pH

英美['pi 'etʃ]

低频词常用词汇

pH 酸碱值

来自德语pH,来自Potenz,能力，力量，词源同potent,H,氢离子，缩写自hydrogen ion.

pH: 1909, from German PH, introduced by S.P.L. Sörensen, from P, for German Potenz "potency, power" + H, symbol for the hydrogen ion that determines acidity or alkalinity.
ph: now in English usually representing "f," originally it was the combination used by Romans to represent Greek letter phi (cognate with Sanskrit -bh-, Germanic -b-), which at first was an aspirated "p," later the same sound as German -pf-. But by 2c. B.C.E. had become a simple sound made by blowing through the lips (bilabial spirant).

Roman "f," like modern English "f," was dentilabial; by c. 400, however, the sounds had become identical and in some Romanic languages (Italian, Spanish), -ph- regularly was replaced by -f-. This tendency took hold in Old French and Middle English, but with the revival of classical learning the words subsequently were altered back to -ph- (except fancy and fantastic), and due to zealousness in this some non-Greek words in -f- began to appear confusedly in -ph-, though these forms generally have not survived.

1. Skin is naturally slightly acidic and has a pH of 5.5.: 皮肤具有天然弱酸性，pH值为5.5。

2. A pH test measures the acidity or alkalinity of a substance.: pH值测试可检测物质的酸碱度。

4. The fluid that emerges from the vents is acidic (pH 3) and hot.: 从那些出口出来的液体呈酸性（pH值为3），且是热的。

5. pH is a measure of the concentration of free hydrogen atoms in a solution.: pH值是测试溶液中自由氢原子浓度的单位。