A method and system for transmitting messages in a communications network is disclosed. The conference type is associated with preset resources. The steam quality measuring device can be adapted to measure an impedance of a two-phase steam to determine steam quality. Once the valve assembly is releasably mounted to the handpiece, the physician using the endoscope can manually control the flow of irrigation fluid, and optionally suction, with the same hand as the one that supports the handpiece, thereby leaving the other hand of the physician free for surgical procedures. This construction can realize the provision of a method for the formation of an evenly oriented, high-quality crystalline silicon layer in a large area, and a crystalline silicon semiconductor device produced by this method.