Abstract: The present invention provides an oscillation measuring method comprising: a laser beam emission step S1 for emitting a laser beam to an object to be measured; a return beam reception step S2 for receiving a return beam reflected by the object and having an object Doppler frequency according to a velocity of the object; a self-mixing step S3 for mixing the return beam having the Doppler frequency with another beam emitted upon reception of the return beam and generating a self-frequency according to a resonator change during a time from the emission to the reception of the return beam, so as to generate a beat wave containing the object Doppler frequency superposed with the self-frequency; and an oscillation information output step S4 for outputting the beat wave or information obtained from signal processing of the beat wave as the object oscillation information. This enables to measure a fine oscillation of an object to be measured.

Abstract: The present invention provides an oscillation measuring method comprising: a laser beam emission step S1 for emitting a laser beam to an object to be measured; a return beam reception step S2 for receiving a return beam reflected by the object and having an object Doppler frequency according to a velocity of the object; a self-mixing step S3 for mixing the return beam having the Doppler frequency with another beam emitted upon reception of the return beam and generating a self-frequency according to a resonator change during a time from the emission to the reception of the return beam, so as to generate a beat wave containing the object Doppler frequency superposed with the self-frequency; and an oscillation information output step S4 for outputting the beat wave or information obtained from signal processing of the beat wave as the object oscillation information. This enables to measure a fine oscillation of an object to be measured.

Abstract: A noble solid electrolyte fuel cell includes a generating layer (5), an interconnector layer (9), and a support layer (10) disposed between the generating and interconnector layers. The interconnector layer comprises a fuel electrode (6), an interconnector material (7) and an oxygen electrode (8). The support layer (10) forms a fuel passage and an oxidizer passage, and supporting rods (15, 102) for gas sealing are disposed at both ends of the support layer. A sealing film (110) is cemented to the contact surfaces of the supporting rods (15, 102) between the generating layer and the interconnector layer, and this sealing film becomes soft or half melted during the operation of the fuel cell. This construction provides improved cell performances due to better sealing of gases even under large temperature differences. The use of finer particles near the surface of the solid electrolyte only is also disclosed.

Abstract: Adhesives prepared by dissolving polyvinyl alcohol, a filler and a water-soluble boron compound in water are described. These adhesives are "cold-set" adhesives which are liquid at a temperature of 60.degree. C. or more, but lose their fluidity to gelatinize on cooling at a temperature higher than 20.degree. C., they are very useful for a cold corrugation system.

Abstract: A three-layer structure optical fiber comprises a first transparent dielectric core layer having a relatively high refractive index, a second transparent dielectric intermediate layer having a relatively low refractive index and a third transparent dielectric cladding layer having an intermediate refractive index wherein the parameter of the optical fiber is determined as follows: ##EQU1## where B is the bandwidth of the signal to be transmitted, z is the transmission distance, C is the velocity of light in vacuum, .eta.o is the refractive index of the core layer, q is the ratio of refractive indices between the core layer and second layer, V = normalized frequency, ##EQU2## p is the ratio of refractive index between the core layer and the third layer, and U.sub.11 =2,405.

Abstract: In order to expand the product between the transmission length and the transmission bandwidth of an optical fiber for use in the optical communication and to facilitate the connection between the optical fibers, the optical fiber is made of transparent materials of three concentric layers of a core whose refractive index gradually decreases in the radial direction from the center, an intermediate layer which has a uniform refractive index lower than the varying refractive index of the core, and a cladding which has a uniform refractive index substantially equal to the lowest refractive index of the core.

Abstract: In order to make the transmission loss of the lowest order leaky mode over the transmission length 10dB or more, an optical fiber for optical transmission is constructed of a cladding layer whose refractive index is constant, an intermediate layer which has a constant refractive index lower than the refractive index of the cladding layer, and a core whose refractive index is continuously varied so as to be the highest at the central part and to be substantially equal to that of the cladding layer at the peripheral part, and the thickness of the intermediate layer is 0.1-1 times the radius of the core.

Abstract: Adhesive compositions which comprise polyvinyl alcohol having about a 30 to about a 60 mol% residual acetate group content which are produced by dissolving polyvinyl acetate having a degree of polymerization (p) of about 60 to about 200 in methanol, the amount of the methanol ranging from about the stoichiometric amount necessary for obtaining polyvinyl alcohol having the desired degree of hydrolysis to about 2 times as much as the above-defined stoichiometric amount and carrying out alkaline hydrolysis and a process for preparing the same. If desired, a suitable amount of a plasticizer and/or an ethylene-vinyl acetate copolymer can be added thereto.Water soluble or water dispersible hot-melt adhesive compositions containing such polyvinyl alcohol as a main ingredient are suitable for paper making such as bookbinding or paper bag making, etc., in which products are obtained that can be reclaimed after use.

Abstract: Apparatus for producing an optical fiber including apparatus for heating an optical fiber preform, apparatus for drawing out the optical fiber from the optical fiber preform whose fore end part has been made molten by the heating and for taking up the drawn out fiber, apparatus for causing a gas to flow along the outer peripheral surface of the molten part of the optical fiber preform, and apparatus for controlling both the flow rate of the gas and the drawing-out speed of the optical fiber according to a fluctuation in the diameter of the optical fiber.

Abstract: For drawing an optical fiber from an optical fiber preform there are provided means for heating an optical fiber preform, means for pulling out an optical fiber from the optical fiber preform whose fore end part has been fused by heating, and means for causing gas to flow along the outer peripheral surface of the fused part of the optical fiber preform. By further controlling the flow rate of the gas and/or the pulling-out velocity for the optical fiber according to fluctuations in the fiber diameter of the optical fiber, an optical fiber of uniform fiber diameter is easily provided.