mid-air

n.

空中；半空中；

1. She can walk even on a light wire in the air.
   她甚至能在空中的钢丝上走路。
2. This is why it speeds through the air.
   这就是为什么它会快速飞入空中的道理。

Mid-air pan-and-zoom on wall-sized displays
StrikeAPose: revealing mid-air gestures on public displays
Method for safer mid-air refueling
Soap:a pointing device that works in mid-air
UltraHaptics:multi-point mid-air haptic feedback for touch surfaces
A handle bar metaphor for virtual object manipulation with mid-air interaction
Soap: a pointing device that works in mid-air
Consumed endurance: a metric to quantify arm fatigue of mid-air interactions
StrikeAPose: Revealing mid-air gestures on public displays
ZeroN:mid-air tangible interaction enabled by computer controlled magnetic levitation