Fly ash can improve the physical and mechanical properties of the magnesium phosphate cement (MPC) paste. The influence of fly ash on the strength, the mortar fluidity, the durability and the setting time of MPC paste were studied in this paper. The results show that: The function of fly ash to the MPC is as followed: physical fill, superplastic and chemical reactions; the optimal content of fly ash is about 30% by weight, and MPC with 30% fly ash has excellent mechanical property and high fluidity; the fineness of magnesia affected the mechanical properties of MPC.

Flue gas desulphurization (FGD) gypsum and fly ash are two kinds of solid waste in coal-fired power plant. The possible displacement content of fly ash in gypsum plaster was investigated in this paper. The effect of various chemicals retarders, such as Citric acid, sodium citrate and SC gypsum retarder, and water retention agent on the setting time, flexural strength and compressive strength of gypsum plaster was also studied. The results demonstrate that gypsum plaster has maximum mechanical properties and enough setting time at the rate of 20% fly ash replacing calcined gypsum; SC gypsum retarder effectively delays the setting time and has lower strength loss; The optimum level of water-retention agent for effective utilization of gypsum plaster is 0.2%.

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Through filling CS2 into the core, a liquid-core photonic crystal fiber(LCPCF) with a fully circular air hole structure was designed The finite element method(FEM) and numerical analysis are combined to simulate the structure and optimize the parameters of the fiber. When λ = 1550 nm, the geometric optimal parameters are Ʌ = 0.75 μm, d1/Ʌ = 0.86, d2/Ʌ = 0.96, and d3/Ʌ = 0.20. Meanwhile, the LCPCF can achieve a large negative dispersion of -2697.06 ps/nm/km and a high nonlinearity of 50677.77 W-1km-1. The numerical aperture and light acceptance are 0.674 and 65.37%, respectively. By comparison, we believe that this LCPCF has obvious advantages in optical communication compensation and supercontinuum generation.

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