单选题雷达应答器发射的无线电波的极化方式是()。A水平极化B垂直极化C圆极化D以上均可
单选题
雷达应答器发射的无线电波的极化方式是()。
A
水平极化
B
垂直极化
C
圆极化
D
以上均可
参考解析
解析:
暂无解析
相关考题:
单选题When launching a lifeboat,the tricing pennants should be released().Abefore the boat is lowered from the stowed positionBas the boat-fall blocks break clear of the davit headCbefore the boat is lowered from the embarkation levelDafter the boat is released into the water
单选题You see another vessel approaching,and its compass bearing does not significantly change.This would indicate that().AYou are the stand-on vesselBRisk of collision existsCA special circumstances situation existsDThe other vessel is dead in the water
单选题A tow bridle is attached to the main tow hawser at the().Abight ringBtow hookCfishplateDswivel
单选题在微机控制的船舶自动电站中,若主开关ACB合闸失败或ACB异常分闸,系统处理的方式是()。A报警并启动备用机组B报警并使电站控制方式转为“手动”C报警并使故障发电机立即停机D仅提供故障报警
单选题When a fuel injection nozzle overheats, which of the problems listed can be expected?()AThe fuel metering will varyBThe fuel will explodeCThe cylinder head will crackDThe engine will stop
单选题当代船用二冲程超长行程柴油机使用的无冷却式喷油器的优点是()。 Ⅰ.结构简单 Ⅱ.备车时可对喷油器预热 Ⅲ.机动航行时不必换油 Ⅳ.喷油器驱气AⅠ+Ⅱ+ⅢBⅠ+Ⅱ+ⅣCⅡ+Ⅲ+ⅣDⅠ+Ⅱ+Ⅲ+Ⅳ
单选题Small droplets of water entrained in the flashed vapor produced in a flash-type evaporator, are removed by the ()Aspray pipesBdemistersCcondensersDsplash baffles
单选题在实船操纵性能试验中,为了使实船试验尽可能准确可靠,试验时一般应注意做到:()。 ①选择海面平静、海流潮流较小的水域。螺旋试验要求无风和静水,逆螺旋试验和Z形试验要求风力不超过四级; ②一般应在满载条件下进行试验,油轮和散货船还应进行压载状态的试验; ③试验前主机转速、航速应达到稳定的试验速度; ④校准有关仪器设备A①②B①③C②③④D①②③④
问答题已知某内河船船模长4m,湿面积4.6m2,缩尺比α=25,在试验水池中速度为1.8m/s时测得总阻力为3.6kgf,求:实船相应航速、总阻力、有效马力(摩擦阻力按1957ITTC公式;不考虑粗糙度补贴,ν=1.3064*10-6m2/s,ρ=999.63kg/m)
单选题All portable fine extinguishers must be capable of being().Acarried by hand to a fireBcarried or rolled to a fireCrecharged in the fieldDused on class B fires