^4Heの凍上現象
1991 年 18 巻 2 号 p. 217-223
詳細
1991 年 18 巻 2 号 p. 217-223
The frost heave phenomena of ^4He on porous glasses are reported. When a boundary between bulk solid and liquid in the porous glass is cooled below bulk melting point, in equilibrium the pressure of the bulk solid surpasses that of the liquid across the boundary. This pressure jump in equilibrium condition is called maximum frost heave pressure. The maximum frost heave pressure was measured at constant pressure in the range 26-60 bars and at temperatures above 1.3 K, using two kinds of porous glasses with pore diameters of 40Å and 140Å. The maximum frost heave pressure obtained for samples above 28.5 bar was in good agreement with the formula, so-call-ed modified Clausius-Clapeyron equation, which is deduced by assuming that the chemical potantial in the solid and liquid phase is the same. For samples below 28 bar, the measured maximum frost heave pressure became less than that of the prediction of the above formula.
