| Popis: |
The charging and levitation of particles deposited on a surface were investigated. Glass beads, alumina particles, and ferrite particles with mass median diameters ranging from 61 to 104 µm were used as samples. UV light with a wavelength ranging from 250 to 400 nm was irradiated on the particle layers in an upward electric field. The particles that were positively charged by photoemission were levitated along the electric field. However, some particles immediately fell down. The charge of each particle was estimated by fitting the calculation result based on the equation of motion to the particle trajectory obtained by a high-speed camera. It was observed that the particle charge decreases with time due to the photoelectron layers and a negative-ion cloud. The particle charge was seen to increase with a decrease in the work function of the particles. |
