1. The bullet-proof clothes, made of 7A52 Al alloy plates and bullet-proof nylon, can not meet the requirement of type 54 pistol lead core bullet ballistic performance. 由于采用7A52铝合金装甲板与进口防弹尼龙制成的防弹衣不能满足54式手枪铅芯弹抗弹性能指标要求，对7A52铝合金进行了研究。
2. Maxim used the energy of each bullet's recoil force to eject the spent cartridge and insert the next bullet. 马克沁利用每枚子弹的后座力弹出废弹并压进新弹。
3. Maxim used the energy of each bullet's recoil force to eject the spent cartridge and insert the next bullet. 马克沁利用每枚子弹的后座力弹出废弹并压进新弹。
4. Absolute braking distance The distance between a train following another train must be equal to or greater than the braking distance of the following train. 绝对制动距离列车与跟随它的列车之间的距离必须等于或大于跟随列车的制动距离。
5. Absolute braking distance The distance between a train following another train must be equal to or greater than the braking distance of the following train. 绝对制动距离列车与跟随它的列车之间的距离必须等于或大于跟随列车的制动距离。
