Figure 1: Schematic illustration of the magnetic-induced directional motion for gaseous substances in UV ozonation.
From: Patterning Graphene Film by Magnetic-assisted UV Ozonation

Yellow arrows represent UV irradiation at λ = 172 nm; Purple arrows represent the magnetic field ; Orange arrows represent the magnetic force
for paramagnetic (O, O2) and diamagnetic (O3, CO, CO2, N2) substances.