最終更新日:2022/12/24
In about 1951, the same company sealed into their vacuum doughnuts the regenerative peelers so that X-ray beams or electron beams could be obtained with the sealed off commercial tubes used in […]
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In about 1951, the same company sealed into their vacuum doughnuts the regenerative peelers so that X-ray beams or electron beams could be obtained with the sealed off commercial tubes used in […]