Figure 6
Time records of pressure, p, (right axes) and temperatures \(T_{{\text{B}}}\), \(T_{{\text{T}}}\) and \(T_\mathrm{{Ge}}^{05} (t)\) (as indicated, left axes) for the case when the top plate temperature was modulated at two frequencies \(f_{\text{T1}} \ll f_{\text{T2}}\) simultaneously. The phase shift between the averaged temperature of the plates \(T_{{\text{m}}}(t)=(T_{{\text{T}}}(t)+T_{{\text{B}}})/2\) and the temperature of the bulk recorded by sensor \(T_\mathrm{{Ge}}^{05} (t)\) (in phase with the pressure trace p(t)) is clearly visible at \(f_{\text{T2}}\) (a) as well as at \(f_{\text{T1}}\) (b).
