标题： 星际介质的尘埃-气体比和相变 显示英文标题

标题： Dust-to-Gas Ratio and Phase Transition of Interstellar Medium

摘要： 我们讨论在星际介质多相模型背景下尘埃与气体质量比的时间演化。根据星际介质的非线性开放系统模型，星际气体的相变被认为发生在$10^{7--8}$年的时间尺度上。由于相变改变了尘埃的形成和破坏速率，尘埃与气体的比率也在同一时间尺度上波动。这定量化地解释了螺旋星系的尘埃与气体比率的散射，尽管我们应该注意观测上的较大不确定性。 显示英文摘要

摘要： We discuss the time evolution of dust-to-gas mass ratio in the context of multi-phase model of interstellar medium. Phase transition of interstellar gas is considered to occur on a timescale of $10^{7--8}$ yr, according to a nonlinear open system model of interstellar medium. Since the phase transition changes the dust formation and destruction rates, the dust-to-gas ratio also fluctuates on the same timescale. This explains the scatter of the dust-to-gas ratios of spiral galaxies quantitatively, though we should note the large observational uncertainty.