Papers by Author: Xiang Li

Abstract: Recently, Far-infrared Light Emitting Diodes have attracted considerable interest in the research field worldwide. Emerging light therapy requires effective red/far-infrared light resources in clinical and plant photomorphogenesis to target or promote the interaction of light with living organisms. Here, Gd₃Al₄GaO₁₂:Cr³⁺ (hereinafter referred to as: GAGG:Cr³⁺) phosphor was synthesized by high-temperature solid-phase method, and the crystal structure, morphology, and luminescence properties of this series of phosphor samples were studied. Through X-ray powder diffraction to obtain pure phase GAGG:Cr³⁺ series phosphor. Under the excitation of 420nm blue light, a broad band emission from 640 to 850nm is obtained, which is the result of the transition of Cr^{3+ 4}T₂→⁴A₂ level. A sharp emission peak at 693nm is the R line belonging to Cr³⁺ in Gd₃Al₄GaO₁₂ garnet. R line is assigned to the spin-forbidden ²E→⁴A₂ transitions of Cr³⁺ ions that occupy the ideal octahedral sites. As the Cr³⁺ doping concentration increases, the luminous intensity of the sample increases first and then decreases. When the doping concentration of Cr³⁺ is 0.1mol phosphor,the luminous intensity is strongest at one single broad peak at about 712nm. At 440k, the R sharp line (693nm) and broad band (712nm) emission intensity maintained 78.6% and 71.8% , compared to room temperature intensity, respectively. The change of fluorescence lifetime at different temperatures gives the mechanism of fluorescence change with temperature. The current exploration will pave a promising way to engineer GAGG:Cr³⁺ activated optoelectronic devices for all kinds of photobiological applications.

Abstract: Through analysis of various concept methods, developing route selection device based on double tree complex wavelet and transient energy, use the method based on transient component can improve line selection accuracy effectively. sensitivity and directional selectivity can improved by using dual tree complex wavelet transform than using discrete wavelet translation, the method can’t infect by the line of power system and the condition of the fault line. The simulation results show that by using the dual tree complex wavelet analysis in suitable scale can select the fault line correctly.

Abstract: SiO2/ SiO2 nanocomposites dipped with silicon resin was ablated and the physical state and phase transformation were characterized. Trace impurity in raw material and compound obtained by chemical reaction were analyzed. Moreover, the high-temperature dielectric properties were investigated. On the basis of above, it is found that the impurity carbon and silicon carbide are the key factors influencing dielectric properties.