[1] Phillips W.D., The end of artefacts. Nature Physics, 2019, 15: 518.
[2] Gibney E., New definitions of scientific units are on the horizon. Nature, 2017, 550: 312–313.
[3] Klitzing K.V., Metrology in 2019. Nature Physics, 2017, 13: 198.
[4] Mise en pratique for the definition of the kelvin in the SI. https://www.bipm.org/utils/en/pdf/si-mep/SI-App2-kelvin.pdf, 2019 (accessed on May 20, 2019).
[5] Rourke P.M., Gaiser C., Gao B., Ripa D.M., Moldover M.R., Pitre L., Underwood R.J., Refractive-index gas thermometry. Metrologia, 2019, 56: 032001.
[6] Gao B., Zhang H.Y., Han D.X., Pan C.Z., Chen H., Song Y.N., Hu J.F., Kong X.J., Sparasci F., Plimmer M., Luo E.C., Pitre L., Measurement of thermodynamic temperature between 5 K and 24.5 K with single-pressure refractive-index gas thermometry. Metrologia, 2020, 57: 065006.
[7] Gao B., Pitre L., Luo E.C., Plimmer M.D., Lin P., Zhang J.T., Feng X.J., Chen Y.Y., Sparasci F., Feasibility of primary thermometry using refractive index measurements at a single pressure. Measurement, 2017, 103: 258–262.
[8] Pitre L., Sparasci F., Truong D., Guillou A., Risegari L., Himbert M.E., Determination of the Boltzmann constant using a quasi-spherical acoustic resonator. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2011, 369: 4014–4027.
[9] Gaiser C., Fellmuth B., Haft N., Primary dielectric-constant gas thermometry in the range from 2.4 K to 26 K at PTB. International Journal of Thermophysics, 2008, 29: 18–30.
[10] Pitre L., Sparasci F., Risegari L., Guianvarc’h C., Martin C., Himbert M., Plimmer M., Allard A., Marty B., Albo P.G., New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas. Metrologia, 2017, 54: 856–873.
[11] Rourke P.M.C., NRC microwave refractive index gas thermometry implementation between 24.5 K and 84 K. International Journal of Thermophysics, 2017, 38: 107.
[12] Gavioso R.M., Madonna Ripa D., Steur P.P.M., Dematteis R., Imbraguglio D., Determination of the thermodynamic temperature between 236 K and 430 K from speed of sound measurements in helium. Metrologia, 2019, 56: 045006.
[13] Osadchii S.М., Potapov B.G., Petukhov A.A., Sokolov N. A., Dragunov О.E., Pilipenko K.D., Stabilization of the temperature of resonator of an acoustic gas thermometer. Measurement Techniques, 2018, 61: 932–936.
[14] Berry K.H., NPL-75: A low temperature gas thermometry scale from 2.6 K to 27.1 K. Metrologia, 1979, 15(2): 89–115.
[15] Gaiser C., Fellmuth B., Haft N., Primary dielectric-constant gas thermometry in the range from 2.4 K to 26 K at PTB. International Journal of Thermophysics, 2008, 29: 18–30.
[16] Zhang H.Y., Gao B., Liu W.J., Pan C.Z., Han D.X., Plimmer M.D., Luo E.C., Pitre L., Resonance frequency measurement with accuracy and stability at the 10-12 level in a copper microwave cavity below 26 K by experimental optimization. 2020, 31: 075011.
[17] Gao B., Chen H., Han D.X., Gambette P., Zhang H.Y., Pan C.Z., Liu Y.W., Yu B., Luo E.C., Plimmer M.D., Pitre L., Realization of ppm level pressure stability for primary thermometry using a primary piston gauge. Measurement, 2020, 160: 107807.
[18] Rusby R., Head D., Meyer C., Tew W., Astrov D., Key comparison: Final report on CCT-K1: realizations of the ITS90, 0.65 K to 24.5561 K, using rhodium iron resistance thermometers. Metrologia, 2006, 43: 03002.
[19] Gaiser C., Fellmuth B., Steur P., Szmyrka-Grzebyk A., Manuszkiewicz H., Lipinski L., Peruzzi A., Rusby R., Head D., EURAMET key comparison no. EURAMET. T-K1: realisations of the ITS-90 from 2.6 K to 24.5561 K, using rhodium-iron resistance thermometers. Metrologia, 2017, 54: 03002.
[20] Nakano T., Tamura O., Sakurai H., Comparison system for the calibration of Capsule-type standard Platinum resistance thermometers at NMIJ/AIST. International Journal of Thermophysics, 2008, 29: 881–889.
[21] Preston-Thomas H., The international temperature scale of 1990. Journal of Chemical Thermodynamics, 1990, 27: 3–10.
[22] Gao B., Pan C.Z., Chen Y.Y., Song Y.N., Zhang H.Y., Han D.X., Liu W.J., Chen H., Luo E.C., Pitre L., Realization of an ultra-high precision temperature control in a cryogen-free cryostat. Review of Scientific Instruments, 2018, 89: 104901.
[23] Chen Y.Y., Zhang H.Y., Song Y.N., Pan C.Z., Gao B., Liu W., Chen H., Han D., Luo E.C., Plimmer M.D., Pitre L., Thermal response characteristics of a SPRIGT primary thermometry system. Cryogenics, 2019, 97: 1–6.
[24] Pan C.Z., Gao B., Song Y.N., Zhang H.Y., Han D.X., Hu J.F., Liu W.J., Chen H., Plimmer M., Sparasci F., Luo E.C., Pitre L., Active suppression of temperature oscillation from a pulse-tube cryocooler in a cryogen-free cryostat: Part 1. Simulation modeling from thermal response characteristics. Cryogenics, 2020, 209: 103097.
[25] Pan C.Z., Hu J.F., Zhang H.Y., Song Y.N., Han D.X., Liu W.J., Chen H., Plimmer M., Sparasci F., Luo E.C., Gao B., Pitre L., Active suppression of temperature oscillation from a pulse-tube cryocooler in a cryogen-free cryostat: Part 2. Experimental realization. Cryogenics, 2020, 109: 103096.
[26] F18 Operator’s Handbook.
http://www.isotechna.com/v/vspfiles/product_manuals/asl/F18.pdf, (accessed on May 10, 2019).
[27] Angel E., Problem-solving strategies (Problem books in Mathematics), Springer-Verlag, New York, 1998, pp. 163.
[28] F900 Operator’s Handbook.
http://www.isotechna.com/v/vspfiles/product_manuals/asl/F900.pdf, (accessed on June 29, 2019).
[29] Allan D.W., Statistics of atomic frequency standards, Proceedings of the IEEE, 1966, 54: 221–230.
