A new kind offl biomedical titanium alloy, Ti-35Nb-4Sn-6Mo-9Zr, composed of non-toxic elements Nb, Mo, Zr and Sn with lower elastic modulus and higher strength was designed based on d-electron alloy design theory and ...A new kind offl biomedical titanium alloy, Ti-35Nb-4Sn-6Mo-9Zr, composed of non-toxic elements Nb, Mo, Zr and Sn with lower elastic modulus and higher strength was designed based on d-electron alloy design theory and JMatPro software using orthogonal experiment. The microstructure and basic mechanical properties of designed alloy were investigated. The results show that the alloy is composed of single fl equiaxed grains after solution treatment at 800 ~C. Compared with Ti-6A1-4V, the mechanical properties of the designed alloy are more excellent： E=65 GPa, σb=834 MPa, σ0.2=802 MPa, and σ=11%, which is expected to become a promising new type implanted material. The research approach adopted can reduce the experimental time and cost effectively, and get the ideal experimental results.展开更多
The coordination-dependent force fleld of TersofF for covalently bonded Si has been used tocalculate the cleavage force as a function of interplanar separation and hence to estimate surfaceenergies. This force field i...The coordination-dependent force fleld of TersofF for covalently bonded Si has been used tocalculate the cleavage force as a function of interplanar separation and hence to estimate surfaceenergies. This force field is already fitted to density functional results. The relation to bond-breaking and electron correlation will be emphasized. Finnis-Sinclair-type many-body potentialshave then been used to treat some d-electron metals. In particular, results for cleavage forcein bcc Fe will be presented, and also some calculations as two perfectly planar Fe surfaces arerubbed together' at different interplanar separations. Finally, lattice dynamical models for thesteady-state propagation of a screw dislocation, and then of a crack, will be used, again within abond-breaking type of force field. For the screw dislocation propagation. a solitary wave equationis shown to follow in the 'almost continuum' limit. Energy radiated by phonons as the dislocationmoves can thereby be calculated.展开更多
Electrocatalytic CO_(2) reduction reaction(CO_(2)RR)to high-value-added products is a crucial approach for promoting carbon recycling and mitigating energy challenges.Here,extensive theoretical screenings were conduct...Electrocatalytic CO_(2) reduction reaction(CO_(2)RR)to high-value-added products is a crucial approach for promoting carbon recycling and mitigating energy challenges.Here,extensive theoretical screenings were conducted on the nitrogen-doped graphene-supported heteronuclear dual-atom catalysts(DACs)M_(1)/M_(2)-NC(M=V,Cr,Mn,Fe,Co,Ni,and Cu)for CO_(2)RR using density functional theory(DFT)calculations.The calculations indicate that Mn/Cu-NC exhibits superior catalytic activity and selectivity for the CO_(2)RR to HCOOH with a limiting potential as low as−0.15 V.The superior performance is attributed to the strong d-electron coupling between Mn and Cu dual atoms in Mn/Cu-NC,which results in an upward shift of the d-band center of the Mn single atom closer to the Fermi level.Moreover,the adsorption of the key intermediate*OCHO on the Mn single atom was further enhanced,thereby reducing the limiting potential and improving the catalytic performance for CO_(2)RR.This work offers a comprehensive theoretical insight into the catalytic mechanism of the novel Mn/Cu-NC DAC for CO_(2)RR and establishes a critical descriptor of d-band center of the catalytic active center to determine the catalytic activity of DACs for CO_(2)RR,thereby providing guidance for the future design and fabrication of graphene-based metal DACs for CO_(2)RR.展开更多
开发地球电子辐射带的数据同化模型,对于理解辐射带电子的动态演化过程和辐射带空间天气预报具有重要意义.结合范阿伦卫星的辐射带电子观测数据和外辐射带三维扩散模型,采用卡尔曼滤波算法,本文开发了基于Fortran语言的外辐射带电子三...开发地球电子辐射带的数据同化模型,对于理解辐射带电子的动态演化过程和辐射带空间天气预报具有重要意义.结合范阿伦卫星的辐射带电子观测数据和外辐射带三维扩散模型,采用卡尔曼滤波算法,本文开发了基于Fortran语言的外辐射带电子三维数据同化模型(Three-dimensional Data Assimilative Model of Outer Radiation belt Electrons,简称TDAMORE),实现对L^(*)=3~7、能量范围为0.1~5 MeV、投掷角范围为5°~90°的外辐射带电子时空变化过程的三维重构.通过对2018年8月期间外辐射带电子通量演化过程的重构,证实TDAMORE模型可以较好地重现不同能量和不同投掷角电子通量在磁暴前后的演化特征.通过分析电子通量的观测和同化结果之间的相关系数、平均误差、平均绝对误差和均方误差,发现对于能量低于4 MeV的电子,观测与同化结果之间的相关系数基本大于0.8且误差相对较低.而对于更高能量的电子,观测与同化结果之间的误差相对较高,这可能是同化模型忽略了电磁离子回旋波对电子的散射损失导致的.展开更多
基金Project(BE2011778)supported by Science and Technology Support Program of Jiangsu Province,ChinaProject(20133069014)supported by Aeronautical Science Foundation of China
文摘A new kind offl biomedical titanium alloy, Ti-35Nb-4Sn-6Mo-9Zr, composed of non-toxic elements Nb, Mo, Zr and Sn with lower elastic modulus and higher strength was designed based on d-electron alloy design theory and JMatPro software using orthogonal experiment. The microstructure and basic mechanical properties of designed alloy were investigated. The results show that the alloy is composed of single fl equiaxed grains after solution treatment at 800 ~C. Compared with Ti-6A1-4V, the mechanical properties of the designed alloy are more excellent： E=65 GPa, σb=834 MPa, σ0.2=802 MPa, and σ=11%, which is expected to become a promising new type implanted material. The research approach adopted can reduce the experimental time and cost effectively, and get the ideal experimental results.
文摘The coordination-dependent force fleld of TersofF for covalently bonded Si has been used tocalculate the cleavage force as a function of interplanar separation and hence to estimate surfaceenergies. This force field is already fitted to density functional results. The relation to bond-breaking and electron correlation will be emphasized. Finnis-Sinclair-type many-body potentialshave then been used to treat some d-electron metals. In particular, results for cleavage forcein bcc Fe will be presented, and also some calculations as two perfectly planar Fe surfaces arerubbed together' at different interplanar separations. Finally, lattice dynamical models for thesteady-state propagation of a screw dislocation, and then of a crack, will be used, again within abond-breaking type of force field. For the screw dislocation propagation. a solitary wave equationis shown to follow in the 'almost continuum' limit. Energy radiated by phonons as the dislocationmoves can thereby be calculated.
基金supported by the National Key R&D Project(2022YFA1503900)the National Natural Science Foundation of China(22363001,22479032 and 22250710677)+1 种基金the NSFC Center for SingleAtom Catalysis(22388102)the Natural Science Special Foundation of Guizhou University(202140)。
文摘Electrocatalytic CO_(2) reduction reaction(CO_(2)RR)to high-value-added products is a crucial approach for promoting carbon recycling and mitigating energy challenges.Here,extensive theoretical screenings were conducted on the nitrogen-doped graphene-supported heteronuclear dual-atom catalysts(DACs)M_(1)/M_(2)-NC(M=V,Cr,Mn,Fe,Co,Ni,and Cu)for CO_(2)RR using density functional theory(DFT)calculations.The calculations indicate that Mn/Cu-NC exhibits superior catalytic activity and selectivity for the CO_(2)RR to HCOOH with a limiting potential as low as−0.15 V.The superior performance is attributed to the strong d-electron coupling between Mn and Cu dual atoms in Mn/Cu-NC,which results in an upward shift of the d-band center of the Mn single atom closer to the Fermi level.Moreover,the adsorption of the key intermediate*OCHO on the Mn single atom was further enhanced,thereby reducing the limiting potential and improving the catalytic performance for CO_(2)RR.This work offers a comprehensive theoretical insight into the catalytic mechanism of the novel Mn/Cu-NC DAC for CO_(2)RR and establishes a critical descriptor of d-band center of the catalytic active center to determine the catalytic activity of DACs for CO_(2)RR,thereby providing guidance for the future design and fabrication of graphene-based metal DACs for CO_(2)RR.
基金partial financial support from the National Natural Science Foundation of China (No. 52101231)the Science Fund of Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing,China (No. AMGM2021F09)the Natural Science Foundation of Shandong Province,China (No. ZR2021QE044)。
文摘开发地球电子辐射带的数据同化模型,对于理解辐射带电子的动态演化过程和辐射带空间天气预报具有重要意义.结合范阿伦卫星的辐射带电子观测数据和外辐射带三维扩散模型,采用卡尔曼滤波算法,本文开发了基于Fortran语言的外辐射带电子三维数据同化模型(Three-dimensional Data Assimilative Model of Outer Radiation belt Electrons,简称TDAMORE),实现对L^(*)=3~7、能量范围为0.1~5 MeV、投掷角范围为5°~90°的外辐射带电子时空变化过程的三维重构.通过对2018年8月期间外辐射带电子通量演化过程的重构,证实TDAMORE模型可以较好地重现不同能量和不同投掷角电子通量在磁暴前后的演化特征.通过分析电子通量的观测和同化结果之间的相关系数、平均误差、平均绝对误差和均方误差,发现对于能量低于4 MeV的电子,观测与同化结果之间的相关系数基本大于0.8且误差相对较低.而对于更高能量的电子,观测与同化结果之间的误差相对较高,这可能是同化模型忽略了电磁离子回旋波对电子的散射损失导致的.
