Zur Eiskeimbildungsfähigkeit von Kupferoxyden und Kupfersulfiden

  • Ulrich Katz
Kurze Mitteilungen


The icing nucleability of Cu2O, CuO, Cu2S, Cu9S5, and CuS has been measured as a function of the temperature. After a short description of the way in which the substances were prepared, the measuring apparatus is explained.Figure 1 shows the cloud chamber with a particulary small temperature gradient and the apparatus with which a supercooled cloud is first produced in the chamber, before the seeding substance from the disperser (Figure 2) is injected into the cloud by means of the dosing instrument. The fall-out of ice crystals is observed visually and their number estimated. The concentration of the seeding particles is obtained through a sedimentation tube (Figure 2). The size distribution of the particles is represented inFigure 3, and it should be noted that no diameter of less than 0·5 μ occurs.Figures 4 and5 show the activity in terms of icing nucleabilityq, which is defined as the ratio of observed ice crystals to the number of nuclei injected into the cloud. A brief comparison is made of these measurements with the theory ofFletcher [3] concerning the dependence of particle size on the threshold temperature, and with the experiments of other authors. The only explanation attempted of the differences which have been established here has been for the time being in qualitative terms. The threshold temperatures of the substances in question are (±0·5°C), Cu2O: −4·2°C, CuO: −13·5°C, CuS: −5·1°C, Cu9S5: −5·7°C, Cu2S: −6·4°C.


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Copyright information

© Birkhäuser-Verlag 1960

Authors and Affiliations

  • Ulrich Katz
    • 1
  1. 1.Laboratorium für Atmosphärenphysik an der ETHZürich

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