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Progress in the Determination of the Avogadro Constant |
ZHANG Ji-tao1,LUO Zhi-yong2,ZHAO Ke-gong2 |
1.State Key Lab of Precision Measurement Technology & Instruments, Department of Precision Instruments & Mechanology, Tsinghua University, Beijing 100084, China
2.National Institute of Metrology, Beijing 100013, China |
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Abstract The progress in the determination of the Avogadro constant(NA) is reviewed. The x-ray crystal density method is considered as one of the most accurate route to determine NA. According to this method, the molar mass, density and lattice parameter of the single crystal silicon could be measured accurately, then a relative measurement uncertainty 2×10-8 of NA is achievable. The determination of the molar mass, the diameter of the silicon sphere, and the thickness of the oxide layer on the silicon sphere are key issues that affect the measurement accuracy of NA currently,and the focal points for further reseach of the datermination NA is presented.
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[1]Mana G, Zosi G. The Avogadro constant[J]. Rev Nuovo Cimento, 1995, 18(3):1-23.
[2]Becker P. History and progress in the accurate determination of the Avogadro constant[J]. Rep Prog Phys, 2001, 64:1945-2008.
[3]Murrell J N. Avogadro and his constant[J]. Helvetica Chimica Acta, 2001, 84:1314-1327.
[4]Becker P, Bièvre P De, Fujii K, et al. Considerations on future redefinitions of the kilogram, the mole and of other units[J]. Metrologia, 2007, 44:1-14.
[5]Becker P, Friedrich H, Fujii K, et al. The Avogadro constant determination via enriched silicon-28[J]. Meas Sci Technol, 2009, 20:092002.
[6]Fujii K, Waseda A, Kuramoto N, et al. Present state of the Avogadro constant determination from silicon crystals with natural isotopic compositions[J]. IEEE Trans Instrum Meas, 2005, 54(2):854-859.
[7]赵克功. 更新计量基本单位kg定义的研究现状[J]. 计量学报, 2001, 22(2):133-141.
[8]罗志勇. 质量自然基准的研究进展及发展方向[J]. 计量学报, 2004, 25(2):138-141.
[9]罗志勇,杨丽峰,顾英姿,等. 固体密度基准研究[J]. 科学通报, 2007, 52(12):1382-1386.
[10]罗志勇,杨丽峰,陈允昌. 标准硅球直径精密测量系统的设计[J]. 计量学报, 2005, 26(4):289-294.
[11]罗志勇,陈朝晖,顾英姿,等. 基于数值模拟的高准确度五步相移算法研究[J]. 光学学报, 2006, 26(11):1687-1690.
[12]Zhang J T,Li Y, Wu X J, et al. Determining mean thickness of the oxide layer by mapping the surface of a silicon sphere[J]. Opt Exp, 2010, 18(7):7331-7339.
[13]张继涛, 李岩, 罗志勇. 一种可溯源的光谱椭偏仪标定方法[J]. 物理学报, 2010, 59(1):186-191.
[14]Zhang J T, Li Y, Luo Z Y, Wu X J. Determination of mean thickness of an oxide layer on a silicon sphere by spectroscopic ellipsometry[J]. Chin Phys Lett, 2010, 27(5):050601.
[15]Ferroglio L, Mana G, Massa E. Si lattice parameter measurement by centimeter X-ray interferometry[J]. Opt Exp, 2008, 16(21):877-888.
[16]Borys M, Giser M, Mecke M. Mass determination of silicon spheres used for the Avogadro project[J]. Measurement, 2007, 40:785-790.
[17]Picard A, Bignell N, Borys M, et al. Mass comparison of the 1 kg silicon sphere AVO#3 traceable to the international prototype K[J]. Metrologia, 2009, 46:1-10.
[18]Becker P, Schiel D, Pohl H-J, et al. Large-scale production of highly enriched 28 Si for the precise determination of the Avogadro constant[J]. Meas Sci Technol, 2006, 17:1854-1860.
[19]Ding T, Wan D, Bai R, et al. Silicon isotope abundance ratios and atomic weights of NBS-28 and other reference materials[J]. Geochimica et Cosmochimica Acta, 2005, 69(23):5487-5494.
[20]Busch I, Danzebrink H, Krummy M, et al. Oxide layer mass determination at the silicon sphere of the Avogadro project[J]. IEEE Trans Instrum Meas, 2009, 58(4):891-896. |
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