membrane
- Domaine
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- matière plastique
- Date
Terme :
- membrane n. f.
Traductions
-
anglais
Date :Définition
An extremely thin, porous layer of film of material, either natural of synthetic; the thickness is approximately 100 angstom units, the diameter of the pores ranging from as little as 8 angstroms for natural cellular membranes up to 100 angstroms for manufactured membranes.
Note :
Membranes which have pores so small that only the molecules of solvent, ions, and a few substances of very low molecular weight can pass through are called semipermeable; these are characteristic of living cell tissue and are an essential feature of osmosis. Membranes made of cellophane, collodion, parchment, and certain types of plastics are used un many industrial procedures (waste liquor recovery,desalination, and chemical separation techniques). All types are vistually impermeable to macromolecules and colloidal particles.
Terme :
- membrane