[3+2]-cycloreactions of 1,2-diacylcyclopropenes with ynamines. Aminofurane- versus aminocyclopentadiene-formation

Electron deficient 1,2-diacylcyclopropenes represent synthetic equivalent for both acylcarbenes and vinylcarbenes; in their cycloreaction with ynamines aminofuranes and/or aminocyclopentadienes are formed.     

Beiträge zur Analyse nuklearer Rohmaterialien. X

Zusammenfassung Eine Methode wurde beschrieben, die es ermöglicht, Mangan von großen Mengen Uran zu trennen und der Endbestimmung mittels Spektrophotometrie zugänglich zu machen. Die Abtrennung des Mangans aus der Uranmatrix erfolgt durch Adsorption auf einer Säule des stark sauren Kationenaustauschers Dowex 50, X8 aus einer Mischung von 80 Vol.% Hexon, 10 Vol.% Aceton und 10 Vol.% 12-m Salpetersäure. Nach Elution des adsorbierten Mangans mittels 2-m Salpetersäure wird dieses unter Anwendung der Formaldoximmethode spektrophotometrisch bestimmt. Das Verfahren wurde zur Bestimmung des Mangans in U₃O₈-Standardproben (0,9 bis 8,1 ppm Mn) herangezogen und dabei eine sehr gute Übereinstimmung der Resultate erzielt.

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Contributions to the analysis of nuclear raw materials. X

Summary A method has been described that makes possible to separate manganese from large amounts of uranium and to render possible the end-determination by means of spectrophotometry. The separation of the manganese and of the uranium material is conducted by adsorption on a column of the strongly acidic cation exchanger Dowex 50, X 8 from a mixture of 80 vol.% hexone, 10 vol.% acetone and 10 vol.% of 12M nitric acid. Following elution of the adsorbed manganese by means of 2M nitric acid the manganese is determined spectrophotometrically by employing the formaldoxime method. The method was employed for the determination of manganese in standard specimens of U₃O₈ (0.9 to 8.1 ppm manganese) and a very good agreement of the results was achieved.

     

Heavy metals in human urinary calculi

Summary Heavy metals are incorporated in human urinary calculi during a complex pathological process. The trace metals cadmium, lead, chromium, nickel and mercury are determined with regard to significance in pathogenesis and therapy. The amounts of cadmium, lead and chromium were determined as well directly in the solid sample as after chemical digestion by Zeeman-GFAAS. Both analyzing techniques show corresponding results. Nickel could be determined after chemical digestion only, while mercury was determined by a solid sampling technique. The evaluation of the results of trace metal analysis in the pilot study of 11 urinary calculi showed increased amounts of lead and cadmium compared to the results of tartar and salivary calculi.     

Category equivalences of clones

This note was inspired by McKenzie's recent paper [8] whose main result is a characterization of categorical equivalence (for short category equivalence) between varieties. Here we use this result to define category equivalent clones and to describe all clones category equivalent to maximal clones. If one is interested in maximal clones only up to category equivalence it is sufficient to consider very simple maximal clones, essentially the same as considered in Jablonski's early papers about maximal clones [6]. The results we have found encourage us in our feeling that category equivalence could be a useful tool in clone theory.Dedicated to the memory of Alan Day.Presented by J. Sichler.     

Hybrid extension of Schottky space

Part of this work was written while the author was feliow of the Graduiertenkolleg Geometrie und Mathematische Physik at the University of Bochum, Germany.     

Weak decays of heavy mesons in the instantaneous Bethe Salpeter approach

In the framework of the instantaneous Bethe Salpeter equation we investigate weak decays ofB andD mesons. Mesons are described asq $\bar q$ states interacting via a mixture of a scalar and a vector confining kernel and a one gluon exchange. The model parameters are fixed by a fit to the meson mass spectrum including also the light mesons. We calculate form factors and compare our results to the pole dominance hypothesis. From a fit to ARGUS and CLEO data onB→D ^*?v semileptonic decay we extract the Cabbibo Kobayashi Maskawa matrix element to beV _cb =(0.032 ± 0.003)(1.49ps/τ _b )^1/2 The Isgur Wise function is calculated utilizing the heavy quark mass limit. Finally, we give some results on nonleptonic decays.     

On the interpretation of positron-annihilation data in powders and fine-grained materials

Monte-Carlo simulations of positron diffusion are carried out for powders consisting of spherical and ellipsoidal particles with and without defects. Following Bergersen et al. [1], elastic positron-phonon interaction is considered to be dominant for scattering processes in positron diffusion. The central question is which fraction of the positrons would be able to reach the particle boundaries. Hence, we calculate the Fraction of Positrons reaching particle Surface (FPS). The presence of defects in the particles can drastically reduce FPS depending on the defect concentration and capture rate. We demonstrate that for small-grained materials the grain surface can influence the lifetime signal significantly.Paper presented at the 132nd WE-Heraeus-Seminar on Positron Studies of Semiconductor Defects, Halle, Germany, 29 August to 2 September 1994     

Hot atom chemistry of mixed cristals 35 years of research

A historical survey of the author's contribution to the progress of solid state hot atom chemistry including more personal commentaries is presented.Presented at the International Seminar on the Chemistry of High Energy Atoms, Tokyo Institute of Technology, Ookayama, Meguro-ko, Tokyo 152, Japan, October 28–30, 1992, organised by T. MATSUURA, Institute for Atomic Energy, Rikkyo University, Nagasaka, Yokosuka 240-01, co-editor of the Handbook of Hot Atom Chemistry. I thank Professor MATSUURA for the permission to publish my contribution to the seminar slightly modified compared with the version submitted in the seminar proceedings.     

Applications of capillary electrophoresis in element speciation analysis of plant and food extracts

The performance of a new separation technique for metal-speciation — capillary electrophoresis (CE) — is presented. Polyhydroxy compounds such as polyphenols and organic tanning agents can be determined in the g/L range. Certain complexes of these compounds with iron (III) ions may also be directly or indirectly verified. The work has shown that it is possible to determine certain complexes existing in beverages (tea and coffee) by decomplexation with chelating agents (CDTA). The ligands released can be separated by CE and identified by their migration time and UV/VIS absorption spectra.