| http://www.w3.org/ns/prov#value | - Choe U.S. Pat. No. 4,605,869 discloses a laser frequency converter containing a polymer of the structure: ##STR1## where n is an integer of at least 3 and Y is disclosed to be nitro, cyano, trifluoromethyl, acyl, carboxy, alkanoyloxy, aroyloxy, carboxymido, alkoxysulfonyl, aryloxysulfonyl, and the like.
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