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The security protection of power system is still the focus of power enterprises. In order to solve the problem of untimely and inaccurate secret-related detection of the existing power monitoring system, cloud computing access control technology was used to improve the detection accuracy and efficiency. Firstly, a hierarchical architecture of the power monitoring system was built; with the focus on the control center of the system application layer, the data module and service module in the business layer were regularly scanned, and the system access control and database detection sub modules were connected. Finally, the security model of cloud computing access control was constructed in the sub module, and the self-test process of database secret-related sensitive data was designed to realize the system user access control and confidential and sensitive data self-test. The results show that the average accuracy of the designed secret-related self inspection model is more than 90%, and its response time is less than 7 s, which is better than the comparison model. With the support of the designed model, the power monitoring system can quickly complete the system secret-related detection and response, prevent users from accessing and ensure the security of the system.

White light emitting diodes (WLEDs) are widely used due to their advantages of high efficiency, low electricity consumption, long service life, quick response time, environmental protection, and so on. The addition of red phosphor is beneficial to further improve the quality of WLEDs. The search for novel red phosphors has focused mainly on Eu2+ ion- and Mn4+ ion-doped compounds. Both of them have emissions in the red region, absorption in blue region, and similar quantum yields. Eu2+-doped phosphors possess a rather broad-band emission with a tail in the deep red spectral range, where the sensitivity of the human eye is significantly reduced, resulting in a decrease in luminous efficacy of WLEDs. Mn4+ ions provide a narrow emission band ~670 nm in oxide hosts, which is still almost unrecognizable to the human eye. Mn4+-doped fluoride phosphors have become one of the research hotspots in recent years due to their excellent fluorescent properties, thermal stability, and low cost. They possess broad absorption in the blue region, and a series of narrow red emission bands at around 630 nm, which are suitable to serve as red emitting components of WLEDs. However, the problem of easy hydrolysis in humid environments limits their application. Recent studies have shown that constructing a core–shell structure can effectively improve the water resistance of Mn4+-doped fluorides. This paper outlines the research progress of Mn4+-doped fluoride A2MF6 (A = Li, Na, K, Cs, or Rb; M = Si, Ti, Ge or Sn), which has been based on the core–shell structure in recent years. From the viewpoint of the core–shell structure, this paper mainly emphasizes the shell layer classification, synthesis methods, luminescent mechanism, the effect on luminescent properties, and water resistance, and it also gives some applications in terms of WLEDs. Moreover, it proposes challenges and developments in the future. [ABSTRACT FROM AUTHOR]