Abstract: The present invention provides single body and composite sliding members comprising a resin composition containing 30-98% by weight of an aromatic polyether ketone, 1-35% by weight of polytetrafluoroethylene and 1-35% by weight of a metal fluoride, and single and composite sliding members comprising a resin composition containing 30-97% by weight of an aromatic polyether ketone, 1-35% by weight of polytetrafluoroethylene, 1-35% by weight of a metal fluoride and 1-20% by weight of potassium titanate fiber. These sliding members are remarkably improved in low frictional properties and wear resistance in comparison with the conventional products and therefore very useful.

Abstract: Ultrapure water are produced and used by subjecting deionized water, which has been obtained from a deionization step making use of an ion-exchange resin, successively to a sterilization treatment, an activated carbon treatment, an ion-exchange resin treatment and a permeable membrane treatment. The water is fed from each of the steps of the treatments after at least the sterilization tretment (inclusive) to the next step through first piping made of a crystalline polyether ether ketone resin having a recurring unit of the following formula: ##STR1## The thus-produced ultrapure water is then fed through second piping, which is also made of the crystalline polyether ether ketone resin, to and through a use system of the ultrapure water.