Classification of involutions on Enriques surfaces

We present the classification of involutions on Enriques surfaces. We classify those into 18 types with the help of the lattice theory due to Nikulin. We also give all examples of the classification.Comment: 25 pages, 42 figure

Enhancement of the extraction of lanthanide(III) with 2- thenoyltrifluoroacetone in the presence of foreign metal(III) ions: Coextraction of light lanthanide(III) with Al3+, Sc3+ and Fe 3+

金沢大学大学院自然科学研究科物質情報解析Enhancement of the extraction, or coextraction of lanthanide(III) (Ln) with metal(III) ions (M3+) such as Al3+, Sc3+, and Fe3+ was found in a typical chelate extraction system of 2-thenoyltrifluoroacetone (Htta)-benzene. The distribution ratio of La 3+ was enhanced by a factor of 6 with 3.0 x 10-2 M Al 3+, while that of Lu3+ was not affected at all. The magnitude of the coextraction decreased with the atomic number of Ln. Equilibrium analysis and spectroscopic studies indicated that the coextraction was ascribed to the formation of the 1:1 adduct between Ln(tta)3 and M(tta)3 extracted into the organic phase. The overall equilibrium of the coextraction was expressed as Ln3+ + M3+ + 6 Htta org ⇌ Ln(tta)3(M(tta)3)org + 6 H+