The effect of H impurity on the misfit dislocation in Ni-based single-crystal superalloy is investigated using the molecular dynamic simulation. It includes the site preferences of H impurity in single crystals Ni and...The effect of H impurity on the misfit dislocation in Ni-based single-crystal superalloy is investigated using the molecular dynamic simulation. It includes the site preferences of H impurity in single crystals Ni and Ni3Al, the interaction between H impurity and the misfit dislocation and the effect of H impurity on the moving misfit dislocation. The calculated energies and simulation results show that the misfit dislocation attracts H impurity which is located at the γ/γ′ interface and Ni3Al and H impurity on the glide plane can obstruct the glide of misfit dislocation, which is beneficial to improving the mechanical properties of Ni based superalloys.展开更多
In this study, we investigate the effect of nitrogen and hydrogen impurities on colors, morphologies, impurity structures and synthesis conditions of diamond crystals in Fe–C systems with C3N6H6 additives at pressure...In this study, we investigate the effect of nitrogen and hydrogen impurities on colors, morphologies, impurity structures and synthesis conditions of diamond crystals in Fe–C systems with C3N6H6 additives at pressures in the range 5.0–6.5 GPa and temperatures of 1400–1700℃ in detail. Our results reveal that the octahedron diamond nucleation in a Fe–C system is evidently inhibited by co-doped N–H elements, thereby resulting in the increase of minimum pressure and temperature of diamond synthesis by spontaneous nucleation. The octahedron diamond crystals synthesized from a pure Fe–C system are colorless, while they become green in the system with C3N6H6 additive. The surface defects of diamond will deteriorate when the nitrogen and hydrogen atoms simultaneously incorporate in the diamond growth environment in the Fe–C system. We believe that this study will provide some important information and be beneficial for the deep understanding of the crystallization of diamonds from different component systems.展开更多
We have calculated the electron energy of the ground and lower excited states for H_2^+-like impurity statesconfined in finite spherical quantum dots in GaAs.Based on the characteristics of energy levels,we have propo...We have calculated the electron energy of the ground and lower excited states for H_2^+-like impurity statesconfined in finite spherical quantum dots in GaAs.Based on the characteristics of energy levels,we have proposed ascheme for realizing charge qubit composed by the the ground and the first excited states of this confined double donorsystem for the first time.In the proposed scheme the charge qubit is coded in terms of the located electronic states.展开更多
基金supported by the National Basic Research Program of China (Grant No.2011CB606402)the National Natural Science Foundation of China (Grant No.51071091)
文摘The effect of H impurity on the misfit dislocation in Ni-based single-crystal superalloy is investigated using the molecular dynamic simulation. It includes the site preferences of H impurity in single crystals Ni and Ni3Al, the interaction between H impurity and the misfit dislocation and the effect of H impurity on the moving misfit dislocation. The calculated energies and simulation results show that the misfit dislocation attracts H impurity which is located at the γ/γ′ interface and Ni3Al and H impurity on the glide plane can obstruct the glide of misfit dislocation, which is beneficial to improving the mechanical properties of Ni based superalloys.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11504267,11504269,and 51172089)the Open Project of State Key Laboratory of Superhard Materials,Jilin University,China(Grant No.201504)the Doctoral Fund of Tianjin Normal University,China(Grant No.52XB1518)
文摘In this study, we investigate the effect of nitrogen and hydrogen impurities on colors, morphologies, impurity structures and synthesis conditions of diamond crystals in Fe–C systems with C3N6H6 additives at pressures in the range 5.0–6.5 GPa and temperatures of 1400–1700℃ in detail. Our results reveal that the octahedron diamond nucleation in a Fe–C system is evidently inhibited by co-doped N–H elements, thereby resulting in the increase of minimum pressure and temperature of diamond synthesis by spontaneous nucleation. The octahedron diamond crystals synthesized from a pure Fe–C system are colorless, while they become green in the system with C3N6H6 additive. The surface defects of diamond will deteriorate when the nitrogen and hydrogen atoms simultaneously incorporate in the diamond growth environment in the Fe–C system. We believe that this study will provide some important information and be beneficial for the deep understanding of the crystallization of diamonds from different component systems.
基金National Natural Science Foundation of China under Grant No.10374119
文摘We have calculated the electron energy of the ground and lower excited states for H_2^+-like impurity statesconfined in finite spherical quantum dots in GaAs.Based on the characteristics of energy levels,we have proposed ascheme for realizing charge qubit composed by the the ground and the first excited states of this confined double donorsystem for the first time.In the proposed scheme the charge qubit is coded in terms of the located electronic states.
