Cassette tapes are produced of a polyester type plastic celluloid with a magnetized coating. The gamma ferric oxide (Fe2O3) was the basis of the original magnetized stuff. About 1970, a doping cobalt volume procedure with a double-coating method to heighten overall tape output levels was developed and introduced by 3M company.
William Clinton
entretien piscines
Shaquille O'neal
idée d entreprise
John Sargent
Saturday, February 26, 2011
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