Topochemical photo-dimerization of 7-acetoxycoumarin - the acetoxy group as a steering agent

Among the various substituted coumarins investigated only 7-acetoxycoumarin is observed to photodimerize topochemically in the crystalline state and this observation may be of importance in the context of "crystal engineering".

Bianca and Julius Rosenbaum with unidentified group Portraits Couples

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School group class portrait including Susan (Susi) Ehrlich; Ulm Portraits; Groups

(l-r): Ruth Altman, Irene Hirsch, Hilde Dannhauser, Suse Barth, Anneliese Hirsch, Suse Saenger, Esther Nathan, Hannelore Baer, Heinz Koerner, Ruth Bauland, Marianne Leiter, Heinz Krippel, Hanna Ullmann, Edith Weil, Otto Eckstein, Susi Ehrlich, Hans Klein, Julie Klappholz, Hanna Chose, Minna Hirsch and Rudolf Loewy

Group portrait, 10th Anniversary Dinner, Display Novelties Co. Ltd.; New York.

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Outdoor group portrait, Haus Horst Changer?, including Ernst Peter Pick (first row center) Portraits Groups

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Resistance fluctuation at the mobility edge

Following a Migdal-Kadanoff-type bond moving procedure, we derive the renormalisation-group equations for the characteristic function of the full probability distribution of resistance (conductance) of a three-dimensional disordered system. The resulting recursion relations for the first two cumulants, K, the mean resistance and K ~ t,he meansquare deviation of resistance exhibit a mobility edge dominated by large dispersion, i.e., K $ ’/ K=, 1, suggesting inadequacy of the one-parameter scaling ansatz.

Group portrait at the farewell banquet for Dr. William Antopol from the laboratory staff of Mount Sinai Hospital; Ken's Chop House, New York city Portraits Groups

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Group US Army military portrait including Dr. William Levison (top row, third from left); Schofield Barracks, Hawaii Portraits Groups Men

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Invariance group properties and exact solutions of equations describing time-dependent free surface flows under gravity

Using the method of infinitesimal transformations, a 6-parameter family of exact solutions describing nonlinear sheared flows with a free surface are found. These solutions are a hybrid between the earlier self-propagating simple wave solutions of Freeman, and decaying solutions of Sachdev. Simple wave solutions are also derived via the method of infinitesimal transformations. Incomplete beta functions seem to characterize these (nonlinear) sheared flows in the absence of critical levels.

Outdoor group portrait of attendees of the International Meeting of the World Union for Progressive Judaism; London.

Includes Rabbi Leo Baeck, E.L. Ehrlich of Basel, Herbert Strauss of Bern, and Rabbi Eugen Messinger of Bern

Group portrait including Kurt Rosenberg (seated second from left).

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Group of two women, one man and one child, sit on chairs outdoors Portraits Groups

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Group of two women, one man and one child, sit on chairs outdoors Portraits Groups

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nvestigations on the Stability and Extinction of a Laminar Diffusion Flame Over a Porous Flat Plate

The limits of stability and extinction of a laminar diffusion flame have been experimentally studied in a two-dimensional laminar boundary layer over a porous flat plate through which n-pentane vapour was uniformly injected. The stability and extinction boundaries are mapped on a plot of free stream oxidant velocity versus fuel injection velocity. Effects of free stream temperature and of dilution of fuel and oxidant on these boundaries have been examined. The results show that there exists a limiting oxidant flux beyond which the diffusion flame cannot be sustained. This limiting oxidant flux has been found to depend_on the free stream oxygen concentration, fuel concentration and injection'velocity of the fuel.