Based on the new viewpoint of solid and gas interaction mechanics, gas leakage in a double deformable coal seam can be understood. That is, under the action of geophysical fields, the methane flow in a double deformab...Based on the new viewpoint of solid and gas interaction mechanics, gas leakage in a double deformable coal seam can be understood. That is, under the action of geophysical fields, the methane flow in a double deformable coal seam can be essentially considered to be compressible with time dependent and mixed permeation and diffusion through a pore cleat deformable heterogeneous and anisotropy medium. Based on this new viewpoint, a coupled mathematical model for coal seam deformation and gas leakage in a double coal seam was formulated and numerical simulations for gas emission from the coal seam are presented. It is found that coupled models might be closer to reality.展开更多
The existence of rolling deformation area in the rolling mill system is the main characteristic which dis- tinguishes the other machinery. In order to analyze the dynamic property of roll system＇s flexural deformatio...The existence of rolling deformation area in the rolling mill system is the main characteristic which dis- tinguishes the other machinery. In order to analyze the dynamic property of roll system＇s flexural deformation, it is necessary to consider the transverse periodic movement of stock in the rolling deformation area which is caused by the flexural deformation movement of roll system simul- taneously. Therefore, the displacement field of roll system and flow of metal in the deformation area is described by kinematic analysis in the dynamic system. Through intro- ducing the lateral displacement function of metal in the deformation area, the dynamic variation of per unit width rolling force can be determined at the same time. Then the coupling law caused by the co-effect of rigid movement and flexural deformation of the system structural elements is determined. Furthermore, a multi-parameter coupling dynamic model of the roll system and stock is established by the principle of virtual work. More explicitly, the cou- pled motion modal analysis was made for the roll system. Meanwhile, the analytical solutions for the flexural defor- mation movement＇s mode shape functions of rolls are discussed. In addition, the dynamic characteristic of the lateral flow of metal in the rolling deformation area has been analyzed at the same time. The establishment ofdynamic lateral displacement function of metal in the deformation area makes the foundation for analyzing the coupling law between roll system and rolling deformation area, and provides a theoretical basis for the realization of the dynamic shape control of steel strip.展开更多
This paper points out that a successful numerical simulation is to construct a correct conceptional model which is very dose to the natural condition. A new model, two dimensional coupled three dimensional model (2D -...This paper points out that a successful numerical simulation is to construct a correct conceptional model which is very dose to the natural condition. A new model, two dimensional coupled three dimensional model (2D -3D ) is presented in the Present paper,which is the most suitable one for the dual - structured - aquifer system. An example of Wenyinghu area is shown.By using the 2D-3D model, a satisfied result of the simulated area is achieved.展开更多
in this paper, an electromechanically coupled mathematic model of multi-roller driving system for belt conveyor is set up, and the computing equations for dynamic displacement and dynamic tension of the conveyor are a...in this paper, an electromechanically coupled mathematic model of multi-roller driving system for belt conveyor is set up, and the computing equations for dynamic displacement and dynamic tension of the conveyor are also formulated when the hoister is used for straining. Based on the belt conveyor of main inclined shaft in Chengzhuang coal mine, the driving torque, driving power and starting-speed characteristic of each electric motor are studied and measured when multi-roller variable-frequency drive (power distribution 2∶1) is used. The optimal control and the optimal starting-acceleration of the multi-roller variable-frequency drive are determined by a large number of industrial experiments and theoretical calculations.展开更多
The detailed mechanism of CuI-catalyzed C-O intramolecular coupling reaction of 2-（2-bromo-4-fluoro-phenyl）-l- cyclohexen-1-yl trifluoromethane-sulfonate was studied with the density functional theory （DFT）. The g...The detailed mechanism of CuI-catalyzed C-O intramolecular coupling reaction of 2-（2-bromo-4-fluoro-phenyl）-l- cyclohexen-1-yl trifluoromethane-sulfonate was studied with the density functional theory （DFT）. The geometries of the reactants, transition states, intermediates and products were optimized at the B3LYP/6-31 ＋G＊ level. Meanwhile, the single point energy of species involved in gas and solvent at B3LYP/6-31 I＋G＊ level was individually investigated. Polarizable continuum models （PCM） were applied to the dioxane and water solutions at the same level, respectively. Results show that the rate-limiting step, M3→TS3, does not change in different solutions. However, the activation energy in a dioxane solution is lower than that in water, which explains the previous experimental results. Compared with the non-catalyzed reaction process, the activation energy of the rate- limiting step is reduced by 56.53 kJ mo1-1 in gas and 44.84 kJ mol-l in solvent, demonstrating a high catalytic efficiency of CuI.展开更多
文摘Based on the new viewpoint of solid and gas interaction mechanics, gas leakage in a double deformable coal seam can be understood. That is, under the action of geophysical fields, the methane flow in a double deformable coal seam can be essentially considered to be compressible with time dependent and mixed permeation and diffusion through a pore cleat deformable heterogeneous and anisotropy medium. Based on this new viewpoint, a coupled mathematical model for coal seam deformation and gas leakage in a double coal seam was formulated and numerical simulations for gas emission from the coal seam are presented. It is found that coupled models might be closer to reality.
基金Supported by National Natural Science Foundation of China(Grant No.51375424)
文摘The existence of rolling deformation area in the rolling mill system is the main characteristic which dis- tinguishes the other machinery. In order to analyze the dynamic property of roll system＇s flexural deformation, it is necessary to consider the transverse periodic movement of stock in the rolling deformation area which is caused by the flexural deformation movement of roll system simul- taneously. Therefore, the displacement field of roll system and flow of metal in the deformation area is described by kinematic analysis in the dynamic system. Through intro- ducing the lateral displacement function of metal in the deformation area, the dynamic variation of per unit width rolling force can be determined at the same time. Then the coupling law caused by the co-effect of rigid movement and flexural deformation of the system structural elements is determined. Furthermore, a multi-parameter coupling dynamic model of the roll system and stock is established by the principle of virtual work. More explicitly, the cou- pled motion modal analysis was made for the roll system. Meanwhile, the analytical solutions for the flexural defor- mation movement＇s mode shape functions of rolls are discussed. In addition, the dynamic characteristic of the lateral flow of metal in the rolling deformation area has been analyzed at the same time. The establishment ofdynamic lateral displacement function of metal in the deformation area makes the foundation for analyzing the coupling law between roll system and rolling deformation area, and provides a theoretical basis for the realization of the dynamic shape control of steel strip.
文摘This paper points out that a successful numerical simulation is to construct a correct conceptional model which is very dose to the natural condition. A new model, two dimensional coupled three dimensional model (2D -3D ) is presented in the Present paper,which is the most suitable one for the dual - structured - aquifer system. An example of Wenyinghu area is shown.By using the 2D-3D model, a satisfied result of the simulated area is achieved.
文摘in this paper, an electromechanically coupled mathematic model of multi-roller driving system for belt conveyor is set up, and the computing equations for dynamic displacement and dynamic tension of the conveyor are also formulated when the hoister is used for straining. Based on the belt conveyor of main inclined shaft in Chengzhuang coal mine, the driving torque, driving power and starting-speed characteristic of each electric motor are studied and measured when multi-roller variable-frequency drive (power distribution 2∶1) is used. The optimal control and the optimal starting-acceleration of the multi-roller variable-frequency drive are determined by a large number of industrial experiments and theoretical calculations.
文摘The detailed mechanism of CuI-catalyzed C-O intramolecular coupling reaction of 2-（2-bromo-4-fluoro-phenyl）-l- cyclohexen-1-yl trifluoromethane-sulfonate was studied with the density functional theory （DFT）. The geometries of the reactants, transition states, intermediates and products were optimized at the B3LYP/6-31 ＋G＊ level. Meanwhile, the single point energy of species involved in gas and solvent at B3LYP/6-31 I＋G＊ level was individually investigated. Polarizable continuum models （PCM） were applied to the dioxane and water solutions at the same level, respectively. Results show that the rate-limiting step, M3→TS3, does not change in different solutions. However, the activation energy in a dioxane solution is lower than that in water, which explains the previous experimental results. Compared with the non-catalyzed reaction process, the activation energy of the rate- limiting step is reduced by 56.53 kJ mo1-1 in gas and 44.84 kJ mol-l in solvent, demonstrating a high catalytic efficiency of CuI.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences [grant number XDA 19060102]supported by the National Natural Science Foundation of China[grant number 42030410]+2 种基金the Laoshan Laboratory [grant number LSL202202402]the Strategic Priority Research Program of the Chinese Academy of Sciences [grant number XDB40000000]the Startup Foundation for Introducing Talent of NUIST
基金Project(52078498)supported by the National Natural Science Foundation of ChinaProject(2021-Special-04-2)supported by the Science and Technology Research and Development Program Project of China Railway Group Limited+2 种基金Project(2022JJ30745)supported by the Natural Science Foundation of Hunan Province,ChinaProject(2023QYJC006)supported by the Frontier Cross Research Project of Central South University,ChinaProject(2020TJQ19)supported by the Hunan Provincial Science and Technology Promotion Talent Project,China。
