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Abstract Novel neutrino self-interaction can open up viable parameter space for the relic abundance of sterile-neutrino dark matter (S ν DM). In this work, we constrain the relic target using core-collapse supernova which features the same fundamental process and a similar environment to the early universe era when S ν DM is dominantly produced. We present a detailed calculation of the effects of a massive scalar mediated neutrino self-interaction on the supernova cooling rate, including the derivation of the thermal potential in the presence of non-zero chemical potentials from plasma species. Our results demonstrate that the supernova cooling argument can cover the neutrino self-interaction parameter space that complements terrestrial and cosmological probes. 

A nanoporous Ni/NiO/C nanocomposite with a gyroid nanostructure was fabricated by using a nanoporous polymer with gyroid nanochannels as a template. The polymer template was obtained from the self-assembly of a degradable block copolymer, polystyrene- b -poly( l -lactide) (PS-PLLA), followed by the hydrolysis of PLLA blocks. Templated electroless plating followed by calcination was performed to create a precisely controlled Ni/NiO gyroid nanostructure. After carbon coating, a well-interconnected nanoporous gyroid Ni/NiO/C nanocomposite can be successfully fabricated. Benefiting from the well-interconnected nanoporous structure with ultrafine transition metal oxide and uniform carbon coating, the gyroid nanoporous Ni/NiO/C nanocomposite electrodes exhibited high specific capacities at various rates (1240 mA h g −1 at 0.2 A g −1 , 902 mA h g −1 at 2 A g −1 and 424 mA h g −1 at 10 A g −1 ) and excellent cyclability (809 mA h g −1 at 1 A g −1 after 1000 cycles, average coulombic efficiency 99.86%). This research demonstrates a universal approach for constructing a nanostructured electrode with explicitly controlled block copolymer phase separation.