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【单选题】
在Genbank数据库中,生物学工作者提交有两种方式,其中用于提交少量数据的是基于Web方式的( )A.
Bankit
B.
Sequin
C.
Version
D.
Matrix
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【简答题】How to define the specific gravity of the crude oil?
【单选题】已知某正弦交流电压的表达式为:u=220 sin628t V,则此正弦交流电压的有效值和周期分别为 :
A.
V,314s
B.
220V,0.01s
C.
220V,50s
D.
V,0.02s
【判断题】The specific gravity of a gas is defined as the densities of the gas and air when both are measured at the same temperature and pressure.
A.
正确
B.
错误
【单选题】已知某正弦交流电压的表达式为:u=220 2 sin628t V,则此正弦交流电压的有效值和周期分别为________ 。
A.
2 V,314s
B.
220V,0.01s
C.
220V,50s
D.
2 V,0.02s
【单选题】_____ shows 1.2 meter and the specific gravity of the oil is 0.96According to the measuring scale, that makes 150 tons.
A.
The piston rod
B.
The push rod
C.
The sounding rod
D.
The connecting rod
【单选题】______ the weight and the specific gravity of a body, you can calculate its volume.
A.
Giving
B.
Gives
C.
Given
D.
Give
【单选题】The specific gravity of fuel oil is a ___
A.
absolute value
B.
relative value
C.
constant
D.
set value
【单选题】The specific gravity of fuel oil is a _____.
A.
absolute value
B.
relative value
C.
constant value
D.
set value
【单选题】已知某正弦交流电压:U=220V,f=50Hz,初相为60°,则其正确的瞬时表达式为( )
A.
u=220sin(50t+60°)V
B.
u=220sin(314t+60°)V
C.
u=311sin(50t+60°)V
D.
u=311sin(314t+60°)V
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