Über Polysilane. I. Kristallstruktur von Dodecaphenylcyclohexasilan Heptabenzol

On Polysilanes. I. Crystal Structure of Dodecaphenylcyclohexasilane Heptabenzene The crystal structure of the title compound has been determined and refined to a R of 0.112. The crystal benzenes are slightly disordered. The molecular structure of (Ph₂Si)₆ is a centrosymmetric Si₆-chair with 6 axial and 6 equatorial phenyl substituents respectively. The mean Si–Si distance of 239.4(3) pm is at the upper limit of the range 231–241 pm experimental determined for the Si–Si homo bond.     

The analyzing power Ay(θ) for the 9Be(p, n)9B reaction from 8 TO 15 MeV

The analyzing power A_y(θ) for the ⁹Be(p, n)⁹B reaction was measured at seven energies between 8.1 to 15.0 MeV for reaction angles between 0° and 100° (c.m.). The A_y(θ) values are predominantly negative and exhibit a smooth variation with energy. The significance of these results in Lane optical- model calculations for the ⁹Be + nucleon system and in comparisons between the observables P^y(θ) and A_y(θ) is indicated.     

Über Dahlquist-Distributionen

Ohne Zusammenfassung     

Einige Kennzeichnungen der homothetischen Abbildungen eines Riemannschen Raumes unter den kreistreuen Abbildungen

In a previous note the author has shown that each circular mapping of a Riemannian manifold is a conformal mapping. Circular mappings therefore are situated between the conformal and the homothetic mappings. In the following paper some local and global theorems are proved characterizing homothetic mappings among the circular mappings. For example: Let Vⁿ, be complete Riemannian manifolds and let f: be a circular mapping, which transforms a single geodesic triangle of Vⁿ into a geodesic triangle of . Then f is a homothetic mapping.

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Herrn Prof. Dr. H. R. Müller gewidmet     

Zustandsgrössen eines schweren Plasmas in Abhängigkeit von temperatur und Dichte

Summary Assuming thermodynamic equilibrium we calculate ion and electron densities of a uranium plasma in the temperature range between 0,5 keV and 50 keV for densities around 10²³ ions per cm³ using a simplified Saha equation. The ionization energies are found by extrapolation from known data or by a Slater approximation.The ratios of the partition functions of two successive stages of ionization are set equal to one. A depression of the ionization energies caused by electrostatic interactions is considered. The numerical results include the internal energy of the plasma as a function of temperature.     

A critical examination of the salicylaldehyde method for the determination of primary amines in the presence of secondary amines

Summary The salicylaldehyde method for the differentiation of primary and secondary amines in mixtures has been critically evaluated. This method yields best results in acetonitrile. In mixtures of amines one can expect high results for the primary amine with correspondingly low results for the secondary amine. Corrections can be made with known mixtures of the amines.Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore Laboratory under contract number W-7405-ENG-48.     

Über ein Verfahren zur Erzeugung zweiseitig eingespannter,kurzer Polyethylen-Modellketten

Zusammenfassung Ein Algorithmus zur Erzeugung zweiseitig eingespannter Polyethylen-Modellketten im Diamantgitter wird vorgestellt, dessen Grundidee folgendermaßen angegeben werden kann: Die Gesamtheit der Modellketten bestimmter Kettenlängen zu einem vorgegebenen Anfang-End-Vektor erhält man, indem man zunächst die Grundverteilung zu diesem Anfang-End-Vektor bestimmt, durch Hinzufügen von geeigneten Paaren einander entgegengesetzter Gittervektoren die für die gegebene Kettenlänge möglichen Vektorverteilungen ermittelt und schließlich zu diesen alle möglichen Anordnungsmöglichkeiten der Gittervektoren sucht. Der Algorithmus wird im Abschnitt 2.1. am Beispiel des ebenen Wabengitters erläutert und dann im Abschnitt 2.2. auf das dreidimensionale Diamantgitter angewendet. Das Flußschema des entsprechenden Computerprogramms ist im Anhang angegeben.

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An instruction is given for generating polyethylene model chains fixed at their two ends in the diamond lattice. The fundamental thought is as follows: The ensemble of model chains of given length and end-to-end vector is obtained in three steps. First of all the basic distributions of chain vectors belonging to is determined. Secondly, all the possible distribution of chain vectors consistent with given chain length are found by addition of suitable pairs of opposite chain vectors to the basic distribution. Thirdly, all the allowed sequences of chain vectors are arranged.In section 2.1. this method is demonstrated for the plane honeycomb lattice. In section 2.2. it is applied to the tridimensional diamond lattice.The flow diagram of the computer programme is given in the appendix.

     

Ein Irrfahrten-Problem und seine Anwendung auf die Theorie der sequentiellen Versuchs-Pläne

Ohne Zusammenfassung     

Die flammenphotometrische Analyse (Atomabsorption) der Elemente Na, K, Mg, Mn und Ca im Zement

Ohne Zusammenfassung