Starting with sustainable utilization of tourist resources, this paper points out Karst scenery and minority nationalites'
culture are irretrievable tourist resources, their utiliation will either promote the economic and cultural development in Guizhou Karst areas, or destory their environment, and cause tourist resource loss. This paper analyses some conditions causing changes, and puts forward the comprehensive regulations of sustainable utilization. Key Words Karst; tourist resources; change; sustainable utilizationof Azo Compounds on the Surface of Titanium Dioxide(Ⅰ) The Discovery and Kinetic Behaviors Researching of Intermadiates$$$$ MA Wan Hong, CAI Ru Xiu *, LIU Zhi Hong, LIN Zhi Xin (Department of Chemistry, Wuhan University, Wuhan 430072, China) Abstract The kinetics and electron transfer of the photo
degradation procedure of five azo compounds, mainly DBC carboxyazo, on the surface of titanium dioxide were studied by using UV\|Vis absorption and differential spectra. An
intermediate with rather long life( t 1/2 =8 86 min) formed and then destructed during the procedure of the capture of the photo induced charge carrier. The theoretically fit peak shape curve of the intermediate with error compensated algorithm parallel accorded with the experimental c~t curve. Thus we have got the rate constants of DBC carboxyazo and TBC CPA at 25 ℃, being 0 170( k 1/min -1 ) and 2 96×10 -2 ( k 2/min -1 ) as well as 0 104( k 1/min -1 ) and 9 56×10 -2 ( k 2/min -1 ), respectively. The effect of the initial pH value on the photo degradation rate was tested. pH 3—7 was found to be the optimal pH range for the photo degradation. In addition, the reaction solution without being buffered was found to tend to be weak acidic. The sensitization mechanism of TiO 2 by azo was discussed. That is, electrons transferred from the excited azo to the conductive band of semiconductor TiO 2, which made the bandgap energy match the energy of visible light. The degradation course was presumed as that, after the electron injection and the self oxidaiton of azo, the intermediate naphthoquinone was oxidized by O ·- 2 to produce phthalic acid, followed by the final mineralization of the phthalic acid to yield CO 2, H 2O and other inorganic compounds.