The mercury sulfidation experiments were conducted in the pH range from 1 to 13. The results show that Hg（II） reacted with equimolar S（ II ） has the lowest remained Hg（II ） concentration （9.7 μg/L） at pH 1.0 ...The mercury sulfidation experiments were conducted in the pH range from 1 to 13. The results show that Hg（II） reacted with equimolar S（ II ） has the lowest remained Hg（II ） concentration （9.7 μg/L） at pH 1.0 and the highest remained concentration （940.8μg/L） at pH 13.0. Meanwhile, the changes of pH values were monitored exactly, which reveal that solution pH values change when mixing the same pH value solutions of HgCI2 and Na2S. In order to explain the phenomena and determine the reaction paths of Hg（II） reacting with S（ II ） in the solution, the concerned thermodynamics was studied. Species of S（ II ）-H2O system and Hg（II）-H2O system at different pH values were calculated, and then the species distribution diagrams of S（II）-H2O system, Hg（ II ）-H2O system and Hg（ II ）-Cl-OH--H20 system were drawn. Combining the experimental data and thermodynamic calculation, the mechanism of Hg（II） reacting with S（II） was deduced. The results indicate that different species of S（ II ） and Hg（II） have the diverse reaction paths to form HgS precipitate at different pH values and the standard Gibbs free energies change （△tGm^⊙） of those equations are also calculated, which can provide a guidance for mercury-containing wastewater treatment with Na2S.展开更多
We investigate the evolution of cooperation with evolutionary public goods games based on finite populations, where four pure strategies： cooperators, defectors, punishers and loners who are unwilling to participate ...We investigate the evolution of cooperation with evolutionary public goods games based on finite populations, where four pure strategies： cooperators, defectors, punishers and loners who are unwilling to participate are considered. By adopting approximate best response dynamics, we show that the magnitude of rationality not only quantitatively explains the experiment results in [Nature （London） 425 （2003） 390], but also it will heavily influence the evolution of cooperation. Compared with previous results of infinite populations, which result in two equilibriums, we show that there merely exists a special equilibrium cooperation. In addition, we characterize that loner＇s and the relevant high value of bounded rationality will sustain payoff plays an active role in the maintenance of cooperation, which will only be warranted for the low and moderate values of loner＇s payoff. It thus indicates the effects of rationality and loner＇s payoff will influence the cooperation. Finally, we highlight the important result that the introduction of voluntary participation and punishment will facilitate cooperation greatly.展开更多
The effect of varying pore structures on the kinetics of S02-CaO reactions is not fully understood in the previous studies. Combining fractal pore model, gas molecular movement model and two-stage reaction model, a ne...The effect of varying pore structures on the kinetics of S02-CaO reactions is not fully understood in the previous studies. Combining fractal pore model, gas molecular movement model and two-stage reaction model, a new desulfurization model is established in this paper. Fractal pore model is used to simulate CaO particle and gas molecular movement model is used to simulate gas diffusion in pores. Fractal dimension is used to characterize complexity of pore structure instead of tortuosity factor. It is found that the reaction is significantly affected by pore structures. A modulus φ is introduced to characterize the relationship between varying pore structures and apparent reaction parameters. And this relationship is verified by thermo-gravimetric analysis （TGA） data. Comparing to the previous models, the effect of varying pore structure on the kinetics of the reaction is described more accurately by the desulfurization model.展开更多
We numerically study the dynamics of meandering spiral waves in the excitable system subjected to a feedback signal coming from two measuring points located on a straight line together with the initial spiral core. Th...We numerically study the dynamics of meandering spiral waves in the excitable system subjected to a feedback signal coming from two measuring points located on a straight line together with the initial spiral core. The core location and size radius of the final attractors are computed, and they change with the position of the moving measuring point in a unique way. By the Fourier Spectral analysis, we find the frequency-locked behaviors different from the driving scheme of the external periodic force. It when the moving measuring point approaches closely is also found that the meandering spiral wave can be eliminated the boundary and its feedback gain is large enough. This offers an effective and convenient method for eliminating meandering spiral waves.展开更多
In order to evaluate the effects of the FHs （flow holes） on the inner barrel, which were installed in the upper plenum of the Monju reactor vessel, a high resolution meshes around the FHs was constructed. Using this...In order to evaluate the effects of the FHs （flow holes） on the inner barrel, which were installed in the upper plenum of the Monju reactor vessel, a high resolution meshes around the FHs was constructed. Using this model, it was mainly clear that in the 40% rated operational conditions, the shape of the FHs on the inner barrel did not change largely to the upper plenum thermal-hydraulics. The effect of the FHs on the honeycomb structure in the upper structure was also investigated in these calculations. The results indicated that the height of thermal stratification interface became lower than that evaluated from the test data.展开更多
The low NOx emission technology has become an important feature of advanced aviation engine.A wide range of applications attempt to take advantage of the fact that staged combustion under lean-premixed-prevaporized(LP...The low NOx emission technology has become an important feature of advanced aviation engine.A wide range of applications attempt to take advantage of the fact that staged combustion under lean-premixed-prevaporized(LPP)conditions can significantly cut down emission and improve combustion efficiency.This paper proposes a scheme with fuel centrally staged and multi-point injection.The mixing of fuel and air is improved,and the flame temperature is relative low in combustion zone,minimizing the formation of nitrogen oxides(NOx),especially thermal NOx.In terms of the field distribution of equivalence ratio and temperature obtained from Computational Fluid Dynamics(CFD),a chemical reactor network(CRN),including several different ideal reactor,namely perfectly stirred reactor(PSR)and plug flow reactor(PFR),is constructed to simulate the combustion process and predict pollution emission.The influences of the pilot equivalence ratio and percentage of pilot/main fuel on NOx and carbon monoxide(CO)emission were investigated by CRN model.The effects of the pilot fuel and primary fuel on pollution emission were investigated experimentally.Finally,the effects of pilot equivalence ratio and pilot fuel proportion on NOx emission were discussed in detail by comparing predict of CRN and experimental results.展开更多
We prove the global existence and stability of a wave structure containing a stationary Mach con- figuration, which occurs when an incident shock front hits a wall with a large incident angle. Our result shows that ti...We prove the global existence and stability of a wave structure containing a stationary Mach con- figuration, which occurs when an incident shock front hits a wall with a large incident angle. Our result shows that tile data of the upstream flow and the pressure at downstream part jointly determine the whole flow, as well a the wave structure. Particularly, we show that the height of the Mach stem depends not only on the data of upstream flow, but also on the pressure at downstream flow. The flow with the assigned wave structure is governed by a free boundary value problem for the Euler system. In the problem the location of the triple point, the shock fronts and the contact discontinuity are all unknown, they are finally determined together with the solution.展开更多
Predictive simulation of engine combustion is key to understanding the underlying complicated physicochemical processes,improving engine performance,and reducing pollutant emissions.Critical issues as turbulence model...Predictive simulation of engine combustion is key to understanding the underlying complicated physicochemical processes,improving engine performance,and reducing pollutant emissions.Critical issues as turbulence modeling,turbulence-chemistry interaction,and accommodation of detailed chemical kinetics in complex flows remain challenging and essential for highfidelity combustion simulation.This paper reviews the current status of the state-of-the-art large eddy simulation(LES)/probability density function(PDF)/detailed chemistry approach that can address the three challenging modelling issues.PDF as a subgrid model for LES is formulated and the hybrid mesh-particle method for LES/PDF simulations is described.Then the development need in micro-mixing models for the PDF simulations of turbulent premixed combustion is identified.Finally the different acceleration methods for detailed chemistry are reviewed and a combined strategy is proposed for further development.展开更多
基金Project(50925417) supported by China National Funds for Distinguished Young ScientistsProject(50830301) supported by the Key Project of the National Natural Science Foundation of China+2 种基金Project(308019) supported by the Key Science and Technical Project of Ministry of Science and Technology of ChinaProject(2007BAC25B01) supported by the National Key Project of Science and Technical Supporting Programs Funded by Ministry of Science and Technology of China during the 11th Five-Year PlanProject(08JJ3020) supported by the Natural Science Foundation of Hunan Province, China
文摘The mercury sulfidation experiments were conducted in the pH range from 1 to 13. The results show that Hg（II） reacted with equimolar S（ II ） has the lowest remained Hg（II ） concentration （9.7 μg/L） at pH 1.0 and the highest remained concentration （940.8μg/L） at pH 13.0. Meanwhile, the changes of pH values were monitored exactly, which reveal that solution pH values change when mixing the same pH value solutions of HgCI2 and Na2S. In order to explain the phenomena and determine the reaction paths of Hg（II） reacting with S（ II ） in the solution, the concerned thermodynamics was studied. Species of S（ II ）-H2O system and Hg（II）-H2O system at different pH values were calculated, and then the species distribution diagrams of S（II）-H2O system, Hg（ II ）-H2O system and Hg（ II ）-Cl-OH--H20 system were drawn. Combining the experimental data and thermodynamic calculation, the mechanism of Hg（II） reacting with S（II） was deduced. The results indicate that different species of S（ II ） and Hg（II） have the diverse reaction paths to form HgS precipitate at different pH values and the standard Gibbs free energies change （△tGm^⊙） of those equations are also calculated, which can provide a guidance for mercury-containing wastewater treatment with Na2S.
基金Supported by National Nature Science Foundation under Grant No.60904063the Tianjin municipal Natural Science Foundation under Grant Nos.11JCYBJC06600,11ZCKF6X00900,11ZCKFGX00900
文摘We investigate the evolution of cooperation with evolutionary public goods games based on finite populations, where four pure strategies： cooperators, defectors, punishers and loners who are unwilling to participate are considered. By adopting approximate best response dynamics, we show that the magnitude of rationality not only quantitatively explains the experiment results in [Nature （London） 425 （2003） 390], but also it will heavily influence the evolution of cooperation. Compared with previous results of infinite populations, which result in two equilibriums, we show that there merely exists a special equilibrium cooperation. In addition, we characterize that loner＇s and the relevant high value of bounded rationality will sustain payoff plays an active role in the maintenance of cooperation, which will only be warranted for the low and moderate values of loner＇s payoff. It thus indicates the effects of rationality and loner＇s payoff will influence the cooperation. Finally, we highlight the important result that the introduction of voluntary participation and punishment will facilitate cooperation greatly.
基金Supported by the National Natural Science Foundation of China(51176096)
文摘The effect of varying pore structures on the kinetics of S02-CaO reactions is not fully understood in the previous studies. Combining fractal pore model, gas molecular movement model and two-stage reaction model, a new desulfurization model is established in this paper. Fractal pore model is used to simulate CaO particle and gas molecular movement model is used to simulate gas diffusion in pores. Fractal dimension is used to characterize complexity of pore structure instead of tortuosity factor. It is found that the reaction is significantly affected by pore structures. A modulus φ is introduced to characterize the relationship between varying pore structures and apparent reaction parameters. And this relationship is verified by thermo-gravimetric analysis （TGA） data. Comparing to the previous models, the effect of varying pore structure on the kinetics of the reaction is described more accurately by the desulfurization model.
基金Supported by the National Natural Science Foundation of China under Grant No. 11005030Science Foundations of Hebei Education Department under Grant No. 2009135+1 种基金Science Foundations of Inner Mongolia Education Department under Grant No. NJ09178Science Foundation of Hebei Normal University
文摘We numerically study the dynamics of meandering spiral waves in the excitable system subjected to a feedback signal coming from two measuring points located on a straight line together with the initial spiral core. The core location and size radius of the final attractors are computed, and they change with the position of the moving measuring point in a unique way. By the Fourier Spectral analysis, we find the frequency-locked behaviors different from the driving scheme of the external periodic force. It when the moving measuring point approaches closely is also found that the meandering spiral wave can be eliminated the boundary and its feedback gain is large enough. This offers an effective and convenient method for eliminating meandering spiral waves.
文摘In order to evaluate the effects of the FHs （flow holes） on the inner barrel, which were installed in the upper plenum of the Monju reactor vessel, a high resolution meshes around the FHs was constructed. Using this model, it was mainly clear that in the 40% rated operational conditions, the shape of the FHs on the inner barrel did not change largely to the upper plenum thermal-hydraulics. The effect of the FHs on the honeycomb structure in the upper structure was also investigated in these calculations. The results indicated that the height of thermal stratification interface became lower than that evaluated from the test data.
基金supported by the National Natural Science Foundation of China(Grant No.51306182)
文摘The low NOx emission technology has become an important feature of advanced aviation engine.A wide range of applications attempt to take advantage of the fact that staged combustion under lean-premixed-prevaporized(LPP)conditions can significantly cut down emission and improve combustion efficiency.This paper proposes a scheme with fuel centrally staged and multi-point injection.The mixing of fuel and air is improved,and the flame temperature is relative low in combustion zone,minimizing the formation of nitrogen oxides(NOx),especially thermal NOx.In terms of the field distribution of equivalence ratio and temperature obtained from Computational Fluid Dynamics(CFD),a chemical reactor network(CRN),including several different ideal reactor,namely perfectly stirred reactor(PSR)and plug flow reactor(PFR),is constructed to simulate the combustion process and predict pollution emission.The influences of the pilot equivalence ratio and percentage of pilot/main fuel on NOx and carbon monoxide(CO)emission were investigated by CRN model.The effects of the pilot fuel and primary fuel on pollution emission were investigated experimentally.Finally,the effects of pilot equivalence ratio and pilot fuel proportion on NOx emission were discussed in detail by comparing predict of CRN and experimental results.
基金supported by National Natural Science Foundation of China(Grant Nos.11031001 and 11101101)
文摘We prove the global existence and stability of a wave structure containing a stationary Mach con- figuration, which occurs when an incident shock front hits a wall with a large incident angle. Our result shows that tile data of the upstream flow and the pressure at downstream part jointly determine the whole flow, as well a the wave structure. Particularly, we show that the height of the Mach stem depends not only on the data of upstream flow, but also on the pressure at downstream flow. The flow with the assigned wave structure is governed by a free boundary value problem for the Euler system. In the problem the location of the triple point, the shock fronts and the contact discontinuity are all unknown, they are finally determined together with the solution.
基金supported by the 111 Project(Grant No.B13001)by the Young Thousand Talents Program from the Organization Department of the Communist Party of China Central Committee
文摘Predictive simulation of engine combustion is key to understanding the underlying complicated physicochemical processes,improving engine performance,and reducing pollutant emissions.Critical issues as turbulence modeling,turbulence-chemistry interaction,and accommodation of detailed chemical kinetics in complex flows remain challenging and essential for highfidelity combustion simulation.This paper reviews the current status of the state-of-the-art large eddy simulation(LES)/probability density function(PDF)/detailed chemistry approach that can address the three challenging modelling issues.PDF as a subgrid model for LES is formulated and the hybrid mesh-particle method for LES/PDF simulations is described.Then the development need in micro-mixing models for the PDF simulations of turbulent premixed combustion is identified.Finally the different acceleration methods for detailed chemistry are reviewed and a combined strategy is proposed for further development.
