TY JOUR TI EFFICIENT ACOUSTIC COMPOSITE PANELS BASED ON GRAPHITE KW sound absorption KW sound insulation index KW composite panel KW carbon-graphite material JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Fanina, E.A. PY 2021 IS 6 PB Belgorod State Technological University named after V.G. Shukhov