磨机中磨熔体的运动状态有()、抛落式、离心式,其中抛落式对物料粉磨效果最好.
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小容量配电所高压侧通常采用隔离开关-熔断器或跌落式熔断器、()等主接线形式。
A. 隔离开关
B. 负荷开关-熔断器
C. 熔断器
D. 断路器-熔断器
为什么选择陨石(通常选择球粒陨石)作为地球物质演化(元素和同位素)的起点?
卧式注塑机是目前最常见的类型,其合模部分和注射部分处于同一水平中心线上,且模具是()打开的。
A. 沿水平方向
B. 沿垂直方向
C. 呈一定角度方向
D. 可沿多方向
You are performing a block media recovery on the tools01.dbf data file in the SALES database by using RMAN. Which two statements are correct in this scenario?()
A. You must ensure that the SALES database is mounted or open.
B. You must restore a backup control file to perform a block media recovery.
C. You must take the tools01.dbf data file offline before you start a block media recovery.
D. You must put the database in NOARCHIVELOG mode to perform a block media recovery.
E. You can perform only a complete media recovery of individual blocks; point-in-time recovery of individual data blocks is not supported.