Abstract: A solid polymer electrolyte composite for an electrochemical reaction apparatus that possesses satisfactory ion conduction properties and has excellent mechanical strength and heat resistance, is provided. The solid polymer electrolyte composite is characterized in that a solid polymer electrolyte is contained in the continuous pores of an expanded porous polytetrafluoroethylene sheet which has continuous pores and in which the inner surfaces defining the pores are covered with a functional material such as a metal oxide. An electrochemical reaction apparatus containing an electrolyte, wherein said electrochemical reaction apparatus is characterized in that the aforementioned solid polymer electrolyte composite is used as this electrolyte is also provided.

Abstract: An ultrasonic sensor for testing tubes of a heat exchanger having a U-shaped tube bundle includes a probe head unit having an ultrasonic vibrator and two opposite ends. Two flexible hollow shafts are each connected to a respective one of the ends of the probe head unit. One of the hollow shafts is rotatably supported in a guide tip and the other of the hollow shafts is rotatably supported in a cylindrical sheath. An electric drive unit is connected to and fixed against torque relative to the other hollow shaft. The flexible hollow shafts have supports at predetermined axial intervals. A sealing body is connected to the cylindrical sheath for sealing off a flow of a fluid for coupling the ultrasonic vibrator and a pusher hose is also connected to the cylindrical sheath.