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Now showing 1 - 10 of 16
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    Functional access to electronic media collections using emulation-as-a-service
    (2014) Bähr, Thomas; Lindlar, Michelle; Rechert, Klaus; Liebetraut, Thomas
    Over the last 30 years the German National Library of Science and Technology (TIB) accumulated a large collection of various electronic media, such as floppies or CD-ROMs. This poster describes both practical workflows as well as technical infrastructure to provide authentic and interactive access to the TIB’s large electronic media collection.
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    Building information modeling – A game changer for interoperability and a chance for digital preservation of architectural data?
    (2014) Lindlar, Michelle
    Digital data associated with the architectural design-andconstruction process is an essential resource alongside -and even past- the lifecycle of the construction object it describes. Despite this, digital architectural data remains to be largely neglected in digital preservation research – and vice versa, digital preservation is so far neglected in the design-and-construction process. In the last 5 years, Building Information Modeling (BIM) has seen a growing adoption in the architecture and construction domains, marking a large step towards much needed interoperability. The open standard IFC (Industry Foundation Classes) is one way in which data is exchanged in BIM processes. This paper presents a first digital preservation based look at BIM processes, highlighting the history and adoption of the methods as well as the open file format standard IFC (Industry Foundation Classes) as one way to store and preserve BIM data.
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    Target-skyrmions and skyrmion clusters in nanowires of chiral magnets
    (Les Ulis : EDP Sciences, 2014) Leonov, A.O.; Rößler, U.K.; Mostovoy, M.
    In bulk non-centrosymmetric magnets the chiral Dzyaloshinskii-Moriya exchange stabilizes tubular skyrmions with a reversed magnetization in their centers. While the double-twist is favorable in the center of a skyrmion, it gives rise to an excess of the energy density at the outskirt. Therefore, magnetic anisotropies are required to make skyrmions more favorable than the conical spiral in bulk materials. Using Monte Carlo simulations, we show that in magnetic nanowires unusual skyrmions with a doubly twisted core and a number of concentric helicoidal undulations (target-skyrmions) are thermodynamically stable even in absence of single-ion anisotropies. Such skyrmions are free of magnetic charges and carry a non-integer skyrmion charge s. This state competes with clusters of s = 1 skyrmions. For very small radii, the target-skyrmion transforms into a skyrmion with s < 1, that resembles the vortex-like state stabilized by surface-induced anisotropies.
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    Crystallization of Fe82Si2B16 and Fe82Si4B14 metallic glasses upon isothermal and non-isothermal annealing
    (Les Ulis : EDP Sciences, 2011) Shpak, A.P.; Il’inskii, A.G.; Marunyak, A.V.; Slukhovskyy, O.I.; Lepeeva, Yu. V.; Dekhtyar, A.; Kaban, I.; Mattern, N.; Eckert, J.
    Crystallization of Fe82Si2B16 and Fe82Si4B14 metallic glasses upon heat treatment has been studied. The amorphous ribbons have been isothermally annealed at different temperatures (673, 693, 733 and 743 K) and for various times (from 15 min to 78 hours). Phase compositions and the sequence of their appearance in dependence on the annealing temperature and time have been established.
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    Chirality selection in the vortex state of magnetic nanodisks with a screw dislocation
    (Les Ulis : EDP Sciences, 2014) Butenko, A.B.; Rößler, U.K.
    Structural defects in magnetic crystalline materials may locally change magnetic properties and can significantly influence the behavior of magnetic nanostructures. E.g., surface-induced Dzyaloshinskii-Moriya interactions can strongly affect vortex structures in magnetic nanodisks causing a chirality selection. Near lattice defects, the spin-orbit interactions induce local antisymmetric Dzyaloshinskii-Moriya exchange and cause effective anisotropies, which can result in spin canting. Broken inversion symmetry near a defect leads to locally chiral exchange. We present a phenomenological approach for dislocation-induced Dzyaloshinskii-Moriya couplings. As an example we investigate effects of a screw dislocation at the center of a magnetic nanodisk with a vortex state. By numerical calculations on vortex profiles we analyze equilibrium parameters of the vortex as functions of applied magnetic field and the material and geometrical parameters. It is proposed that magnetic nanodisks with defects provide a suitable experimental setting to study induced chirality by spin-orbit effects.
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    Microstructure evolution during annealing of an SPD- processed supersaturated Cu – 3 at.% Ag alloy
    (Bristol : IOP Publishing, 2014) Gubicza, J.; Hegedűs, Z.; Lábár, J.L.; Sarma, V.S.; Kauffmann, A.; Freudenberger, J.
    Supersaturated Cu-3 at.% Ag alloy was processed by rolling at liquid nitrogen temperature and subsequent annealing at 623 K up to 20 min. It was found that after annealing, an inhomogeneous solute atom distribution developed, since the Ag particles with small size and/or large specific interfacial energy were dissolved due to the Gibbs-Thomson effect. In the region where the solute concentration increased, a high dislocation density was retained in the Cu matrix even after annealing, while in the region where the Ag solute content did not increase, the dislocation density decreased by more than one order of magnitude. Therefore, in the cryorolled and annealed samples, heterogeneous microstructures were developed where both the dislocation density and the solute concentration varied considerably.
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    Data Science: History repeated? – The heritage of the Free and Open Source GIS community
    (München : European Geosciences Union, 2014) Löwe, Peter; Neteler, Markus
    [no abstract available]
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    Measuring soot particles from automotive exhaust emissions
    (Les Ulis : EDP Sciences, 2014) Andres, Hanspeter; Lüönd, Felix; Schlatter, Jürg; Auderset, Kevin; Jordan-Gerkens, Anke; Nowak, Andreas; Ebert, Volker; Buhr, Egbert; Klein, Tobias; Tuch, Thomas; Wiedensohler, Alfred; Mamakos, Athanasios; Riccobono, Francesco; Discher, Kai; Högström, Richard; Yli-Ojanperä, Jaakko; Quincey, Paul
    The European Metrology Research Programme participating countries and the European Union jointly fund a three year project to address the need of the automotive industry for a metrological sound base for exhaust measurements. The collaborative work on particle emissions involves five European National Metrology Institutes, the Tampere University of Technology, the Joint Research Centre for Energy and Transport and the Leibniz Institute for Tropospheric Research. On one hand, a particle number and size standard for soot particles is aimed for. Eventually this will allow the partners to provide accurate and comparable calibrations of measurement instruments for the type approval of Euro 5b and Euro 6 vehicles. Calibration aerosols of combustion particles, silver and graphite proof partially suitable. Yet, a consensus choice together with instrument manufactures is pending as the aerosol choice considerably affects the number concentration measurement. Furthermore, the consortium issued consistent requirements for novel measuring instruments foreseen to replace today’s opacimeters in regulatory periodic emission controls of soot and compared them with European legislative requirements. Four partners are conducting a metrological validation of prototype measurement instruments. The novel instruments base on light scattering, electrical, ionisation chamber and diffusion charging sensors and will be tested at low and high particle concentrations. Results shall allow manufacturers to further improve their instruments to comply with legal requirements.
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    Selective lateral germanium growth for local GeOI fabrication
    (Pennington, NJ : ECS, 2014) Yamamoto, Yuji; Schubert, Markus Andreas; Reich, Christian; Bernd Tillack, Bernd Tillack
    High quality local Germanium-on-oxide (GeOI) wafers are fabricated using selective lateral germanium (Ge) growth technique by a single wafer reduced pressure chemical vapor deposition system. Mesa structures of 300 nm thick epitaxial silicon (Si) interposed by SiO2 cap and buried oxide are prepared. HCl vapor phase etching of Si is performed prior to selective Ge growth to remove a part of the epitaxial Si to form cavity under the mesa. By following selective Ge growth, the cavity was filled. Cross section TEM shows dislocations of Ge which are located near Si / Ge interface only. By plan view TEM, it is shown that the dislocations in Ge which direct to SiO2 cap or to buried-oxide (BOX) are located near the interface of Si and Ge. The dislocations which run parallel to BOX are observed only in [110] and [1–10] direction resulting Ge grown toward [010] direction contains no dislocations. This mechanism is similar to aspect-ratio-trapping but here we are using a horizontal approach, which offers the option to remove the defective areas by standard structuring techniques. A root mean square of roughness of ∼0.2 nm is obtained after the SiO2 cap removal. Tensile strain in the Ge layer is observed due to higher thermal expansion coefficient of Ge compared to Si and SiO2.