ーExcerpt from JIS Z 8203（2000）ーsAKYZEPTGMkhdadcmμnｐｆazyThe International System of Units is used to clear up the inconvenience of international technical communion and international trade caused by the metric system and British measurement system, SI is formed by base units, derived units and prefixes. The system definition is shown in Table 1 and other items are shown in Table 2 to Table 5.Thermodynamic[plane］ AngleSolid angleFrequencyForcePressure, stressEnergy, work, quantity of heatPower, radiant fluxQuantity of electricityElectric potential, potential difference, voltage, electromotive forceVoltCapacitanceElectric resistanceElectric conductanceMagnetic fluxMagnetic flux densityInductanceCelsius temperatureLuminous fluxIlluminanceActivity referred to a radionuclideBecquerelAbsorbed dose, Specific energy（imparted）, KermaDose equivalentSI base unitNameSymbolmMeterSI unitSILengthThe meter is the length of the path traveled by light in a vacuum during a time interval of 1/299,792,458 of a second.MassKilogramkgThe kilogram is a unit of mass, it is equal to the mass of international prototype of the kilogram.TimeSecondThe second is the duration of 9,192,631,770 periods of radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in a vacuum, would produce between these conductors a force equal to 2×10-7 Newton per meter of length.Kelvin, a unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.Table 5 SI derived units expressed in terms of base unitsElectric currentAmpereKelvinemperatureAmount of substanceMolemolLuminous intensityCandelacdRadianSteradianHertzNewtonPascalJouleWattCoulombFaradOhmSiemensWeberTeslaHenryDegree Celsius℃1 ℃＝1 KLumenLuxGraySievertSI base units（7）…Table 2SI derived unitsSI prefixes（20）…Table 6lm1 lm＝1 cd･sr1 lx＝1 lm/m2lxBq1 Bq＝1 s−1Gy1 Gy＝1 J/kgSv1 Sv＝1 J/kgSI derived unit with special names including supplementary units…Table 3, Table 4Other forms of SI derived units…Table 5SquareAreaCubicVolumeMeter/secondVelocityMeter/second2AccelerationEvery meterWave numbersDensityKilogram every cubic meterElectric current densityAmpere every square meterMagnetic field strengthAmpere every meterConcentration of substanceMole every cubic meterSpecific volumeLuminanceTable 6 SI prefixesCubic meter every kilogramCandela every square meter1122Table 2 SI base units and their definitionTable 3 SI derived units with special names including supplementary unitsTable 4 the derived units with special names established with a view to safeguarding human healthSI derived unitsVolumeVolumeNameItemNameTable 1 The Composing of the International System of UnitsSI derived unitsExpression in terms of SI base units and SI Symbolderived units.rad1 rad＝1 m/m1 sr＝1 m2/m2sr1 Hz＝1 s−1Hz1 N＝1 kg･m/s2N1 Pa＝1 N/m2PaJ1 J＝1 N･mW1 W＝1 J/s1 C＝1 A･sC1 V＝1 W/AVF1 F＝1 C/VΩ1 Ω＝1 V/A1 S＝1 Ω−1SWb1 Wb＝1 V･s1 T＝1 Wb/m2TH1 H＝1 Wb/ASymbolExpression in terms of SI base units and SI derived units.DefinitionVolumeFactor1024102110181015101210910610310210110−110−210−310−610−910−1210−1510−1810−2110−24Derived unitsNameSymbolm2m3m/sm/s2m−1kg/m3A/m2A/mmol/m3m3/kgcd/m2PrefixesNameYottaZettaExaPetaTeraGigaMegaKiloHectoDekaDeciCentiMilliMicroNanoPicoFemtoAttoZeptoYoctoSymbolInternational System of Units （SI）
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