In the interlayer expansion of the layered zeolite precursor COK-5, a Sn, salt, bis（2,4-pentanedionate）- dichlorotin [Sn（acac）2CL2], instead of a silylating agent was used to link the layers at 180 ℃. The obtaine...In the interlayer expansion of the layered zeolite precursor COK-5, a Sn, salt, bis（2,4-pentanedionate）- dichlorotin [Sn（acac）2CL2], instead of a silylating agent was used to link the layers at 180 ℃. The obtained material, which is designed as Sn-COE-5, shows a shift of the first XRD reflection, which is very similar to that of COK-5 interlayer expanded with dichlorodimethylsilane （DCDMS）, indicating an increase in interlayer distance. X-ray diffraction （XRD）, N2 sorption isotherms, inductively coupled plasma （ICP）, and X-ray photo- electron spectroscopy （XPS） support the incorporation of isolated Sn sites in the sample. In the conversion of glucose to levulinic acid. Sn-COE-5 exhibits much higher activity than COK-5, which is due to the presence of Lewis acidic sites in the Sn-COE-5.展开更多
Phenolic compounds and their derivatives have been found in industrial wastewater, which pose threats to the natural environment. Ordered mesoporous carbon(OMC) has been identified as an ideal adsorbent possessing hig...Phenolic compounds and their derivatives have been found in industrial wastewater, which pose threats to the natural environment. Ordered mesoporous carbon(OMC) has been identified as an ideal adsorbent possessing high specific surface area and large pore volume to alleviate these pollutants. A novel ordered mesoporous carbon was prepared using COK-19 template with the cubic Fm3 m structure for the first time. Ordered mesoporous silica COK-19 was synthesized and reported in 2015. Sucrose as the carbon precursor was impregnated into the mesopores of silica and converted to carbon through carbonization process using sulfuric acid as a catalyst. Ordered mesoporous carbon was obtained after the removal of silica framework using hydrofluoric acid. Boric acid was employed for the preparation of OMCs with tunable pore sizes in the range of 6.9–16.6 nm. Several characterization techniques such as nitrogen adsorption–desorption isotherms, transmission electron microscope(TEM), Fourier transform infrared spectroscopy, Boehm titration and elemental analysis were employed to characterize the OMCs. The pore size analysis and TEM images confirmed that OMC has replicated the mesostructure of the COK-19. Results obtained from adsorption kinetics and isotherms suggest that the Pseudo-second-order model and Langmuir isotherm well described the experimental data.展开更多
In order to get the spatial grid data of monthly precipitation and monthly average temperature of Sanjiangyuan area, the Co-Kriging (COK) and thin plate smoothing splines(TPS) interpolation methods were applied by usi...In order to get the spatial grid data of monthly precipitation and monthly average temperature of Sanjiangyuan area, the Co-Kriging (COK) and thin plate smoothing splines(TPS) interpolation methods were applied by using the climate data during 1971-2000 of 58 meteorological stations around Qinghai Province and the 3 arc-second digital elevation model (DEM) data. The performance was evaluated by the smallest statistical errors by general cross validation (GCV). Root-mean-squared predicted errors (RMSE) and mean absolute errors (MAE) were used to compare the performance of the two methods. The results showed that: 1) After combing covariates into the models, both methods performed better; 2) The performance of TPS was significantly better than COK: for monthly average temperature, the RMSE derived from TPS was 69.48% higher than COK, as MAE increased by 70.56%. And for monthly precipitation, the RMSE derived from TPS was 28.07% higher than COK, as MAE increased by 29.06%.展开更多
基金supported by the National Natural Science Foundation of China (21422306 and 21403192)Zhejiang Provincial Natural Science Foundation of China under grant no. LR15B030001the Fundamental Research Funds for the Central Universities (2015XZZX004-04)
文摘In the interlayer expansion of the layered zeolite precursor COK-5, a Sn, salt, bis（2,4-pentanedionate）- dichlorotin [Sn（acac）2CL2], instead of a silylating agent was used to link the layers at 180 ℃. The obtained material, which is designed as Sn-COE-5, shows a shift of the first XRD reflection, which is very similar to that of COK-5 interlayer expanded with dichlorodimethylsilane （DCDMS）, indicating an increase in interlayer distance. X-ray diffraction （XRD）, N2 sorption isotherms, inductively coupled plasma （ICP）, and X-ray photo- electron spectroscopy （XPS） support the incorporation of isolated Sn sites in the sample. In the conversion of glucose to levulinic acid. Sn-COE-5 exhibits much higher activity than COK-5, which is due to the presence of Lewis acidic sites in the Sn-COE-5.
基金supported by the University of Louisiana at Lafayette and Louisiana Board of Regents (Nos.LEQSFRD-C-15 and LEQSF-ENH-TR-32)
文摘Phenolic compounds and their derivatives have been found in industrial wastewater, which pose threats to the natural environment. Ordered mesoporous carbon(OMC) has been identified as an ideal adsorbent possessing high specific surface area and large pore volume to alleviate these pollutants. A novel ordered mesoporous carbon was prepared using COK-19 template with the cubic Fm3 m structure for the first time. Ordered mesoporous silica COK-19 was synthesized and reported in 2015. Sucrose as the carbon precursor was impregnated into the mesopores of silica and converted to carbon through carbonization process using sulfuric acid as a catalyst. Ordered mesoporous carbon was obtained after the removal of silica framework using hydrofluoric acid. Boric acid was employed for the preparation of OMCs with tunable pore sizes in the range of 6.9–16.6 nm. Several characterization techniques such as nitrogen adsorption–desorption isotherms, transmission electron microscope(TEM), Fourier transform infrared spectroscopy, Boehm titration and elemental analysis were employed to characterize the OMCs. The pore size analysis and TEM images confirmed that OMC has replicated the mesostructure of the COK-19. Results obtained from adsorption kinetics and isotherms suggest that the Pseudo-second-order model and Langmuir isotherm well described the experimental data.
基金Supported by Forestry Science and Technology Support Project (2008BADB0B0203)National Technology Support Project (2007BAC03A08-5)
文摘In order to get the spatial grid data of monthly precipitation and monthly average temperature of Sanjiangyuan area, the Co-Kriging (COK) and thin plate smoothing splines(TPS) interpolation methods were applied by using the climate data during 1971-2000 of 58 meteorological stations around Qinghai Province and the 3 arc-second digital elevation model (DEM) data. The performance was evaluated by the smallest statistical errors by general cross validation (GCV). Root-mean-squared predicted errors (RMSE) and mean absolute errors (MAE) were used to compare the performance of the two methods. The results showed that: 1) After combing covariates into the models, both methods performed better; 2) The performance of TPS was significantly better than COK: for monthly average temperature, the RMSE derived from TPS was 69.48% higher than COK, as MAE increased by 70.56%. And for monthly precipitation, the RMSE derived from TPS was 28.07% higher than COK, as MAE increased by 29.06%.
