搜题请搜索小程序“爱下问搜题”
问题 单项选择题

有关回波链的叙述错误的是（）

A.FSE序列在一次90°脉冲后施加多次180°相位重聚脉冲，形成回波链

B.回波链越长，扫描时间越短

C.回波链越长，信噪比也越低

D.回波链越长，允许扫描的层数增多

E.主要用于FSE及IR序列

答案

参考答案：D

单项选择题

(41) is a protocol that a host uses to inform a router when it joins or leaves an Internet multicast group.
(42) is an error detection code that most data communication networks use.
(43) is an interior gateway protocol that uses a distance vector algorithm to propagate routing information.
(44) is a transfer mode in which all types of information are organized into fixed form cells on an asynchronous or non-periodic basis over a range of media.
(45) is an identifier of a web page.

A．OSPF

B．RIP

C．RARP

D．BGP
查看答案
单项选择题

决定猫的毛色基因位于X染色体上，基因型为bb、BB、Bb的猫依次是黄色、黑色、虎斑色。现有虎斑色雌猫与黄色雄猫交配，生下三只虎斑色小猫和一只黄色小猫。它们的性别应是（）

A.全为雌猫或三雌一雄

B.全为雄猫或三雄一雌

C.全为雄猫或全为雌猫

D.一半雄猫一半雌猫
查看答案