183 research outputs found

    Facetten eines MissverstĂ€ndnisses: Ein Debattenbeitrag zum Terminus „Diamond Open Access“

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    In der letzten Zeit nehmen wir eine zunehmende Verwendung der Bezeichnung „Diamond Open Access“ (im Folgenden „Diamond OA“) in der Bibliothekswelt wahr. Dabei fĂ€llt auf, dass mit „Diamond OA“ unterschiedliche Konzepte und Sachverhalte bezeichnet werden, die nicht immer dasselbe meinen. Der folgende Beitrag lĂ€dt zu einer Auseinandersetzung mit dem Terminus „Diamond OA“ ein. Wie wir darstellen werden, sehen wir die Verwendung der Bezeichnung mit Skepsis: Das liegt vor allem an den vagen und unterschiedlichen Definitionen, von denen sich manche sogar gegenseitig widersprechen. Dennoch scheint sich die Bezeichnung zunehmend zu institutionalisieren – es werden sogar Fördergelder fĂŒr „Diamond OA“-Projekte bereitgestellt, was eine KlĂ€rung des Terminus umso dringlicher macht. Wir möchten ein Bewusstsein fĂŒr die unscharfe Verwendung der Bezeichnung wecken und anregen, „Diamond OA“ prĂ€ziser zu definieren, um dadurch zielgerichteter ĂŒber das jeweilige Anliegen diskutieren zu können. Um es vorweg deutlich zu sagen: Die verschiedenen Konzepte, die mit „Diamond OA“ beschrieben werden – Author Processing Charges (APC)-freies OA und seine Finanzierung, Publizieren und Publikationsinfrastrukturen in den HĂ€nden der Wissenschaft – finden wir ĂŒberaus unterstĂŒtzenswert. Unsere Kritik richtet sich explizit nicht gegen solche Publikationsmodelle. Auch begrĂŒĂŸen wir nachdrĂŒcklich das verstĂ€rkte Interesse in Bibliothekswelt und Forschungsförderung an Open-Access-GeschĂ€ftsmodellen und Infrastrukturen des wissenschaftlichen Publizierens. Die Bezeichnung „Diamond OA“ ist unserer Ansicht jedoch nur bedingt dazu geeignet, Klarheit ĂŒber die zu erreichenden Ziele zu schaffen, insbesondere wenn sie mit ebenso mehrdeutigen Bezeichnungen wie „community-owned“ oder „scholar-led“ kombiniert wird

    The effect of dopants on magnetic properties of the ordered FE 65-XAL35-YMX,Y (MX,Y=GA,B,V; X,Y=5,10) alloys

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    The results of X-ray diffraction, complex in-field (up to 9 T) and temperature (5-300 K) Mössbauer and magnetometric studies of the ordered Fe65Al35-xMx (M=Ga, B; x=0,5,10) and Fe 65-xVxAl35(x=5,10) alloys are presented. Analysis of the magnetometry studies shows that the systems Fe 65Al35 H Fe65Al35-xGax (x=5, 10) are characterized by two different magnetic states with essentially distinguishing hysteresis loops and AC susceptibility values. The temperature and external magnetic field values inducing the transition from one magnetic state to another are higher in the Ga-doped alloys than in the reference Fe 65Al35 alloy. The boron addition transforms the magnetic state of the initial alloy Fe65Al35 into a ferromagnetic one exhibiting high magnetic characteristics. Substitution of V for Fe in the ternary alloys Fe65-xVxAl35 results in reduction of magnetic characteristics and collapsing of 57Fe hyperfine magnetic filed. © (2012) Trans Tech Publications

    179^{179}Ta(n, Îł) cross-section measurement and the astrophysical origin of the 180^{180}Ta isotope

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    180m^{180m}Ta is nature\u27s rarest (quasi) stable isotope and its astrophysical origin is an open question. A possible production site of this isotope is the slow neutron capture process in asymptotic giant branch stars, where it can be produced via neutron capture reactions on unstable 179^{179}Ta. We report a new measurement of the 179^{179}Ta(n,Îł) 180^{180}Ta cross section at thermal-neutron energies via the activation technique. Our results for the thermal and resonance-integral cross sections are 952±57 and 2013±148 b, respectively. The thermal cross section is in good agreement with the only previous measurement [Phys. Rev. C 60, 025802 (1999)], while the resonance integral is different by a factor of ≈1.7. While neutron energies in this work are smaller than the energies in a stellar environment, our results may lead to improvements in theoretical predictions of the stellar cross section

    Coexistence of the spin-density-wave and superconductivity in the (Ba,K)Fe2As2

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    The relation between the spin-density-wave (SDW) and superconducting order is a central topic in current research on the FeAs-based high Tc superconductors. Conflicting results exist in the LaFeAs(O,F)-class of materials, for which whether the SDW and superconductivity are mutually exclusive or they can coexist has not been settled. Here we show that for the (Ba,K)Fe2As2 system, the SDW and superconductivity can coexist in an extended range of compositions. The availability of single crystalline samples and high value of the energy gaps would make the materials a model system to investigate the high Tc ferropnictide superconductivity.Comment: 4 pages, 5 figure

    Indirect measurements of neutron-induced reaction cross sections at storage rings

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    Neutron-induced reaction cross sections of unstable nuclei are essential for understanding the synthesis of heavy elements in stars. However, their measurement is very difficult due to the radioactivity of the targets involved. We propose to circumvent this problem by using for the first time the surrogate reaction method in inverse kinematics at heavy-ion storage rings. In this contribution, we describe the developments we have done to perform surrogate-reaction studies at the storage rings of GSI/FAIR. In particular, we present the first results of the proof of principle experiment, which we conducted recently at the Experimental Storage Ring (ESR)

    Storage, Accumulation and Deceleration of Secondary Beams for Nuclear Astrophysics

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    Low-energy investigations on rare ion beams are often limited by the available intensity and purity of the ion species in focus. Here, we present the first application of a technique that combines in-flight production at relativistic energies with subsequent secondary beam storage, accumulation and finally deceleration to the energy of interest. Using the FRS and ESR facilities at GSI, this scheme was pioneered to provide a secondary beam of 118^{118}Te52+^{52+} for the measurement of nuclear proton-capture at energies of 6 and 7 MeV/u. The technique provided stored beam intensities of about 10610^6 ions at high purity and brilliance, representing a major step towards low-energy nuclear physics studies using rare ion beams
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