CeO2/γ-Al2O3, La203/γ-Al2O3, CeO2-La203/γ-Al2O3 and CeO2-La2O3, which were prepared by impregnating in certain ratio, were used as the catalysts for the reduction of SO2 and NO by CO. Separate and simultaneous removal of SO2 and NO over LaEO3/γ-Al2O3, CeOE/γ-Al2O3, CeOE-LaEO3/γ-Al2O3 were investigated. The phase characteristics of catalysts were also analyzed by X-ray diffraction. The result shows that the conversions of SO2 and NO are above 98 % over CeOE/γ-Al2O3 and CeOE-LaEO3/γ-Al2O3. After SO2 is added in the NO-CO-N2 system （NO ：SO2 = 1：2 - 1 ： 3）, the conversions of SO2 and NO are both above 98%. Furthermore, it is found that CeO2-La2O3 with various ratios has different activity for the simultaneous reduction of SO2 and NO.
This paper investigates the development,the breakdown process,and the discharge path selection of the lightning discharges in two-phase mixtures(TPMs).13 kinds of solid-gas mixtures and 3 kinds of liquid-gas mixtures are employed to study effect of two phase mixtures on the selection of the discharge path under lightning impulses.Grain size effects are shown upon these experimental results.When the diameter of solid or liquid grains is less than about 10 μm,the discharge path does not select TPM but air.And the discharge path selects TPM when the diameter is greater than about 100 μm.And when the diameter is between about 10 μm and 100 μm,the discharge path selects TPM under negative lightning impulses,but it has a greater selection of air than TPMs under positive lightning impulses.Volume fraction and permittivity of solid/liquid can also influence the selection of the discharge path.
