Sunday, September 11, 2022
问题:对于线型聚合物,在注射成形时应加热到黏流态,在挤出成形时应加热到(),在中空成形时应加热到高弹态。A、Tg温度附近B、Tf温度附近C、玻璃态D、高弹态
Sunday, September 11, 2022
Saturday, February 17, 2024
问题:手工电弧焊、埋弧自动焊、氩弧焊、CO2气体保护焊均可焊接一定直径的环焊缝。
Thursday, November 16, 2023
Sunday, December 24, 2023
Saturday, October 14, 2023
Sunday, December 24, 2023
问题:离子化合物或离子晶体的熔点,沸点,硬度均很高热膨胀系数(),但相对脆性较()。
Thursday, January 18, 2024
Thursday, January 18, 2024
Sunday, February 4, 2024
Thursday, November 16, 2023
Tuesday, July 25, 2023
Tuesday, July 25, 2023
问题:在塑料制品成形过程中,模具温度、制件厚度、注射压力、充模时间等对大分子取向度的影响较为显著,其中制件厚度越大、注射压力越大,制件中大分子的取向度越大。
Friday, April 28, 2023
Sunday, February 4, 2024
Sunday, February 4, 2024
Sunday, February 4, 2024
Sunday, September 11, 2022