Jumps of Minimal Degrees Below 0'

We show that there is a degree a REA in and low over 0' suchthat no minimal degree below 0' jumps to a degree above a. Wealso show that every nonlow recursively enumerable degree boundsa nonlow minimal degree.     

Mixing automorphisms of compact groups and a theorem of Schlickewei

Summary We prove that every mixing ^d by automorphisms of a compact, connected, abelian group is mixing of all orders.Oblatum 5-II-1992The second author gratefully acknowledges support from NSF grant DMS-91-03056 at the Ohio State University     

Ein einfaches Verfahren zur infrarotspektrographischen Untersuchung von Mikrogramm-Mengen

Zusammenfassung Ein einfaches Verfahren zur reflexionsspektroskopischen Untersuchung von Mikrogramm-Mengen im Infrarotbereich wird beschrieben. Bei den verwandten Spiegeln ist ein sicheres Einengen der Lösungen, welche die zu untersuchenden Substanzen enthalten, möglich, ohne daß diese den Rand der spiegelnden Flächen überkriechen. Präparationsmethoden, die zur Herstellung eines gleichmäßigen Films der zu untersuchenden Substanzen auf dem Spiegel führen, werden angegeben. Mengen ab etwa 1 g können auf einem Spiegel mit 3 mm Durchmesser untersucht werden. Die Reproduzierbarkeit der Präparation beträgt für 10 g ungefähr 15–30%.

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Summary A simple method for the investigation of microgram amounts by infrared reflection spectroscopy is proposed. Special mirrors are described by means of which the solutions, that are to be investigated, can be evaporated quite easily without losses. Samples of at least 1 g can be measured.

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Herrn Prof. Dr. F. Strassmann zum 65. Geburtstag gewidmet.     

carbon-carbon bond formation between 1,3-dienes and electron deficient alkenes

1,3-Dienes and electron deficient alkenes are coupled in a one pot carbon-carbon bond formation reaction under mild conditions.     

Gold

Ohne Zusammenfassung     

Verfolgung von Phasenreaktionen in Flüssigkeiten

For a great number of processes of technical importance (separation precipitating, adsorption and chemical conversion) an indication of progress of reaction without any temporal delay and gap is required with regard to process optimation. Beside and in addition to thermal analyses and optical methods electrical methods can be used, which depend on measuring of those electric properties, which are connected with each change of phases of the material under test. By use of potentials of medium or high frequency the cell of reaction is free of test probes. This is especially favourable for investigations of such mixtures of phases, in which the surfaces of electrodes would be changed irreversible by sedimentation or separation of phase. In this way the following reactions were studied: precipitation processes in supersaturated aqueous solutions, solution of crystals of potassium chloride, adsorption of alkali solution by ground quartz, sedimentation of mineral substances, separation processes of the system phenol-water and transformation of high polymers.     

Correlation energy extrapolation by intrinsic scaling. III. Compact wave functions

The information gained in the context of extrapolating the correlation energy by intrinsic scaling is used to shorten the full configurational expansions of electronic wave function without compromising their chemical accuracy. The truncations are accomplished by judiciously limiting the participation of the ranges of predetermined approximate sets of natural orbitals in the various excitation categories.