The temperature dependence of the crystal and molecular structure of TTF-(2,5-DIETHYL)TCNQ

The structures of the charge transfer salt tetrathiofulvalenium 2,5-diethyltetracyanoquinodimethane (TTF-DETCNQ), which undergoes a metal-insulator transition at 111°K, were examined at 120° and 81°K by single crystal X-ray diffraction. The variation of the cell parameters with temperature was determined from measurements ranging from 40°K to room temperature. The properties of TTF-DETCNQ are compared to those of the parent compound TTF-TCNQ.     

Ward identities for non-commutative geometry

We interpret the cocycle condition in quantum field theory as a set of integrated Ward identities for non-commutative geometry.Dedicated to Res Jost and Arthur WightmanSupported in part by the National Science Foundation under Grants DMS/PHY 88-16214 and INT 87-22044     

Some observations on high resolution thermogravimetry

The advantages and disadvantages of ramp-iso-ramp-iso heating rate TG are discussed using water and copper sulphate pentahydrate as examples.     

An index theorem for super derivations

We show that the Chern character given by a super-KMS functional on a quantum algebra can be interpreted in terms of the index of a super derivation on a projection of the algebra.Dedicated to Roland DobrushinSupported in part by the National Science Foundation under Grant DMS/PHY 8816214     

Generating Travelling-Salesman Problems with Known Optimal Tours

An algorithm is presented for randomly generating travelling-salesman problems (TSPs) for which the optimal tour is known. Both asymmetric and symmetric problems can be generated, with the option of having the distance matrix satisfying the triangle inequality. No limit exists to the number of nodes that can be considered, making the use of the generator attractive to those involved in the design and comparison of TSP solution approaches. Empirical testing of the generator indicates that the resultant problems are as difficult as problems generated in a completely random manner.     

p-Carboxybenzoldiazoniumchlorid als Reagens zur Bestimmung von Verbindungen mit aktiven Methylengruppen

Zusammenfassung Durch Reaktion zwischenp-Carboxybenzoldiazoniumionen und Verbindungen mit aktiven Methylengruppen werdenp-Carboxyphenylhydrazone gebildet, die die Ermittlung des Äquivalentgewichtes der Verbindung mit aktiver Meth yengruppe durch alkalimetrische Titration ermöglichen.Um die Tendenz zum Weiterreagieren unter Bildung von Formazan-Derivaten zu beschränken, wird die Kupplung bei pH<6 durchgeführt.Mit 2 AbbildungenHerrn Professor Dr.F. Wessely, im Gedenken an unsere erste Begegnung (Haupttagung des Vereins Österreichischer Chemiker, Linz 1949), zum 70. Geburtstag freundschaftlichst gewidmet.