在质量的比较中,1千克=()英磅:

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基本正确，但实际上u和amu是不同的单位。
mu=amu=atomic mass unit。
现在的原子质量单位是指1960年IUPAP和1961年IUPAC通过定义的unified atomic mass unit (u), u=D=Da=道尔顿。amu是基于O-16的质量的1/16（物理学），或O的平均质量的1/16（化学）为基准的，和现在u的标准（C-12的1/12）不同。
基本上，1u≈1amu。
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http://bbs.antpedia.com/thread-357-1-1.html
原子质量单位（amu 或u）有时称统一原子质量单位，或道而顿（Dalton，Da，D）是用来衡量原子或分子质量的单位，它被定义为碳12原子质量的1/12。
1 u ＝ 1/NA 克 = 1/(1000 NA) 千克 (NA为阿伏加德罗常数)
1 u ≈ 1.66053886 × 10-27 千克
“amu”这个符号一般出现在较老的文献中。在书写原子量的时候经常不写任何单位，而将原子质量单位作为默认的单位。在生物化学和分子生物学文献中（特别是描述蛋白质的时候），一般使用道而顿这个名词，或者使用Da。由于蛋白是大分子，他们通常有上千道而顿的分子量，这时候使用kDa也就是1000Da作为单位。
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以下摘自英语Wiki`pedia。
The unified atomic mass unit (u), or dalton (Da) or, sometimes, universal mass unit, is a unit of mass used to express atomic and molecular masses. It is the approximate mass of a hydrogen atom, a proton, or a neutron.
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说明：以上http://bbs.antpedia.com/thread-357-1-1.html 是抄中文Wiki`pedia的，在英语版本中如下（关于amu的说法和中文版本有细微差别，主要是翻译原因）：
The atomic mass unit (amu) is an older name for a very similar scale (unified atomic mass unit, dalton, or universal mass unit). The symbol amu for atomic mass unit is not a symbol for the unified atomic mass unit. Its use is an historical artifact (written during the time when the amu scales were used), an error (possibly deriving from confusion about historical usage), or correctly referring to the historical scales that used it (see History). Atomic masses are often written without any unit and then the unified atomic mass unit is implied.
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History
The chemist John Dalton was the first to suggest the mass of one atom of hydrogen as the atomic mass unit. Francis Aston, inventor of the mass spectrometer, later used 1⁄16 of the mass of one atom of oxygen-16 as his unit.

Before 1961, the physical atomic mass unit (amu) was defined as 1⁄16 of the mass of one atom of oxygen-16, while the chemical atomic mass unit (amu) was defined as 1⁄16 of the average mass of an oxygen atom (taking the natural abundance of the different oxygen isotopes into account). Both units are slightly smaller than the unified atomic mass unit, which was adopted by the International Union of Pure and Applied Physics in 1960 and by the International Union of Pure and Applied Chemistry in 1961. Hence, before 1961 physicists as well as chemists used the symbol amu for their respective (and slightly different) atomic mass units. One still sometimes finds this usage in the scientific literature today. However, the accepted standard is now the unified atomic mass unit (symbol u), with: 1 u = 1.000 317 9 amu (physical scale) = 1.000 043 amu (chemical scale). Since 1961, by definition the unified atomic mass unit is equal to one-twelfth of the mass of a carbon-12 atom.

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