Gas alarms; gasometers measuring instruments; semiconductor gas sensors for measuring gas concentration; resistance measuring instruments; light-emitting diodes LED; solar batteries; fuel cells; separating membranes for fuel cell; printed circuit boards; electrodes for use in electrodeposition coating; light emitting elements of fluoride single crystals as components of neutron scintillation detectors; crystal sapphire wafers for integrated circuits; crystal aluminum nitride wafers for integrated circuits; single-crystal aluminum nitride substrates used for integrated circuits; semiconductor wafers; solar wafers