Considering both the characteristics of construction scheme evaluation and the lack of consideration of index proportionality after introducing comprehensive evaluation of independent perspectives into construction sc...Considering both the characteristics of construction scheme evaluation and the lack of consideration of index proportionality after introducing comprehensive evaluation of independent perspectives into construction scheme evaluation, a construction scheme evaluation model of independent perspectives was put forward through the study and optimization of comprehensive evaluation of independent perspectives. The feasibility and rationality of the optimized method were illustrated through a case study and the evaluation results were compared between the optimized method and non-optimized method. The optimized method has the practical value in construction scheme comparison.展开更多
The effects of low-level PES on the overall accuracy of the final surface constructed by using hierarchical construction were investigated with the constructions of a number of global surfaces for the H3 system at UHF...The effects of low-level PES on the overall accuracy of the final surface constructed by using hierarchical construction were investigated with the constructions of a number of global surfaces for the H3 system at UHF （UMP2, DFT-B3LYP, UCCSD（T））/vtz, and UCCSD（T）/avqz levels of theory. The total reaction probabilities for the H＋H2 reaction calculated on these surfaces revealed that the accuracy of UCCSD（T）/avqz surface is very close to the well-known BKMP2 surface, while the UCCSD（T）/vtz PES has a slightly higher barrier. In contrast, the low-level theories （UHF, UMP2, DFT-B3LYP） with vtz basis set can only provide a qualitative description of this simplest reaction despite the fact that they are widely used to study reactions in complex systems. On the other hand, although these theories are not accurate on describing the reaction, they can be used to provide the low- level PESs for hierarchical construction of the UCCSD（T）/avqz PES with the number of UCCSD（T）/avqz energies substantially reduced.展开更多
There are various construction methods of long-span steel structure. In this paper, sap2000 is used to analyze the overall lifting technology of a 72*144m long-span steel structure. The grid structure is divided into ...There are various construction methods of long-span steel structure. In this paper, sap2000 is used to analyze the overall lifting technology of a 72*144m long-span steel structure. The grid structure is divided into two areas for lifting, and there are four different areas for different repair welding areas and lifting methods. By analyzing the indexes of stress, deformation and internal force of structure construction under different construction zoning schemes, the best construction scheme can be selected. The calculation results show that the construction deformation of the second scheme is the smallest, with the final deformation of 49.164mm, the maximum stress ratio of the components after construction being 0.204, and the stress ratio of the components under the load of 1.3D+1.5L being 0.8098, which is basically the same as the stress ratio of 0.80 obtained by the one-time loading design, so the second scheme is finally selected.展开更多
The bounds on the discrepancy of approximate solutions constructed by Gedunov's scheme to IVP of isentropic equations of gas dynamics are obtained, Three well-knowu results obtained by Lax for shock waves with sma...The bounds on the discrepancy of approximate solutions constructed by Gedunov's scheme to IVP of isentropic equations of gas dynamics are obtained, Three well-knowu results obtained by Lax for shock waves with small jumps for general quasilinear hyperbolic systems of conservation laws are extended to shock waves for isentropic equations of gas dynamics in a bounded invariant region with ρ=0 as one of boundries of the region. Two counterexamples are given to show that two iuequalities given by Godunov do not hold for all rational numbers γ∈(1, 3]. It seems that the approach by Godunov to obtain the forementioned bounds may not be possible.展开更多
In the background of the construction of Sutong Yangtze River Bridge(short as Sutong Bridge),the cable construction method and techniques of a thousand-meter scale cable-stayed bridge are introduced.Some key construct...In the background of the construction of Sutong Yangtze River Bridge(short as Sutong Bridge),the cable construction method and techniques of a thousand-meter scale cable-stayed bridge are introduced.Some key construction techniques,such as outspreading cable on deck,installing cable at pylon,pulling and fixing cable at the attachment with decks and cable PE sheath protection are discussed.展开更多
On Jan.25,2018,the Ministry of Land and Resources(MLR)declared that the Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11Cities including Shenyang,Nanjing,Ha...On Jan.25,2018,the Ministry of Land and Resources(MLR)declared that the Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11Cities including Shenyang,Nanjing,Hangzhou,etc.,has been approved.MLR emphasized that the pilot areas should follow the principle of house for living,not for speculation.And according展开更多
In this paper, we develop a new technique called multiplicative extrapolation method which is used to construct higher order schemes for ordinary differential equations. We call it a new method because we only see add...In this paper, we develop a new technique called multiplicative extrapolation method which is used to construct higher order schemes for ordinary differential equations. We call it a new method because we only see additive extrapolation method before. This new method has a great advantage over additive extrapolation method because it keeps group property. If this method is used to construct higher order schemes from lower symplectic schemes, the higher order ones are also symplectic. First we introduce the concept of adjoint methods and some of their properties. We show that there is a self-adjoint scheme corresponding to every method. With this self-adjoint scheme of lower order, we can construct higher order schemes by multiplicative extrapolation method, which can be used to construct even much higher order schemes. Obviously this constructing process can be continued to get methods of arbitrary even order.展开更多
文摘Considering both the characteristics of construction scheme evaluation and the lack of consideration of index proportionality after introducing comprehensive evaluation of independent perspectives into construction scheme evaluation, a construction scheme evaluation model of independent perspectives was put forward through the study and optimization of comprehensive evaluation of independent perspectives. The feasibility and rationality of the optimized method were illustrated through a case study and the evaluation results were compared between the optimized method and non-optimized method. The optimized method has the practical value in construction scheme comparison.
文摘The effects of low-level PES on the overall accuracy of the final surface constructed by using hierarchical construction were investigated with the constructions of a number of global surfaces for the H3 system at UHF （UMP2, DFT-B3LYP, UCCSD（T））/vtz, and UCCSD（T）/avqz levels of theory. The total reaction probabilities for the H＋H2 reaction calculated on these surfaces revealed that the accuracy of UCCSD（T）/avqz surface is very close to the well-known BKMP2 surface, while the UCCSD（T）/vtz PES has a slightly higher barrier. In contrast, the low-level theories （UHF, UMP2, DFT-B3LYP） with vtz basis set can only provide a qualitative description of this simplest reaction despite the fact that they are widely used to study reactions in complex systems. On the other hand, although these theories are not accurate on describing the reaction, they can be used to provide the low- level PESs for hierarchical construction of the UCCSD（T）/avqz PES with the number of UCCSD（T）/avqz energies substantially reduced.
文摘There are various construction methods of long-span steel structure. In this paper, sap2000 is used to analyze the overall lifting technology of a 72*144m long-span steel structure. The grid structure is divided into two areas for lifting, and there are four different areas for different repair welding areas and lifting methods. By analyzing the indexes of stress, deformation and internal force of structure construction under different construction zoning schemes, the best construction scheme can be selected. The calculation results show that the construction deformation of the second scheme is the smallest, with the final deformation of 49.164mm, the maximum stress ratio of the components after construction being 0.204, and the stress ratio of the components under the load of 1.3D+1.5L being 0.8098, which is basically the same as the stress ratio of 0.80 obtained by the one-time loading design, so the second scheme is finally selected.
基金Project supported by National Natural Science Foundation of China.
文摘The bounds on the discrepancy of approximate solutions constructed by Gedunov's scheme to IVP of isentropic equations of gas dynamics are obtained, Three well-knowu results obtained by Lax for shock waves with small jumps for general quasilinear hyperbolic systems of conservation laws are extended to shock waves for isentropic equations of gas dynamics in a bounded invariant region with ρ=0 as one of boundries of the region. Two counterexamples are given to show that two iuequalities given by Godunov do not hold for all rational numbers γ∈(1, 3]. It seems that the approach by Godunov to obtain the forementioned bounds may not be possible.
基金National Science and Technology Support Program of China(No.2006BAG04B02)
文摘In the background of the construction of Sutong Yangtze River Bridge(short as Sutong Bridge),the cable construction method and techniques of a thousand-meter scale cable-stayed bridge are introduced.Some key construction techniques,such as outspreading cable on deck,installing cable at pylon,pulling and fixing cable at the attachment with decks and cable PE sheath protection are discussed.
文摘On Jan.25,2018,the Ministry of Land and Resources(MLR)declared that the Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11Cities including Shenyang,Nanjing,Hangzhou,etc.,has been approved.MLR emphasized that the pilot areas should follow the principle of house for living,not for speculation.And according
文摘In this paper, we develop a new technique called multiplicative extrapolation method which is used to construct higher order schemes for ordinary differential equations. We call it a new method because we only see additive extrapolation method before. This new method has a great advantage over additive extrapolation method because it keeps group property. If this method is used to construct higher order schemes from lower symplectic schemes, the higher order ones are also symplectic. First we introduce the concept of adjoint methods and some of their properties. We show that there is a self-adjoint scheme corresponding to every method. With this self-adjoint scheme of lower order, we can construct higher order schemes by multiplicative extrapolation method, which can be used to construct even much higher order schemes. Obviously this constructing process can be continued to get methods of arbitrary even order.
