Article is a study analyzing the global perceptions and perspectives towards COVID-19 vaccination using a worldwide Twitter dataset, natural language processing, and machine learning.

Article argues that traditional acidic oxygen evolution reaction (OER) electrocatalysts are more prone to be oxidized and corroded as results of unstable carrier structures and variable electronic states of active species, so a high-performing biochar aerogel (BA) based electrocatalyst was realistically designed and synthetized via joint utilization of the terrestrial lignin and seaweed polysaccharide as carbon sources. This work puts forward a novel and effective strategy towards the enhancement of the acidic OER process by rational regulations of the BA and the coupling effect in micro-interface.

Article proposes a gap waveguide (GW)-based 4 × 4 dual-band, dual-circularly polarized antenna array. The combination of dual-band, dual-circularly polarized capability, high gain, high efficiency, lightweight, low cost and compact size renders the proposed design a potential candidate for commercial millimeter wave communication applications.