Abstract: According to the present invention, there is provided a heterodyne interferometer comprising a laser oscilator, a frequency modulator which splits the laser beam into two beams and causes the beams to have different frequencies, a photodetector which composes both beams after at least one beam is reflected or transmitted by an object under test, and produces an interference signal from a composed laser beam, a frequency analyzer which reveals a Doppler frequency component of the interference signal, and an x-axis and y-axis fine movement command circuit and a photodetector positioning mechanism which detects the amplitude of the a.c.(alternating current) component of the interference signal and positions the photodetector so that the amplitude is maximum.

Abstract: An antifouling paint which containing as a vehicle a copolymer comprising units (a) and (b) ##STR1## wherein R.sub.1 represents a hydrogen atom or a methyl group, and R.sub.2, R.sub.3, and R.sub.4 each represents an alkyl group having from 1 to 8 carbon atoms or a phenyl group; ##STR2## wherein R.sub.5 and R.sub.6 each represents hydrogen atom or a methyl group, R.sub.7 represents an alkyl group having from 1 to 4 carbon atoms or an acyl group, and n is a positive number from 1 to 30, wherein the total weight of unit (b) per molecule is at least 5 wt %, and said paint further contains from 0 to 80 wt % of a non-polymeric antifouling agent.

Abstract: An antifouling paint is described, that contains as its essential components an antifoulant and a polymer of one or more of the monomers A represented by general formula (1) and/or copolymer composed of one or more of the monomers A and one or mroe vinyl polymerizable monomers B that are copolymerizable with said monomer A: ##STR1## wherein X is a hydrogen atom or a methyl group; n is an integer of 2 to 4; and m signifies the average degree of polymerization and is zero or a real number. The antifouling paint may contain a slipping agent as the third essential component to provide an even greater fouling resistance.

Abstract: An antifouling coating is described, that contains as its essential components a polymer of one or more of the monomers A represented by formula (1) and/or a copolymer composed of one or more of the monomers A and one or more monomers B that are radical-copolymerizable with said monomer A: ##STR1## wherein X is a hydrogen atom or a methyl group; n is an integer of 2 to 4; and m signifies the average degree of polymerization and ranges from 0 to 70.

Abstract: This invention relates to a hydrated adhesive gel using a product which is obtained by reacting an aqueous solution consisting essentially of protein having amino groups at the side chains thereof, a gelling retarder, and a hydrophilic tackifier with a N-hydroxyimidoester compound.

Abstract: A stretchable cloth adhesive tape useful for taping which comprises a tape support woven from warps and wefts and having stretchability in at least one direction and a pressure-sensitive adhesive layer formed on one surface of the support. The tape support is fixed in a state stretched at least 3% of its maximum elongation upon being stretched to a limit.

Abstract: Compositions including the dithiocarbamic acid derivative having ##STR1## group and at least one organo-tin compound selected from the group consisting of polymers having recurring units containing organo-tin, copolymers which are copolymerized with acryl compounds or vinyl compounds and organo-tin chemicals of ##STR2## are extremely effective for preventing the adhesion of marine organisms including marine microorganisms. This effect of the said composition is enlarged in the presence of copper compounds. R.sub.1, R.sub.2, and R.sub.3 represent an alkyl or phenyl, cycloalkyl group: Z; monovalent functional group containing sulphur or oxygen: and W; divalent functional group.

Abstract: A solar energy absorber consisting of a metallic copper or copper alloy substrate and a black to dark brown copper oxide coating on its surface. The copper oxide coating is formed by treating the surface of the substrate with an aqueous alkaline solution containing peroxodisulfuric acid or an inorganic peroxodisulfate. The solution may be activated by adding an oxidizing agent or applying ultraviolet or ultrasonic irradiation.