The distribution and anomalies of rare earth elements(REEs) of granitic regolith were studied in Inner Mongolia and Hainan Island, China. One profile showed slight REE enrichment of an upper layer and no obvious light...The distribution and anomalies of rare earth elements(REEs) of granitic regolith were studied in Inner Mongolia and Hainan Island, China. One profile showed slight REE enrichment of an upper layer and no obvious light REE/heavy REE(LREE/HREE) fractionation(La_N/Yb_N of 0.9). The second profile was significantly enriched in REEs and enriched in LREEs in the upper portion(La_N/Yb_N>1.8). Eu, Ce, and Gd anomalies of the two profiles are different. Slightly negative Eu, Ce, and Gd anomalies in NMG-3-1 indicate slow dissolution of primary minerals and little secondary products; in contrast, a positive Eu anomaly in HN-2 suggests the vegetation cycle may contribute to soil. The Ce anomaly of HN-2 reflects oxidation of Ce and coprecipitation by Fe-and Mn-oxides and organic matter. Correlation between Ce and Gd anomalies in HN-2 suggests Ce and Gd are both influenced by redoxreduction.展开更多
Effects of rare earth element La on the microstructure of Cumatrix diamond tools were researched under the conditions of variousmaterials components and the process parameters in order to improvematerials properties. ...Effects of rare earth element La on the microstructure of Cumatrix diamond tools were researched under the conditions of variousmaterials components and the process parameters in order to improvematerials properties. SEM, XPS and X-ray were used to investigate thefracture section, microstructure and the element valence inmaterials. The Results shown that the combination of rare earthelement La and transition element Ti is advantageous to the bondingstate Between diamond particles and matrix, so it can improve thematerials properties. Suitable sintering temperature is 790 deg. C.展开更多
The obstacles of inferior microstructure and poor magnetic properties of(La,Ce)-Fe-B type magnets stand in the way of expanding their applications.In this work,(La,Ce)-Fe-B melt-spun ribbons were prepared with differe...The obstacles of inferior microstructure and poor magnetic properties of(La,Ce)-Fe-B type magnets stand in the way of expanding their applications.In this work,(La,Ce)-Fe-B melt-spun ribbons were prepared with different La/Ce ratios and rare earth contents.The microstructure and magnetic properties of these ribbons were investigated.With the La/Ce ratio increased,the fraction of the CeFe_(2)phase decreased and the β-La phase segregated among matrix grains,which deteriorated the coercivity of the ribbons.Reducing the rare earth content effectively suppressed the β-La phase and improved the proportion of the matrix phase in the ribbons.Here,the optimal alloy composite(La_(15)Ce_(85))_(14)Fe_(80)B_(6) has been obtained with modified microstructure and inhibited secondary phases.Good ribbon performance was tested,with H_(cj)=4.51 kOe,B_(r)=6.29 kG and(BH)_(max)=6.81 MGOe.展开更多
Fe-La, Fe-Ce, Fe-La-P, Fe-Ce-P and Fe-P alloys were obtained f rom aqueous solutions by using optimized electroplaing solutions and process con ditions. The experimental results show that these alloys (Fe-La-P, Fe-Ce-...Fe-La, Fe-Ce, Fe-La-P, Fe-Ce-P and Fe-P alloys were obtained f rom aqueous solutions by using optimized electroplaing solutions and process con ditions. The experimental results show that these alloys (Fe-La-P, Fe-Ce- P and Fe-P) have amorphous structure. The crystallization activation energy a nd kinetics equation of three kinds amorphous coatings have been determined by D SC method. The results indicated that the crystallization activation energy of F e-P, Fe-La-P, Fe-Ce-P amorphous coatings are 175.2, 370.1, 434.6kJ·m ol-1 respectively. The crystallization mechamism of three kinds amorphous alloy s may be expressed by Avrami-Erofeev equation (n=1), the kinetics equation is .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
基金supported by the National Natural Science Foundation of China(Grant No.4121000441661144042)National Basic Research Program(973 project)of China(2013CB956401)
文摘The distribution and anomalies of rare earth elements(REEs) of granitic regolith were studied in Inner Mongolia and Hainan Island, China. One profile showed slight REE enrichment of an upper layer and no obvious light REE/heavy REE(LREE/HREE) fractionation(La_N/Yb_N of 0.9). The second profile was significantly enriched in REEs and enriched in LREEs in the upper portion(La_N/Yb_N>1.8). Eu, Ce, and Gd anomalies of the two profiles are different. Slightly negative Eu, Ce, and Gd anomalies in NMG-3-1 indicate slow dissolution of primary minerals and little secondary products; in contrast, a positive Eu anomaly in HN-2 suggests the vegetation cycle may contribute to soil. The Ce anomaly of HN-2 reflects oxidation of Ce and coprecipitation by Fe-and Mn-oxides and organic matter. Correlation between Ce and Gd anomalies in HN-2 suggests Ce and Gd are both influenced by redoxreduction.
文摘Effects of rare earth element La on the microstructure of Cumatrix diamond tools were researched under the conditions of variousmaterials components and the process parameters in order to improvematerials properties. SEM, XPS and X-ray were used to investigate thefracture section, microstructure and the element valence inmaterials. The Results shown that the combination of rare earthelement La and transition element Ti is advantageous to the bondingstate Between diamond particles and matrix, so it can improve thematerials properties. Suitable sintering temperature is 790 deg. C.
基金Project supported by the fifth batch of major scientific and technological research projects in the Panxi Experimental Zone of Sichuan Province,the new functional materials and applications of rare earth vanadium titanium(Grant No.2020SCUNG201).
文摘The obstacles of inferior microstructure and poor magnetic properties of(La,Ce)-Fe-B type magnets stand in the way of expanding their applications.In this work,(La,Ce)-Fe-B melt-spun ribbons were prepared with different La/Ce ratios and rare earth contents.The microstructure and magnetic properties of these ribbons were investigated.With the La/Ce ratio increased,the fraction of the CeFe_(2)phase decreased and the β-La phase segregated among matrix grains,which deteriorated the coercivity of the ribbons.Reducing the rare earth content effectively suppressed the β-La phase and improved the proportion of the matrix phase in the ribbons.Here,the optimal alloy composite(La_(15)Ce_(85))_(14)Fe_(80)B_(6) has been obtained with modified microstructure and inhibited secondary phases.Good ribbon performance was tested,with H_(cj)=4.51 kOe,B_(r)=6.29 kG and(BH)_(max)=6.81 MGOe.
文摘Fe-La, Fe-Ce, Fe-La-P, Fe-Ce-P and Fe-P alloys were obtained f rom aqueous solutions by using optimized electroplaing solutions and process con ditions. The experimental results show that these alloys (Fe-La-P, Fe-Ce- P and Fe-P) have amorphous structure. The crystallization activation energy a nd kinetics equation of three kinds amorphous coatings have been determined by D SC method. The results indicated that the crystallization activation energy of F e-P, Fe-La-P, Fe-Ce-P amorphous coatings are 175.2, 370.1, 434.6kJ·m ol-1 respectively. The crystallization mechamism of three kinds amorphous alloy s may be expressed by Avrami-Erofeev equation (n=1), the kinetics equation is .
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。
