A visible-light photocatalyst was prepared by calcination of the hydrolysis product of Ti(SO_4)_2 with ammonia as precipitator. The color of this photocatalyst was vivid yellow. It could absorb light under 550 nm wave...A visible-light photocatalyst was prepared by calcination of the hydrolysis product of Ti(SO_4)_2 with ammonia as precipitator. The color of this photocatalyst was vivid yellow. It could absorb light under 550 nm wavelength. The crystal structure of anatase was characterized by XRD. The structure analysis result of X-ray fluorescence(XRF) shows that doped-nitrogen was presented in the sample. The photocatalytic activities were evaluated using methyl orange and phenol as model pollutants. The photocatalytic activities of samples were increasing gradually with calcination temperature from 400℃ to 700℃ under UV irradiation. It can be seen that the degradation of methyl orange follows zero-order kinetics. However, the calcination temperatures have no significant influence on the degradation of phenol under sunlight. The N-doped catalyst shows higher activity than the bare one under solar irradiation.展开更多
In this paper, a two-species nonautonomous competitive model with stage structure and harvesting is considered. Sufficient conditions for the existence, uniqueness, global attractivity of positive periodic solution an...In this paper, a two-species nonautonomous competitive model with stage structure and harvesting is considered. Sufficient conditions for the existence, uniqueness, global attractivity of positive periodic solution and the existence, uniform asymptotic stability of almost periodic solution are obtained.展开更多
文摘A visible-light photocatalyst was prepared by calcination of the hydrolysis product of Ti(SO_4)_2 with ammonia as precipitator. The color of this photocatalyst was vivid yellow. It could absorb light under 550 nm wavelength. The crystal structure of anatase was characterized by XRD. The structure analysis result of X-ray fluorescence(XRF) shows that doped-nitrogen was presented in the sample. The photocatalytic activities were evaluated using methyl orange and phenol as model pollutants. The photocatalytic activities of samples were increasing gradually with calcination temperature from 400℃ to 700℃ under UV irradiation. It can be seen that the degradation of methyl orange follows zero-order kinetics. However, the calcination temperatures have no significant influence on the degradation of phenol under sunlight. The N-doped catalyst shows higher activity than the bare one under solar irradiation.
基金This work is supported by Master's Science Research Foundation of Anhui Institute of Architecture and Industry (Y2004-43).
文摘In this paper, a two-species nonautonomous competitive model with stage structure and harvesting is considered. Sufficient conditions for the existence, uniqueness, global attractivity of positive periodic solution and the existence, uniform asymptotic stability of almost periodic solution are obtained.
