Abstract: A pressure sensor has a stem in which a pressure introduction hole into which a pressure medium is introduced and a diaphragm deformable according to the pressure of the pressure medium are formed, and a strain detecting element which is arranged on the diaphragm via an insulating film and being configured to output a detection signal according to the deformation of the diaphragm. The strain detecting element is configured to have a portion made of polysilicon. A low doping layer having a higher electrical resistivity than polysilicon and a higher crystallinity than the insulating film is arranged between the insulating film and the strain detecting element.

Abstract: Gas turbine system is constructed such that no fuel gas compressor is used and a turbine is operated at low temperature so that a life of the system is elongated and the safety is enhanced. Air compressed at a compressor (11) of about 200° C. enters a heat exchanger (12) to be heated by combustion gas to about 760 to 900° C. to enter the turbine (13) and to work to rotate a generator (15). Exhaust air of the turbine (13) of which temperature is lowered to about 500 to 750° C. is supplied into a combustor (14) for fuel combustion to generate high temperature combustion gas of about 800 to 950° C. This combustion gas enters the heat exchanger (12) to heat the air from the compressor (11). The air is heated by the high temperature combustion gas with no fuel gas compressor being used and the turbine is operated by the lower temperature air as compared with a conventional case. Hence, the system is made less expensive, the life is elongated and the safety is enhanced.