Beiträge zur Spurenanalyse

Zusammenfassung Zur Spurenanalyse von Reinstselen werden die Spurenelemente aus 1 g Probematerial mit Oxin/Dithizon (in Chloroform) extraktiv angereichert und spektralanalytisch bestimmt. Mit diesem Verfahren sind 30 Elemente mit einem mittleren Fehler von ± 10% erfaßbar. Die Bestimmungsgrenze der Methode liegt bei 0,00001% und kann durch geeignete Maßnahmen noch um etwa zwei Zehnerpotenzen herabgesetzt werden.

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Summary In the trace analysis of the purest selenium the trace elements from 1 g of the sample are accumulated with oxine/dithizone (in chloroform) and determined spectrometrically. This procedure makes it possible to deal with 30 elements with a mean error of ±10%. The limit of determination of the method lies at 0.00001%, and can be lowered by about 2 powers of 10 if suitable precautions are taken.

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Résumé Pour le dosage de traces dans le sélénium pur, les éléments analysés sont enrichis par extraction par le réactif oxine/dithizone (dans le chloroforme) sur une prise d'essai de 1 g. Ils sont ensuite dosés par analyse spectrale. Cette méthode permet de déterminer trente éléments avec une erreur moyenne de ± 10%. La limite inférieure de sensibilité de la méthode est voisine de 0,00001% et peut encore être divisée par dix à la puissance deux par la mise en uvre de mesures appropriées.

     

Quadrupole interactions in pionic and kaonic atoms

We discuss the quadrupole hyperfine structure in mesonic atoms for nuclei with spin I 1. The optical potential is expanded in terms of the non-spherical density contributions. Examples are given for the hyperfine splitting of peripheral and deeper-lying states in pionic and kaonic atoms.     

Results on the measurement ofK-series X-rays from antiprotonic hydrogen

The X-ray spectrum emerging from a liquid-hydrogen target when stopping antiprotons was measured with high resolution in order to determine the strong interaction shift and width of the atomic 1s level. Owing to strong Stark quenching only weak structures could be observed. The upper limit of the yield of any one of theK-series transitions is 3.5×10^?4 (95% C.L.) per stopped antiproton, assuming no broadening of the 1s level. Possible identifications of the weak lines with theK-series transitions are discussed.     

Model processes and cavitation indicators for a quantitative description of an ultrasonic cleaning vessel: Part I: experimental results

In this paper, four sensor types are presented for quantitative measurements in an ultrasonic cleaning vessel: (1) a hydrophone to measure spectral components of the sound field; (2) an aluminium foil technique as a model process for erosion; (3) a test tube filled with a solution of luminol to measure the emission of light; and (4) a test tube filled with potassium iodide solution to measure the oxidation of iodide. Thus a broad range of diverse cavitation effects is covered. The quantities were measured in dependence on three parameters: the electrical input power of the transducers, the temperature and the O₂ concentration of the water. To ensure constant environmental conditions, a flow system was built up which continuously exchanges the water in the vessel. The comparability of the data measured in subsequent measurement cycles is discussed and the influence of the different sensor types on the cavitation field is considered. Dependences on the three parameters are shown. A quantitative analysis of correlations between the data is carried out in the second part of the study (Koch and Jüschke, 2012 [1]).