Oxides with different crystal phases can have important effects on the configuration of surface atoms,which can further affect the distribution of hydrogenation sites and acidic sites as well as the competitions of th...Oxides with different crystal phases can have important effects on the configuration of surface atoms,which can further affect the distribution of hydrogenation sites and acidic sites as well as the competitions of these varied types of catalytic sites.This could be potentially used to tailor the distribution of the products.In this study,zirconium oxides with different crystal phases supported copper catalysts were prepared for the hydrogenation of the biomass-derived furfural,vanillin,etc.The results showed that both calcination temperature and Cu species affected the shift of zirconia from tetragonal phase to the monoclinic phase.Monoclinic zirconia supported copper catalyst can effectively catalyze the hydrogenation of furfural to furfuryl alcohol via hydrogenation route due to its low amount of Brønsted acidic sites,although the surface area and the exposed metallic Cu surface area were much lower than the tetragonal zirconia supported copper catalyst.Zirconia with tetragonal or tetragonal/monoclinic phases supported copper catalysts contain abundant acidic sites and especially the Br?nsted acidic sites,which catalyzed mainly the conversion of furfural via the acid-catalyzed routes such as the acetalization,rather than the hydrogenation.The acidic sites over the Cu/ZrO_(2)catalyst played more predominant roles than the hydrogenation sites in determining the conversion of the organics like furfural and vanillin.展开更多
A highly dispersed Cu catalyst supported on silica was prepared by an incipient wetness impregnation method with citric acid.The synthesis was studied by nitrogen physisorption,X-ray diffraction,and temperature-progra...A highly dispersed Cu catalyst supported on silica was prepared by an incipient wetness impregnation method with citric acid.The synthesis was studied by nitrogen physisorption,X-ray diffraction,and temperature-programmed reduction by comparing with a reference prepared without citric acid.The catalyst precursor obtained after impregnation was X-ray amorphous.The precursor was readily transformed to crystalline CuO upon calcination.The CuO particles were of uniform size in a highly dispersed state and can be reduced to Cu at a lower temperature.The activity of the Cu catalyst obtained was an order of magnitude higher than that of the reference for the hydrogenolysis of methyl laurate to dodecanol.展开更多
AIM: To investigate the effect of adrenalectomy (ADX) on the epididymidis of Sprague-Dawley rats. METHODS: The histological, biochemical (cholesterol protein, zinc, copper, alkaline and acid phosphatase aryl sulphatas...AIM: To investigate the effect of adrenalectomy (ADX) on the epididymidis of Sprague-Dawley rats. METHODS: The histological, biochemical (cholesterol protein, zinc, copper, alkaline and acid phosphatase aryl sulphatase, lactic dehydrogenase and leucine amino peptidase) and hormonal (FSH, LH and testosterone) changes of caput and cauda epididymis in ADX rats were observed. RESULTS: Organ wet weight, histological studies and morphometric measurements indicated a cellular degeneration in caput and cauda epididymis of ADX rats. Serum testosterone level was significantly lower in ADX than in sham-operated rats, while the serum FSH and LH were below the detection limit of 1 mIU/mL. The enzymatic activity was higher in ADX than in sham-operated rats. Epididymal zinc level increased whereas copper level decreased in ADX rats compared to the sham-operated. CONCLUSION: Adrenalectomy leads to degeneration of caput and cauda epididymidis epithelial cells as a result of decreased supply of testosterone.展开更多
基金supported by the National Natural Science Foundation of China(No.51876080)the Program for Taishan Scholars of Shandong Province Government。
文摘Oxides with different crystal phases can have important effects on the configuration of surface atoms,which can further affect the distribution of hydrogenation sites and acidic sites as well as the competitions of these varied types of catalytic sites.This could be potentially used to tailor the distribution of the products.In this study,zirconium oxides with different crystal phases supported copper catalysts were prepared for the hydrogenation of the biomass-derived furfural,vanillin,etc.The results showed that both calcination temperature and Cu species affected the shift of zirconia from tetragonal phase to the monoclinic phase.Monoclinic zirconia supported copper catalyst can effectively catalyze the hydrogenation of furfural to furfuryl alcohol via hydrogenation route due to its low amount of Brønsted acidic sites,although the surface area and the exposed metallic Cu surface area were much lower than the tetragonal zirconia supported copper catalyst.Zirconia with tetragonal or tetragonal/monoclinic phases supported copper catalysts contain abundant acidic sites and especially the Br?nsted acidic sites,which catalyzed mainly the conversion of furfural via the acid-catalyzed routes such as the acetalization,rather than the hydrogenation.The acidic sites over the Cu/ZrO_(2)catalyst played more predominant roles than the hydrogenation sites in determining the conversion of the organics like furfural and vanillin.
基金Supported by Malaysian Ministry of Science, Technology and Innovation (IRPA-SR-03-02-03-3010)
文摘A highly dispersed Cu catalyst supported on silica was prepared by an incipient wetness impregnation method with citric acid.The synthesis was studied by nitrogen physisorption,X-ray diffraction,and temperature-programmed reduction by comparing with a reference prepared without citric acid.The catalyst precursor obtained after impregnation was X-ray amorphous.The precursor was readily transformed to crystalline CuO upon calcination.The CuO particles were of uniform size in a highly dispersed state and can be reduced to Cu at a lower temperature.The activity of the Cu catalyst obtained was an order of magnitude higher than that of the reference for the hydrogenolysis of methyl laurate to dodecanol.
文摘AIM: To investigate the effect of adrenalectomy (ADX) on the epididymidis of Sprague-Dawley rats. METHODS: The histological, biochemical (cholesterol protein, zinc, copper, alkaline and acid phosphatase aryl sulphatase, lactic dehydrogenase and leucine amino peptidase) and hormonal (FSH, LH and testosterone) changes of caput and cauda epididymis in ADX rats were observed. RESULTS: Organ wet weight, histological studies and morphometric measurements indicated a cellular degeneration in caput and cauda epididymis of ADX rats. Serum testosterone level was significantly lower in ADX than in sham-operated rats, while the serum FSH and LH were below the detection limit of 1 mIU/mL. The enzymatic activity was higher in ADX than in sham-operated rats. Epididymal zinc level increased whereas copper level decreased in ADX rats compared to the sham-operated. CONCLUSION: Adrenalectomy leads to degeneration of caput and cauda epididymidis epithelial cells as a result of decreased supply of testosterone.
