Abstract: An organic light-emitting device containing both a compound represented by the following general formula (1) and a compound represented by the following general formula (2) has a high light emission efficiency. The rings a to c each are a benzene ring that can be optionally condensed, R1 and R2 each represent a substituted or unsubstituted aryl group, etc., four of R31 to R35 each are a substituted or unsubstituted carbazol-9-yl group, but all of these four are not the same, and the remaining one is a hydrogen atom, a cyano group, etc.

Abstract: A 1.5 .mu.m zero dispersion single mode optical fiber comprising a center core, a side core disposed on an outer side of the center core and having a refractive index lower than that of the center core, and a cladding portion disposed on an outer side of the side core. Each of the refractive indices of the center core and the side core has a step-like profile in the direction of the radius of the optical fiber. The bending loss is low. The mode field diameter can be increased without deteriorating the bending loss, and the splice loss can be reduced. The chromatic dispersion varies only to a small extent with respect to changes in the core diameter, so that the zero dispersion wavelength can be well controlled.

Abstract: A glass fiber for optical transmission comprising a glass fiber having provided thereon a first coating layer of a hardened resin and a second fluorine-containing resin layer formed by extrusion molding is disclosed. At least one of the first and second layers contains an adsorbable solid powder which is capable of adsorbing fluorine gas and/or hydrofluoric acid generated from the fluorine-containing resin during the extrusion molding. The glass fiber has an improved mechanical strength without adversely affecting transmission properties of the glass fiber.

Abstract: A method for producing an elongated optical fiber element is disclosed. The method envolves preparing two optical fiber elements by removing their outer coating layers to expose bare glass fiber portions. The glass fiber portions are melt-joint together. A material which is chemically compatible with the removed outered layer is then molded about the joined bare glass portions. A thermoplastic resin is then extruded continuously over the molded material in order to form a single elongated optical fiber element. The bonding method produces a structure which can withstand bending stress exerted on the coated optical fiber and prevent the concentration of any stress in the bonded area.

Abstract: This invention relates to a thermosensitive recording system whereby recording is performed by thermal means, more specifically a thermal recording method which is capable of transmitting or recording concavo-convex stereo information by using in combination a thermosensitive stereo recording material principally composed of thermo-expandable microspheres and a thermorecording medium having a thermoplastic ink coating layer.