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    Roles of hydrogenation, annealing and field in the structure and magnetic entropy change of Tb-based bulk metallic glasses
    (New York : American Institute of Physics, 2013) Luo, Qiang; Schwarz, Björn; Mattern, Norbert; Shen, Jun; Eckert, Jürgen
    The reduction of open-volume regions in Tb-based metallic glass (MG) by annealing and hydrogen charging was found to rearrange the atomic structure and tune the magnetic behaviors. After crystallization, the magnetic structure and magnetic entropy change (MEC) alters due to the structural transformation, and a plateau-like-MEC behavior can be obtained. The hydrogen concentration after charging at 1mA/cm2 for 576 h reaches as high as 3290 w-ppm. The magnetization behavior and the MEC change due to the modification of the exchange interaction and the random magnetic anisotropy (RMA) upon hydrogenation. At low temperatures, irreversible positive MEC was obtained, which is related to the internal entropy production. The RMA-to-exchange ratio acts as a switch to control the irreversible entropy production channel and the reversible entropy transfer channel. The field dependence of the MEC is discussed in term of the competition among Zeeman energy, exchange interaction and RMA.
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    Pronounced ductility in CuZrAl ternary bulk metallic glass composites with optimized microstructure through melt adjustment
    (New York : American Institute of Physics, 2012) Liu, Zengqian; Li, Ran; Liu, Gang; Song, Kaikai; Pauly, Simon; Zhang, Tao; Eckert, Jürgen
    Microstructures and mechanical properties of as-cast Cu47.5Zr47.5Al5 bulk metallic glass composites are optimized by appropriate remelting treatment of master alloys. With increasing remelting time, the alloys exhibit homogenized size and distribution of in situ formed B2 CuZr crystals. Pronounced tensile ductility of ∼13.6% and work-hardening ability are obtained for the composite with optimized microstructure. The effect of remelting treatment is attributed to the suppressed heterogeneous nucleation and growth of the crystalline phase from undercooled liquid, which may originate from the dissolution of oxides and nitrides as well as from the micro-scale homogenization of the melt.
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    Stimuli‐responsive microjets with reconfigurable shape
    (Hoboken, NJ : Wiley, 2014) Magdanz, Veronika; Stoychev, Georgi; Ionov, Leonid; Sanchez, Samuel; Schmidt, Oliver.G.
    Flexible thermoresponsive polymeric microjets are formed by the self‐folding of polymeric layers containing a thin Pt film used as catalyst for self‐propulsion in solutions containing hydrogen peroxide. The flexible microjets can reversibly fold and unfold in an accurate manner by applying changes in temperature to the solution in which they are immersed. This effect allows microjets to rapidly start and stop multiple times by controlling the radius of curvature of the microjet. This work opens many possibilities in the field of artificial nanodevices, for fundamental studies on self‐propulsion at the microscale, and also for biorelated applications.
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    Correlation between the microstructures and the deformation mechanisms of CuZr-based bulk metallic glass composites
    (New York : American Institute of Physics, 2013) Song, K.K.; Pauly, S.; Sun, B.A; Tan, J.; Stoica, M.; Kühn, U.; Eckert, J.
    The variation of the transformation-mediated deformation behavior with microstructural changes in CuZr-based bulk metallic glass composites is investigated. With increasing crystalline volume fraction, the deformation mechanism gradually changes from a shear-banding dominated process as evidenced by a chaotic serrated flow behavior, to being governed by a martensitic transformation with a pronounced elastic-plastic stage, resulting in different plastic deformations evolving into a self-organized critical state characterized by the power-law distribution of shear avalanches. This is reflected in the stress-strain curves by a single-to-"double"-to-"triple"- double yielding transition and by different mechanical properties with different serrated flow characteristics, which are interpreted based on the microstructural evolutions and a fundamental energy theorem. Our results can assist in understanding deformation behaviors for high-performance metastable alloys.
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    Ceria/silicon carbide core–shell materials prepared by miniemulsion technique
    (Frankfurt, M. : Beilstein-Institut zur Förderung der Chemischen Wissenschaften, 2011) Borchardt, Lars; Oschatz, Martin; Frind, Robert; Kockrick, Emanuel; Lohe, Martin R.; Hauser, Christoph P.; Weiss, Clemens K.; Landfester, Katharina; Büchner, Bernd; Kaskel, Stefan
    For the first time we present the synthesis of CeO2/Si(O)C core–shell particles prepared by the miniemulsion technique. The Si(O)C core was obtained by means of a polycarbosilane precursor (SMP10), which was subsequently functionalized with ceria and pyrolyzed to the ceramic. The size of these particles could easily be adjusted by varying the surfactants and the surfactant concentration, or by the addition of comonomers. Hence particle sizes ranged from 100 to 1000 nm, tunable by the preparation conditions. All materials were characterized by photon cross correlation spectroscopy, scanning electron microscopy and elemental mapping investigations. Furthermore, first catalytic tests were carried out by temperature programmed oxidation (TPO) of methane, and the activity of this material in lowering the onset temperature of methane combustion by 262 K was documented.
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    EIN Portal der TIB (nicht nur) für Ingenieure, Naturwissenschaftler, Informatiker, Mathematiker und Architekten
    (Berlin : de Gruyter, 2014) Hohlfeld, Michael; Tobschall, Esther
    Der Beitrag beschreibt zunächst den Ist-Zustand des Zusammenspiels der von der TIB betriebenen Virtuellen Fachbibliotheken sowie dem Fachportal GetInfo. Er gibt einen Ausblick auf ein neues übergreifendes Webportal der TIB, in welchem GetInfo aufgehen wird und welches künftige Fachinformationsdienste der TIB in Form von erweiterten Facheinstiegen anbieten wird – unter Einbindung neuartiger Dienste für Fachcommunities sowie Fachausschnitten der medienspezifischen Portale der TIB.
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    Linked Heritage – ein europäisches Projekt
    (Berlin : de Gruyter, 2013) Mensing, Petra
    Das Hauptziel des EU-Projektes Linked Heritage1 war die Einspielung von 3 Millionen neuen Datensätzen in die Europeana. Die 38 Projektpartner kamen aus 20 europäischen Ländern plus Israel und Russland. Die Technische Informationsbibliothek (TIB) Hannover stellte für dieses Projekt Metadaten aus dem Kompetenzzentrum für nichttextuelle Materialen sowie aus dem Bereich Forschungsdaten bereit und war an drei der sieben Arbeitspakete2 beteiligt.
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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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    Deep Geothermal Energy for Lower Saxony (North Germany) – Combined Investigations of Geothermal Reservoir Characteristics
    (Amsterdam [u.a.] : Elsevier, 2014) Hahne, Barbara; Thomas, Rüdiger; Bruckman, Viktor J.; Hangx, Suzanne; Ask, Maria
    For the economic success of a geothermal project the hydraulic properties and temperature of the geothermal reservoir are crucial. New methodologies in seismics, geoelectrics and reservoir geology are tested within the frame of the collaborative research programme “Geothermal Energy and High-Performance Drilling” (gebo). Within nine geoscientific projects, tools were developed that help in the evaluation and interpretation of acquired data. Special emphasis is placed on the investigation of rock properties, on the development of early reservoir assessment even during drilling, and on the interaction between the drilling devices and the reservoir formation. The propagation of fractures and the transport of fluid and heat within the regional stress field are investigated using different approaches (field studies, seismic monitoring, multi-parameter modelling). Geologic structural models have been created for simulation of the local stress field and hydromechanical processes. Furthermore, a comprehensive dataset of hydrogeochemical environments was collected allowing characterisation and hydrogeochemical modelling of the reservoir.