The catalytic performance of core-shell platinum alloy nanoparticles is typically superior to that of pure platinum nanoparticles for the oxygen reduction reaction in fuel cell cathodes. Thorough understanding of core-shell formation is critical for atomic-scale design and control of the platinum shell, which is known to be the structural feature responsible for the enhancement. Here we reveal details of a counter-intuitive core-shell formation process in platinum-cobalt nanoparticles at elevated temperature under oxygen at atmospheric pressure, by using advanced in situ electron microscopy. Initial segregation of a thin platinum, rather than cobalt oxide, surface layer occurs concurrently with ordering of the intermetallic core, followed by the layer-by-layer growth of a platinum shell via Ostwald ripening during the oxygen annealing treatment. Calculations based on density functional theory demonstrate that this process follows an energetically favourable path. These findings are expected to be useful for the future design of structured platinum alloy nanocatalysts.

We investigate the production and detection prospects for the quintuplet heavy leptons at the LHC in the context of a new model which is proposed as a viable and testable solution to the neutrino mass problem. We classify the signals, carry out a full simulation on the signals and the relevant backgrounds at the 14 TeV LHC. After applying suitable kinematic cuts, the background events are substantially suppressed. The signals of the heavy leptons might be detected at the 14 TeV LHC.

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In this paper, we present the design and test results of LOCx2, a transmitter ASIC for the ATLAS Liquid Argon Calorimeter trigger upgrade. LOCx2 consists of two channels and each channel encodes ADC data with an overhead of 14.3% and transmits serial data at 5.12 Gbps with a latency of less than 27.2 ns. LOCx2 is fabricated with a commercial 0.25-µm Silicon-on-Sapphire CMOS technology and is packaged in a 100-pin QFN package. The power consumption of LOCx2 is about 843 mW.