The experimental results on the abnormal melting of crystallized raw rubber by Wood and Bekkedahl are theoretically studied. The effect can be explained by the fact that the relaxation time for the thermal expansion of the crystalline particles differs from that of the amorphous particles. At the point where the melting begins, the time interval of observation becomes comparable to the relaxation time of amorphous particles. The point will become higher when the time rate of heating increases, and also when the relaxation time itself becomes larger. The point at which the melting completes itself is determined by the relaxation times of amorphous and crystallized state, heating rate and previous history. This effect will become remarkable at a suitable heating rate, and will be more remarkable in natural rubber than vulcanized rubber.

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The temperature-dependence of rectifying action of silicon and iron pyrite detectors was measured between −183°C and 300°C. The maximum rectification ratio for Si-W detector occurs at about 60°C, while for some iron pyrites a kink appears at about −60°C in the rectification-ratio versus temperature curves, although we have no maximum in the measured range of temperatures. Mott’s and Davydov’s theories on the reetification are insufficient o explain these results. The author proposes a theory based on the tunnel effect of electrons through the upper part of a blocking layer. in which the calculation was made for the thickness 20 Å∼30 Å of the blocking layer. It is expected from our theory that there exists a critical temperature at which the inversion of rectification occurs and that the rectifylng action is a function of the thickness of layer and the conductivity of the crystal in bulk, The inversion of rectification at different places on the surface of the crystal can also qualitatively be explained by our theory.

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