File:Assortment of Kovar metal.jpg
此为最大尺寸。
Assortment_of_Kovar_metal.jpg （468 × 518像素，文件大小：54 KB，MIME类型：image/jpeg）
摘要
| 描述 |
English: An assortment of Kovar metal shapes from an advertisement in an electronics magazine. Kovar is a nickel-cobalt ferrous alloy used to make metal-to-glass seals in vacuum tubes and other scientific vacuum systems because it has the same thermal expansion as glass. Alterations to image: cropped out ad copy |
| 日期 | |
| 来源 | Retrieved November 10, 2015 from Electronics magazine, McGraw-Hill Publishing Co., New York, Vol. 23, No. 7, July 1950, p. 142 |
| 作者 | 未知 |
| 授权 (二次使用本文件) |
This image is from an advertisement without a copyright notice published in a 1950 US magazine. In the United States, advertisements published in collective works (magazines and newspapers) are not covered by the copyright notice for the entire collective work. (See U.S. Copyright Office Circular 3, "Copyright Notice", page 3, "Contributions to Collective Works".) Since the advertisement was published before 1978 without a copyright notice, it falls into the public domain. |
许可协议
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| 日期/时间 | 缩略图 | 大小 | 用户 | 备注 | |
|---|---|---|---|---|---|
| 当前 | 2015年11月11日 (三) 18:01 | | 468 × 518（54 KB） | Chetvorno | User created page with UploadWizard |
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