通常把从速度为零的壁面到速度达到来流速度的()处的距离作为速度边界层的厚度。
A. 100%
B. 80%
C. 99%
D. 50%
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Which of the following options is true about shutting down an Automatic Storage Management (ASM) instance?()
A. If the SHUTDOWN IMMEDIATE command is issued to the ASM instance, the ASM instance immediately shuts down.
B. If the SHUTDOWN ABORT command is issued to the ASM instance, the ASM instance will shut down all the database instances and then shut down immediately.
C. If the SHUTDOWN NORMAL command is issued to the ASM instance, before shutting down, the ASM instance waits for the dependent database instances to shut down.
D. If the SHUTDOWN TRANSACTIONAL command is issued to the ASM instance, the ASM instance passes the same SHUTDOWN command to the dependent database instances, but does not wait for any active transactions to complete before it shuts down.
在车下移动作业和用力紧固部件前应注意观察周围环境和工具是否可靠。
A. 正确
B. 错误
空调压缩机2允许启动的脉冲信号为K27。
A. 正确
B. 错误