Miscible-order fluoride-phosphate blocky phosphor (FBP), composed with ordered-phase of NaYF4 crystals and unordered phase of tin-fluorophosphate glass, is prepared by a two-step process and luminescent properties of FBPs embedded with different particle sizes of NaYF4 crystals are presented. High-frequency fluorescence from higher metastable 5D
J
(J = 1, 2 and 3) energy levels are effectively released in Eu3+ doped fluoride crystals. Taking the blue emission of Sn2+ as the framework, multi-peak emissions from metastable energy levels are controlled to adjust the color coordinates of the FBP to the white-light region, which the color rendering index (CRI) reaches 89. Tunable color FBP with high CRI retains splendid luminescence property of fluoride, providing a potential candidate for the development of white LED.
With the development of human society, light pollution has gradually become one of the major problems faced by today’s society. In order to improve human awareness of the impact of light pollution and reduce the impact of light pollution, we constructed a “light pollution risk assessment” model and proposed relevant strategies to mitigate the impact of light pollution. We established a 3-level Analytical Hierarchy Process (AHP) combined with Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) model by dividing into three major factors: economic, social, and natural, and selected each index to take data collection and data analysis, then the determination of weights among factors in the model was carried out by entropy weighting method, and the light pollution risk level assessment model was obtained by K-clustering analysis. The model can systematically assess and classify the risk level of light pollution in the investigated area, which is conducive to the establishment of a scientific system for the evaluation and prevention of urban light pollution in the future, and propose effective countermeasures for how to reduce urban light pollution.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.