Study of the anomalous sorption behavior of CO2 into poly(methyl methacrylate) films in the vicinity of the critical pressure and temperature using a quartz crystal microbalance (QCM).

The anomalous solubility maximum of CO2 in polymer thin films in the vicinity of the critical temperature and pressure has not yet been clearly understood when the quartz crystal microbalance (QCM) technique has been used to determine the micromass change. In this study, the adsorption of CO2 on the surface of bare polished and unpolished crystals at different pressures and temperatures was investigated using the QCM technique to illustrate why a plot of the true frequency shift as a function of temperature and pressure can intuitively exhibit the adsorption behavior of CO2 on bare crystals. The sorption of CO2 into a PMMA film at different temperatures, pressures, and PMMA film thicknesses was also investigated.

[An epidemiological survey of atrial fibrillation in China].

Objective: To know the current prevalence of atrial fibrillation (AF) in China and contribute to further Chinese studies on AF in future.

Methods: We chose 14 natural populations from 14 different provinces across China. Using international standardized methods, we performed an epidemical study which was mainly on AF.