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>The Thermionic Valve of Professor J. H. Fleming—a Piece of Apparatus Capable of Amplifying Sound, with a Demonstration to show the Possibilities of Applying the Thermionic Valve to Aid the Deaf
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The Thermionic Valve of Professor J. H. Fleming—a Piece of Apparatus Capable of Amplifying Sound, with a Demonstration to show the Possibilities of Applying the Thermionic Valve to Aid the Deaf
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机译:J. H. H. Fleming教授的热水阀 - 一块能够放大声音的装置,并展示施加热水阀以帮助聋人的可能性