-equilibrium thermodynamics of a few examples, notably a continuum ferromagnet, a network of classical spin-oscillators and the Frenkel-Kontorova model of nano friction.

  • 381. Borlenghi, Simone
    et al.
    Mahani, Mohammad Reza
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Fangohr, Hans
    Franchin, M.
    Delin, Anna
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik. KTH, Centra, SeRC - Swedish e-Science Research Centre. Uppsala Univ, Sweden.
    Fransson, Jonas
    Micromagnetic simulations of spin-torque driven magnetization dynamics with spatially resolved spin transport and magnetization texture2017Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, nr 9, artikkel-id 094428Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a simple and fast method to simulate spin-torque driven magnetization dynamics in nanopillar spin-valve structures. The approach is based on the coupling between a spin transport code based on random matrix theory and a micromagnetics finite-elements software. In this way the spatial dependence of both spin transport and magnetization dynamics is properly taken into account. Our results are compared with experiments. The excitation of the spin-wave modes, including the threshold current for steady-state magnetization precession and the nonlinear frequency shift of the modes are reproduced correctly. The giant magneto resistance effect and the magnetization switching also agree with experiment. The similarities with recently described spin-caloritronics devices are also discussed.

  • 382. Born, A.
    et al.
    Johansson, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Leitner, T.
    Bidermane, I.
    Kühn, D.
    Mårtensson, N.
    Föhlisch, A.
    The degree of electron itinerancy and shell closing in the core-ionized state of transition metals probed by Auger-photoelectron coincidence spectroscopy2022Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 24, nr 32, s. 19218-19222Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Auger-photoelectron coincidence spectroscopy (APECS) has been used to examine the electron correlation and itinerance effects in transition metals Cu, Ni and Co. It is shown that the LVV Auger, in coincidence with 2p photoelectrons, spectra can be represented using atomic multiplet positions if the 3d-shell is localized (atomic-like) and with a self-convoluted valence band for band-like (itinerant) materials as explained using the Cini-Sawatzky model. For transition metals, the 3d band changes from band-like to localized with increasing atomic number, with the possibility of a mixed behavior. Our result shows that the LVV spectra of Cu can be represented by atomic multiplet calculations, those of Co resemble the self-convolution of the valence band and those of Ni are a mixture of both, consistent with the Cini-Sawatzky model.

  • 383.
    Borynskyi, V. Yu
    et al.
    NAS Ukraine, Inst Magnetism, 36-b Akad Vernadsky Blvd, UA-03142 Kiev, Ukraine.;MES Ukraine, 36-b Akad Vernadsky Blvd, UA-03142 Kiev, Ukraine..
    Polishchuk, Dmytr
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik. NAS Ukraine, Inst Magnetism, 36-b Akad Vernadsky Blvd, UA-03142 Kiev, Ukraine.;MES Ukraine, 36-b Akad Vernadsky Blvd, UA-03142 Kiev, Ukraine..
    Melnyk, A. K.
    NAS Ukraine, Inst Sorpt & Problems Endoecol, 13 Naumov Str, UA-03164 Kiev, Ukraine..
    Kravets, Anatolii
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik. NAS Ukraine, Inst Magnetism, 36-b Akad Vernadsky Blvd, UA-03142 Kiev, Ukraine.;MES Ukraine, 36-b Akad Vernadsky Blvd, UA-03142 Kiev, Ukraine..
    Tovstolytkin, A. , I
    Korenivski, Vladislav
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Higher-order ferromagnetic resonances in periodic arrays of synthetic-antiferromagnet nanodisks2021Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 119, nr 19, artikkel-id 192402Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate spin dynamics in nanodisk arrays of synthetic-antiferromagnets (SAF) made of Py/NiCu/Py trilayers, where the NiCu spacer undergoes a Curie transition at about 200 K. The observed ferromagnetic resonance spectra have three distinct resonance modes at room temperature, which are fully recreated in our micromagnetic simulations, showing also how the intra-SAF asymmetry can be used to create and control the higher-order resonances in the structure. Below the Curie temperature of the spacer, the system effectively transitions into a single-layer nanodisk array with only two resonance modes. Our results show how multilayering of nanoarrays can add tunable GHz functionality relevant for such rapidly developing fields as magnetic metamaterials, magnonic crystals, arrays of spin-torque oscillators, and neuromorphic junctions.

  • 384.
    Borynskyi, V. Yu
    et al.
    Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, Kyiv 03142, Ukraine.
    Polishchuk, Dmytr
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik. Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, Kyiv 03142, Ukraine.
    Savina, Yu O.
    B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Kharkiv 61103, Ukraine.
    Pashchenko, V. O.
    B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Kharkiv 61103, Ukraine.
    Kravets, Anatolii
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik. Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, Kyiv 03142, Ukraine.
    Tovstolytkin, A. I.
    Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, Kyiv 03142, Ukraine.
    Korenivski, Vladislav
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Thermomagnetic transition in nanoscale synthetic antiferromagnets Py/NiCu/Py2023Inngår i: Low temperature physics (Woodbury, N.Y., Print), ISSN 1063-777X, E-ISSN 1090-6517, Vol. 49, nr 7, s. 863-869Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using the method of SQUID magnetometry, the features of the antiferromagnet-ferromagnet thermomagnetic transition in arrays of the nanosized disks of Py/NiCu/Py synthetic antiferromagnets (SAFs) have been investigated. The effective interlayer interaction in individual SAFs “ferromagnet/diluted ferromagnet/ferromagnet” (F2/f/F1) changes from high-temperature antiferromagnetic to low-temperature ferromagnetic upon the transition at the Curie temperature T C f of the interlayer f. Temperature dependence of the magnetic parameters of individual layers and their effect on the features of the thermomagnetic transition are determined. The observed properties are important for the development of temperature-controlled nanoscale SAFs and multilayer nanostructures based on them.

  • 385.
    Borynskyi, Vladyslav
    et al.
    Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, Department of Physics of Films, Kyiv, Ukraine.
    Kravets, Anatolii
    Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, Department of Physics of Films, Kyiv, Ukraine.
    Polishchuk, Dmytr
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Tovstolytkin, Alexandr
    Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, Department of Physics of Films, Kyiv, Ukraine.
    Sharai, Iryna
    Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, Department of Physics of Films, Kyiv, Ukraine.
    Korenivski, Vladislav
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Melnyk, Andrii
    Center for the collective use of scientific equipment 'EPR spectroscopy' Institute for Sorption and Problems of Endoecology of the NAS of Ukraine, Kyiv, Ukraine.
    Spin-wave Resonance in Arrays of Nanoscale Synthetic-antiferromagnets2022Inngår i: Proceedings of the 2022 IEEE 12th International Conference "Nanomaterials: Applications and Properties", NAP 2022, Institute of Electrical and Electronics Engineers (IEEE) , 2022Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The study concerns dynamics of standing spin waves in arrays of sub-100 nm elliptic synthetic-antiferromagnet (SAF) nanodisks. We performed a detailed ferromagnetic resonance analysis in conjunction with micro magnetic modeling to find out several prominent traits of such systems. One broad line is shown to be the sole resonant response for a SAF of the considered sizes. We demonstrate that this mode is degenerated, and its excitation map resembles a superposition of in-center and edge-type oscillations. We also show how this hybrid excitation leads to almost twofold enhancement in the shape-induced anisotropy of the mode.

  • 386.
    Borysov, Stanislav
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik. KTH, Centra, Nordic Institute for Theoretical Physics NORDITA.
    Roudi, Yasser
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA. The Kavli Institute for Systems Neuroscience, NTNU, Trondheim, Norway.
    Balatsky, Alexander V.
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA. Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, NM, United States.
    U.S. stock market interaction network as learned by the Boltzmann machine2015Inngår i: European Physical Journal B: Condensed Matter Physics, ISSN 1434-6028, E-ISSN 1434-6036, Vol. 88, nr 12, s. 1-14Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study historical dynamics of joint equilibrium distribution of stock returns in the U.S. stock market using the Boltzmann distribution model being parametrized by external fields and pairwise couplings. Within Boltzmann learning framework for statistical inference, we analyze historical behavior of the parameters inferred using exact and approximate learning algorithms. Since the model and inference methods require use of binary variables, effect of this mapping of continuous returns to the discrete domain is studied. The presented results show that binarization preserves the correlation structure of the market. Properties of distributions of external fields and couplings as well as the market interaction network and industry sector clustering structure are studied for different historical dates and moving window sizes. We demonstrate that the observed positive heavy tail in distribution of couplings is related to the sparse clustering structure of the market. We also show that discrepancies between the model’s parameters might be used as a precursor of financial instabilities.

  • 387.
    Borysov, Stanislav S.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik. KTH, Centra, Nordic Institute for Theoretical Physics NORDITA. Stockholm University, Sweden.
    Balatsky, Alexander V.
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA. Stockholm University, Sweden.
    Cross-Correlation Asymmetries and Causal Relationships between Stock and Market Risk2014Inngår i: PLOS ONE, E-ISSN 1932-6203, Vol. 9, nr 8, s. e105874-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study historical correlations and lead-lag relationships between individual stock risk (volatility of daily stock returns) and market risk (volatility of daily returns of a market-representative portfolio) in the US stock market. We consider the cross-correlation functions averaged over all stocks, using 71 stock prices from the Standard & Poor's 500 index for 1994-2013. We focus on the behavior of the cross-correlations at the times of financial crises with significant jumps of market volatility. The observed historical dynamics showed that the dependence between the risks was almost linear during the US stock market downturn of 2002 and after the US housing bubble in 2007, remaining at that level until 2013. Moreover, the averaged cross-correlation function often had an asymmetric shape with respect to zero lag in the periods of high correlation. We develop the analysis by the application of the linear response formalism to study underlying causal relations. The calculated response functions suggest the presence of characteristic regimes near financial crashes, when the volatility of an individual stock follows the market volatility and vice versa.

  • 388.
    Borysov, Stanislav S.
    et al.
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA.
    Forchheimer, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Haviland, David B.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Dynamic calibration of higher eigenmode parameters of a cantilever in atomic force microscopy by using tip-surface interactions2014Inngår i: Beilstein Journal of Nanotechnology, ISSN 2190-4286, Vol. 5, s. 1899-1904Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a theoretical framework for the dynamic calibration of the higher eigenmode parameters (stiffness and optical lever inverse responsivity) of a cantilever. The method is based on the tip-surface force reconstruction technique and does not require any prior knowledge of the eigenmode shape or the particular form of the tip-surface interaction. The calibration method proposed requires a single-point force measurement by using a multimodal drive and its accuracy is independent of the unknown physical amplitude of a higher eigenmode.

  • 389.
    Borysov, Stanislav S.
    et al.
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA.
    Platz, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    de Wijn, Astrid S.
    Forchheimer, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Tolén, Eric A.
    Balatsky, Alexander V.
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA.
    Haviland, David B.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Nanostrukturfysik.
    Reconstruction of tip-surface interactions with multimodal intermodulation atomic force microscopy2013Inngår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 88, nr 11, s. 115405-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose a theoretical framework for reconstructing tip-surface interactions using the intermodulation technique when more than one eigenmode is required to describe the cantilever motion. Two particular cases of bimodal motion are studied numerically: one bending and one torsional mode, and two bending modes. We demonstrate the possibility of accurate reconstruction of a two-dimensional conservative force field for the former case, while dissipative forces are studied for the latter.

  • 390.
    Boskovic, Andrea
    et al.
    Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts 01002.
    Jones, Kate M.
    Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts 01002.
    Velasquez, Alejandra
    Department of Physics and Astronomy, Amherst College, Amherst, 01002, MA, United States.
    Hardy, Isabel P.
    Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts 01002.
    Bulos, Maya L.
    Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts 01002.
    Carter, Ashley R.
    Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts 01002.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik.
    Acoustic trapping in the undergraduate laboratory2024Inngår i: American Journal of Physics, ISSN 0002-9505, E-ISSN 1943-2909, Vol. 92, nr 1, s. 59-64Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Acoustic trapping is used in modern biophysics laboratories to study cell adhesion or aggregation, to sort particles, or to build model tissues. Here, we create an acoustic trapping setup in liquid for an undergraduate instructional laboratory that is low-cost, easy to build, and produces results in a 1-hour laboratory period. In this setup, we use a glass slide, cover slip, and double-sided tape to make the sample chamber. A piezo-electric transducer connected to a function generator serves as the acoustic source. We use this setup to measure the node spacing (millimeters) and the acoustic trap force (picoNewtons). We anticipate that the simplicity of the experimental setup, the tractability of the theoretical equations, and the richness of the research topics on the subject will lead to an undergraduate laboratory with many interesting student projects.

  • 391.
    Boström, Caroline
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Investigation on Cell-Cell Junctions by Inhibition of Na,K-ATPase Activity2021Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis report investigates the effect on cellcell junction proteins when the Na,K-ATPase (NKA) is inhibited. The main goal is to develop an understanding of how the NKA activity regulates the cell junction proteins. The investigated proteins are the adherens junction protein ECadherin, and the tight junction proteins Occludin and Claudin7.The NKA is inhibited by introducing the cardiotonic steroid Ouabain to the cells. The treatment is tested for different time lapse and different concentrations. The results show that all proteins are down regulated when treated with high concentrations (500 nM) of Ouabain. ECadherin is up regulated when treated with lower concentrations (10 nM) of Ouabain while Claudin7 is down regulated at low levels.

    Fulltekst (pdf)
    fulltext
  • 392. Bouchard, F.
    et al.
    de la Hoz, P.
    Björk, Gunnar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Kvantelektronik och -optik, QEO.
    Boyd, R. W.
    Grassl, M.
    Hradil, Z.
    Karimi, E.
    Klimov, A. B.
    Leuchs, G.
    Rehacek, J.
    Sanchez-Soto, L. L.
    Quantum metrology at the limit with extremal Majorana constellations2017Inngår i: Optica, E-ISSN 2334-2536, Vol. 4, nr 11, s. 1429-1432Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Quantum metrology allows for a tremendous boost in the accuracy of measurement of diverse physical parameters. The estimation of a rotation constitutes a remarkable example of this quantum-enhanced precision. The recently introduced Kings of Quantumness are especially germane for this task when the rotation axis is unknown, as they have a sensitivity independent of that axis and they achieve a Heisenberg-limit scaling. Here, we report the experimental realization of these states by generating up to 21-dimensional orbital angular momentum states of single photons, and confirm their high metrological abilities.

  • 393.
    Boucly, Anthony
    et al.
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France..
    Rochet, Francois
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France.;Synchrotron SOLEIL, BP 48, F-91192 Gif Sur Yvette, France..
    Arnoux, Quentin
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France..
    Gallet, Jean-Jacques
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France.;Synchrotron SOLEIL, BP 48, F-91192 Gif Sur Yvette, France..
    Bournel, Fabrice
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France.;Synchrotron SOLEIL, BP 48, F-91192 Gif Sur Yvette, France..
    Tissot, Heloise
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik. Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France.;Synchrotron SOLEIL, BP 48, F-91192 Gif Sur Yvette, France.
    Marry, Virginie
    Sorbonne Univ, CNRS UMR 8234, Physicochim Electrolyses & Nanosyst Interfaciaux, 4 Pl Jussieu, F-75252 Paris 05, France..
    Dubois, Emmanuelle
    Sorbonne Univ, CNRS UMR 8234, Physicochim Electrolyses & Nanosyst Interfaciaux, 4 Pl Jussieu, F-75252 Paris 05, France..
    Michot, Laurent
    Sorbonne Univ, CNRS UMR 8234, Physicochim Electrolyses & Nanosyst Interfaciaux, 4 Pl Jussieu, F-75252 Paris 05, France..
    Soft X-ray Heterogeneous Radiolysis of Pyridine in the Presence of Hydrated Strontium-Hydroxyhectorite and its Monitoring by Near-Ambient Pressure Photoelectron Spectroscopy2018Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 8, artikkel-id 6164Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The heterogeneous radiolysis of organic molecules in clays is a matter of considerable interest in astrochemistry and environmental sciences. However, little is known about the effects of highly ionizing soft X-rays. By combining monochromatized synchrotron source irradiation with in situ Near Ambient Pressure X-ray Photoelectron Spectroscopy (in the mbar range), and using the synoptic view encompassing both the gas and condensed phases, we found the water and pyridine pressure conditions under which pyridine is decomposed in the presence of synthetic Sr2+-hydroxyhectorite. The formation of a pyridine/water/Sr2+ complex, detected from the Sr 3d and N 1s core-level binding energies, likely presents a favorable situation for the radiolytic breaking of the O-H bond of water molecules adsorbed in the clay and the subsequent decomposition of the molecule. However, decomposition stops when the pyridine pressure exceeds a critical value. This observation can be related to a change in the nature of the active radical species with the pyridine loading. This highlights the fact that the destruction of the molecule is not entirely determined by the properties of the host material, but also by the inserted organic species. The physical and chemical causes of the present observations are discussed.

  • 394. Boudrioua, A.
    et al.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Moretti, P.
    Loulerque, C.
    Depth dependence of the second harmonic generationof ion implanted waveguides2000Konferansepaper (Fagfellevurdert)
  • 395.
    Bowers, Mark S.
    et al.
    Lockheed Martin Rotary & Mission Syst, 22121 20th Ave SE, Bothell, WA 98021 USA..
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Mirov, Sergey
    AdValue Photon Inc, 3440 E Britannia Dr,Suite 190, Tucson, AZ 85706 USA.;IPG Photon Southeast Technol Ctr, 100 Lucerne Lane, Birmingham, AL 35211 USA.;Univ Alabama Birmingham, 1530 3rd Ave S, Birmingham, AL 35294 USA..
    Nilsson, Johan
    Univ Southampton, Optoelect Res Ctr, Southampton SO17 1BJ, Hants, England..
    Saraceno, Clara J.
    Ruhr Univ Bochum, Photon & Ultrafast Laser Sci, Univ Str 150, D-44801 Bochum, Germany..
    Schunemann, Peter G.
    BAE Syst, MER15-1813,POB 868, Nashua, NH 03061 USA..
    Feature issue introduction: advanced solid-state lasers2022Inngår i: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 12, nr 6, s. 2283-2287Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This Joint Issue of Optics Express and Optical Materials Express features 36 state of-the art articles written by authors who participated in the international conference Advanced Solid State Lasers held online from October 3-7, 2021. This review provides a summary of these articles covering a wide spectrum of topics around solid-state lasers from materials research to sources and from design innovation to applications.

  • 396.
    Bowers, Mark S.
    et al.
    Lockheed Martin Rotary & Mission Syst, 22121 20th Ave SE, Bothell, WA 98021 USA..
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Mirov, Sergey
    AdValue Photon Inc, 3440 E Britannia Dr,Suite 190, Tucson, AZ 85706 USA.;IPG Photon Southeast Technol Ctr, 100 Lucerne Lane, Birmingham, AL 35211 USA.;Univ Alabama Birmingham, 1530 3rd Ave S, Birmingham, AL 35294 USA..
    Nilsson, Johan
    Univ Southampton, Optoelect Res Ctr, Southampton SO17 1BJ, Hants, England..
    Saraceno, Clara J.
    Ruhr Univ Bochum, Photon & Ultrafast Laser Sci, Univ Str 150, D-44801 Bochum, Germany..
    Schunemann, Peter G.
    BAE Syst, MER15-1813,POB 868, Nashua, NH 03061 USA..
    Feature issue introduction: advanced solid-state lasers2022Inngår i: Optics Express, E-ISSN 1094-4087, Vol. 30, nr 12, s. 20762-20766Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This joint issue of Optics Express and Optical Materials Express features 36 state-of-the art articles written by authors who participated in the international conference advanced solid state lasers held online from October 3-7, 2021. This review provides a summary of these articles covering a wide spectrum of topics around solid-state lasers from materials research to sources and from design innovation to applications.

  • 397. Boyko, A. A.
    et al.
    Kostyukova, N. Y.
    Badikov, V.
    Badikov, D.
    Panyutin, V.
    Shevyrdyaeva, G.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Marchev, G. M.
    Kolker, D. B.
    Petrov, V.
    Intracavity difference-frequency mixing of OPO signal and idler pulses in BaGa4Se72017Inngår i: Optics InfoBase Conference Papers, Optical Society of America, 2017, Vol. Part F41Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An overall quantum conversion efficiency of 7.8% is achieved by intracavity mixing the signal and idler of a 1.064-μm pumped Rb:PPKTP OPO in BaGa4Se7, generating >0.7 mJ pulse energy at ~7 μm and 100 Hz.

  • 398. Boyko, A. A.
    et al.
    Marchev, G. M.
    Petrov, V.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Kolker, D. B.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Kostyukova, N. Y.
    Intracavity-pumped, cascaded AgGaSe2 optical parametric oscillator tunable up to 18 μm2016Inngår i: Optics InfoBase Conference Papers, OSA - The Optical Society , 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We report on a AgGaSe2 optical parametric oscillator (OPO), intracavity pumped by the 1.85-μm signal pulses of a 1.064-μm pumped Rb:PPKTP OPO. It operates at 100 Hz with idler tunability from ~8 to 18 μm. 

  • 399. Boyko, A. A.
    et al.
    Marchev, G. M.
    Petrov, V.
    Pasiskevicius, Valdus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Kolker, D. B.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Kostyukova, N. Y.
    Intracavity-pumped, cascaded Mid-IR optical parametric oscillator based on AgGaSe22015Inngår i: Advanced Solid State Lasers, ASSL 2015, Optical Society of America, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We report on an AgGaSe2 optical parametric oscillator (OPO), intracavity pumped by the 1.85-μm signal pulses from a 1.064-μm pumped Rb:PPKTP OPO. It operates at 100 Hz with idler tunability from 5.8 to 8.3 μm.

  • 400. Boyko, A.
    et al.
    Badikov, V.
    Shevyrdyaeva, G.
    Badikov, D.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Petrov, V.
    Intracavity-pumped, cascaded optical parametric oscillator based on BaGa2GeSe62018Inngår i: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We employ the new chalcogenide crystal BaGa2GeSe6 for the first time for frequency down-conversion into the mid-IR, in an optical parametric oscillator (OPO), intracavity pumped by the signal wave of a 1.064-μm pumped Rb:PPKTP OPO. .

567891011 351 - 400 of 4448
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf