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== வெளி இணைப்புகள் ==
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|image1=BIPM: [http://www.bipm.org/en/scientific/mass/pictures_mass/prototype.html The IPK in three nested bell jars]
|image2=NIST: [http://www.mel.nist.gov/galleryph/calres/pages/049a.htm K20, the US National Prototype Kilogram], resting on an egg crate fluorescent light panel
|image3=BIPM: ''[http://www.bipm.org/en/scientific/mass/pictures_mass/cleaning.html Steam cleaning a 1 kg prototype before a mass comparison]''
|image4=BIPM: [http://www.bipm.org/en/scientific/mass/pictures_mass/vault.html The IPK and its six sister copies in their vault]
|image5=The Age: [http://www.theage.com.au/ffximage/2007/06/14/rgN1506_csiro_wideweb__470x343,0.jpg Silicon sphere for the Avogadro Project]
|image6=NPL: [http://www.npl.co.uk/server.php?show=conMediaFile.1083 The NPL’s Watt Balance project]
|image7=NIST: [http://museum.nist.gov/object.asp?ObjID=51 The Rueprecht Balance], Austrian-made, precision balance used by the NIST from 1945 until 1960
|image8=BIPM: [http://www.bipm.org/en/scientific/mass/research_mass/flexure-strip.html The FB-2 flexure-strip balance], the BIPM’s modern precision balance featuring a standard deviation of one ten-billionth of a kilogram (0.1 µg)
|image9=BIPM: [http://www.bipm.org/en/scientific/mass/pictures_mass/mettler.html Mettler HK1000 balance], featuring 1 µg resolution and a 4 kg maximum mass. Also used by NIST and Sandia National Laboratories’ Primary Standards Laboratory
|image10=Micro-g LaCoste: [http://www.microglacoste.com/images/FG5.small.jpg FG-5 absolute gravimeter,] ([http://www.microglacoste.com/images/fg5schem.jpg diagram]), used in national labs to measure gravity to 2 [[Gal (unit)|µGal]]<!--NOTE TO EDITORS: The Micro-g LaCoste Web site does not display properly on some computer systems. The accuracy is NOT 2 mGal and is indeed 2 µGal. Please see discussion topic at [[Talk:Kilogram#Micro-g_LaCoste_FG-5_accuracy]]--> accuracy
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* National Institute of Standards and Technology (NIST): ''[http://www.nist.gov/public_affairs/releases/electrokilogram.htm NIST Improves Accuracy of ‘Watt Balance’ Method for Defining the Kilogram]''
* The U.K.’s National Physical Laboratory (NPL): [http://www.npl.co.uk/server.php?show=ConWebDoc.2087 An overview of the problems with an artifact-based kilogram]
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