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翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク History of mass spectrometry ： ウィキペディア英語版 History of mass spectrometry The history of mass spectrometry has its roots in physical and chemical studies regarding the nature of matter. The study of gas discharges in the mid 19th century led to the discovery of anode and cathode rays, which turned out to be positive ions and electrons. Improved capabilities in the separation of these positive ions enabled the discovery of stable isotopes of the elements. The first such discovery was with the element neon, which was shown by mass spectrometry to have at least two stable isotopes: 20Ne (neon with 10 protons and 10 neutrons) and 22Ne (neon with 10 protons and 12 neutrons). Mass spectrometers were used in the Manhattan Project for the separation of isotopes of uranium necessary to create the atomic bomb. ==Prout's Hypothesis== Prout's hypothesis was an early 19th-century attempt to explain the properties of the chemical elements using the internal structure of the atom. In 1815, the English chemist William Prout observed that the atomic weights that had been measured were integer multiples of the atomic weight of hydrogen.〔William Prout (1815). On the relation between the specific gravities of bodies in their gaseous state and the weights of their atoms. ''Annals of Philosophy'', 6: 321–330. (Online reprint )〕〔William Prout (1816). Correction of a mistake in the essay on the relation between the specific gravities of bodies in their gaseous state and the weights of their atoms. ''Annals of Philosophy'', 7: 111–13. (Online reprint )〕 Prout's hypothesis remained influential in chemistry throughout the 1820s. However, more careful measurements of the atomic weights, such as those compiled by Jöns Jakob Berzelius in 1828 or Edward Turner in 1832, appeared to disprove it. In particular the atomic weight of chlorine, which is 35.45 times that of hydrogen, could not at the time be explained in terms of Prout's hypothesis. It would take the better part of a century for this problem to be resolved. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「History of mass spectrometry」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.