Zur Temperaturabhängigkeit der Rechteckigkeits-Koeffizienten der Mangan-Magnesium-Ferrite

Ohne Zusammenfassung

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Abschließend danken wir der Kollegin A. Hadincová für die mit Sorgfalt durchgeführten Messungen.     

Phonon thermal conductivity of amorphous selenium doped by germanium

The thermal conductivity of the amorphous semiconducting system Se-Ge in the temperature range of 100 to 300°K was measured. The Debye model was used for the analysis of the experimental values and the calculated mean free path of phonons was related to the size of the basic structure units of the selenium glass. The shift of the thermal conductivity of amorphous selenium doped with germanium was explained by means of the increase of the velocity of sound observed together with the occurrence of the covalent bond Se-Ge between the basic structure units of the studied amorphous system.     

On the mechanism of rendering visible dislocations on the surface of iron crystals by anodic dissolving

The paper contains further results of studying dislocations rendered visible by anodic dissolving on the surface of single crystals of alpha-iron. The influence of the crystallographic orientation of the surface is investigated, the effect of carbon is confirmed and the anodic process is studied. The mechanism of dissolving of the crystal is given and a new more suitable method of rendering dislocations visible is derived.

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The author thanks F. Kroupa and J. Hejduk for critical remarks and discussion.     

The sub-structure of crystals of silicon-iron alloy

After electrolytic polishing and etching a network of boundaries between mosaic blocks was observed on the surface of single crystals of silicon-iron alloy prepared from the melt. Some of the boundaries are formed by a number of distinguishable pits, also found singly outside the boundary. An explanation is given on the basis of the conception that the pits are etched points of intersection of edge dislocations with the surface of the crystals.