A porous silk fibroin membrane could be prepared through freeze-drying process, with dense topsurface, porous bottom surface in low porosity and porous inner portion in high porosity.
Batch production shows there are no shrinkage cavity and porosity in casting, and no blowholes and sand inclusions on the topsurface. The yield of the casting is 81%.
经批量生产验证，铸件内无缩孔、缩松缺陷，上表面无渣孔、气孔缺陷，工艺出品率81%。
3
Near the décollement structure surface, at the bottom of the Cambrian and the top of the Archean, developed an interjacent fractured zone which shows high porosity and high permeability.