The removal of inorganic ions from solutions with fibrous ion-exchange cellulose and checking of the purified substances by neutron-activation analysis

Summary For the rapid removal of heavy metal impurities from large volumes of solutions, ion-exchange cellulose loose fibres have proved to be effective. Distilled water and absolute ethanol were purified by the column technique. For the checking of the effectiveness of the purification, analysis with carboxycellulose and neutron activation were used. The results were in good agreement. The purification is effective up to ppt concentrations.

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Zusammenfassung Zur Entfernung von Schwermetallverunreinigungen aus Flüssigkeiten großen Volumens entsprachen am besten die watte-förmigen Ionaustausch-Zellulosen. Wir haben destilliertes Wasser und absoluten Äthylalkohol von ihren Verunreinigungen in Kolonnen gereinigt. Zur Kontrolle der Wirksamkeit der Reinigung haben wir 1) die Carboxy-Zellulose-Analyse und 2) die Neutronen-Aktivierungsanalyse verwendet. Die Resultate der Methoden 1) und 2) stimmen gut überein. Die Reinigung ist bis zur ppt-Konzentration wirksam.

     

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Stability of Ritz procedure for nonlinear two-point boundary value problem

In this paper we establish the stability of Ritz procedure in sense of Michlin and Tucker for a class of nonlinear two-point boundary value problems which has been considered by Varga, Schultz and Ciarlet in [1].     

Zur Bestimmung von 2-Thio-3,5-dimethyltetrahydro-1,3,5-thiadiazin (Mylon)

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Charge-dependent three-nucleon potential

The charge-dependent three-nucleon potential due to simultaneous photon and pion exchange was derived. The intermediate state of the three-nucleon system was considered to consist of a Δ (1236) resonance. The contribution of this charge-dependent three-nucleon potential to the charge asymmetric energy of ³He−³H is then evaluated using a reasonable trial wave function for a three-nucleon bound system. This contribution turns out to be small but makes the charge asymmetric energy of ³He−³H slightly larger.     

Die Titration von Kondensationsprodukten von Formaldehyd und p-Kresol

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Optical phonon modes and structure of ZnGa2Se4 and ZnGa2S4

We present the infrared and Raman study of the optical phonon modes of the defective compounds ZnGa₂Se₄ and ZnGa₂S₄. Most of the compounds have been found to crystallize in the thiogallate structure (defect chalcopyrite) with space group where all cations and vacancies are ordered. For some Zinc compounds a partially disordered cationic sublattice with various degrees of cation and vacancy statistical distribution, which lead to the higher symmetry (defect stannite), has been reported. For ZnGa₂Se₄ we have found three modes of A symmetry, showing Raman activity only. In addition, we have observed each five modes of B and E symmetry, showing infrared as well as Raman activity. The number of modes and their symmetry assignment, based on polarized measurements, clearly indicate space group for the investigated crystals of ZnGa₂Se₄.Regarding ZnGa₂S₄ we have found three modes exclusively showing Raman activity (2A⊕1B₁), and only eight modes showing infrared as well as Raman activity (3B₂⊕5E). The assignment of the modes has been derived by analyzing the spectral positions of the vibrational modes in comparison to a number of compounds. From the number and symmetry assignment of the optical phonon modes we confirm that ZnGa₂S₄ most likely crystallizes in space group .