ppm(part per million)通常有两种用法,一种用于表示浓度,如大气中二氧化硫的浓度为若干ppm等;另一种是运用磁共振中化学位移δ的标度。前者是必须禁用的,这也许是由于浓度的单位过于繁杂(当然ppm本质上并不是单位),加之英、美对于ppm及其延伸ppb、ppt的理解不同,经常导致其歧义所致。但后者的正确运用却是举世公认的,它对于清晰地表达某一共振信号的相对化学位移及不同共振信号间的位移差带来了莫大的好处。 在磁共振中,有两种实现NMR的方法, ppm (part per million) There are two common uses, one for concentration, such as a few ppm for sulfur dioxide in the atmosphere, and the other for scaling the chemical shift, δ, in magnetic resonance. The former must be disabled, which may be due to the concentration of units is too complicated (of course, ppm is not the unit in essence), combined with the United Kingdom, the United States for the ppm and its extended ppb, ppt understanding of different, often lead to its ambiguity. However, the latter’s correct application is universally acknowledged. It brings great benefits to clearly expressing the relative chemical shifts of a resonance signal and the difference in displacement between different resonance signals. In magnetic resonance, there are two ways to achieve NMR,