Improvements in the realization of the ITS-90 over the temperature range from the melting point of gallium to the freezing point of silver at NIM Abstract. The WC-C peritectic fixed point, nominal melting and freezing temperature 2747 qC, shows extremely good metrological potential. Elsewhere, we published a prototype scale comparison of the ITS-90 between NPL, NIM and CEM, using high temperature eutectic fixed points (HTFPs) of Co-C (1324 qC), Pt-C (1738 qC), and Re-C (2474 qC). In this paper we present the further results of the bilateral comparison of the ITS-90 at an even higher temperature, 2747 qC, between NIM and NPL using WC-C peritectic fixed points. A NIM single zone high temperature furnace, model Chino IR-80, was modified to extend its temperature to 2800 qC. Then, an NPL researcher, on secondment to NIM, filled two WC-C cells in the modified furnace in a vertical position. The two WC-C cells were then realized in the same furnace, in an horizontal position. Their melting temperatures, defined by the inflection point of the melting curves, were measured by a linear pyrometer, model NIM-PSP. NIM's ITS-90 scale was assigned to the two cells, which were then transported to NPL. The realization of NPL's ITS-90 was then assigned to the two cells by using a model HT9500 Thermogauge furnace to realize the fixed points and a linear pyrometer, model LP3, to determine their temperature. The difference from the mean value of the NIM and NPL ITS-90 values for the WC-C points was derived. This allowed us to compare ITS-90 as realized by the two institutes and to determine the uncertainty in the scale comparison..
The zirconium phosphate α-Zr(HPO4)2·H2O (α-ZrP) with layered structure has been synthesized by refluxing method. Power X-ray diffraction (XRD), vibrational spectroscopy (FT-IR, FT-Raman), thermal analysis (TG-DSC), transition electron spectroscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS) was respectively used for structure characterization of the compound α-ZrP. The result of intercalation reactions with tetramethylammonium bromide and cetyltrimethylammonium bromide showed interlayer distances increase of ~ 0.46 nm and ~ 1.68 nm, respectively. The BET surface area of α-ZrP is 12.29 m2·g-1. The cyclic voltammetry behaviors of the compound on Au electrode showed a typical reversible process. Moreover, the strong fluorescent property of the α-ZrP was measured. The maximum emission peaks occurred at ca. 390 nm upon excitation at ca. 288 nm.
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