2,940 research outputs found

    Interaction between crofer 22 APU current collector and LSCF cathode contacting layer under cell operation

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    In this work the oxidation of Crofer 22 APU and its interaction with La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) applied as contacting layer have been investigated in air at 750\ub0C under a current load of 0.5 Acm-2 with the aim to reproduce as close as possible the interconnect interface in real operating conditions. The effects of such interaction and of the pre-oxidation treatment have been studied by means of ASR measurement and post-experiment characterizations. The behavior of such samples has been compared with the results on a working Crofer 22 APU bipolar plate tested as cathode current collector of an anode-supported cell reproducing the stack cathode compartment conditions

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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