directional

Unless he was equipped with a directional microphone, he was out of earshot..除非给他配备一个定向扬声器，否则谁也听不见他。

directional drilling,定向钻进；定向钻井；定向钻孔

directional solidification,定向凝固

directional valve,方向阀；定向阀

directional control,定向控制

solenoid directional valve,电磁换向阀

directional coupler,定向耦合器

directional derivative,方向导数

directional antenna,定向天线

directional control valve,n. 定向控制阀

directional distribution,方向分布

directional light,平行光；定向光源；方位灯

directional filter,方向滤波器；分带网络

directional stability,方向稳定性；航向保持性；航向稳定性

directional property,定向性；方向性