Non-uniqueness is a fundamental limit to the reproducibility of a defined temperature scale. In this paper, the non-uniqueness of temperatures, T 90 , on the International Temperature Scale of 1990 (ITS-90) above the silver point is fully investigated for the first time. The non-uniqueness arises from three causes: inconsistency in extrapolation with the choice of the three allowable ITS-90 reference fixed points; a wavelength dependence of T 90 due to the difference between thermodynamic temperature, T , and T 90 at these reference fixed points; and a further wavelength dependence arising from the discrepancy between the value of the second radiation constant defined on ITS-90 and its value derived from fundamental constants. The non-uniqueness is quantified by deriving an exact expression for T − T 90 above the silver point and calculating the differences in this expression as a function of reference ...

中文翻译：

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ITS-90在银点以上的非唯一性及其对T-T 90值的影响

非唯一性是确定的温度标度可重复性的基本限制。本文首次对银点以上1990年国际温度标度（ITS-90）上温度的非唯一性T 90进行了全面研究。这种不唯一性是由三个原因引起的：外推与三个允许的ITS-90参考固定点的选择不一致；由于在这些参考固定点的热力学温度T和T 90之间的差异，T 90的波长依赖性；以及由ITS-90上定义的第二辐射常数的值与其从基本常数得出的值之间的差异引起的进一步的波长依赖性。