【单选题】当施主能级Ed与费米能级Ef相等时,电离施主的浓度为施主浓度的( )倍。
【单选题】关系型数据库中的“关系”主要是指_______。
【简答题】若一个n型半导体的施主能级离导带底距离为E d ,N d ,n d 和n分别表示单位体积中施主、施主能级上电子和导带电子的数目,证明 式中, ;m * 是导带电子的有效质量。
【单选题】When we try to decide the meaning of a word in a sentence or a paragraph,we should ...
B.
judging from parts of speech.
C.
judging from collocation.
【单选题】For the word "scale", decide which best expresses the meaning of the author.
C.
to climb to the top of something very high and steep
D.
a set of musical notes that are played in an upward or downward order
【单选题】是指以当事人的意志为转移,能够引起劳动法律关系产生、变更和消灭,具有一定法律后果的活动。