pH

英美['pi 'et?]

低頻詞常用詞匯

pH 酸堿值

來(lái)自德語(yǔ)pH,來(lái)自Potenz,能力，力量，詞源同potent,H,氫離子，縮寫自hydrogen ion.

pH: 1909, from German PH, introduced by S.P.L. S?rensen, 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.: 皮膚具有天然弱酸性，pH值為5.5。

2. A pH test measures the acidity or alkalinity of a substance.: pH值測(cè)試可檢測(cè)物質(zhì)的酸堿度。

4. The fluid that emerges from the vents is acidic (pH 3) and hot.: 從那些出口出來(lái)的液體呈酸性（pH值為3），且是熱的。

5. pH is a measure of the concentration of free hydrogen atoms in a solution.: pH值是測(cè)試溶液中自由氫原子濃度的單位。