Abstract: An injection flame burner in which temperature of the generated flame itself can be sustained around the flame. A plurality of double structure injection nozzles each consisting of an outer tube and an inner tube provided coaxially with the outer tube, are arranged such that hydrogen gas is ejected from one of the outer tubes and the inner tubes and oxygen gas is ejected from the other tubes, and the injection port of each injection nozzle is located on the injection surface. Each injection nozzle includes at least one main injection nozzle having an inner tube formed to spread toward the injection surface side, another sub-injection nozzle arranged around the main injection nozzle, wherein gas is injected from the inner tube of the main injection nozzle under a higher pressure state as compared with gas injected from the sub-injection nozzle.

Abstract: A method and system for distributing a key is provided which make use of effects of noise caused at the time of transmitting or receiving a signal to send a key. A transmission signal is amplified at a plurality of stages while the relationship between the transmission signal and noise is being maintained at a level enough to satisfy predetermined criteria for security measures against eavesdropping activities, and the key is sent over a long distance. The aforementioned operation makes it possible to transmit or distribute a key over a long distance while maintaining the relationship between the transmission signal and noise at a level enough to satisfy the criteria for security measures against eavesdropping activities.

Abstract: An optical receiver includes a squeezer for changing the quantum state of a signal lightwave to a squeezed state, a slave laser put in an injection locking state by the signal lightwave outputted from the squeezer, and an optical homodyne detector for carrying out optical homodyne detection for the signal lightwave outputted from the slave laser.