摘要:
An optical resolution method of (.+-.)-3,4-dihydroxybutanoic acid, by reacting (.+-.)-3,4-dihydroxybutanoic acid with an optically active primary amine or secondary amine. Also a method for producing optically active 3-hydroxy-.gamma.-butyrolactone, by reacting (.+-.)-3,4-dihydroxybutanoic acid with an optically active primary amine or secondary amine for optical resolution, and ring closing the resulting optically active 3,4-dihydroxybutanoic acid.
摘要:
The ceramic member of this invention is formed on the surfaces of crystal grains with a plurality of protrusions having smaller diameter than that of the crystal grain, said crystal grain composing at least the surface or its vicinity of a dense ceramic base material of purity being 95 wt % or higher. Such ceramic members may be produced by performing the surface of a dense ceramic base material with a corrosion treatment in an acid etchant, the dense ceramic base material having purity of 95 wt % or higher and exceeding 90% of a theoretical density, whereby ceramic grains existing on the surface or its vicinity of the base material are formed on the surface thereof with a plurality of protrusions.