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21.
The problem considered is the fitting of a many-body interaction potential to bulk crystal data. A parameterisation of the
potential is assumed which is based on physical considerations. The free parameters are determined by using global optimization
to perform a least squares fit, to a large number of crystal properties. This has been achieved for body centered cubic (bcc)
materials. The approach adopted here fits the bcc crystal structure, as the preferred minimum energy configuration for tungsten,
and also fits the dimer energetics and the elastic properties of crystalline tungsten. 相似文献
22.
F. Khuong-Huu D. Herlem-Gaulier MM. Qui Khuong-Huu E. Stanislas R. Goutarel 《Tetrahedron》1966,22(10):3321-3327
The following alkaloides have been extracted from the leaves of Buxus balearica Willd.: cyclomicrophylline-B, cycloprotobuxines A, C and D, baleabuxine (N-isobutyryl-baleabuxine-F), buxamine-E and buxaminol-E (already reported), N-isobutyryl- and N-benzoyl-baleabuxidine-F, baleabuxoxazine-C, N-isobutyryl- and N-benzoyl-baleabuxidienine-F, N-isobutyryl-baleabuxaline-F, the structures of which are proposed. The stereochemistry of baleabuxidines and baleabuxoxazines is established on the base of chemical correlations between these two groups and cyclomicrophyllines. 相似文献