Measurements of the molar specific heat cp "ofliquid Hee/He4 mixtures at saturated vapor pressure near the junction of the g and phase-separation curves reported in an earlier paper have been used to calculate values of (Bs/8T)p "=cp "/T, (8&/8T)p "=--(9s/Bx)p g, s, and (15 -(II) 0 at saturated vapor pressure throughout the junction region. Here Q is the difference p3. -p4 between molar chemical potentials, x is the mole fraction of He present, and the subscript 0 denotes the value of a quantity at the junction. Comparisons of (8s/8T)p "and (8$/8T)p "with their respective upper bounds at the X curve (ds/dT)p, g+ (dQ/dT)p g(dx/dT)p g and (dQ/dT)s "suggest but do not require that (es/ST)I z = c~z/T diverge all along theX curve, as our results indicate that it does at the junction. Our results are consistent with the following asymptotic behaviors at the junction: (Bs/ST)s, ",o -(es/BT)~, "™ (T -To) at x =x0 for T &TO, I4 -Qol-Ixxol at T=Toforx&xo., (Ss/ST)J, e-IT -TOI~2 at $=)0 for T &To.
The specific heat of liquid He /He mixtures has been measured at saturated vapor pressure for eight values of the He mole fraction~in the range 0. 53 «x «0.73 at temperatures from -0.6 tol. 4 K. For purposes of comparison, the specific heat of pure liquid He has also been measured under similar conditions. The measured specific heat, obtained with a calorimeter almost completely full of liquid, has been corrected to yield the specific heat of the liquid cJ. "at constant pressure and mole fraction. For the mixtures, the correction required was everywhere & 17&. To a resolution in temperature which varies from 0.1 to 3 m'K from one value of x to another, the specific heat at the A. peak appears to be finite, continuous, and cusped. Both the A. peak and the discontinuity in cJ, "as the system goes from the two-liquid-phase region to the one-liquid-phase region tend to disappear as the junction of phase boundaries is approached.
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