updated daily in real time. Test questions are organised by country of origin, with countries in alphabetical order. Identical questions that appeared in two or more countries on the same day posted only once (no duplicates). TheNEWlabel indicates most recently added questions. ...
Liu et al. [83] recently reported an ultra-sensitive sensor based on the use of nickel atoms attached to SnO2 nanorods (SAC-Ni/H-SnO2), which are oxygen-rich vacancy sensing materials. The sensor response was 48 toward 20 ppm of SO2 gas with a detection limit of 100 ppb. The sensing...