The range of pore sizes spans many orders of magnitude [1] but pores can be classified into two categories:– large (0.05–10 m) and small (10–50 nm) capillary pores;– gel pores with three kinds of pores (pores of ‘‘outer’’ hydrates: 2.5–10 nm; micropores of dense gelatinous ‘‘inner’’ hydrates: 0.5–2.5 nm; and ‘‘interlayers’’ micropores: