【单选题】钢材的时效强化是指经一定处理后,钢材的( )会随时间的延长而逐渐提高的现象。
【判断题】凡经过整车大修、总成大修、二级维护后竣工出厂的车辆,在维修竣工验收合格后,必须由承修方签发《汽车维修竣工出厂合格证》,并向托修方提供相应的维修技术资料
【判断题】沉淀淬硬钢是一种高抗拉强度钢,它通过形成碳氮化铌沉淀物来提高钢材的强度。()
【多选题】钢材的化学成分中,对提高钢材强度有帮助的是( )。
【简答题】People think that writing short stories is easy because they are short. But in fact they are hard to write well. There are only a few writers of good short stories and the American writer O. Henry is ...