Abstract: An ignition distributor for an internal combustion engine with reduced electric discharge energy and suppressed radio noise generation comprises a rotor electrode capable of rotary motion and a plurality of stationary electrodes arranged substantially in a circle around the rotor electrode through an electric discharge clearance therebetween, where the rotor electrode is made of a sintered mixture comprising zirconium oxide and an electroconductive inorganic compound having a specific resistance of not more than 10.sup.6 .OMEGA.cm as main components. The sintered mixture can be ZrO.sub.2 and an oxide selected from ZnO, NiO and CoO; or ZrO.sub.2, aluminum oxide and an oxide selected from ZnO, CoO, Al.sub.2 TiO.sub.5 and SrTiO.sub.3 or a carbide selected from ZrC, TiC and TaC.

Abstract: An ignition distributor for an internal combustion engine with reduced electric discharge energy and suppressed radio noise generation comprises a rotor electrode capable of rotary motion and a plurality of stationary electrodes arranged substantially in a circle around the rotor electrode through an electric discharge clearance therebetween, where the rotor electrode is a sintered mixture comprising an aluminum compound and/or a boron compound and silicon carbide and having a specific resistance of 10 to 10.sup.6 .OMEGA.cm at room temperature.

Abstract: A laser beam reflection system for applying a laser beam to an area to be treated. The laser beam reflection system has a hollow head housing, first reflecting mirror means disposed in the rotary head housing and adapted to deflect the laser beam introduced into the rotary head housing away from the axis, second reflecting mirror means disposed in the rotary head housing and adapted to reflect the laser beam coming from the first reflecting mirror means to such a direction as to traverse the axis, and third reflecting mirror means disposed in the head housing movably in the direction traversing the axis and adapted to reflect and focus onto the area the laser beam coming from the second reflecting mirror means. The laser beam reflection system of the invention can be used for welding, surface treatment, heat treatment, cutting of various materials, and a light source of laser communication systems.