搜题请搜索小程序“爱下问搜题”
问题 多项选择题

环氧精制系统停车空气置换后，进容器内动火的要求有（）。

A、氮气纯度至少为99.5%

B、系统中氧含量至少为21%

C、系统中总烃含量最大为2000ppm

D、系统中环氧含量为0.3%

答案

参考答案：B, C

选择题

质量相等的木块和蜡块，漂浮在同一盆水中，它们所受浮力的大小关系是：[ ]

A.木块受浮力大

B.木块和蜡块受浮力相等

C.蜡块受浮力大

D.条件不足，无法比较

查看答案
单项选择题

A multicast router may receive thousands of multicast (6) every day for different groups. If a router has no knowledge about the membership status of the (7) , it must broadcast all of these packets. This creates a lot of traffic and consumes (8) . A better solution is to keep a list of groups in the network for which there is at least one loyal member. (9) helps the multicast router create and update this list. For each group, there is one router that has the duty of distributing the (10) packets destined for that group. This means that if there are three multicast routers connected to a network, their lists of groupids are mutually exclusive. A host or multicast router can have membership in a group.

A．capability

B．power

C．bandwidth

D．address
查看答案