Abstract: An intra-liquid optical measuring sensor is provided having an optical fiber including a cladding in the form of a hollow tube, and a core. The core includes both a solid portion, and a liquid portion at an end of the core, which latter portion serves as the sensing portion of the fiber. The liquid portion has a light transmitting liquid substance therein.

Abstract: An ocean environment monitoring system has a sensor inside a sensor chamber provided with a pair of electrodes at the inlet port of the chamber and a pump for introducing seawater inside the chamber. When a voyage is applied to the electrodes, seawater is electrolyzed to produce an antifouling substance. By operating the pump and a power supply unit for the electrodes intermittently, the antifouling substance is supplied to the filter, the interior of the sensor chamber and the sensor. The monitoring system is compact, consumes a reduced amount of electric power, performs measurement substantially without producing errors for a prolonged period of time, and effectively prevents settlement of marine organisms onto the sensor.

Abstract: The invention relates to the removal of detrimental metal ions represented by Cu ion from a hydrofluoric acid solution for use in the manufacturing of semiconductor devices to clean silicon wafer surfaces. The acid solution is brought into contact with silicon granules which are used for the adsorption of the detrimental metal ions. To enhance the adsorption power and the rate of adsorption, the silicon granules are treated in advance to deposit a metal which is lower in ionization tendency than silicon on the surface of each silicon granule so as to partly cover the silicon granule surface by the deposited metal. Particularly Au or Ag is suitable as the metal deposited on the silicon granules.