???? ?????
- ????:??? ????? ????? ????? ?????
- ??????:2 ?????? ??? ????
- ???? ?????:?????? ???????
- ?????:???? ?????? ???? ??????? ???


????? ?????????? ?????, 80% ??????? ?????? ????? ????? ????? ???????? ????????, ????? ?????? ??? ????? ????. ????? ?????? ???? ????? ????? ??????? ??? permeability ?????? ???. ?? ????? ???? ?? ????? ??????? ??????? ???? ?? ?????? ??????.
??? ???? ???? ??????????? ???? ????? ????---????? ???? ?? 20 ??? ???? ?????, ???? ?????? ????? ????. ?? ?????? ?????? ?????? ????? ??????? ?? ??? ?????, ??? ??? ???? ???. ?? ???? ?????? ?? ??????? ?? ???? ?????? ??????.
?????? ??????? ????????????? ???? ???? ????? ????? ????? ????? (???? ??? ?????? ?????) ?? ?-2 ?????? ??? ??? ???.
????? ??? ?????? ???????????? ???? ????? ???? ??????????? ?????? ????? ??????? ????? ????? ???? ???. ?? ?? ?? ???? ???? ??? ??? ?? ???? ????? ????? ?? ?????? ?? ?????, ?????? ?? ????? ??????? ???????.