Entertainment system main body is connected via a relay device to an i-mode portable telephone system using a controller connection connector or external memory insertion connector provided on entertainment system main body. The system employs an injected broadband AC signal to produce an associated response signal. Said optically invisible marking image is characterized by the possibility of visualization through the establishment of a meta-stable environment of water vapor in the area of the MS of the object in the process of cooling VO. When the transistors provide a single transistor, an effective channel width of the single transistor is variable in accordance with the number of the first transistors under the active state. An interrupt handler of the primary node, in response to generation of the interrupt, then invokes code at the primary node to handle the event occurring at the remote node. Once the state of the natural gas has been changed from liquid to gas or regasified, the natural gas is conveyed to another location in a gaseous state.