【单选题】What is Omni-directional antenna?
A.
An antenna which is capable of line-of-sight communication with a satellite without requiring any pointing
B.
Generally it is used on an INMARSAT-M MES
C.
Generally it is used on an INMARSAT-F MES
D.
This is a kind of directional antenna
【单选题】长效的 β受体激动剂,特别适合夜间哮喘发作的有:
【单选题】原子吸收光谱仪中,产生共振发射线和共振吸收线的部件是
【单选题】机修钳工常用的錾了、锉刀、锯条等手动工具应选用()制造。
【单选题】A parabolic dish antenna is a(n) _________ antenna.
【简答题】天线色素(antenna pigment)
【单选题】Antenna gain is obtained by...? ()
A.
A power amplifier in the antenna system
B.
Concentration of radiation
C.
Highly effective antenna cables
D.
Good SWR (Standing Wave Ratio)
E.
A spherical radiation pattern
【单选题】What is omni-directional antenna?
A.
An antenna which is capable of line-of-sight communication with a satellite without requiring any pointing.
B.
Generally it is used on an Inmarsat-B MES.
C.
Generally it is used on an Inmarsat-F MES.
D.
This is a kind of directional antenna.
【简答题】2008年,G淀粉公司雇用临时工将一仓库改建为第三生产车间。该车间为长80m、宽50m、高15m的桁架型砖混结构建筑,分成包装间和产品暂存间,包装间用8m高砖墙与暂存间分隔。第三生产车间拥有8台打包机、6台振动筛。振动筛安装在6m高的二层钢制平台上,振动筛内的筛子采用木质框架,筛子四角与振动筛用铁质螺栓连接,振动筛开关和电机为防爆电器设备。 2010年3月2日10时25分,"-3班班长甲发现5号振...
【单选题】长效的 β受体激动剂,特别适合夜间哮喘发作的是: