The structures of closo-hedral cluster (HAlNH)12 and endohedral complexes X@(HAlNH)12 (X = He, Ne, Ar, Kr) have been studied by using density functional theory (DFT) at the B3LYP/6-31G(d) level. The geometries, natura...The structures of closo-hedral cluster (HAlNH)12 and endohedral complexes X@(HAlNH)12 (X = He, Ne, Ar, Kr) have been studied by using density functional theory (DFT) at the B3LYP/6-31G(d) level. The geometries, natural bond orbital (NBO), vibrational frequency, energetic parameters, magnetic shielding constants and nucleus independent chemical shifts (NICS) were discussed. The potential surface of guest X shifting from the cage center to a face of six- membered ring was calculated at the same level. The exit transition state was demonstrated with IRC calculations. It is found that X@(HAlNH)12 complexes are dynamically stable, and Ne@(HAlNH)12 is more energetically favorable than the other complexes in thermodynamics.展开更多
The interaction between free surface flow and structure is investigated using a new level set immersed boundary method.The incorporation of an improved immersed boundary method with a free surface capture scheme imple...The interaction between free surface flow and structure is investigated using a new level set immersed boundary method.The incorporation of an improved immersed boundary method with a free surface capture scheme implemented in a Navier-Stokes solver allows the interaction between fluid flow with free surface and moving body/bodies of almost arbitrary shape to be modelled.A new algorithm is proposed to locate exact forcing points near solid boundaries,which provides an accurate numerical solution.The discretized linear system of the Poisson pressure equation is solved using the Generalized Minimum Residual(GMRES)method with incomplete LU preconditioning.Uniform flow past a cylinder at Reynolds number Re=100 is modelled using the present model and results agree well with the experiment and numerical data in the literature.Water exit and entry of a cylinder at the prescribed velocity is also investigated.The predicted slamming coefficient is in good agreement with experimental data and previous numerical simulations using a ComFlow model.The vertical slamming force and pressure distribution for the free falling wedge is also studied by the present model and comparisons with available theoretical solutions and experimental data are made.展开更多
China has been the world’s largest automobile producer since 2009,but it still lags behind other countries in terms of productivity. Based on theNational Bureau of Statistics of China (NBSC) firm-level data and the i...China has been the world’s largest automobile producer since 2009,but it still lags behind other countries in terms of productivity. Based on theNational Bureau of Statistics of China (NBSC) firm-level data and the improvedapproach proposed by Ackerberg et al. (2015), this paper investigates thecontribution of total factor productivity (TFP) growth to the Chinese automobileindustry and evaluates the impact of firm entry and exit on TFP growth. Theempirical results show that the TFP of the Chinese automobile industry grows at10.7% per year. Joint venture and foreign-owned firms have a significantly higherTFP growth rate than others. Large-scale firms have a higher TFP growth rate thando small-scale firms, but the latter have caught up after 2004. Moreover, the entryof new firms and exit of old firms significantly improve the aggregate TFP growthrate.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 20341005), Natural Science Foundation of Shanxi Province (No. 20011015) and the Foundation for University Key Teachers by the Ministry of Education
文摘The structures of closo-hedral cluster (HAlNH)12 and endohedral complexes X@(HAlNH)12 (X = He, Ne, Ar, Kr) have been studied by using density functional theory (DFT) at the B3LYP/6-31G(d) level. The geometries, natural bond orbital (NBO), vibrational frequency, energetic parameters, magnetic shielding constants and nucleus independent chemical shifts (NICS) were discussed. The potential surface of guest X shifting from the cage center to a face of six- membered ring was calculated at the same level. The exit transition state was demonstrated with IRC calculations. It is found that X@(HAlNH)12 complexes are dynamically stable, and Ne@(HAlNH)12 is more energetically favorable than the other complexes in thermodynamics.
基金the support of the South West of England Regional Development Agency in funding this project through Peninsular Research Institute for Marine Renewable Energy(http://www.primare.org/).
文摘The interaction between free surface flow and structure is investigated using a new level set immersed boundary method.The incorporation of an improved immersed boundary method with a free surface capture scheme implemented in a Navier-Stokes solver allows the interaction between fluid flow with free surface and moving body/bodies of almost arbitrary shape to be modelled.A new algorithm is proposed to locate exact forcing points near solid boundaries,which provides an accurate numerical solution.The discretized linear system of the Poisson pressure equation is solved using the Generalized Minimum Residual(GMRES)method with incomplete LU preconditioning.Uniform flow past a cylinder at Reynolds number Re=100 is modelled using the present model and results agree well with the experiment and numerical data in the literature.Water exit and entry of a cylinder at the prescribed velocity is also investigated.The predicted slamming coefficient is in good agreement with experimental data and previous numerical simulations using a ComFlow model.The vertical slamming force and pressure distribution for the free falling wedge is also studied by the present model and comparisons with available theoretical solutions and experimental data are made.
基金This work is supported by the Fundamental Research Funds for the Central Universities(Program No.2662018QD008)a project funded by the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.All errors are ours。
文摘China has been the world’s largest automobile producer since 2009,but it still lags behind other countries in terms of productivity. Based on theNational Bureau of Statistics of China (NBSC) firm-level data and the improvedapproach proposed by Ackerberg et al. (2015), this paper investigates thecontribution of total factor productivity (TFP) growth to the Chinese automobileindustry and evaluates the impact of firm entry and exit on TFP growth. Theempirical results show that the TFP of the Chinese automobile industry grows at10.7% per year. Joint venture and foreign-owned firms have a significantly higherTFP growth rate than others. Large-scale firms have a higher TFP growth rate thando small-scale firms, but the latter have caught up after 2004. Moreover, the entryof new firms and exit of old firms significantly improve the aggregate TFP growthrate.
