The optimized descriptions of the phase diagram and thermodynamic properties for Ce-Al system have been obtained from experimental thermodynamic and phase diagram data by means of the computer program THERMO-CALC bas...The optimized descriptions of the phase diagram and thermodynamic properties for Ce-Al system have been obtained from experimental thermodynamic and phase diagram data by means of the computer program THERMO-CALC based on the least squares method, using models for the Gibbs energy of individual phases. The system contains five intermetallic compounds. The calculated standard enthalpies of Ce_3Al, CeAl, CeAl_2, CeAl_3 and Ce_3Al_ 11 are -26.7, -48.9, -48.4, -44.0 and -41.7 kJ/mol, respectively. A consistent set of thermodynamic parameters was derived. The optimized and experimental data are in good agreement.展开更多
La-Al2O3 and Ce-Al2O3 binary monolithic column materials with dual functions of carrier and promoter were prepared in one-step by the sol-gel method.Using the as-synthesized binary monolithic column materials as carri...La-Al2O3 and Ce-Al2O3 binary monolithic column materials with dual functions of carrier and promoter were prepared in one-step by the sol-gel method.Using the as-synthesized binary monolithic column materials as carrier,the 9%Mn/M-Al2O3(M=La/Ce)catalyst was prepared by the impregnation method.The binary carrier and catalyst were characterized by BET,SEM,XRD,H2-TPR,and O2-TPD techniques,and the methane combustion performance was tested in a micro fixed-bed reactor.Results showed that the Mn-based binary carrier catalyst with dual functions of carrier and promoter had higher catalytic activity than that with single alumina acting as the carrier.The catalyst activity gradually increased with an increasing content of La,while there was no significant effect with the increase in Ce content.When the ratio of La content in La-Al2O3 is 11%,1%of methane contained in the ventilation air can be completely converted over the 9%Mn/11%La-Al2O3 catalyst at a temperature as low as 550℃.展开更多
The Mg-Al-Zn-Y-Ce system is one of the key systems for designing high-strength Mg alloys. The purpose of the present article is to develop a thermodynamic database for the Mg-Al-Zn-Y-Ce multicomponent system to design...The Mg-Al-Zn-Y-Ce system is one of the key systems for designing high-strength Mg alloys. The purpose of the present article is to develop a thermodynamic database for the Mg-Al-Zn-Y-Ce multicomponent system to design Mg alloys using the calculation of phase diagrams （CALPHAD） method, where the Gibbs energies of solution phases such as liquid, fcc, bcc, and hcp phases were described by the subregular solution model, whereas those of all the compounds were described by the sublattice model. The thermodynamic parameters describing Gibbs energies of the different phases in this database were evaluated by fitting the experimental data for phase equilibria and thermodynamic properties. On the basis of this database, a lot of information concerning stable and metastable phase equilibria of isothermal and vertical sections, molar fractions of constituent phases, the liquidus projection, etc., can be predicted. This database is expected to play an important role in the design of Mg alloys.展开更多
文摘The optimized descriptions of the phase diagram and thermodynamic properties for Ce-Al system have been obtained from experimental thermodynamic and phase diagram data by means of the computer program THERMO-CALC based on the least squares method, using models for the Gibbs energy of individual phases. The system contains five intermetallic compounds. The calculated standard enthalpies of Ce_3Al, CeAl, CeAl_2, CeAl_3 and Ce_3Al_ 11 are -26.7, -48.9, -48.4, -44.0 and -41.7 kJ/mol, respectively. A consistent set of thermodynamic parameters was derived. The optimized and experimental data are in good agreement.
基金This work was supported by the National Youth Science Foundation(51704086)the National Natural Science Foundation of China(51772294,51972306).
文摘La-Al2O3 and Ce-Al2O3 binary monolithic column materials with dual functions of carrier and promoter were prepared in one-step by the sol-gel method.Using the as-synthesized binary monolithic column materials as carrier,the 9%Mn/M-Al2O3(M=La/Ce)catalyst was prepared by the impregnation method.The binary carrier and catalyst were characterized by BET,SEM,XRD,H2-TPR,and O2-TPD techniques,and the methane combustion performance was tested in a micro fixed-bed reactor.Results showed that the Mn-based binary carrier catalyst with dual functions of carrier and promoter had higher catalytic activity than that with single alumina acting as the carrier.The catalyst activity gradually increased with an increasing content of La,while there was no significant effect with the increase in Ce content.When the ratio of La content in La-Al2O3 is 11%,1%of methane contained in the ventilation air can be completely converted over the 9%Mn/11%La-Al2O3 catalyst at a temperature as low as 550℃.
基金This study was financially supported by the National Natural Science Foundation of China and Chongqing Science and Technology Commission.
文摘The Mg-Al-Zn-Y-Ce system is one of the key systems for designing high-strength Mg alloys. The purpose of the present article is to develop a thermodynamic database for the Mg-Al-Zn-Y-Ce multicomponent system to design Mg alloys using the calculation of phase diagrams （CALPHAD） method, where the Gibbs energies of solution phases such as liquid, fcc, bcc, and hcp phases were described by the subregular solution model, whereas those of all the compounds were described by the sublattice model. The thermodynamic parameters describing Gibbs energies of the different phases in this database were evaluated by fitting the experimental data for phase equilibria and thermodynamic properties. On the basis of this database, a lot of information concerning stable and metastable phase equilibria of isothermal and vertical sections, molar fractions of constituent phases, the liquidus projection, etc., can be predicted. This database is expected to play an important role in the design of Mg alloys.
