The fixed set of pulleys (called sheaves) located at the top of the derrick or mast, over which the drilling line is threaded.

位于重型井架或桅架式井架顶部的固定的滑轮组（称之为滑车轮槽轮），通过该滑轮组钻井钢丝绳进行穿绳。

youdao

In the present study, rabbit mesentery was fixed in three different fixatives and stained with thionine and thionine-toluidine blue respectively in order to find a good method to display mast cells.

为寻求一种较好的显示肥大细胞的方法，采用硫堇染色法和硫堇-甲苯胺蓝染色法分别对用不同固定液固定的兔肠系膜中肥大细胞进行染色。

youdao

It said fixed line broadband had been restored on Thursday, and mobile telephones were still working, despite a mast in Herm being out of order.

BBC: Herm phones and net 'down for days' following snow