Ceramic LaNiO3 samples were prepared by solid state reaction method at different sintering temperatures. It was found that the resultant was not ABO3 perovskite single phase but dual phase La2NiO4 and NiO, and the per...Ceramic LaNiO3 samples were prepared by solid state reaction method at different sintering temperatures. It was found that the resultant was not ABO3 perovskite single phase but dual phase La2NiO4 and NiO, and the percentage of the two phases varied with sintering temperature. Ceramics sintered at 1400 ℃ were well crystallized and the phase ratio of La2NiO4 was the maximum. The surface morphology observed by scanning electron microscopy （SEM） indicated that the grains of the ceramics sintered at 1400 ℃ were uniform and compact, which were in agreement with the properties of high density and low electrical resistivity of the samples. X-ray diffraction （XRD） patterns of ceramics before and after arc erosion indicated their high structural stability, which resulted in the good arc erosion resistance properties for silver-based electrical contact materials. The contact materials prepared with the ceramic sintered at 1400 ℃ exhibited better mass transition and arc erosion resisting properties.展开更多
采用柠檬酸溶胶 凝胶法制备的Ce Zr La O固溶体为载体,制备CuO Ce Zr La O催化剂,用XRD,Raman,TPR等实验技术对Ce Zr La O固溶体及CuO Ce Zr La O的物相、Redox性能进行了表征。实验结果表明,Ce0.7Zr0 3-yLayO固溶体的还原性能与La含量...采用柠檬酸溶胶 凝胶法制备的Ce Zr La O固溶体为载体,制备CuO Ce Zr La O催化剂,用XRD,Raman,TPR等实验技术对Ce Zr La O固溶体及CuO Ce Zr La O的物相、Redox性能进行了表征。实验结果表明,Ce0.7Zr0 3-yLayO固溶体的还原性能与La含量有关,适量的La能促进固溶体的氧化还原。CuO的负载量为6%时,CuO Ce0.7Zr0.15La0.15O的活性最高,高分散且与载体相互作用的CuO是CO氧化活性相。展开更多
Important effects exist between precious metals and rare earths oxides in three-way catalyst, especially the coordinated effects. These effects were studied by using H2PtCl6, Pt(NH3)2(NO2)2 and Pt(OH)2(C2H5ONH2)2 as P...Important effects exist between precious metals and rare earths oxides in three-way catalyst, especially the coordinated effects. These effects were studied by using H2PtCl6, Pt(NH3)2(NO2)2 and Pt(OH)2(C2H5ONH2)2 as Pt precursors, and the mixed oxide of (Ce-Zr-La-Pr)O as base material to prepare a series of catalysts, and their performances of the catalysts were studied by TPR and CO pulse titration technologies. The results shown that Pt precursors and their solutions pH values influenced the oxygen storage capabilities, the active metal distribution degrees of the catalysts obviously, and every catalyst prepared by different precursors had an optimal pH values. It indicates that the active metals precursors and their solutions acidities have outstanding influences on the catalysts performances for the mutual effects existing between the active metals and the Rare Earth metal oxides, which results from the mate groups of the precursors and the solution acidity.展开更多
The Ce-Zr-La-O solid solution was prepared by the sol-gel method. Thestructure and the redox behavior of Ce-Zr-La-O solid solution and CuO/Ce-Zr-La-O catalysts wereinvestigated by using XRD, Raman and TPR techniques. ...The Ce-Zr-La-O solid solution was prepared by the sol-gel method. Thestructure and the redox behavior of Ce-Zr-La-O solid solution and CuO/Ce-Zr-La-O catalysts wereinvestigated by using XRD, Raman and TPR techniques. The result shows that the reduction capabilityof Ce_(0.7)Zr_(0.3-y)La_yO solid solution is related to content of La. Appropriate content of La canenhance the redox capability of the solid solution. The oxidation activity of the CuO (6 percent)/Ce_(0.7)Zr_(0.15)La_(0.15)O catalyst is the highest. CuO, which finely dispersed and interacted withthe support, is the site of oxidation activity.展开更多
El Nio or La Nia manifest in December over the Pacific and will serve as an index for the forecasting of subsequent Indian summer monsoon,which occurs from June to mid-September.In the present article,an attempt i...El Nio or La Nia manifest in December over the Pacific and will serve as an index for the forecasting of subsequent Indian summer monsoon,which occurs from June to mid-September.In the present article,an attempt is made to study the variation of latent heat flux (LHF) over the north Indian Ocean during strong El Nio and strong La Nia and relate it with Indian monsoon rainfall.During strong El Nio the LHF intensity is higher and associated with higher wind speed and lower cloud amount.During El Nio all India rainfall is having an inverse relation with LHF.Seasonal rainfall is higher in YY+1 (subsequent year) than YY (year of occurrence).However there is a lag in rainfall during El Nio YY+1 from June to July when compared with the monthly rainfall.展开更多
基金supported by the National Basic Research Program of China (2007CB607504)HI-TECH Research and Development Program of China (2001AA327150)
文摘Ceramic LaNiO3 samples were prepared by solid state reaction method at different sintering temperatures. It was found that the resultant was not ABO3 perovskite single phase but dual phase La2NiO4 and NiO, and the percentage of the two phases varied with sintering temperature. Ceramics sintered at 1400 ℃ were well crystallized and the phase ratio of La2NiO4 was the maximum. The surface morphology observed by scanning electron microscopy （SEM） indicated that the grains of the ceramics sintered at 1400 ℃ were uniform and compact, which were in agreement with the properties of high density and low electrical resistivity of the samples. X-ray diffraction （XRD） patterns of ceramics before and after arc erosion indicated their high structural stability, which resulted in the good arc erosion resistance properties for silver-based electrical contact materials. The contact materials prepared with the ceramic sintered at 1400 ℃ exhibited better mass transition and arc erosion resisting properties.
文摘采用柠檬酸溶胶 凝胶法制备的Ce Zr La O固溶体为载体,制备CuO Ce Zr La O催化剂,用XRD,Raman,TPR等实验技术对Ce Zr La O固溶体及CuO Ce Zr La O的物相、Redox性能进行了表征。实验结果表明,Ce0.7Zr0 3-yLayO固溶体的还原性能与La含量有关,适量的La能促进固溶体的氧化还原。CuO的负载量为6%时,CuO Ce0.7Zr0.15La0.15O的活性最高,高分散且与载体相互作用的CuO是CO氧化活性相。
基金Project supported by the National High Technology Research and Development Programs (863 ) of China (2002 AA321060, 2004AA649040) Yunnan Province Science Technology Program (2004B0028Q)
文摘Important effects exist between precious metals and rare earths oxides in three-way catalyst, especially the coordinated effects. These effects were studied by using H2PtCl6, Pt(NH3)2(NO2)2 and Pt(OH)2(C2H5ONH2)2 as Pt precursors, and the mixed oxide of (Ce-Zr-La-Pr)O as base material to prepare a series of catalysts, and their performances of the catalysts were studied by TPR and CO pulse titration technologies. The results shown that Pt precursors and their solutions pH values influenced the oxygen storage capabilities, the active metal distribution degrees of the catalysts obviously, and every catalyst prepared by different precursors had an optimal pH values. It indicates that the active metals precursors and their solutions acidities have outstanding influences on the catalysts performances for the mutual effects existing between the active metals and the Rare Earth metal oxides, which results from the mate groups of the precursors and the solution acidity.
文摘The Ce-Zr-La-O solid solution was prepared by the sol-gel method. Thestructure and the redox behavior of Ce-Zr-La-O solid solution and CuO/Ce-Zr-La-O catalysts wereinvestigated by using XRD, Raman and TPR techniques. The result shows that the reduction capabilityof Ce_(0.7)Zr_(0.3-y)La_yO solid solution is related to content of La. Appropriate content of La canenhance the redox capability of the solid solution. The oxidation activity of the CuO (6 percent)/Ce_(0.7)Zr_(0.15)La_(0.15)O catalyst is the highest. CuO, which finely dispersed and interacted withthe support, is the site of oxidation activity.
基金Key Project of Chinese National Programs for Fundamental Research and Development (973 program) (2011CB403500,2011CB403504)
文摘El Nio or La Nia manifest in December over the Pacific and will serve as an index for the forecasting of subsequent Indian summer monsoon,which occurs from June to mid-September.In the present article,an attempt is made to study the variation of latent heat flux (LHF) over the north Indian Ocean during strong El Nio and strong La Nia and relate it with Indian monsoon rainfall.During strong El Nio the LHF intensity is higher and associated with higher wind speed and lower cloud amount.During El Nio all India rainfall is having an inverse relation with LHF.Seasonal rainfall is higher in YY+1 (subsequent year) than YY (year of occurrence).However there is a lag in rainfall during El Nio YY+1 from June to July when compared with the monthly rainfall.
