词条 | barn |
释义 | barn farm building ![]() Wood is the traditional barn material, but sheet steel and aluminum have been increasingly used since World War II, particularly on large farms. Barns usually consist of two stories, the first to shelter animals or machines and the second to store hay or grain, though one-story barns were gaining in popularity in the late 20th century. measurement unit of area used to measure the reaction cross section (generally different from the geometric cross section) of atomic nuclei and subatomic particles in the study of their interactions with other nuclei or particles. It is equal to 10−24 square cm. The name, coined by U.S. scientists, is derived from the proverbial phrase “side of a barn,” something easy to hit. See cross section. |
随便看 |
|
百科全书收录100133条中英文百科知识,基本涵盖了大多数领域的百科知识,是一部内容开放、自由的电子版百科全书。