ultralown.超低ultraadj.超；过激的；极端的n.过激论者；急进论者ultrafine particulates超细颗粒物Ultrashortwave therapy超短波Ultrafine carbon black超细碳黑Ultra-microstructure超微结构ultrametric inequality超度量不等式ultrasound degradation超声降解Ultra-smooth surface超光滑表面ultra fine-line grid超精细分辨率低能准直器ultra-tone generator超音频发生器ultra-light aircraft超轻型飞机; 超轻型航空器