UNITS OF THE INTERNATIONAL SYSTEM 国际制度的单位
The International System (abbreviated SI, for Systeme International, the French name for the system) was adopted in 1960 by the 11th General Conference on Weights and Measures. An expanded and modified version of the metric system, the International System addresses the needs of modern science for additional and more accurate units of measurement. The key features of the International System are decimalization, a system of prefixes, and a standard defined in terms of an invariable physical measure.
国际制度（国际制度的缩写为SI，是国际制度的法语名称）被1960年的第十一届大会用于度量衡。公制的扩大和修改版本，即国际制度针对了现代科学附加的及更加正确的度量单位的需要。国际制度的主要特点是采用了十进制法、字首体系、以不变的物理度量方式解释的标准。
BASE UNITS 基本单位
The International System has base units from which all others in the system are derived. The standards for the base units, except for the kilogram, are defined by unchanging and reproducible physical occurrences. For example, the meter is defined as the distance traveled by light in a vacuum in 1/299,792,458 of a second. The standard for the kilogram is a platinum-iridium cylinder kept at the International Bureau of Weights and Standards in Sevres, France.
国际制度有基本单位，由此衍生出此制度中的其他单位。除千克以外，基本单位的标准以不变的且可再生的物理事件为解释。例如，公尺被解释为光在真空中以每1/299,792,458秒的速度所穿越的距离。千克的标准是指置于法国塞夫勒的国际度量及标准局的白金铱圆柱为准。
UNITQUANTITYSYMBOL
单位数量符号
meter公尺length长度m
kilogram千克mass质量kg
second秒time时间s
ampere安培electric current电流A
kelvin开temperature温度K
mole摩尔amount of matter数量mol
candela烛光luminous intensity发光强度cd
SUPPLEMENTARY UNITS辅助单位
The International System uses two supplementary units that are based on abstract geometrical concepts rather than physical standards.
国际制度采用了两种辅助单位，其依据于抽象的几何概念而非物理标准。
UNITQUANTITYSYMBOL
单位数量符号
radian弧度plane angles平面角rad
steradian立体弧度solid angles立方角sr
PREFIXES 字首
A multiple of a unit in the International System is formed by adding a prefix to the name of that unit. The prefixes change the magnitude of the unit by orders often from 10 18 to 10 -18.
经由在单位名称前面加一字首构成国际制度单位的倍数。字首通常按顺序从10的18次幂到10的-18次幂改变单位的量。
PREFIXSYMBOL MULTIPLYING FACTOR
字首符号乘法因数
exa-代表10的18次幂E10的18次幂 = 1,000,000,000,000,000,000
peta-代表10的15次幂P10的15次幂 = 1,000,000,000,000,000
tera-代表"万亿"T10的12次幂 = 1,000,000,000,000
giga-代表"十亿"G10的9次幂 = 1,000,000,000
mega-代表"百万"M10的6次幂 = 1,000,000
kilo-代表"千"K10的3次幂 = 1,000
hecto-代表"百"h10的2次幂 = 100
deca-代表"十"da10 = 10
deci-代表"十分之一"d10的-1次幂 = 0.1
centi-代表"百分之一"c10的-2次幂 = 0.01
milli-代表"千分之一"m10的-3次幂 = 0.001
micro-代表"百万分之一" μ10的-6次幂 = 0.000,001
nano-代表"毫微"n10的-9次幂 = 0.000,000,001
pico-代表"万亿分之一"p10的-12次幂 = 0.000,000,000,001
femto-代表"千万亿分之一" f10的 15次幂 = 0.000,000,000,000,001
atto-代表"百亿亿分之一" a10的 18次幂 = 0.000,000,000,000,000,001
ADDITIONAL UNITS 附加单位
Listed below are a few of the non-SI units that are commonly used with the International System.
如下所列的几个非国际制度单位通常用于国际制度
UNITQUANTITYSYMBOL
单位数量符号
angstrom ( = 10 -10m)lengthA
埃(=10 -10米)长度
electron-volt ( = 0.160 aJ) energyeV
电子伏特(=0.160焦耳)能量
hectare ( = 10,000 m2)land areaha
公顷(=10,000平方米)面积
liter ( = 1.0 dm3)volume or capacityl
升(=1.0立方米)容积或容量
standard atmosphere (= 101.3 kPa) pressureatm
标准大气压(=101.3毫巴)压强
DERIVED UNITS 导出单位
Most of the units in the International System are derived units, that is units defined in terms of base units and supplementary units. Derived units can be divided into two groups - those that have a special name and symbol, and those that do not.
国际制度中大多数单位都是衍生单位，即以基本单位和补充单位的方式加以解释的单位。衍生单位可分为两组──具有特定名称和符号的一组，不具有特定名称和符号的一组
WITHOUT NAMES AND SYMBOLS 无名称和符号
MEASURE OF DERIVATION
量 导出
acceleration加速度 m/s2
angular acceleration角加速度 rad/s2
angular velocity角速度 rad/s
density密度 kg/m3
electric field strength电场量 V/m
luminance亮度 cd/m2
magnetic field strength磁场量 A/m
velocity速度 m/s
WITH NAMES AND SYMBOLS 带名称和符号
UNITMEASURE OFSYMBOLDERIVATION
单位量符号导出
coulomb库electric charge电量CA·s
farad法拉electric capacitance电容 FA·s/V
henry亨利inductance电感HV·s/A
hertz赫兹frequency频率Hzcycles/s
joule焦耳quantity of energy能量JN·m
lumen流明flux of light光通量lmcd·sr
lux勒克斯illumination照度lxlm/m2
newton牛顿force力Nkg·m/s2
ohm欧姆electric resistance电阻ΩV/A
pascal帕斯卡pressure压强PaN/m2
tesla特斯拉magnetic flux density磁通量密度 TWb/m2
volt伏特voltage电压VW/A
watt瓦特power功率WJ/s
weber韦伯magnetic flux磁通量WbV·s
