It is reacted for the agency of the organic compound particularly fluorination of the compound of acetylene, preparation process and using its IN nucleophilic displacement of fluorine 'or' addition

摘要

PCT No. PCT/FR85/00167 Sec. 371 Date Feb. 25, 1986 Sec. 102(e) Date Feb. 25, 1986 PCT Filed Jun. 24, 1985 PCT Pub. No. WO86/00193 PCT Pub. Date Jan. 16, 1986.The invention concerns a procedure for undermining underwater terrain (S) thus creating an upward rising current (Tj) able to lift items lying on the terrain (S) or half-buried in it, in order to collect them in a recovery net. The invention also covers devices to be used for harrowing and cleaning shell-fish beds or for dredge-fishing shell-fish.