RESUMO
The dynamic fluctuation of the U3+ coordination structure in a molten LiCl-KCl mixture was studied using first principles molecular dynamics (FPMD) simulations. The radial distribution function, probability distribution of coordination numbers, fluctuation of coordination number and cage volume, self-diffusion coefficient and solvodynamic mean radius of U3+, dynamics of the nearest U-Cl distances, and van Hove function were evaluated. It was revealed that fast exchange of Cl- occurred between the first and second coordination shells of U3+ accompanied with fast fluctuation of coordination number and rearrangement of coordination structure. It was concluded that 6-fold coordination structure dominated the coordination structure of U3+ in the molten LiCl-KCl-UCl3 mixture and a high temperature was conducive to the formation of low coordinated structure.
RESUMO
A temperature-insensitive all fiber Fabry-Pérot (F-P) and Mach-Zehnder (M-Z) hybrid compact structure and its sensing characteristics are proposed and theoretically and experimentally demonstrated. In one sensor, two kinds of sensing principles are existing, which is shown in the sensing process that with the increase in the refractive index (RI) of the liquid, the dip wavelengths coming from the F-P interference do red-drift, and the dips from the M-Z interference do blue-drift, respectively. Due to the opposite shift and almost the same temperature sensitivities, the dip difference between M-Z and F-P refractometers is used to eliminate temperature cross-sensitivity and improve the RI sensitivity of the sensor. In our experiments, the liquid RI sensitivity is 134.383 nm/RIU, and temperature cross-sensitivity is effectively eliminated within the ±21.74 °C change range at room temperature. This sensing structure also has advantages of simple structure, good integration, and low power loss.