writing style - What is the origin of shorthand for with - gt; w . . . 8 CyberDefinitions gives a plausible explanation: Although its origin is contested, w has been used at least since the rise of the fast-food industry in the 1950s As a form of shorthand to save time when writing down food orders, waiters replaced the words "with" and "without" with the abbreviations w and w o
w w 和w v 直接表示浓度吗？ - 知乎 w w, w v 都表示浓度。 浓度从底层上可以理解为两种物质的比例（就是通常概念下的溶质和溶剂） 后一个单位具体是w v取决于行业习惯与实际需求，比如生产上配个50L 底物溶液，溶剂肯定是用称来取样的，那么这时候操规上浓度用w w更为合适一些。 浓度与药效无