396 research outputs found
STTS 2.0. Guidelines für die Annotation von POS -Tags für Transkripte gesprochener Sprache in Anlehnung an das Stuttgart Tübingen Tagset (STTS)
Die Guidelines sind eine Erweiterung des STTS (Schiller et al. 1999) für die Annotation von Transkripten gesprochener Sprache. Dieses Tagset basiert auf der Annotation des FOLK-Korpus des IDS Mannheim (Schmidt 2014) und es wurde gegenüber dem STTS erweitert in Hinblick auf typisch gesprochensprachliche Phänomene bzw. Eigenheiten der Transkription derselben. Es entstand im Rahmen des Dissertationsprojekts „POS für(s) FOLK – Entwicklung eines automatisierten Part-of-Speech-Tagging von spontansprachlichen Daten“ (Westpfahl 2017 (i.V.))
Highlighting Current Trends in Volunteered Geographic Information
Volunteered Geographic Information (VGI) is a growing area of research. This Special Issue aims to capture the main trends in VGI research based on 16 original papers, and distinguishes between two main areas, i.e., those that deal with the characteristics of VGI and those focused on applications of VGI. The topic of quality assessment and assurance dominates the papers on VGI characteristics, whereas application-oriented work covers three main domains: human behavioral analysis, natural disasters, and land cover/land use mapping. In this Special Issue, therefore, both the challenges and the potentials of VGI are addressed
Skyrmion Lattice in a Chiral Magnet
Skyrmions represent topologically stable field configurations with
particle-like properties. We used neutron scattering to observe the spontaneous
formation of a two-dimensional lattice of skyrmion lines, a type of magnetic
vortices, in the chiral itinerant-electron magnet MnSi. The skyrmion lattice
stabilizes at the border between paramagnetism and long-range helimagnetic
order perpendicular to a small applied magnetic field regardless of the
direction of the magnetic field relative to the atomic lattice. Our study
experimentally establishes magnetic materials lacking inversion symmetry as an
arena for new forms of crystalline order composed of topologically stable spin
states
Long-range crystalline nature of the skyrmion lattice in MnSi
We report small angle neutron scattering of the skyrmion lattice in MnSi
using an experimental set-up that minimizes the effects of demagnetizing fields
and double scattering. Under these conditions the skyrmion lattice displays
resolution-limited Gaussian rocking scans that correspond to a magnetic
correlation length in excess of several hundred {\mu}m. This is consistent with
exceptionally well-defined long-range order. We further establish the existence
of higher-order scattering, discriminating parasitic double-scattering with
Renninger scans. The field and temperature dependence of the higher-order
scattering arises from an interference effect. It is characteristic for the
long-range crystalline nature of the skyrmion lattice as shown by simple mean
field calculations.Comment: 4 page
Thermodynamic investigations in the precursor region of FeGe
High-resolution DC magnetization and AC-specific heat data of the cubic
helimagnet FeGe have been measured as function of temperature and magnetic
field. The magnetization data as well as the isothermal susceptibility data
confirm the complexity of the magnetic phase diagram in the vicinity of the
onset of long-rang magnetic order (Tc = 278.5 K) and the existence of a
segmented A-phase region. Moreover, these data revealed independent and clear
indications of phase boundaries and crossovers within the A-phase region.
Together with the anomalies in the specific-heat data around Tc and at small
magnetic fields (H < 600 Oe) a complex magnetic phase diagram of FeGe is
obtained.Comment: Presented at the QCNP conference in Dreden, Germany, August 201
Spin Transfer Torques in MnSi at Ultra-low Current Densities
Spin manipulation using electric currents is one of the most promising
directions in the field of spintronics. We used neutron scattering to observe
the influence of an electric current on the magnetic structure in a bulk
material. In the skyrmion lattice of MnSi, where the spins form a lattice of
magnetic vortices similar to the vortex lattice in type II superconductors, we
observe the rotation of the diffraction pattern in response to currents which
are over five orders of magnitude smaller than those typically applied in
experimental studies on current-driven magnetization dynamics in
nanostructures. We attribute our observations to an extremely efficient
coupling of inhomogeneous spin currents to topologically stable knots in spin
structures
Theory of current-driven motion of Skyrmions and spirals in helical magnets
We study theoretically the dynamics of the spin textures, i.e., Skyrmion
crystal (SkX) and spiral structure (SS), in two-dimensional helical magnets
under external current. By numerically solving the Landau-Lifshitz-Gilbert
equation, it is found that (i) the critical current density of the motion is
much lower for SkX compared with SS in agreement with the recent experiment,
(ii) there is no intrinsic pinning effect for SkX and the deformation of the
internal structure of Skyrmion reduces the pinning effect dramatically, (iii)
the Bragg intensity of SkX shows strong time-dependence as can be observed by
neutron scattering experiment.Comment: 4 pages, 3 figure
Indecent Bodies in Early Modern Visual Culture
The life-like depiction of the body became a central interest and defining characteristic of the European Early Modern period that coincided with the establishment of which images of the body were to be considered ʻdecentʼ and representable, and which disapproved, censored, or prohibited. Simultaneously, artists and the public became increasingly interested in the depiction of specific body parts or excretions. This book explores the concept of indecency and its relation to the human body across drawings, prints, paintings, sculptures, and texts. The ten essays investigate questions raised by such objects about practices and social norms regarding the body, and they look at the particular function of those artworks within this discourse. The heterogeneous media, genres, and historical contexts north and south of the Alps studied by the authors demonstrate how the alleged indecency clashed with artistic intentions and challenges traditional paradigms of the historiography of Early Modern visual culture
Room temperature chiral magnetic skyrmion in ultrathin magnetic nanostructures
Magnetic skyrmions are chiral spin structures with a whirling configuration.
Their topological properties, nanometer size and the fact that they can be
moved by small current densities have opened a new paradigm for the
manipulation of magnetisation at the nanoscale. To date, chiral skyrmion
structures have been experimentally demonstrated only in bulk materials and in
epitaxial ultrathin films and under external magnetic field or at low
temperature. Here, we report on the observation of stable skyrmions in
sputtered ultrathin Pt/Co/MgO nanostructures, at room temperature and zero
applied magnetic field. We use high lateral resolution X-ray magnetic circular
dichroism microscopy to image their chiral N\'eel internal structure which we
explain as due to the large strength of the Dzyaloshinskii-Moriya interaction
as revealed by spin wave spectroscopy measurements. Our results are
substantiated by micromagnetic simulations and numerical models, which allow
the identification of the physical mechanisms governing the size and stability
of the skyrmions.Comment: Submitted version. Extended version to appear in Nature
Nanotechnolog
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