可燃物与空气的混合物,在没有火源的情况下,达到一定的温度能够自然的温度。纯甲烷比较稳定,在大气压下条件下,温度达到()摄氏度方可自然。
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You require the Oracle server to manage the undo segments and space among various active sessions automatically. You created an undo tablespace, UNDO_TBS1, in your database. Which two additional steps would you perform to achieve this?()
A. Set the UNDO_RETENTION parameter to 900 or more.
B. Create an initial undo segment in the undo tablespace.
C. Enable the retention guarantee for the undo tablespace.
D. Set the UNDO_TABLESPACE parameter to UNDO_TBS1.
E. Set the UNDO_MANAGEMENT initialization parameter to AUT
检测室门窗打开空气流通情况下,在硫化氢检测箱内检测硫化氢传感器时,可以不开检测箱的排风扇进行检测吗?有何危害?