In this paper, we investigate the Raman and photoluminescence spectra of Y_2O_3/Eu^（3＋） and Y_2O_3/Eu^（3＋）/Mg^（2＋） nanorods under high pressures using 514-nm and 532-nm laser light excitation. We observe tran...In this paper, we investigate the Raman and photoluminescence spectra of Y_2O_3/Eu^（3＋） and Y_2O_3/Eu^（3＋）/Mg^（2＋） nanorods under high pressures using 514-nm and 532-nm laser light excitation. We observe transitions from the initial cubic phase to amorphous at pressures higher than 24 GPa for both Y_2O_3/Eu^（3＋） and Y_2O_3/Eu^（3＋）/Mg^（2＋） nanorods. In addition, Y_2O_3/Eu^（3＋） and Y_2O_3/Eu^（3＋）/Mg^（2＋） nanorods exhibit different distorted states after the pressure has been raised to 8 GPa. The analyses of intensity ratios, I_（0-2）/I_（0-1） from ~5D_（0–）~7F2_to^5D_（0–）~7F_1and I_（0-2）A/B of ~5D_（0–）7F_2 transitions indicate that Y_2O_3/Eu^（3＋）/Mg^（2＋） nanorods exhibit stronger local micro-surrounding characteristics for Eu^（3＋） ions in a pressuremodulated crystal field. The doped Mg2＋ion results in reducing the crystal ionicity in the distorted lattice state under high pressures. The use of doped ions as an ion modifier can be applied to the study of small local microstructural changes through Eu^（3＋） luminescence.展开更多
以V_2O_5,AgNO_3和Y(NO_3)_3×6H_2O为原料、十二烷基苯磺酸钠为辅助剂,采用直接沉淀法和浸渍法制备单斜晶相Ag_3VO_4和Y_2O3_/Ag_3VO_4复合催化剂,表征了产物的结构和形貌,并分析了其形成机理;在可见光下研究了其催化可见光降解罗...以V_2O_5,AgNO_3和Y(NO_3)_3×6H_2O为原料、十二烷基苯磺酸钠为辅助剂,采用直接沉淀法和浸渍法制备单斜晶相Ag_3VO_4和Y_2O3_/Ag_3VO_4复合催化剂,表征了产物的结构和形貌,并分析了其形成机理;在可见光下研究了其催化可见光降解罗丹明B(Rh B)的性能.结果表明,所得Y_2O_3/Ag_3VO_4复合催化剂吸收边相对纯相Ag_3VO_4发生红移,禁带宽度减小至1.83 e V,电子-空穴对复合几率降低,对Rh B有较好的可见光催化活性和稳定性,可见光照射15 min后,0.08 g 3%Y2O_3/Ag_3VO_4催化200 m L 8 mg/L Rh B溶液的降解率达94.2%.展开更多
A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer...A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer were investigated. The composite layer has graded microstructures and compositions, due to the fast melting followed by rapid solidification and cooling during laser cladding. The TiC powders are completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified. The size of TiC dendrites decreases with increasing depth. Y2O3 fine particles distribute in the whole clad layer. The Y2O3 particle enhanced Ni/TiC composite layer has a quite uniform hardness along depth with a maximum value of HV1380, which is 4 times higher than the initial hardness. The wear resistance of the Ti alloy is significantly improved after laser cladding due to the high hardness of the composite coating.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11304380,11404241,11275138,11604240,and 51320105007)the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT1132)
文摘In this paper, we investigate the Raman and photoluminescence spectra of Y_2O_3/Eu^（3＋） and Y_2O_3/Eu^（3＋）/Mg^（2＋） nanorods under high pressures using 514-nm and 532-nm laser light excitation. We observe transitions from the initial cubic phase to amorphous at pressures higher than 24 GPa for both Y_2O_3/Eu^（3＋） and Y_2O_3/Eu^（3＋）/Mg^（2＋） nanorods. In addition, Y_2O_3/Eu^（3＋） and Y_2O_3/Eu^（3＋）/Mg^（2＋） nanorods exhibit different distorted states after the pressure has been raised to 8 GPa. The analyses of intensity ratios, I_（0-2）/I_（0-1） from ~5D_（0–）~7F2_to^5D_（0–）~7F_1and I_（0-2）A/B of ~5D_（0–）7F_2 transitions indicate that Y_2O_3/Eu^（3＋）/Mg^（2＋） nanorods exhibit stronger local micro-surrounding characteristics for Eu^（3＋） ions in a pressuremodulated crystal field. The doped Mg2＋ion results in reducing the crystal ionicity in the distorted lattice state under high pressures. The use of doped ions as an ion modifier can be applied to the study of small local microstructural changes through Eu^（3＋） luminescence.
文摘以V_2O_5,AgNO_3和Y(NO_3)_3×6H_2O为原料、十二烷基苯磺酸钠为辅助剂,采用直接沉淀法和浸渍法制备单斜晶相Ag_3VO_4和Y_2O3_/Ag_3VO_4复合催化剂,表征了产物的结构和形貌,并分析了其形成机理;在可见光下研究了其催化可见光降解罗丹明B(Rh B)的性能.结果表明,所得Y_2O_3/Ag_3VO_4复合催化剂吸收边相对纯相Ag_3VO_4发生红移,禁带宽度减小至1.83 e V,电子-空穴对复合几率降低,对Rh B有较好的可见光催化活性和稳定性,可见光照射15 min后,0.08 g 3%Y2O_3/Ag_3VO_4催化200 m L 8 mg/L Rh B溶液的降解率达94.2%.
基金Projects (51101096, 51002093) supported by the National Natural Science Foundation of ChinaProject (1052nm05000) supported by Special Foundation of the Shanghai Science and Technology Commission for Nano-Materials ResearchProject (J51042) supported by Leading Academic Discipline Project of the Shanghai Education Commission, China
文摘A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer were investigated. The composite layer has graded microstructures and compositions, due to the fast melting followed by rapid solidification and cooling during laser cladding. The TiC powders are completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified. The size of TiC dendrites decreases with increasing depth. Y2O3 fine particles distribute in the whole clad layer. The Y2O3 particle enhanced Ni/TiC composite layer has a quite uniform hardness along depth with a maximum value of HV1380, which is 4 times higher than the initial hardness. The wear resistance of the Ti alloy is significantly improved after laser cladding due to the high hardness of the composite coating.
