File:Zone refining Bell Labs 1954.jpg
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Summary
| Description |
English: The first zone refining equipment from an advertisement by Bell Telephone Laboratories in an electronics magazine. Zone refining, a technique for purifying materials now widely used in the semiconductor industry, was invented by William Gardner Pfann in 1953. This was the first zone refining tube, with induction heating coiles. |
| Date | |
| Source | Retrieved July 20, 2014 from Radio and Television News magazine, Ziff-Davis Publishing Co., Chicago, Vol. 52, No. 4, October 1954, p. 6 on American Radio History site |
| Author | Unknown author |
| Permission (Reusing this file) |
This 1954 issue of Radio and Television News magazine would have the copyright renewed in 1982. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. [1] Search of the Renewals for Periodicals for 1982 show no renewal entries for Radio and Television News. Therefore the magazine's copyright was not renewed and it is in the public domain. |
Licensing
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This work is in the public domain because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs.
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 00:46, 21 July 2014 | | 705 × 618 (79 KB) | wikimediacommons>Chetvorno | User created page with UploadWizard |
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