Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two com...Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two competitive mechanisms in which the carbon atom of acetylene or carbon monoxide attacked and inserted from two different directions of the six-membered ring reactant to clarify the principle characteristics of this transformation.The calculation results reveal that:(i)the insertion process of alkyne or carbon monoxide is the key step of the reaction;(ii)for the(5+2)cycloaddition reaction of acetylene,higher energy is required to break the Rh−O bond of the reactant,and the reaction tends to complete the insertion from the side of the Rh−C bond;(iii)for the(5+1)cycloaddition of carbon monoxide,both reaction paths have lower activation free energy,and the two will generate a competition mechanism.展开更多
The genetic and breeding progress of Dahen S06M line was analyzed, in order to improve the selection efficiency. The results showedthat six generations of selection was effective in selecting main characters of S06M l...The genetic and breeding progress of Dahen S06M line was analyzed, in order to improve the selection efficiency. The results showedthat six generations of selection was effective in selecting main characters of S06M line, especially the selection of growth rate had no adverse effecton reproductive performance. All indicators of reproductive performance were improved in varying degrees during breeding, particularly the egg production at 68 weeks of age. The breeding progress of main target traits significantly slowed down after the second generation, but they still maintained at higher levels and the characters of S06M tended to be stable.展开更多
In this paper, we discuss the concept of local structure-preserving algorithms (SPAs) for partial differential equations, which are the natural generalization of the corresponding global SPAs. Local SPAs for the probl...In this paper, we discuss the concept of local structure-preserving algorithms (SPAs) for partial differential equations, which are the natural generalization of the corresponding global SPAs. Local SPAs for the problems with proper boundary conditions are global SPAs, but the inverse is not necessarily valid. The concept of the local SPAs can explain the difference between different SPAs and provide a basic theory for analyzing and constructing high performance SPAs. Furthermore, it enlarges the applicable scopes of SPAs. We also discuss the application and the construction of local SPAs and derive several new SPAs for the nonlinear Klein-Gordon equation.展开更多
In this paper some new parallel difference schemes with interface extrapolation terms for a quasi-linear parabolic system of equations are constructed. Two types of time extrapolations are proposed to give the interfa...In this paper some new parallel difference schemes with interface extrapolation terms for a quasi-linear parabolic system of equations are constructed. Two types of time extrapolations are proposed to give the interface values on the interface of sub-domains or the values adjacent to the interface points, so that the unconditional stable parallel schemes with the second accuracy are formed. Without assuming heuristically that the original boundary value problem has the unique smooth vector solution, the existence and uniqueness of the discrete vector solutions of the parallel difference schemes constructed are proved. Moreover the unconditional stability of the parallel difference schemes is justified in the sense of the continuous dependence of the discrete vector solution of the schemes on the discrete known data of the original problems in the discrete W2(2,1) (Q△) norms. Finally the convergence of the discrete vector solutions of the parallel difference schemes with interface extrapolation terms to the unique generalized solution of the original quasi-linear parabolic problem is proved. Numerical results are presented to show the good performance of the parallel schemes, including the unconditional stability, the second accuracy and the high parallelism.展开更多
In this paper,we developed a class of the fourth order accurate finite volume Hermite weighted essentially non-oscillatory(HWENO)schemes based on the work(Computers&Fluids,34:642-663(2005))by Qiu and Shu,with Tota...In this paper,we developed a class of the fourth order accurate finite volume Hermite weighted essentially non-oscillatory(HWENO)schemes based on the work(Computers&Fluids,34:642-663(2005))by Qiu and Shu,with Total Variation Diminishing Runge-Kutta time discretization method for the two-dimensional hyperbolic conservation laws.The key idea of HWENO is to evolve both with the solution and its derivative,which allows for using Hermite interpolation in the reconstruction phase,resulting in a more compact stencil at the expense of the additional work.The main difference between this work and the formal one is the procedure to reconstruct the derivative terms.Comparing with the original HWENO schemes of Qiu and Shu,one major advantage of new HWENOschemes is its robust in computation of problem with strong shocks.Extensive numerical experiments are performed to illustrate the capability of the method.展开更多
基金This work was supported by the Natural Science Foundation of Gansu Province(20JR5RA479)the Outstanding Youth Research Program of Lanzhou University of Arts and Sciences(2018JCQN008).
文摘Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two competitive mechanisms in which the carbon atom of acetylene or carbon monoxide attacked and inserted from two different directions of the six-membered ring reactant to clarify the principle characteristics of this transformation.The calculation results reveal that:(i)the insertion process of alkyne or carbon monoxide is the key step of the reaction;(ii)for the(5+2)cycloaddition reaction of acetylene,higher energy is required to break the Rh−O bond of the reactant,and the reaction tends to complete the insertion from the side of the Rh−C bond;(iii)for the(5+1)cycloaddition of carbon monoxide,both reaction paths have lower activation free energy,and the two will generate a competition mechanism.
基金Supported by 13~(th) Five-year Broiler Breeding Project of Sichuan Province(2016NYZ0025,2016NY20043)
文摘The genetic and breeding progress of Dahen S06M line was analyzed, in order to improve the selection efficiency. The results showedthat six generations of selection was effective in selecting main characters of S06M line, especially the selection of growth rate had no adverse effecton reproductive performance. All indicators of reproductive performance were improved in varying degrees during breeding, particularly the egg production at 68 weeks of age. The breeding progress of main target traits significantly slowed down after the second generation, but they still maintained at higher levels and the characters of S06M tended to be stable.
文摘In this paper, we discuss the concept of local structure-preserving algorithms (SPAs) for partial differential equations, which are the natural generalization of the corresponding global SPAs. Local SPAs for the problems with proper boundary conditions are global SPAs, but the inverse is not necessarily valid. The concept of the local SPAs can explain the difference between different SPAs and provide a basic theory for analyzing and constructing high performance SPAs. Furthermore, it enlarges the applicable scopes of SPAs. We also discuss the application and the construction of local SPAs and derive several new SPAs for the nonlinear Klein-Gordon equation.
基金This work was supported by the Special Funds for Major State Basic Research Projects (Grant No.2005CB321703)the National Natural Science Foundation of China (Grant Nos. 10476002, 60533020)the Science Foundation of CAEP (Grant No. 20060649)
文摘In this paper some new parallel difference schemes with interface extrapolation terms for a quasi-linear parabolic system of equations are constructed. Two types of time extrapolations are proposed to give the interface values on the interface of sub-domains or the values adjacent to the interface points, so that the unconditional stable parallel schemes with the second accuracy are formed. Without assuming heuristically that the original boundary value problem has the unique smooth vector solution, the existence and uniqueness of the discrete vector solutions of the parallel difference schemes constructed are proved. Moreover the unconditional stability of the parallel difference schemes is justified in the sense of the continuous dependence of the discrete vector solution of the schemes on the discrete known data of the original problems in the discrete W2(2,1) (Q△) norms. Finally the convergence of the discrete vector solutions of the parallel difference schemes with interface extrapolation terms to the unique generalized solution of the original quasi-linear parabolic problem is proved. Numerical results are presented to show the good performance of the parallel schemes, including the unconditional stability, the second accuracy and the high parallelism.
基金the National Natural Science Foundation of China(Grant No.10671097)the European project ADIGMA on the development of innovative solution algorithms for aerodynamic simu-lations+1 种基金Scientific Research Foundation for the Returned Overseas Chinese ScholarsState Education Ministry and the Natural Science Foundation of Jiangsu Province(Grant No.BK2006511)
文摘In this paper,we developed a class of the fourth order accurate finite volume Hermite weighted essentially non-oscillatory(HWENO)schemes based on the work(Computers&Fluids,34:642-663(2005))by Qiu and Shu,with Total Variation Diminishing Runge-Kutta time discretization method for the two-dimensional hyperbolic conservation laws.The key idea of HWENO is to evolve both with the solution and its derivative,which allows for using Hermite interpolation in the reconstruction phase,resulting in a more compact stencil at the expense of the additional work.The main difference between this work and the formal one is the procedure to reconstruct the derivative terms.Comparing with the original HWENO schemes of Qiu and Shu,one major advantage of new HWENOschemes is its robust in computation of problem with strong shocks.Extensive numerical experiments are performed to illustrate the capability of the method.
