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Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Variation of tan d with temperature for films: (a) F0/0 (full squares) and F5/0 (open squares); (b) F5/0.5 (open circles), F5/2 (full circles) and F5/10 (open triangles).