Tour de force analysis of NPN/NPN-O pores
Many thanks to JK, Dean and Gunner (Webster HS) for compiling this table. 
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- NPN-O has smaller pore sizes, lower porosity than NPN at the same thickness (50 nm).
- All materials have slightly asymmetric pores (~ R1/R2 = 0.75).
- Top-side and bottom side pore distributions are not the same.
- The original NPN material has lower asymmetry than NPN.
- NPN-O becomes less asymmetric as it gets thicker.