We derived revised effective diffusion energy barriers following the Boltzmann distribution assumption for impurity atoms in a bulk material under the impact of various kinds of point defects to reveal the insights of...We derived revised effective diffusion energy barriers following the Boltzmann distribution assumption for impurity atoms in a bulk material under the impact of various kinds of point defects to reveal the insights of migration mechanisms. The effective diffusion energy barriers of copper impurities in bulk zirconium were calculated through the first principle method under the presented hypothesis. Our results(?E_(||) =1.27 eV, ?E_⊥=1.31 eV) agreed well with the experimental results(?E_(||) =1.54 eV, ?E_⊥=1.60 eV), which validated bulk diffusion as the major mechanism for copper diffusion in zirconium. The effective diffusion energy barriers could be used for estimating whether the defects will accelerate the diffusion or slow them down by acting as traps of the impurity atoms. On the other hand, the first principle results of the impurity diffusion via defects could be further used as inputs of larger scale computational simulations, such as MC(Monte Carlo) or Phase Field calculations.展开更多
Using Embedded-atom-method (EAM) potential, we have performed in detail molecular dynamics studies on a Fe adatom adsorption and diffusion dynamics on three low miller index surfaces, Fe (110), Fe (001), and Fe (111)....Using Embedded-atom-method (EAM) potential, we have performed in detail molecular dynamics studies on a Fe adatom adsorption and diffusion dynamics on three low miller index surfaces, Fe (110), Fe (001), and Fe (111). Our results present that adatom adsorption energies and diffusion barriers on these surfaces have similar monotonic trend: adsorption energies, Ea(110) Ea(001) Ea(111), diffusion barriers, Ed(110) Ed(001) Ed(111). On the Fe (110) surface, adatom simple jump is the main diffusion mechanism with relatively low energy barrier;nevertheless, adatoms exchange with surface atoms play a dominant role in surface diffusion on the Fe (001).展开更多
The Chemical behavior of binary systems RE(III)-NEB(RE=La→Nd,Sm→Lu,Y;NEB=2,2′,2″nitrilotris(2,1ethanediyloxy)tris benzoic acid)were investigated potentiometrically at 25℃ and 020 mol/L(KNO3)ion strength i...The Chemical behavior of binary systems RE(III)-NEB(RE=La→Nd,Sm→Lu,Y;NEB=2,2′,2″nitrilotris(2,1ethanediyloxy)tris benzoic acid)were investigated potentiometrically at 25℃ and 020 mol/L(KNO3)ion strength in 50% methanolwater mixture.Computer programs MAGEC?MINIQUAD82 and MIQUV were employed for obtaining the results.It was found that two chemical models of binary complexes 112 and 111(RE∶L∶H,L=deprotonated NEB,H=proton)were existed in researching systems,and an apparent"tetrad effect"was also observed for the stability constants logβ112 and logβ111.In addition,the relative position of ytterbium was discussed.展开更多
Belt and Road initiative is a very important strategy for Chinese companies to cooperate with foreign ones.The Middle East is a region that contains abundant oil and gas resources. Meanwhile, many countries in the Mid...Belt and Road initiative is a very important strategy for Chinese companies to cooperate with foreign ones.The Middle East is a region that contains abundant oil and gas resources. Meanwhile, many countries in the Middle East support and join in the Belt and Road initiative. Since oil and gas resources are of vital significance for Chinese industry,the cooperation in oil and gas with countries in the Middle East is an important part in 'Belt and Road' initiative. CNPC began its overseas business from the year 1993 and now it keeps cooperating with many countries in the Middle East. UAE has a large amount of oil and gas reserves and after evaluation, CNPC became the shareholder of ADNOC Onshore and gained 8% of the stocks.In order to improve the development effect, ADNOC appointed several international oil companies as asset leaders for four assets. As a reward, each asset leader can have more income and less tax. As a result, CNPC decided to compete for NEB asset leader with other international oil companies. After analyzing the current development plan, our group conducted the optimization scheme for NEB asset that can help improve the current situation and enhance oil recovery.The optimization scheme is divided into three steps. First is the establishment of effective drainage system.Second is to control water cut and GOR. Third is to enhance oil recovery factor based on first two steps. After discussion with the research group of ADNOC, they admitted that our strategy can solve the problems. Finally, CNPC obtained the asset leader, and has more impact on UAE oil and gas industry since then.展开更多
基金Funded in Part by National Natural Science Foundation of China(Nos.11575129 and 11275142)
文摘We derived revised effective diffusion energy barriers following the Boltzmann distribution assumption for impurity atoms in a bulk material under the impact of various kinds of point defects to reveal the insights of migration mechanisms. The effective diffusion energy barriers of copper impurities in bulk zirconium were calculated through the first principle method under the presented hypothesis. Our results(?E_(||) =1.27 eV, ?E_⊥=1.31 eV) agreed well with the experimental results(?E_(||) =1.54 eV, ?E_⊥=1.60 eV), which validated bulk diffusion as the major mechanism for copper diffusion in zirconium. The effective diffusion energy barriers could be used for estimating whether the defects will accelerate the diffusion or slow them down by acting as traps of the impurity atoms. On the other hand, the first principle results of the impurity diffusion via defects could be further used as inputs of larger scale computational simulations, such as MC(Monte Carlo) or Phase Field calculations.
文摘Using Embedded-atom-method (EAM) potential, we have performed in detail molecular dynamics studies on a Fe adatom adsorption and diffusion dynamics on three low miller index surfaces, Fe (110), Fe (001), and Fe (111). Our results present that adatom adsorption energies and diffusion barriers on these surfaces have similar monotonic trend: adsorption energies, Ea(110) Ea(001) Ea(111), diffusion barriers, Ed(110) Ed(001) Ed(111). On the Fe (110) surface, adatom simple jump is the main diffusion mechanism with relatively low energy barrier;nevertheless, adatoms exchange with surface atoms play a dominant role in surface diffusion on the Fe (001).
文摘The Chemical behavior of binary systems RE(III)-NEB(RE=La→Nd,Sm→Lu,Y;NEB=2,2′,2″nitrilotris(2,1ethanediyloxy)tris benzoic acid)were investigated potentiometrically at 25℃ and 020 mol/L(KNO3)ion strength in 50% methanolwater mixture.Computer programs MAGEC?MINIQUAD82 and MIQUV were employed for obtaining the results.It was found that two chemical models of binary complexes 112 and 111(RE∶L∶H,L=deprotonated NEB,H=proton)were existed in researching systems,and an apparent"tetrad effect"was also observed for the stability constants logβ112 and logβ111.In addition,the relative position of ytterbium was discussed.
文摘Belt and Road initiative is a very important strategy for Chinese companies to cooperate with foreign ones.The Middle East is a region that contains abundant oil and gas resources. Meanwhile, many countries in the Middle East support and join in the Belt and Road initiative. Since oil and gas resources are of vital significance for Chinese industry,the cooperation in oil and gas with countries in the Middle East is an important part in 'Belt and Road' initiative. CNPC began its overseas business from the year 1993 and now it keeps cooperating with many countries in the Middle East. UAE has a large amount of oil and gas reserves and after evaluation, CNPC became the shareholder of ADNOC Onshore and gained 8% of the stocks.In order to improve the development effect, ADNOC appointed several international oil companies as asset leaders for four assets. As a reward, each asset leader can have more income and less tax. As a result, CNPC decided to compete for NEB asset leader with other international oil companies. After analyzing the current development plan, our group conducted the optimization scheme for NEB asset that can help improve the current situation and enhance oil recovery.The optimization scheme is divided into three steps. First is the establishment of effective drainage system.Second is to control water cut and GOR. Third is to enhance oil recovery factor based on first two steps. After discussion with the research group of ADNOC, they admitted that our strategy can solve the problems. Finally, CNPC obtained the asset leader, and has more impact on UAE oil and gas industry since then.
