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Noninvasive sensing of temperature and pressure offers new and exciting opportunities to investigate and monitor the variation of physicochemical and spectroscopic properties of materials under extreme conditions. In this work, Tm2+‐doped SrB4O7 phosphor material—a novel, contactless bifunctional, and multimodal optical sensor for pressure and temperature is reported. A series of SrB4O7: xTm2+ samples are synthesized via a high‐temperature solid‐state method in air. The impact of high pressure (up to ≈13 GPa) and temperature (from 10 to 400 K) on spectroscopic properties of SrB4O7:Tm2+ is investigated. The emission band of Tm2+ demonstrates a significant spectral shift and a band broadening as a function of both pressure and temperature. Such a result is a consequence of a significant change of vibronic components of the Tm2+ 4f125d ↔ 4f13 zero‐phonon line. The emission bandwidth and its spectral position exhibit excellent sensitivities to pressure, that is, ≈23.17 and ≈−11.85 cm−1 GPa−1, respectively. Furthermore, for the first time, it is shown that temperature sensing can be realized via four different pathways in a single material: i) bandwidth, ii) band shift, iii) band intensity ratio, and iv) luminescence lifetime, with maximal sensitivities of ≈3.85 cm−1 K−1, 1.44 cm−1 K−1, 1.48% K−1 and 4.16% K−1, respectively.

Neptunyl / Uranyl / Complexes /Acid constants / Stability constants AbstractThe acid dissociation constants, pK a , and the stability constants for NpOj and UOi + have been measured for certain organic ligands [acetate, α-hydroxyisobutyrate, lactate, ascorbate, oxalate, citrate, EDTA, 8-hydroxyquinoline, 1,10-phenanthroline, and thenoyltrifluoroacetone] in 5 m (NaCl) ionic strength solution. The pK a values were determined by potentiometry or spectrometry. These methods, as well as solvent extraction with 23, U and 217 Np radiotracers, were used to measure the stability constants of the 1:1 and 1:2 complexes of dioxo cations. These constants were used to estimate the concentrations required to result in 10% competition with hydrolysis in the 5 m NaCl solution. Such estimates are of value in assessing the solubility from radioactive waste of AnOJ and An0 2+ in brine solutions in contact with nuclear waste in a salt bed repository.in the brine to the extent measured by the stability constant. This complexation would be influenced by factors such as the temperature and ionic composition of the brine solutions. The latter, which may vary from 0.7 m to 8 m is the concern of this study.For the complexation reaction in solution,a "concentration" stability constant, ß", can be expressed in a particular ionic medium by :In this work, we report the values of log ß" in / = 5.0 m (NaCl) ionic strength solution and the pK a of some organic anions in the same solution. The organic ligands are those likely to be present in the wastes considered for disposal in the WIPP repository.

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