Abstract: The present invention is aimed to produce a cured product having excellent photochromism which can be easily polymerized in a short period of time. The cured product is obtained by photopolymerizing a polymerizable composition comprising (A) a radical polymerizable monomer, (B) an ultraviolet polymerization initiator having the main absorption at an ultraviolet range and a molar absorption coefficient for light having a wavelength of 400 nm of 150 liter/(mol·cm) or more, (C) a thermopolymerization initiator such as a thermopolymerization initiator having a temperature at which the half-life thereof is 10 hours of 60° C. or more and (D) a photochromic compound by irradiating activation energy rays having a wavelength of 400 nm or more as the main emission spectrum, preferably to ensure that the temperature of the cured product does not exceed 50° C., and further thermopolymerizing the composition by heating.

Abstract: A photochromic compound which by itself develops a color tone of a neutral tint, exhibits a large fading rate and offers a good photochromic light resistance.

Abstract: A 1-substituted-2-diphenylphosphinonaphthalene represented by formula (I): ##STR1## wherein at least one of R.sup.1, R.sup.2, R.sup.3, and R.sup.4, which may be the same or different, represents a lower alkyl group having 1 to 4 carbon atoms which may be substituted with an alkoxy group, a phenyl group or --OR.sup.6 (wherein R.sup.6 represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms or an alcohol-protective group), and the rest of them represent a hydrogen atom; A represents a single bond or a methylene group; and R.sup.5 represents a substituted or unsubstituted phenyl group; and a transition metal complex comprising the 1-substituted-2-diphenylphosphinonaphthalene as a ligand. The transition metal complex is useful as a catalyst in asymmetric synthesis.

Abstract: A method of switching from one synchronizing signal source to another in a synchronous data communication network in which a plurality of stations are connected to each other via lines and A plurality of synchronizing signal sources are provided inside or outside the stations; the when a failure occurs a synchronizing signal source is replaced by another synchronizing signal source in correspondence to the failure so that the data communication may be continued. Specifically, flag bit data, indicating whether or not the synchronizing signal transmitted via the line is available, are set in the signal including the synchronizing signal and transmitted via the line. When a failure occurs in any of the plurality of synchronizing signal sources, a table provided in each station and specifying the order of priority for selection of a synchronizing signal source is referred to, and a synchronizing signal source is selected for each station in accordance with said flag bit data.

Abstract: In a first apparatus, transmission signals are inverted in a sending side and are restored in a receiving side in one direction of two-way communication, and transmission signals are not inverted in another direction, to thereby distinguish a signal reflected at a fault point of an optical fiber from normal receiving signals from the station of the other party. In a loopback test, an inverter provided in the receiving side of the former direction is bypassed and an inverter is inserted in the receiving side of the latter direction. In a second apparatus, overhead information for identifying stations is added in a sending side. In a receiving side, the overhead is extracted. The extracted overhead is compared with an identifier of the station of the other party in a normal operation and is compared with an identifier of the station itself in a loopback test.