千分之几 meaning in Chinese

partper thousand
parts per thousand
ppk
ppt

Neon , a rare gas in the air , takes only fractional percentage point of the volume
氖是空气中的稀有气体，只占空气体积的千分之几。
Theoretically , nuke war is one of the most distructive disasters to human world next to the " artificial black hole " , capable of vaporing any person in its explosion range within some thousandths of a second
理论上，核战是紧随“人工黑洞”之后，毁灭人类速度最快的灾难之一，处于核弹爆炸范围中的人，只要千分之几秒，就会被蒸发成一团气体。