Abstract: A control method for the projection optical system of a projection exposure apparatus used in the fabrication of LSIs. The amount of energy incident to the projection optical system during each unit time is maintained constant at all times including each projection and the intervals between the projection operations. This has the effect of cancelling any error in the projected image, particularly any variation of the magnification error with time due to any variation of the optical performance of the projection optical system caused by the illuminating energy.

Abstract: Water-soluble copolymers of 10-30 mole % of (meth)acrylic acids, 1-10 mole % of sulfo group-containing (meth)acrylic monomers and 60-89 mole % of (meth)acrylamides, which copolymers have inherent viscosity of 10-25 dl/g, have improved mechanical shear stability and improved viscosity-increasing property even under contact with water containing impurities and are used for enhanced oil recovery.

Abstract: A sizing composition comprises a carboxylic acid anhydride and a polyoxyalkylene nonionic surfactant blocked with a lower alkyl, acyl or carbamoyl group and/or an alkaline earth metal salt of a sulphur-containing anionic surfactant. The composition can be easily emulsified to form an aqueous emulsion useful for paper sizing.

Abstract: A device for providing an illumination of an object includes first and second optical integrators disposed on an optical axis in spaced-apart relationship. Light rays emitted from a point light source formed by an elliptical reflector mirror having a light-emitting source are incident on the first optical integrator, which forms a plurality of secondary images of the point light source. The second optical integrator receives luminous fluxes emitted from the secondary light source images to form a multiplicity of secondary images of the secondary light source images formed by the first optical integrator. Luminous fluxes from the secondary images formed by the second optical integrator are superimposed by a condenser lens on the object for illuminating the latter with light beams of uniform intensity.

Abstract: An automatic focus adjusting device comprises an optical system for forming the image of a sample to be examined at the image formation point, a first image sensor disposed at a first position for receiving the light image of the sample and converting it into an electrical signal, a second image sensor disposed at a second position for receiving the light image of the sample and converting it into an electrical signal, signal processing systems for processing the signals from the first and second image sensors, and a servo device for controlling the vertical position of the sample relative to the image forming optical system.

Abstract: A water-in-oil polymer emulsion having an excellent fluidity can be obtained by a process which comprises dispersing an aqueous solution of at least one (meth)acrylic monomer containing a quaternary ammonium salt or a tertiary amine salt in a hydrophobic organic liquid in the presence of an oil-in-water type nonionic surfactant, and heating the resulting dispersion to a temperature of at least 40.degree. C. to polymerize the monomer mixture.

Abstract: Sealing apparatus used for sealing the gap between flanges which comprises an O-ring engaged with a circular groove formed in the coupling surface of one of the flanges and two backup rings engaged with the groove and the O-ring, each of the backup rings having an inclined surface to be axially urged by the O-ring whereby the upper backup ring is moved according to the gap to close it.