对于改、扩建工程,若要绘制噪声现状等声级图,可以采用( )布置测点。
A.等距法
B.放射线法
C.网格法
D.同心圆法
参考答案:C
Networks can be interconnected by different devices. In the physical layer, networks can be connected by (66) or hubs, which just move the bits from one network to an identical network. One layer up we find bridges and switches, which operate at data link layer. They can accept (67) , examine the MAC address, and forward the frames to a different network while doing minor protocol translation in the process. In the network layer, we have routers that can connect two networks. If two networks have (68) network layer, the router may be able to translate between the packet formats. In the transport layer we find transport gateway, which can interface between two transport connections. Finally, in the application layer, application gateways translate message (69) . As an example, gateways between Internet e-mail and X.400 e-mail must (70) the e-mail message and change various header fields.
(69)处填()。
A.syntax
B.semantics
C.language
D.format
温度传感器通过检测蒸发器表面的温度,控制电磁离合器的工作。