Figure F1. A. Three nitrogen adsorption/desorption isotherms for a representative sample (Section 301-U1301B-3R-1). Partial pressure is ratio of measured pressure to saturation vapor pressure of the gas. Hysteresis at intermediate to high pressure is consistent with a mesoporous sample with pore throats ranging from 2 to 50 nm. Different symbols = repeat measurements to confirm that analysis was not causing irreversible changes to sample matrix. B. Two argon adsorption isotherms for the same sample. Note different scale on vertical axis. Full adsorption/desorption argon isotherms were not possible because of instrumental limitations. Argon isotherms had more pronounced bends compared to nitrogen isotherms. These bends indicate when a monolayer has formed and secondary layers subsequently begin forming. STP = standard temperature and pressure.
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