Zur theorie der hochstrombogensäule

Zur theorie der hochstrombogensäule

Recensiones. 463 of the heating. If the maximum current is greater than 660A the rod explodes. The final product, tested by the cathode layer method...

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Recensiones.

463

of the heating. If the maximum current is greater than 660A the rod explodes. The final product, tested by the cathode layer method, was very pure and contained the original amount of B, traces of Fe, Mg, Ca and Na, and occasionally a trace of Ti and Cu. The purified rods are suitable for the cathode layer method of spectrographic analysis. The method is essentially the same as described by A. Gatterer in Spectrochim. Acta 2, 49-70 (1941). R. 0. Scott (Aberdeen). Schmidt, R.: The Purification of Carbon Rods for Spectrochemical Analysis. II. Carbon Rods for Spectrochemical Analysis of Solutions. Rec. Trav. Chim. 66, 265-269 (1946). Carbon rods as prepared by HoogZand (Rec. Trav. Chim. 66,257,1946) (cf. precedent review) are unsuitable for the Scheibe-Rivas method of analysis of solutions, the solution being absorbed unevenly in the carbon, mainly due to the presence of a central canal. This is avoided by heating the rods (176 x 7 mm) for two minutes using a 48 volt A.C. supply. The maximum current is adjusted to 26 kW. The rods are slightly less pure than Hoogland’s. For the analysis of solutions, it is advisable to remove the outside porous layer of the rods and to pass an arc between the electrodes to be impregnated, in order to improve the porosity locally. R. 0. Scott (Aberdeen).

Deinum, H. W.: The Purification of Carbon Rods for Spectrochemical Analysis. Rec. Trav. Chim 66, 270-2’72 (1946). The change in current passing through a carbon rod, from 300 amps. initially to about 600 amps. after 5 seconds, can be explained by the partial conversion of the carbon into graphite. The surface temperature of the rods, by measurement and calculation, increased to a maximum of 3 450°K as the load was increased. Above 750 watt/cm2 the temperature no longer increased with increase in load. R. 0. Scott (Aberdeen).

Phywica fontium

lumiuin.

Schulz, P.: Zur Theorie der Hochstrombogensiiule. 8. Naturforschg. 2a, 662-666 (1947). Durch Hiicker und Pidcelnburg wurde gezeigt, dass der Hauptenergieverlust in der S&ule des Hochstrombogens der Wiirmeleit#ung der Elektronen zugeschrieben werden muss. Die experimentelle ifberpriifung des Temperaturverlustes senkrecht zur Bogenachse ergab schlechte tibereinstimmung mit der Theorie. Die vorliegende Arbeit weist darauf hin, dass zwar die W&rmeleitung der Elektronen fiir die Energiebilanz der SLule eine massgebende Rolle spielt, dass aber fiir die quantitative Erfassung die bisher nicht beriicksichtigte Wechselwirkung der Elektronen mit den positiven Ionen stark eingeht. W. Rollwagen (Miinchen).