New photocatalysts: Dispersed semiconductor materials with microheterojunctions

We have obtained new semiconductor materials with microheterojunctions by substitution of surface cadmium ions in CdS by Cu(I), Cu(II), and Bi(III) ions. We have shown that the photocatalytic activity of their dispersions in the reaction of evolution of H₂ from alcohol-water mixtures is considerably higher than in the original cadmium sulfide.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 29, No. 3, pp. 270–274, May–June, 1993.We would like to acknowledge Academician V. D. Pokhodenko of the Academy of Sciences of Ukraine for drawing our attention to the prospects for investigation of complex photocatalytic systems based on semiconductors with different types of conductivity.     

Calculation of the absolute peak efficiency of Ge and Ge(Li) detectors for different counting geometries

A new method is presented to calculate with improved accuracy the absolute peak efficiency of cylindrical Ge and Ge(Li) detectors for point, disk and cylinder sources, positioned at any source-detector distance. Moreover attention was paid to true-coincidence effects. The method is extensively tested and applied for the analysis of reference materials. The accuracy turned out to be 3% or better. Research associate of the “Nationaal Fonds voor Wetenschappelijk Onderzoek”.     

Synthesis of 3-epistrophanthidin and 3-epistrophanthidol

Chemistry of Natural Compounds - 3-Epistrophanthidin and 3-epistrophanthidol have been synthesized from strophanthidin and strophanthidol with yields of 10 and 40%, respectively. The substances...