Abstract: To produce a substrate for information recording media, a substrate consisting essentially of glass for information recording media is subjected to treatment for retarding the extract of the glass component from the substrate by contacting it with a molten salt that contains at least one of hydrogensulfates and pyrosulfates, while being subjected to additional treatment for retarding the crystallization of the molten salt. In the method, preferably, the glass component to be prevented from being extracted from the substrate is a group of alkali ions, and the treatment for retarding the crystallization of the molten salt is water addition treatment of any one of treatment of supplying water to the molten salt or treatment of compensating for water being away from the molten salt.

Abstract: A mold has a moling surface of a material containing silicon carbide and/or silicon nitride as a main component and a carbon thin film formed on the molding surface to prevent fusion sticking. A glass substance which has a sag point not higher than 565.degree. C. and a predetermined composition free from arsenic oxide is introduced into the mold. The glass substance is press-formed in a heated and softened condition into a glass optical element of high precision.

Abstract: In optical glass, P.sub.2 O.sub.5, TiO.sub.2, and Li.sub.2 O are included as essential components together with at least one divalent component, such as ZnO, MgO, and CaO. Such essential component are mixed together to accomplish a sag point not higher than 450.degree. C. and a specific gravity not heavier than 3.0. The optical glass also has water durability not greater than 0.3.

Abstract: A substrate for an information recording medium is prepared from a glass substance having a Young's modulus not smaller than 100 GPa and a liquidus temperature not higher than 1350.degree. C.

Abstract: A mold has a moling surface of a material containing silicon carbide and/or silicon nitride as a main component and a carbon thin film formed on the molding surface to prevent fusion sticking. A glass substance which has a sag point not higher than 565.degree. C. and a predetermined composition free from arsenic oxide is introduced into the mold. The glass substance is press-formed in a heated and softened condition into a glass optical element of high precision.

Abstract: An optical glass containing, as glass components,30.about.55 wt % of SiO.sub.2,5.about.30 wt % of B.sub.2 O.sub.3,the total amount of SiO.sub.2 and B.sub.2 O.sub.3 being 56.about.70 wt % and the SiO.sub.2 /B.sub.2 O.sub.3 weight ratio being 1.3.about.12.0,7.about.12 wt % of Li.sub.2 O, in which 7 wt % is excluded,0.about.5 wt % of Na.sub.2 O,0.about.5 wt % of K.sub.2 O,the total amount of Li.sub.2 O, Na.sub.2 O and K.sub.2 O being 7 to 12 wt % in which 7 wt % is excluded,10.about.30 wt % of BaO,0.about.10 wt % of MgO,0.about.20 wt % of CaO,0.about.20 wt % of SrO, and0.about.20 wt % of ZnOthe total amount of BaO, MgO, CaO, SrO and ZnO being 10.about.30 wt %, and the total amount of SiO.sub.2, B.sub.2 O.sub.3, Li.sub.2 O and BaO being at least 72 wt %.

Abstract: A canned motor pump has a pump section and a canned motor section connected thereto. A portion of the liquid from the pump section is diverted past a front bearing of the pump shaft and then back into the pump intake. Another portion of diverted liquid flows between the stator and the rotor in the canned motor section, and then past a rear shaft bearing, and then is returned to the pump intake. The resistance to flow of the liquid past the front bearing is made substantially greater than that past the rear bearing, so that the total flow diverted from the pump section for purpose of lubricating the front and rear bearings is substantially less than if the two resistances were equal. The resistance to liquid flow of the rear bearing can be reduced by providing it with straight channels parallel to the axis of shaft rotation, or helical channels in the direction the liquid tends to flow.