超调量σ反映系统的相对稳定性,超调量越大,相对稳定性越好。( )
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下列表述中,最符合家庭成长期理财特征的是()。
A. 应该提高寿险保额
B. 以子女教育年金储备高等教育学费
C. 核心资产配置为风险低、收益稳定的银行理财产品
D. 以养老险或递延年金储备退休金
转速、电流双闭环直流调速系统中,电流调节器始终饱和。( )
双闭环调速系统起动时ASR为什么能迅速饱和,而ACR不一定饱和?如果ACR在起动过程中饱和,会出现什么现象?
Which of the following is NOT meant by the author?
Acid rain is found to have affected vast areas of the Northern Hemisphere.
B. A region without industry can still be affected by acid rain.
C. Power plants, automobiles and factories are known to be the major source of acid rain.
D. Terrestrial vegetation is entirely free from acid rain.