A system for defining a plurality of work zones within an otherwise open area. The thermal insert is made of a material having a thermal conductivity different from thermal conductivity of the material of the nozzle tip. 5 to 10% by weight with respect to the basic grease composition total amount of at least one additive selected from the group consisting of an organic molybdenum compound, an organic fatty acid compound or an derivative thereof, and an organic phosphorus compound is added is provided. A Miller compensation circuit receives the feedback signal and generates a second bias. At the time of reverse-direction operation, a second resonance circuit is formed by the capacitors and an inductor on the low voltage side.