An electron emitting element is of a structure in which a semiconductor layer is formed between an upper electrode and a lower electrode, wherein an organic compound adsorption layer is formed on a semiconductor surface of the semiconductor layer by causing the organic compound to be adsorbed on the semiconductor surface. The system includes a turbomachine compressor that delivers charge air to the cathode side of a fuel cell module. The force input to the muscle can be provided by either the mass of the body to which the muscle is connected or by an external mass or resistance to motion. The medium may use dedicated wiring or existing service wiring in a residence or building, including LAN, telephone, AC power and CATV wiring. The method and system may by applied to electric arc furnace installations. As a result, an air flow area of the external air duct becomes substantially zero.