Temporal variations in bar strength A₂ (upper panels) and CMC within the ﹩r=0.5\,\mathrm{kpc}﹩ regions (lower panels) for the cold- (left) and warm-disk models (right). In the cold-disk models, the bar strength increases rapidly and then decays after reaching a peak due to the increase in the CMC. In the warm-disk models, the bar and CMC grow more slowly and steadily. The bar strength at late time is anticorrelated with ﹩{f}_{\mathrm{gas}}﹩ in both cold- and warm-disk models.