Three-Dimensional Positioning for Aircraft Using IoT Devices Equipped with a Fish-Eye Camera.

Radar is an important sensing technology for three-dimensional positioning of aircraft. This method requires detecting the response from the object to the signal transmitted from the antenna, but the accuracy becomes unstable due to effects such as obstruction and reflection from surrounding buildings at low altitudes near the antenna. Accordingly, there is a need for a ground-based positioning method with high accuracy.

Nef reaction with molecular oxygen in the absence of metal additives, and mechanistic insights.

A Nef reaction has been developed that is conducted under mildly basic conditions with molecular oxygen as an oxidant, without the need for metal additives. Whereas nitroalkanes are converted into ketones in good yield, nitroalkenes are transformed into α,β-unsaturated ketones in one-pot by double-bond isomerization followed by the oxygen-mediated Nef reaction. The reaction protocol is both mild and general, and tolerates acid- and base-labile functionality or protecting groups.