Figure 2

Responses of PdCuSi/MSS to hydrogen concentrations of 2000, 4800, 10 000, 20 000, and 40 000 ppm. Their baselines are not corrected (no offset). Horizontal axis represents time, and vertical axes represent the signals of the MSS (V) and the concentration of hydrogen (C) regulated by the mass-flow controller. Inset: Schematic diagram of stress output as piezo voltage by the MSS when hydrogen atoms are absorbed into the amorphous Pd-alloy film.