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Publication of BE555973ApublicationCriticalpatent/BE555973A/xx
H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
H03F3/04—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only
H03F3/14—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only with amplifying devices having more than three electrodes or more than two PN junctions
Werkwijze ter bereiding van een schuimmassa uit copolymeren van een aromatisch monovinylideen-monomeer en een ethenisch onverzadigd carbonzuuranhydride, alsmede de hieruit vervaardigde schuimvormige voorwerpen.