摘要:
The present invention provides a method of manufacturing fine ceramic particles, comprising the steps of supplying a raw gas or raw liquid droplets to a reaction space provided in an annular portion between the stationary outer cylinder and the rotatable inner cylinder of a double coaxial cylindrical reactor, and subjecting the raw gas or raw liquid droplets to a reaction in the reaction space while rotating the inner cylinder. The present invention also provides an apparatus used to practice this method. A Taylor vortex is employed as a fluid flow in a CVD reaction zone or a thermal decomposition reaction zone. Consequently, the temperature distribution in the vortex, the concentration distribution of the reaction gas or concentration distribution in terms of the number of liquid droplets, and the residence time of formed fine particles confined in the vortex become uniform, and uniform fine ceramic particles can be obtained with a high yield.
摘要:
Ultraviolet shielding composite fine particles having transparency in a visible light region, comprising (a) matrix particles comprising an aggregate of primary particles having an average particle diameter of from 0.001 to 0.3 νm, said aggregate being formed while retaining the shapes of the primary particles; and (b) daughter particles having an average particle diameter of from 0.001 to 0.1 νm, said daughter particles being dispersed in and supported by said matrix particles, wherein said daughter particles have a smaller band gap energy than that of particles constituting said matrix particles, and possess capability of absorbing ultraviolet light. The composite fine particles are produced by preparing a liquid mixture containing a mixture comprising starting materials for matrix particles and for daughter particles; forming droplets from the liquid mixture; and drying the formed droplets and/or pyrolyzing starting materials for pyrolysis therein. The cosmetics of the present invention contain the above composite fine particles.