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AIM: To investigate changes of choroidal thickness (ChT) in children with myopia and the effect of current myopia control interventions on ChT. METHODS: Major literature databases were searched for studies relevant to myopia in children. All studies used swept-source optical coherence tomography (SS-OCT) or enhanced depth imaging optical coherence tomography (EDI-OCT) to measure the ChT value. The weighted mean difference (WMD) and 95% confidence interval (CI) were pooled to evaluate ChT in myopia children. RESULTS: A total of 11 eligible articles, including 1693 myopic and 1132 non-myopic eyes, were included in the first Meta-analysis. The sub-foveal choroidal thickness (SFCT; WMD=-40.06, 95%CI, -59.36 to -20.75, P

The phase-to-ground fault occurs frequently in power system, Fault Location is a knotty problem for a long time. This paper presents a novel method to get Fault Current between Adjacent Nodes according to the characteristic of transient current based on WSN (Wireless Sensor Networks). It is used to identify and locate the current fault. The power system is divided into pieces by WSN nodes that could sense the transient three-phase current and identify the fault information based on communication between adjacent nodes. The principle of arranging WSN nodes is also presented. Through the simulation in Matlab, it shows that the method could extract the fault component correctly bypass the influence of variant load and harmonic.

Eu3+ doped CaMoO4 micron phosphors of different concentrations were prepared by chemical precipitation method. The photoluminescence properties were studied in detail. The X-ray diffraction measurements indicate that the samples are scheelite structure, and doping Eu3+ enlarge the lattice parameter of host material. The scanning electron microscope images show that the particle morphology is near-spherical and the size is 4-5 μm. The excitation and emission spectra of CaMoO4:Eu show that CaMoO4:Eu can be effectively excited by blue light and near UV-light, and the red light emission of high colour purity can be realized. The electron-phonon coupling properties were also studied. The results indicate that the magnitude of Huang-Rhys factor is 10-2, so the CaMoO4:Eu is a weak electron-phonon coupling material. The results also indicate that the Huang-Rhys factor increases with the increase of concentration. It is probably because that increasing the doping concentration enhances the lattice relaxation. The transition intensity parameter Ω2 of Eu3+ enlarges while the concentration is increasing. Because Ω2 and the luminescent center environment are closely related, the numerical value of Ω2 enlarges with the increase of degree of environmental disorder. But Ω4 doesn't have obvious change. It can be explained that the environmental sensitivity level of Eu3+5D0→7F2 transition is higher than that of 5D0→7F4 transition. The quantum efficiency of Eu3+ 5D0 energy level decreases with the increase of doping concentration. This can be attributed that the enhancement of Eu3+ doping concentration enlarges the energy transfer rate between luminescent centers, so the energy of excited electrons can be transferred to quenching center more easily and then the nonradiative relaxation rate of excited electrons increases. The best doping concentration of Eu3+ is 25% by drawing the concentration quenching curve. Furthermore, the energy transfer type of Eu3+ in CaMoO4 host is confirmed to be exchange interaction and the critical distance is calculated to be 8.4 Å. The chromaticity coordinate of CaMoO4:Eu phosphors is (0.654, 0.334), so the samples have high colour purity. The study indicates that CaMoO4:Eu micron phosphor prepared by chemical precipitation method is a red phosphor material with excellent property.

Sr0.8-xBaxEu0.2WO4 red phosphors with different Ba2+ doping concentrations is prepared by the co-precipitation method at different sintering temperatures. We study the influences of the crystal orientation and lattice distortion of the samples on the luminescence property. The results show that the Sr0.8-xBaxEu0.2WO4 synthesized by the process has a phase with tetragonal structure and that the red emission 5D0-7F2 of Eu3+ in the sample can be excited effectively by the near-UV light and blue light. The part of Sr2+ replaced with Ba2+ leads to the increase in emission intensity of Sr0.8-xBaxEu0.2WO4. The doping concentration of Ba2+ has a great influence on the crystal parameter, the crystal symmetry and the luminescent property. The optimized doping concentration of Ba2+ is found to be 30%.

Eu3+ doped CaWO4 phosphors of different concentrations are prepared by a co-precipitation method. The X-ray diffraction patterns and field emission scanning electron microscopy images are investigated. The excitation spectra, emission spectra and the curves of fluorescence decays of the samples are measured. The Judd-Ofelt (J-O) parameters, quantum efficiencies of the 5D0 level of Eu3+ and color coordinates are calculated. The dependences of relative intensity of charge transfer band, J-O parameter and quantum efficiency on doping concentration are discussed. The photoluminescence properties of Eu3+ doped CaWO4 luminescent material are studied. The results indicate that the 616 nm red emission of Eu3+5D07F2 transition can be effectively excited by 394.5 nm and 465 nm with high excitation efficiency and the concentration quenching is high. So the CaWO4: Eu red phosphor may have a potential application for white light emitting diode.