Abstract: A bonded structure includes a first member, a second member, an adhesive that bonds the first member and the second member together, and an optical fiber sandwiched between the first member and the second member. When pressure is applied to the optical fiber only from a predetermined direction, the sectional shape of the optical fiber changes to an elliptical shape, so that birefringence occurs, whereby the shape of the light spectrum changes so as to have multiple peaks. The optical fiber is used as a sensor for detecting the bonding condition between the first member and the second member based on the birefringence.

Abstract: A combustor includes a pilot fuel nozzle and a plurality of main premixing nozzles arranged therearound for forming a premixture of air and fuel supplied from a main fuel nozzle, and is improved so as not to cause vibratory combustion. Pilot fuel nozzle unit 104 comprises a plurality of pilot fuel nozzles 103. A plurality of main premixing nozzles 102 are disposed on a coaxial circumference of the pilot fuel nozzle unit 104. The pilot fuel nozzles 103 are arranged irregularly in a circumferential direction of the pilot fuel nozzle unit 104, so as to form portion 105 where there is no pilot fuel nozzle 103. Premature in the main premixing nozzles 102 positioned corresponding to the pilot fuel nozzle 103 burns with comparatively short flames. Premature in the main premixing nozzles 102 positioned corresponding to the portion 105 of no pilot fuel nozzle 103 burns with long flames because of flames spreading from adjacent main fuel nozzles.