parts per million

基本解釋

The light reflected by the newfound extrasolar planet, or exoplanet, changed by only about 6.5 parts per million, relative to the brightness of the host star.
這顆新發(fā)現(xiàn)的太陽系外行星——或者稱為外行星——所反射的光線變化相對于其恒星的亮度只有百萬分之6.5。
At 250 parts per million CO2, the shellfish grew vigorously, and at 750 ppm and higher they were crippled, feeble creatures with thin shells and weak connective tissues.
在 CO2 含量為百萬分之 250 時(shí)，甲殼類生物生長得很好，而到了百萬分之 750 或更高時(shí)，它們的甲殼變薄、連結(jié)物質(zhì)變?nèi)?，成了殘破而虛弱的生物?/li>
They added that concentrations of carbon dioxide, the main greenhouse gas, should be limited to 350 parts per million of the atmosphere -- below current levels of 387 ppm.
同時(shí)應(yīng)該把大氣中二氧化碳的含量應(yīng)該控制在百萬分之350個(gè)單位，目前的含量水平為百萬分之387個(gè)單位。

The team found levels of lead as high as thirty-two thousand parts per million in tests on some paint samples from Ecuador.
Breathing in two hundred parts per million of carbon monoxide will cause the first signs of poisoning.
Twelve thousand parts per million of the gas will cause death in one to three minutes.

Floating sensors hold the oxygen to between 2 and 2.5 parts per million of water.
FORBES: Muckraker

parts s per million 百萬分率;百萬分之
parts w per million 百萬分之一
parts per million concentrationppm 濃度
defective parts per million 缺陷零件每百萬分之幾;每百萬零件不合格數(shù);杰爾還是每百萬缺陷數(shù);每百萬缺陷數(shù)
equivalent parts per million 毫克當(dāng)量