... ensure of a safe operation of the line.4. The duct can be coiled ... hierarchical4.restoration rateVertical pressure distoration rate is 30% of original diameter, immediate unloading, the specimen is ... phenomenon9.exine hardness,HD≥5910. hydraulic pressure leadagetestTemperature 20 , the pressure 50Kpa, maintain 24-hour, the ... /mm≥1515.chemical resistanceThe sample were placed in 5% NaCL, 40% H2SO4, 40% ...