Polyacrylonitrile Fibers with a Gradient Silica Distribution as Precursors of Carbon-Silicon-Carbide Fibers. - Varfolomeeva, Lydia A.; Skvortsov, Ivan Yu.; Levin, Ivan S.; Shandryuk, Georgiy A.; Patsaev, Timofey D.; Kulichikhin, Valery G. (Polymers (20734360), 2023)