Abstract: There is provided a method of production of chlorine.sodium hydroxide capable of being operated stably and economically by preventing calcium from being deposited in an ion exchange membrane. The liquid retention layer 3 having a liquid retention amount per unit volume of the liquid retention layer of 0.10 g-H2O/cm3 or more and 0.80 g-H2O/cm3 or less is put between the ion exchange membrane 12 and the gas diffusion electrode 16. Calcium ions transferred through the ion exchange membrane 12 easily diffuse, thereby making it possible to suppress increase in an electrolytic voltage and drop in current efficiency generated by deposition of the calcium ions inside the ion exchange membrane 12.

Abstract: The invention provides a process for reactivating an active cathode attached to an electrolyzer, wherein a porous cathode that is attached to the electrolyzer by means of a flexible member and has a decreased electrode catalyst activity is provided thereon with a fresh active cathode equivalent to, or smaller in wire diameter or pore diameter than, the porous cathode by bending a mounting piece formed around said fresh active cathode without removal of a deteriorated electrode catalyst substance.

Abstract: A low temperature food drying process dries foods to the substantially absolutely dry state without deterioration by using a low humidity drying gas. This process comprises, in combination, the steps of (a) contacting a food with a low humidity drying gas having a dew point of -75.degree. to 0.degree. C., to dry the food at a temperature less than 60.degree. C., (b) passing the water-containing gas discharged from the step (a) through an adsorbing bed capable of adsorbing water preferentially to effect dehumidification of the discharged wet gas to a low humidity drying gas having a dew point of -75.degree. to 0.degree. C., (c) recycling the so regenerated low humidity gas having a dew point of -75.degree. to 0.degree. C. to the step (a) and using the regenerated gas for drying again, and (d) regenerating the adsorbing bed in which water has been adsorbed, whereby the food is dried to the substantially absolutely dry state.

Abstract: A process for concentrating or liquefying a specified component of a gaseous mixture, characterized by a combination of a step comprising passing a starting gaseous mixture containing a dilute gaseous substance to be selectively separated into one adsorbing layer of an adsorbing device consisting of a pair of adsorbing layers to allow it to adsorb the gaseous substance to be selectively separated, releasing the remainder of the gaseous mixture, and before the amount of the adsorbed gas in the adsorbing layer reaches saturation, switching the passing of the starting gaseous mixture over to the other adsorbing layer; a step comprising maintaining the pressure of the inside of the adsorbing layer which has adsorbed the gaseous substance lower than the pressure of the starting gaseous mixture fed, feeding a part of the gas released from the other adsorbing layer or an inert gas from outside the system to desorb the adsorbed gas, again passing the starting gaseous mixture after the end of desorption, and switching