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【多选题】
在数控机床电气控制系统中,对直流稳压电源的选择说法对的是( )。A.
为了提高系统的可靠性，直流稳压电源工作在50%∽80%额定负载
B.
尽量选用生成厂家提供的标准电源，包括标准尺寸和输出电压
C.
选择电源尽量减少输出电压路数，选用多路输出共地的电源
D.
系统通风较差或环境温度较高时，考虑选择风冷的电源
E.
选择输入电压规格时无需明确系统使用的区域，而是输出电压范围。
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皮皮学刷刷变学霸
举一反三
【单选题】Dr. Myers and other researchers hold that ______.
A.
people should look for a baseline that can't work for a longer time
B.
fisheries should keep the yield below 50% of the biomass
C.
the ocean biomass should restore its original level
D.
people should adjust the fishing baseline to changing situation
【单选题】Dr Myers and other researchers hold that
A.
people should look for a baseline that can’t work for a longer time.
B.
fisheries should keep the yield below 50% of the biomass
C.
the ocean biomass should restored its original level.
D.
people should adjust the fishing baseline to changing situation
【单选题】Dr. Myers and other researchers hold that
A.
people should look for a baseline that can work for a longer time.
B.
fisheries should keep their yields below 50% of the biomass.
C.
the ocean biomass should be restored to its original level.
D.
people should adjust the fishing baseline to the changing situation.
【简答题】Dr. Myers and other researchers hold that ________. [A] people should look for a baseline that can’t work for a longer time [B] fisheries should keep the yield below 50% of the biomass [C] the ocean b...
【单选题】由差动放大器和运算放大器组成的反馈电路如图所示。设A为理想运放，则该电路的反馈组态为______________；【图片】
A.
电压串联负反馈
B.
电压并联负反馈
C.
电流串联正反馈
D.
电流并联负反馈
【单选题】Dr Myers and other researchers hold that ______.
A.
people should look for a baseline that can't work for a longer time
B.
fisheries should keep the yield below 50% of the biomass
C.
the ocean biomass should be restored to its original level
D.
people should adjust the fishing baseline to changing situation
【单选题】Researchers hold that boredom results from______.
A.
natural surroundings
B.
various kinds of factors
C.
sensitive personalities
D.
subjective perceptions
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