Kasper

As the number of atoms in the asyimnetric unit increases, the solution of a structure by any of these phase-independent methods becomes more difficult, and by 1950 a PhD thesis could be based on a single crystal structure. At about that time, however, several groups observed that the fact that the electron density must be non-negative everywhere could be exploited to place restrictions on possible phases. The first use of this fact was by D Marker and J S Kasper [24], but their relations were special cases of more general relations introduced by J Karle and H Hauptman [25]. Denoting by A. the set of indices h., k., /., the Karle-Hauptman condition states that all matrices of the fonu... 

Flarker D and Kasper J S 1948 Phases of Fourier coefficients directly from crystal diffraction data Aota Crystallogr. 70-5... 

Hawkes P Wand Kasper E 1989 Principles of Electron Optics yo 1 (London Academic)... 

Wageningen University and Research Centre Product design and Quality management group, PO Box 8129, 6700EV Wageningen, The Netherlands. E-mail kasper.hettinga wur.nl... 

P. W. Hawkes, E. Kasper Principles of Electron Optics,Vol. 2, Academic Press, Lon-don-San Diego-New York 1996. 

The next seven references are cited not because of the experimental procedures described but because they indicate diversification in the types of enamines prepared and studied. Both Paquette (25) and Kasper 26) have condensed 2,5-methylene-l,2,5,6-tetrahydrobenzaldehyde (5-nor-bornene-2-carboxyaldehyde) (2) with several cyclic and open-chain aliphatic secondary amines. Kasper studied the ratio of endo to exo aldehyde formed upon hydrolysis of these enamines and the dihydro enamines. Paquette investigated the addition of sulfene to the enamines. -Fluoro-... 

Kasper, Joel (Aquagenics). A Look at Steam Systems, Carbon Filters and Condensate Polishers. Ultrapure Water, Tall Oaks Publishing, Inc., USA, February 1998. 

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