A semi-empirical interatomic potential formalism,the second-nearest-neighbor modified embedded-atom method(2NN MEAM),has been applied to obtaining interatomic potentials for the Co-W and Al-W binary system using previ...A semi-empirical interatomic potential formalism,the second-nearest-neighbor modified embedded-atom method(2NN MEAM),has been applied to obtaining interatomic potentials for the Co-W and Al-W binary system using previously developed MEAM potentials of Co,Al and W.The potential parameters were determined by fitting the experimental data on the enthalpy of formation,lattice parameter,melting point and elastic constants.The present potentials generally reproduce the fundamental physical properties of the Co-W and Al-W systems accurately.The lattice parameters,the enthalpy of formation,the thermal stability and the elastic constants match well with experiment and the first-principles results.The enthalpy of mixing and the enthalpy of formation and mixing of liquid are in good agreement with CALPHAD calculations.The potentials can be easily combined with already-developed MEAM potentials for binary cobalt systems and can be used to describe Co-Al-W-based multicomponent alloys,especially for interfacial properties.展开更多
Cobalt-doped gold clusters AunCo （n=1-7） are systematically investigated for the possible stable geometrical configurations and relative stabilities of the lowest-lying isomers using density-functional theory at B3L...Cobalt-doped gold clusters AunCo （n=1-7） are systematically investigated for the possible stable geometrical configurations and relative stabilities of the lowest-lying isomers using density-functional theory at B3LYP/LanL2DZ level. Several low-lying isomers were determined, and many of them are in electronic configurations with a high spin multiplicity. The results indicate that the ground-state AunCo（n=1-7） clusters adopt a planar structure except for n=7. The stability trend of the AunCo （n=1-7） clusters shows that the Au2Co clusters are magic cluster with high stability.展开更多
A double-input–multi-output linearized system is developed using the state-space method for dynamic analysis of methanation process of coke oven gas.The stability of reactor alone and reactor with feed-effluent heat ...A double-input–multi-output linearized system is developed using the state-space method for dynamic analysis of methanation process of coke oven gas.The stability of reactor alone and reactor with feed-effluent heat exchanger is compared through the dominant poles of the system transfer functions.With single or double disturbance of temperature and CO concentration at the reactor inlet,typical dynamic behavior in the reactor,including fast concentration response,slow temperature response and inverse response,is revealed for further understanding of the counteraction and synergy effects caused by simultaneous variation of concentration and temperature.Analysis results show that the stability of the reactor loop is more sensitive than that of reactor alone due to the positive heat feedback.Remarkably,with the decrease of heat exchange efficiency,the reactor system may display limit cycle behavior for a pair of complex conjugate poles across the imaginary axis.展开更多
It was well known that it was very difficult to prepare high performance Fe-based bulk amorphous alloys with both high Fe content and good glass-forming ability, especially for the Fe content （or total magnetic eleme...It was well known that it was very difficult to prepare high performance Fe-based bulk amorphous alloys with both high Fe content and good glass-forming ability, especially for the Fe content （or total magnetic elements content） higher than 80 at%. In this paper, a series of Fe81-xCoxMO1P7.5C5.5B2Si3 （x = 0, 5, 10, 15, 20） bulk amorphous alloys （BAAs） with high saturation magnetization have been developed by copper mold casting method with fluxed ingot. It has been found that using Co replacing Fe in the Fe-Mo-P-C-B-Si alloy could significantly enhance the glass-forming ability and magnetic property. For the BAA with Co content of 0 at%, 5 at%, 10 at%, 15 at% and 20 at%, its saturation magnetization Js（Js=μoMs） was 1.55, 1.60, 1.62, 1.65 and 1.59 T, respectively. Among these alloys, the Fe66Co15- Mo1P7.5C5.5B2Si3 BAA exhibited a critical size of 2 mm in diameter and a high Js of 1.65 T. It suggested that these alloys with high magnetic element content possessed great potential in application due to their high glass-forming ability and high magnetic property.展开更多
基金Project(51274167)supported by the National Natural Science Foundation of ChinaProject(LQ14E010002)supported by the Zhejiang Provincial Natural Science Foundation of ChinaProject(2E24692)supported by the KIST Institutional Programs,Korea
文摘A semi-empirical interatomic potential formalism,the second-nearest-neighbor modified embedded-atom method(2NN MEAM),has been applied to obtaining interatomic potentials for the Co-W and Al-W binary system using previously developed MEAM potentials of Co,Al and W.The potential parameters were determined by fitting the experimental data on the enthalpy of formation,lattice parameter,melting point and elastic constants.The present potentials generally reproduce the fundamental physical properties of the Co-W and Al-W systems accurately.The lattice parameters,the enthalpy of formation,the thermal stability and the elastic constants match well with experiment and the first-principles results.The enthalpy of mixing and the enthalpy of formation and mixing of liquid are in good agreement with CALPHAD calculations.The potentials can be easily combined with already-developed MEAM potentials for binary cobalt systems and can be used to describe Co-Al-W-based multicomponent alloys,especially for interfacial properties.
文摘Cobalt-doped gold clusters AunCo （n=1-7） are systematically investigated for the possible stable geometrical configurations and relative stabilities of the lowest-lying isomers using density-functional theory at B3LYP/LanL2DZ level. Several low-lying isomers were determined, and many of them are in electronic configurations with a high spin multiplicity. The results indicate that the ground-state AunCo（n=1-7） clusters adopt a planar structure except for n=7. The stability trend of the AunCo （n=1-7） clusters shows that the Au2Co clusters are magic cluster with high stability.
基金Supported by the Major Research plan of the National Natural Science Foundation of China(91334101)the National Basic Research Program of China(2009CB219906)the National Natural Science Foundation of China(21276203)
文摘A double-input–multi-output linearized system is developed using the state-space method for dynamic analysis of methanation process of coke oven gas.The stability of reactor alone and reactor with feed-effluent heat exchanger is compared through the dominant poles of the system transfer functions.With single or double disturbance of temperature and CO concentration at the reactor inlet,typical dynamic behavior in the reactor,including fast concentration response,slow temperature response and inverse response,is revealed for further understanding of the counteraction and synergy effects caused by simultaneous variation of concentration and temperature.Analysis results show that the stability of the reactor loop is more sensitive than that of reactor alone due to the positive heat feedback.Remarkably,with the decrease of heat exchange efficiency,the reactor system may display limit cycle behavior for a pair of complex conjugate poles across the imaginary axis.
基金supported by the National Natural Science Foundation of China (51271097)
文摘It was well known that it was very difficult to prepare high performance Fe-based bulk amorphous alloys with both high Fe content and good glass-forming ability, especially for the Fe content （or total magnetic elements content） higher than 80 at%. In this paper, a series of Fe81-xCoxMO1P7.5C5.5B2Si3 （x = 0, 5, 10, 15, 20） bulk amorphous alloys （BAAs） with high saturation magnetization have been developed by copper mold casting method with fluxed ingot. It has been found that using Co replacing Fe in the Fe-Mo-P-C-B-Si alloy could significantly enhance the glass-forming ability and magnetic property. For the BAA with Co content of 0 at%, 5 at%, 10 at%, 15 at% and 20 at%, its saturation magnetization Js（Js=μoMs） was 1.55, 1.60, 1.62, 1.65 and 1.59 T, respectively. Among these alloys, the Fe66Co15- Mo1P7.5C5.5B2Si3 BAA exhibited a critical size of 2 mm in diameter and a high Js of 1.65 T. It suggested that these alloys with high magnetic element content possessed great potential in application due to their high glass-forming ability and high magnetic property.
