To effectively improve flame propagation speed utilizing active species in an internal combustion engine 10 that promotes combustion utilizing active species. The toner base particles having a specific circle-equivalent diameter as measured with a flow type particle image analyzer have a specific average circularity. The organosilicon compound is represented by the following general formula or. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc.