“Technology” relating to the “production” of pyrolytically derived materials formed on a mould, mandrel or other substrate from precursor gases which decompose in the 1 573 K (1 300 °C) to 3 173 K (2 900 °C) temperature range at pressures of 130 Pa to 20 kPa. Note: 1E104 includes “technology” for the composition of precursor gases, flow-rates and process control schedules and parameters.