| 单词 |
boron |
| 释义 |
boron Chem.|ˈbɔərɒn|
[f. bor-ax, with the ending of carb-on, the element being extracted from borax, and resembling carbon in some of its properties.]
a. One of the elementary bodies; a non-metallic solid, not fusible at any known temperature. It is obtained as a dark brown or greenish brown powder (amorphous boron); and in a less pure form as crystals (adamantine boron). In some of its properties it resembles carbon and silicon. Symbol B. boron hydride, any of a series of compounds of boron and hydrogen; at one time considered as potential rocket fuel, and among the earliest examples of electron-deficient compounds; = borane.
1812Sir H. Davy Chem. Philos. 315, I first procured boron in October, 1807, by the electrical decomposition of boracic acid. 1869Roscoe Elem. Chem. 151 Boron combined with oxygen and sodium is found as borax in nature. 1879F. Jones in Jrnl. Chem. Soc. XXXV. 41, I am not aware that any attempt has been made since 1809 to obtain boron hydride. 1933A. Stock Hydrides of Boron & Silicon iii. 40 The yield of boron hydride..was better if they used phosphoric instead of hydrochloric acid for decomposing the boride. 1955Q. Rev. (Chem. Soc.) IX. 176 The boron hydrides and some of their derivatives are examples of electron-deficient compounds. 1961New Scientist IX. 484 These boron hydrides appeared to be of academic interest only until..the need for rocket fuels became apparent.
b. Examples in Nucl. Physics.
1938Proc. Camb. Phil. Soc. XXXIV. 290 (title) The Disintegration of Boron by Slow Neutrons. Ibid. 291 By such measurements on the image of the cloud track resulting from the boron disintegration we have been able to determine the..origin of the He and Li particles. 1949Rossi & Staub Ionization Chambers & Counters viii. 189 The construction of a highly sensitive boron chamber that can be used for detecting neutrons of all energies. Ibid. 194 These detectors have been named long boron counters. 1957Gloss. Terms Nucl. Sci. (A.S.A.) 21/1 Because of its high absorption of neutrons, boron may be used (e.g., in the form of boron steel) as a control absorber in thermal nuclear reactors. 1963B. Fozard Instrumentation Nucl. Reactors iii. 30 Typical sensitivities for a boron-coated reactor control ionisation chamber. |
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