好牛的驢子
Parts-per notation - Wikipedia, the free encyclopedia 主人快點! 我們在趕時間啦!In science and engineering, the parts-per notation is a set of pseudo units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure nu...
全文閱讀