Parts-per 표기

과학과 공학에서 **parts-per 표기**는 기타 무차원량의 작은 값들을 설명하기 위한 의사 단위들의 집합이다. (예: 몰분율, 질량백분율) 이러한 분수들이 원량 대 원량 측정 기준이지만 어떠한 측정 단위와도 관련되지 않은 순수한 숫자들이다. 보통은 **parts-per-million** (**ppm**, 10−6), **parts-per-billion** (**ppb**, 10−9), **parts-per-trillion** (**ppt**, 10−12) and **parts-per-quadrillion** (**ppq**, 10−15) 등이 사용된다. 이 표기법은 국제단위계(SI)에 속하지 않으며 의미는 여러 가지로 정의될 수 있다.
# Parts-per 표현
{| class="wikitable" |1 of →
= ⭨
of ↓ !per
cent
(%) !per
mille
(‰) !per
10,000
(‱) !per
100,000
(pcm) !per
million
(ppm) !per
billion
(ppb) |- !% |1||0.1||0.01||0.001||0.0001||-7 |- !‰ |10||1||0.1||0.01||0.001||-6 |- !‱ |100||10||1||0.1||0.01||-5 |- !pcm |1,000||100||10||1||0.1||0.0001 |- !ppm |10,000||1,000||100||10||1||0.001 |- !ppb |7||6||5||10,000||1,000||1 |}
# SI식 표기
{| class="wikitable" |- | align="right" |A strain of... | align="center" |2 cm/m | align="center" |2 parts per hundred | align="center" | 2%According to BIPM's SI brochure, section 5.3.7, "When [the percent symbol] is used, a space separates the number and the symbol %." This practice has not been well adopted with regard to the % symbol, is contrary to Wikipedia's *Manual of Style*, and is not observed here. | align="center" |2 × 10−2 |- | align="right" |A sensitivity of... | align="center" |2 mV/V | align="center" |2 parts per thousand | align="center" |2 ‰ **!** | align="center" |2 × 10−3 |- | align="right" |A sensitivity of... | align="center" |0.2 mV/V | align="center" |2 parts per ten thousand | align="center" |2 ‱ **!** | align="center" |2 × 10−4 |- | align="right" |A sensitivity of... | align="center" |2 μV/V | align="center" |2 parts per million | align="center" |2 ppm | align="center" |2 × 10−6 |- | align="right" |A sensitivity of... | align="center" |2 nV/V | align="center" |2 parts per billion **!** | align="center" |2 ppb **!** | align="center" |2 × 10−9 |- | align="right" |A sensitivity of... | align="center" |2 pV/V | align="center" |2 parts per trillion **!** | align="center" |2 ppt **!** | align="center" |2 × 10−12 |- | align="right" |A mass fraction of... | align="center" |2 mg/kg | align="center" |2 parts per million | align="center" |2 ppm | align="center" |2 × 10−6 |- | align="right" |A mass fraction of... | align="center" |2 μg/kg | align="center" |2 parts per billion **!** | align="center" |2 ppb **!** | align="center" |2 × 10−9 |- | align="right" |A mass fraction of... | align="center" |2 ng/kg | align="center" |2 parts per trillion **!** | align="center" |2 ppt **!** | align="center" |2 × 10−12 |- | align="right" |A mass fraction of... | align="center" |2 pg/kg | align="center" |2 parts per quadrillion **!** | align="center" |2 ppq **!** | align="center" |2 × 10−15 |- | align="right" |A volume fraction of... | align="center" |5.2 μL/L | align="center" |5.2 parts per million | align="center" |5.2 ppm | align="center" |5.2 × 10−6 |- | align="right" |A mole fraction of... | align="center" |5.24 μmol/mol | align="center" |5.24 parts per million | align="center" |5.24 ppm | align="center" |5.24 × 10−6 |- | align="right" |A mole fraction of... | align="center" |5.24 nmol/mol | align="center" |5.24 parts per billion **!** | align="center" |5.24 ppb **!** | align="center" |5.24 × 10−9 |- | align="right" |A mole fraction of... | align="center" |5.24 pmol/mol | align="center" |5.24 parts per trillion **!** | align="center" |5.24 ppt **!** | align="center" |5.24 × 10−12 |- | align="right" |A stability of... | align="center" |1 (μA/A)/min | align="center" |1 part per million per minute | align="center" |1 ppm/min | align="center" |1 × 10−6/min |- | align="right" |A change of... | align="center" |5 nΩ/Ω | align="center" |5 parts per billion **!** | align="center" |5 ppb **!** | align="center" |5 × 10−9 |- | align="right" |An uncertainty of... | align="center" |9 μg/kg | align="center" |9 parts per billion **!** | align="center" |9 ppb **!** | align="center" |9 × 10−9 |- | align="right" |A shift of... | align="center" |1 nm/m | align="center" |1 part per billion **!** | align="center" |1 ppb **!** | align="center" |1 × 10−9 |- | align="right" |A strain of... | align="center" |1 μm/m | align="center" |1 part per million | align="center" |1 ppm | align="center" |1 × 10−6 |- | align="right" |A temperature coefficient of... | align="center" |0.3 (μHz/Hz)/°C | align="center" |0.3 part per million per °C | align="center" |0.3 ppm/°C | align="center" |0.3 × 10−6/°C |- | align="right" |A frequency change of... | align="center" |0.35 × 10−9 ƒ | align="center" |0.35 part per billion **!** | align="center" |0.35 ppb **!** | align="center" |0.35 × 10−9 |}