采用比例,微分,积分控制的自动舵()。 ①能加快给舵速度; ②能自动消除单侧偏航角; ③结构简单,造价低; ④是比较完善的自动舵。
A、①~③
B、②③④
C、①③④
D、①②④
You are using Oracle Database 10g. You performed an incomplete recovery of your database and opened the database with the RESETLOGS option. What is the effect of opening the database with the RESETLOGS option?()
AThis operation resets the SCN for the database.
BThis operation creates a new incarnation of the database.
CThis operation moves all the redo log files to a different location.
DThis operation deletes the old redo log files and creates new redo log files.
EThis operation updates all current datafiles and online redo logs and all subsequent archived redo logs with a new RESETLOGS SCN and time stamp.
曲线轨道与直线轨道的受力状态有何区别?
高锰钢整铸辙叉的纵向水平裂纹长度重伤标准是什么?
什么是胀轨跑道?
普通线路发生断轨或发现重伤钢轨时,必须立即组织更换,做到两个“不过夜”,即换轨不过夜,向上级()不过夜。