Abstract: There is provided a method for producing colorants which can exhibit excellent color development even in a small amount and are low in thixotropy. The constituent feature of the present invention comprises: enhancing the molecular extinction coefficient of the coloring matter substance by ion exchanging method, to afford a room for increasing B (resin) of P/B; then a composition is designed and employed to enhance the effect increasing the polar group concentration which is a role of resin and the quality of the effect; it thus becomes possible to achieve the limit value of the molecular extinction coefficient as much as possible and to eliminate the factors adversely affecting the present process.

Abstract: A data recording device for recording data on an optical disc by irradiating a laser pulse on the optical disc while controlling rotation of the optical disc at a constant angular velocity. The device includes a laser condition varying unit that changes a peak value of the laser pulse in accordance with a value relating to a linear velocity of the optical disc at a position at which the laser pulse is irradiated.

Abstract: There is provided a method for producing colorants which can exhibit excellent color development even in a small amount and are low in thixotropy.

Abstract: A data recording device for recording data on an optical disc by irradiating a laser pulse on the optical disc while controlling rotation of the optical disc at a constant angular velocity. The device includes a laser condition varying unit that changes a peak value of the laser pulse in accordance with a value relating to a linear velocity of the optical disc at a position at which the laser pulse is irradiated.

Abstract: Carbon fiber precursors from pitchy materials are processed by applying thereonto an aqueous emulsion containing a single silicone oil or a mixture of silicone oils selected from polydimethyl siloxane, phenyl modified polydimethyl siloxane and aminoalkyl modified polydimethyl siloxane and having kinetic viscosity at 25.degree. C. of 100 centistokes or less, an alkanolamine salt of aliphatic monocarboxylic acid with 8-18 carbon atoms, and one or more non-ionic surfactants selected from polyoxyethylene alkylphenylethers polyoxyethylene alkylates, polyoxyethylene alkylaminoethers, and aliphatic monocarboxylic alkanolamides such that 0.1-5 wt % by solid deposit on fiber from this aqueous emulsion apply to the pitch fibers during any of the processes from the spinning and to the oxidizing.