A nonvolatile storage element of a single-layer gate type structure is arranged so that a floating gate is formed of a conductive layer which partly overlaps with a control gate, formed of a diffused layer, and is provided with a barrier layer covering a part of or the whole surface of the floating gate. They are suitable for preparing calcium phosphate cement pastes which cure at room andor body temperature. The transmission unit uses a transmission rate to select a normal packet or a retransmission packet. The nitrogen passes through the catalytic reactor without reacting with the hydrogen, the oxygen, or the water.