precipitation

n. [化学] 沉淀，[化学] 沉淀物；冰雹；坠落；鲁莽

中文词源

precipitation 降水，沉淀，沉积

来自precipitate,降水，降雪，沉积。

precipitation (n.): late 15c., "a casting down" (of the evil angels from heaven), also, in alchemy "separation of a solid substance from a solution," from Middle French precipitation (15c.) and directly from Latin praecipitationem (nominative praecipitatio) "act or fact of falling headlong, haste," noun of action from past participle stem of praecipitare "fall, be hasty," from praeceps "steep" (see precipice). Meaning "sudden haste" is c. 1500. Meaning "act of falling from a height" is attested from 1610s. Meteorological sense of "rain, snow, dew, etc." is from 1670s.

1. pre- "before, forth" + cipit- + -ation.2. 本义为：头向前、朝前倾斜。很显然这会造成不稳定，进而导致摔倒、摔下、坠落，由此引申为：猛然摔下，坠落，又由此引申为沉淀。以及由头向前而表示的那种不沉稳之意，进而引申为：轻率、鲁莽、急促。

2. Techniques for controlling particulates include filtering, washing, centrifugal separation, and electrostatic precipitation.: 控制颗粒污染物的技术包括过滤、洗涤、离心分离、静电沉降.

3. Guitar's experiments did not stimulate any practical study of the electrostatic - precipitation principle.: 吉他的试验均未能激起任何关于电收尘原理的实用性研究.

4. Various substances in plant extracts may cause spontaneous or non - specific precipitation.: 植物提取液中的各种物质都可能引起自发的或非专化性的沉淀.

5. Aerial photography can provide valuable information on precipitation, evapotraspiration, interception, and runoff.: 航空摄影可提供有关降水量、蒸发蒸腾量、入渗和径流量的有价值的资料.