During a five-month field test of HyGreen at the University of Florida's medical center, infection rates dropped to zero.
在佛罗里达大学医疗中心进行的为期五个月的超洁试用过程中，感染率降低到零。
2
The first known use of "zero-gravity" is from Jack Binder (better known for his work as an artist) in 1938, and actually refers to the gravityless state of the center of the Earth's core.
1938年杰克·宾得（作为一个艺术家而闻名）第一次使用“零重力”，事实上是指地球核心的无重力状态。
3
Make v2 zero, and you see exactly that you see here the same result, so this must be the velocity of the center of mass.