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11.
Kurt Schütte 《Archive for Mathematical Logic》1988,27(1):85-99
Summary This paper gives a recursive generalization of a strong notation system of ordinals, which was devellopped by Jäger [3]. The generalized systemT(V) is based on a hierarchy of Veblen-functions for inaccessible ordinals. The definition ofT(V) assumes the existence of a weak Mahlo-ordinal. The wellordering ofT(V) is provable in a formal system of second order arithmetic with the axiom schema of
2
1
-comprehension in a similar way, as it is proved in [6] for the weaker notation systemT(V). 相似文献
12.
U. Kreibig K. Fauth M. Quinten D. Schönauer 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1989,12(1-4):505-514
First, some general remarks concerning macroscopic “cluster matter” are given. In the second part, three recent, mainly optically and electron-microscopically performed investigations are discussed which deal with special properties of noble metal cluster systems forming the building units of this kind of matter:(1) dressed Au-55 clusters,(2) electromagnetic coupling effects among coagulated clusters,(3) the transition towards compact inhomogeneous matter caused by coalescence of clusters. 相似文献
13.
E. Ühlein W. Scherman F. Asinger A. Warner P. Kratochvil G. Kirschstein H. Bergmann H. D. Cremer U. Grigull E. Schleitzer E. Best R. Honerjäger H. Schäfer K. -H. König A. Sippel Hj. Schönert W. Koch B. Frisch H. G. Kilian R. Hähnel H. H. Pfeiffer 《Colloid and polymer science》1966,213(1-2):157-174
Ohne Zusammenfassung 相似文献
14.
15.
16.
Stefan Berger 《Tetrahedron》1977,33(13):1587-1589
The pH dependence of the 13C chemical shifts of ascorbic acid has been measured and interpreted in terms of protonation sites. The transition of the dimer of dehydroascorbic acid into the hydrated monomer form is monitored by 13C spectroscopy. 相似文献
17.
C. Chr Schüler 《Zeitschrift für Physik B Condensed Matter》1987,68(2-3):325-328
The proton conductivity of three layer-type compounds was studied: H3OTi2NbO7. H2O, HTiNbO5 and HTiTaO5. Measurements were made between 20 °C and 90°C on pellets pressed from crystalline powders and soaked with pure water. The hydrated compound had the highest conductivity, (20°C)-6.3–6.9·10–4 (cm)–1. Acid ions from the exchange process were quite firmly retained in its layer structure and contributed significantly to the measured conductivity. Consistent results were obtained after prolonged washing with water.Dedicated to Professor Harry Thomas on the occasion of his 60th birthday 相似文献
18.
Cushman M Yang D Gerhardt S Huber R Fischer M Kis K Bacher A 《The Journal of organic chemistry》2002,67(16):5807-5816
A series of 6-carboxyalkyl and 6-phosphonoxyalkyl derivatives of 7-oxo-8-D-ribityllumazine were synthesized as inhibitors of both Escherichia coli riboflavin synthase and Bacillus subtilis lumazine synthase. The compounds were designed to bind to both the ribitylpurine binding site and the phosphate binding site of lumazine synthase. In the carboxyalkyl series, maximum activity against both enzymes was observed with the 3'-carboxypropyl compound 22. Lengthening or shortening the chain linking the carboxyl group to the lumazine by one carbon resulted in decreased activity. In the phosphonoxyalkyl series, the 3'-phosphonoxypropyl compound 33 was more potent than the 4'-phosphonoxybutyl derivative 39 against lumazine synthase, but it was less potent against riboflavin synthase. Molecular modeling suggested that the terminal carboxyl group of 6-(3'-carboxypropyl)-7-oxo-8-D-ribityllumazine (22) may bind to the side chains of Arg127 and Lys135 of the enzyme. A hypothetical molecular model was also constructed for the binding of 6-(2'-carboxyethyl)-7-oxolumazine (15) in the active site of E. coli riboflavin synthase, which demonstrated that the active site could readily accommodate two molecules of the inhibitor. 相似文献
19.
The reaction of the azomethine ylides 2a–c with cyclopropenones 3 and of 2a with methylene cyclopropenes 7 leads via (3+3)-cycloaddition to pyridones-4 5 and 1,4 - dihydro - N - methyl - 4 - methylene - pyridines 8, respectively. The merocyanine systems 8 exhibit marked solvatochromic and thermochromic properties. 相似文献
20.
The theory of chirality functions described in a previous publication is generalized to allow for chiral ligands. In the earlier theory, all symmetry operations of the molecular frame could be thought of as permutations of the ligands among the sites; in the present work, improper rotations not only permute the ligands, but convert them into mirror images. The group that generates all isomers from a given ordered molecule belonging to a frame with n sites is now the hyperoctahedral group of order 2n
n! consisting of all possible combinations of permutations and site reflections. The representation theory of these groups is described, and applied to the problem of constructing qualitatively complete chirality functions, and of deciding which ligand partitions, and which isomer mixtures, are chiral. It is found useful to classify chiral representations of the covering group as ligand specific and class specific. The ligand specific representations describe chiral properties which are common to all frames and arise purely from the chirality of the ligands, while the class specific representations describe the chiral properties of the frame. A number of examples are explicitly worked out. 相似文献