【简答题】某通信系统的信道带宽为1MHz,信噪比为40dB,则信噪功率比S/N为 。按香农定理可以计算出信道的极限通信容量是 Mb/s。
【简答题】水样有哪几种保存方法?实例说明怎样根据被测物质的性质选择不同的保存方法。
【简答题】水样有哪几种保存方法?试举几个实例说明怎样根据被测物质的性质选用不同的保存方法。
【判断题】企业微博的核心目标是为了增加企业知名度。
【单选题】The story _____ interesting. He wants to read it.
【单选题】如果只考虑温度和压力的影响, 纯物质最多可共存的相有( )
【单选题】What does the professor imply when he says this:
A.
He knows the class wants to read further.
B.
He senses that his students are getting restless to go.
C.
He is just beginning his lecture on Malthus.
D.
He is hungry and wants to go for lunc