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991.
Let (A,M) be a noetherian local ring. For certain equimultiple ideals I in A we try to relate the Gorenstein property of the Rees algebran and of A itself. In particular we n0 treat the case of equimultiple prime ideals of height two and the case I=M. The results underscore a natural conjecture, s. Thm. 2.6. and 3.2. 相似文献
992.
993.
The reaction of Ni(C5H5)2 and Ni(C5H4COOCH3)2 with the acetylene (?)-(R)-C6H5CCCONHCH(CH3)(C6H5)(C6H5), “CC′”, yields tetrahedral Ni2C2 clusters. Besides the compounds with two identical Ni corners (Ni2CC′ types) also compounds with two different Ni corners (NiNi′CC′ types) are formed. These consist of two diastereomers which, for a given (R)-configuration in the acid amide substituent, differ only in the cluster chirality. They are separated chromatographically and turn out to be configurationally stable with respect to a change of the cluster chirality. 相似文献
994.
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998.
We investigated to what an extent mixed crystals of phosphates (arsenates) of Mn and Cd, [M5(HPO4)2(PO4)2 · 4 H2O], with Fe(II), Co, Ni, Zn and Cu can be formed. 相似文献
999.
Rudolf Gretler Elefteria Askitol Hardy Kühne Manfred Hesse 《Helvetica chimica acta》1978,61(5):1730-1755
The Mass Spectral retro-Diels-Alder-Reaction: 1,2,3,4-Tetrahydroisoquinoline and 1,2,3,4-Tetrahydronaphthaline (Tetraline) The retro-Diels-Alder reaction of 1,2,3,4-tetrahydroisoquinoline and of its N-acetyl derivative was confirmed on the basis of labelled derivatives (Scheme 2). Furthermore, the loss of ethylene was investigated with the 1,2,3,4-tetrahydronaphthalene- and 1,2,3,4-tetrahydronaphthalen-1-one-derivatives given in Schemes 4, 5 and 6. In the case of the 1,2,3,4-tetrahydronaphthalen-1-one-derivatives ethylene is lost via a retro-Diels-Alder reaction. The loss of ethylene from 1,2,3,4-tetrahydronaphthalene ( 1 ) and from its derivatives is a rather complex reaction (Scheme 8): 1/3 of ethylene is split off 1 + via a formal retro-Diels-Alder reaction, 2/3 are lost after a specific rearrangement. The ratio of these two fragmentation pathways depends very much on the substituents placed at the aliphatic and the aromatic rings, compare e.g. Table 4. 相似文献
1000.
Current trends and novel concepts in R&D of zeolite membranes like the seeding supported crystallization and the preparation
of Al-containing zeolite membranes are discussed. The influences of adsorption and diffusion on the permeation properties
of zeolite membranes are considered. Dehydration of ethanol by steam permeation and pervaporation as the first zeolite membrane
based industrial separation is presented. Membrane supported dehydrogenation and esterification are discussed as possible
applications of a catalytic membrane reactors.
In memoriam Wolfgang Schirmer. 相似文献