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Hf,symbol for the element hafniumhafnium
, metallic chemical element; symbol Hf; at. no. 72; at. wt. 178.49; m.p. about 2,227°C;; b.p. 4,602°C;; sp. gr. 13.31 at 20°C;; valence +4. Hafnium is a lustrous, ductile, silvery metal with a hexagonal, close-packed crystalline structure.
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The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
On drawings, abbr. for “hot finished.”
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
HF(High Frequency) A range of radio frequencies from 3 to 30 MHz. The HF band is used for amateur radio, marine, aviation and military communications and high-frequency RFID tags.
With regard to audio, high-frequency waves are typically above 3,000 Hz. See frequency bands.
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