In this work,we study the linearized Landau equation with soft potentials and show that the smooth solution to the Cauchy problem with initial datum in L^(2)(ℝ^(3))enjoys an analytic regularization effect,and that the...In this work,we study the linearized Landau equation with soft potentials and show that the smooth solution to the Cauchy problem with initial datum in L^(2)(ℝ^(3))enjoys an analytic regularization effect,and that the evolution of the analytic radius is the same as the heat equations.展开更多
In this work, we study the smoothing effect of Cauchy problem in Sobolev space for the spatially homogeneous Landau equation in the Maxwellian case. We obtain a precise estimate with respect to time variable, which im...In this work, we study the smoothing effect of Cauchy problem in Sobolev space for the spatially homogeneous Landau equation in the Maxwellian case. We obtain a precise estimate with respect to time variable, which implies the ultra-analytic effect of weak solutions.展开更多
This paper studies the long time behavior of solutions to the Navier-Stokes equations with linear damping on R^2. The authors prove the existence of L^2-global attractor and Hi-global attractor by showing that the cor...This paper studies the long time behavior of solutions to the Navier-Stokes equations with linear damping on R^2. The authors prove the existence of L^2-global attractor and Hi-global attractor by showing that the corresponding semigroup is asymptotically compact. Thereafter, they establish that the two attractors are the same and thus reveal the asymptotic smoothing effect of the solutions.展开更多
In this work,we study the Cauchy problem of the spatially homogeneous Landau equation with hard potentials in a close-to-equilibrium framework.We prove that the solution to the Cauchy problem enjoys the analytic regul...In this work,we study the Cauchy problem of the spatially homogeneous Landau equation with hard potentials in a close-to-equilibrium framework.We prove that the solution to the Cauchy problem enjoys the analytic regularizing effect of the time variable with an L^(2)initial datum for positive time.So that the smoothing effect of the Cauchy problem for the spatially homogeneous Landau equation with hard potentials is exactly same as heat equation.展开更多
In this paper, we study the Gevrey class regularity for solutions of the spatially homogeneous Landau equations in the hard potential case and the Maxwellian molecules case.
This paper is devoted to the long time behavior of the solution to the initial boundary value problems for a class of the Kirchhoff wave equations with nonlinear strongly damped terms: . Firstly, in order to prove the...This paper is devoted to the long time behavior of the solution to the initial boundary value problems for a class of the Kirchhoff wave equations with nonlinear strongly damped terms: . Firstly, in order to prove the smoothing effect of the solution, we make efficient use of the analytic property of the semigroup generated by the principal operator of the equation in the phase space. Then we obtain the regularity of the global attractor and construct the approximate inertial manifold of the equation. Finally, we prove that arbitrary trajectory of the Kirchhoff wave equations goes into a small neighbourhood of the approximate inertial manifold after large time.展开更多
This paper presents the influences of plasma layer on the oscillatory flow inarterial stenosis. The analysis demonstrates that the existence of the plasma layer mayobviously change the characteristics of flow such as ...This paper presents the influences of plasma layer on the oscillatory flow inarterial stenosis. The analysis demonstrates that the existence of the plasma layer mayobviously change the characteristics of flow such as velocity-profiles, longitudinalimpedance and pressure gradient, but hardly change the phase of longitudinalimpedance and pressure gradient. Besides. such influences vary with a and degree ofstenosis. These analyses have Special physiological significance in blood circulationsystem.展开更多
Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides.Current...Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides.Currently, commercial calculation programs such as BING have limitations in simulating underwater soil movements. All of these processes can be consistently simulated through a smoothed particle hydrodynamics(SPH) depth integrated model. The basis of the model is a control equation that was developed to take into account the effects of soil consolidation and erosion. In this work, the frictional rheological mode has been used to perform a simulation study of submarine landslides. Time-history curves of the sliding body's velocity, height,and length under various conditions of water depth, slope gradient, contact friction coefficient, and erosion rate are compared; the maximum sliding distance and velocity are calculated; and patterns of variation are discussed.The findings of this study can provide a reference for disaster warnings and pipeline route selection.展开更多
Wind electricity power has fluctuation, and accurate and reasonable wind electricity power prediction is very important for solving wind electricity network and combination. This paper takes an analysis of a lot of ac...Wind electricity power has fluctuation, and accurate and reasonable wind electricity power prediction is very important for solving wind electricity network and combination. This paper takes an analysis of a lot of actual data of a certain wind electricity field. Through wavelet neural network and time series method rolling, it can predict the overall power of wind electricity field. The result shows that for the original data of sampling time length and large sampling frequency, the model constructed by this paper has very good prediction effect. Because of the fan installation position, wind electricity fan flow effect and other random factor influence, wind electricity field overall power and single unit power distribution have difference. Through comparing with the time series parameters, it puts forward that single wind electricity unit power has smooth effect for overall power of wind electricity field. Finally, it summarizes the prediction effect and puts forward some reasonable suzestions for wind electricity network troblems.展开更多
Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable s...Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable simulation but also for discrete variable simulation. In this paper, the X Oilfield in the western South China Sea is taken as an example to compare the sequential indicator simulation method and the Indicator Kriging interpolation method. The results of the final comparison show that the results of the lithofacies model established by the Indicator Kriging deterministic interpolation method are overly smooth, and its coincidence rate with the geological statistical results is not high, thus cannot well reflect the heterogeneity of the underground reservoir, while the simulation results of the lithofacies model established by the sequential indicator stochastic simulation method can fit well with the statistical law of the well, which has eliminated the smoothing effect of Kriging interpolation, thus can better reflect the heterogeneity of the underground reservoir. Therefore, the sequential indicator simulation is more suitable for the characterization of sand bodies and the study of reservoir heterogeneity.展开更多
In this work,we study the Cauchy problem of the nonlinear spatially homogeneous Landau equation with hard potentials in a close-to-equilibrium framework.We prove that the solution to the Cauchy problem with the initia...In this work,we study the Cauchy problem of the nonlinear spatially homogeneous Landau equation with hard potentials in a close-to-equilibrium framework.We prove that the solution to the Cauchy problem with the initial datum in L^(2)enjoys an analytic regularizing effect,and the evolution of the analytic radius is the same as that of heat equations.展开更多
This paper discusses the Cauchy problem of elliptic-elliptic-type Davey-Stewartson systems with zero-order dissipation on R^2. Making use of the Fourier spectral projector, together with a long time comparison between...This paper discusses the Cauchy problem of elliptic-elliptic-type Davey-Stewartson systems with zero-order dissipation on R^2. Making use of the Fourier spectral projector, together with a long time comparison between the solutions to the Davey-Stewartson systems and to an auxiliary problem, we prove that the global attractor in H^1 (R^2) for the addressed Davey-Stewartson systems is a compact subset of H^2(R^2), and thus reveal the asymptotic smoothing effect of the solutions for the systems.展开更多
Based on the spectral decomposition for the linear and nonlinear radially symmetric homogeneous non-cutoff Landau operators under the hard potentialγ=2 in perturbation framework,we prove the existence and Gelfand-Shi...Based on the spectral decomposition for the linear and nonlinear radially symmetric homogeneous non-cutoff Landau operators under the hard potentialγ=2 in perturbation framework,we prove the existence and Gelfand-Shilov smoothing effect for solution to the Cauchy problem of the symmetric homogenous Landau equation with small initial datum.展开更多
The smoothness of the solutions to the full Landau equation for Fermi-Dirac particles is investigated.It is shown that the classical solutions near equilibrium to the Landau-Fermi-Dirac equation have a regularizing ef...The smoothness of the solutions to the full Landau equation for Fermi-Dirac particles is investigated.It is shown that the classical solutions near equilibrium to the Landau-Fermi-Dirac equation have a regularizing effects in all variables (time,space and velocity),that is,they become immediately smooth with respect to all variables.展开更多
Objective: To study the effect of Aloe emodin (AE), an active ingredient of Rhubarb,on the kinetics of proliferation of smooth muscular cells (SMCs) cultured in vitro after rabbit iliac arterial injury. Methods: Forty...Objective: To study the effect of Aloe emodin (AE), an active ingredient of Rhubarb,on the kinetics of proliferation of smooth muscular cells (SMCs) cultured in vitro after rabbit iliac arterial injury. Methods: Forty-eight hours after de-endothelialization (balloon endothelial denudation), the iliac arteries of the Japanese white rabbits were isolated and the smooth muscle cells were cultured primarily.AE was added to culture medium containing 10% fetal calf serum (FCS ). The cultures were pulse-labeled with 3H-TdR and TdR uptake into VSMC were measured and the cell cycle of the cultures were analyzed by using flow cytometer. Results: Compared with control, when the concentration gradient ranged from 10 - 1 to 10-5 g/L, the amount (cpm,count per minute) of 3H-TdR uptake into SMCs has significant differences (P < 0. 05 )and 10 -1 and 10 -2 g/L AE showed strong inhibitory effects on TdR uptake into VSMC and the percentage of inhibition [% inhibition =(cpm without AE-cpm with AE)/cpm without AE] was more than 90%. AE displayed concentration dependent inhibitory effects. The percentage of cells in G0/G1 phase was increased, but the percentage of cells in S phase was decreased in AE group, the transition of SMC cycle phase from G0 to S was blocked.Conclusion: AE is a strong inhibitor to the proliferation of SMCs and the pharmacological action of AE may reduce SMC proliferation in vivo and decrease intimal hyperplasia of restenosis.Original article on CJIM(Chin) 1998; 18(7): 420展开更多
The effects of hypoxic endothelial cell conditioned medium (HECCM) on proliferation and collagen synthesis of cultured porcine pulmonary arterial smooth muscle cells (PASMCs) were studied by 3H-thymidine (3H-TdR) and ...The effects of hypoxic endothelial cell conditioned medium (HECCM) on proliferation and collagen synthesis of cultured porcine pulmonary arterial smooth muscle cells (PASMCs) were studied by 3H-thymidine (3H-TdR) and 3H-proline incorporations, image analysis for determination of DNA content and colorimetric assay using MTT, and the inhibitory effects of radix salviae miltiorrhizae (RSM) on them were also investigated. The results showed that HECCM could induce enhancement of the enzymatic activity of mitochondria, increase of the nucleic DNA content and increases of the 3H-TdR and 3H-proline incorporations in PASMCs. The 3H-proline incorporation in PASMCs cultured in HECCM was 1.83 times as much as that cultured in normoxic endothelial cell conditioned medium (NECCM). Compared with the control, Chinese herb medicine RSM could inhibit the proliferation of PASMCs cultured in HECCM and decrease the 3H-prolinc incorporation in PASMCs cultured in both HECCM and NECCM (P< 0.001). However, RSM had no ef fects on the nucleic DNA content and 3H-TdR incorporation into DNA of PASMCs cultured in NECCM. It suggests that hypoxia may stimulate the endothelia to synthesize and secrete some cytokines which can stimulate the proliferation and the synthesis of collagen of PASMCs and RSM can inhibit this process.展开更多
China has made many strides in large-scale development and centralized integration of wind power in recent years.The wind power penetration of some regions has reached a high level,which brings significant challenges ...China has made many strides in large-scale development and centralized integration of wind power in recent years.The wind power penetration of some regions has reached a high level,which brings significant challenges for power system dispatch due to the inherent variability and uncertainty of wind resources.To increase the dispatch capabilities of wind power generation,the spatial smoothing effect among adjacent wind farms needs to be fully utilized.This paper presents the concept of hierarchical coordinated dispatch for wind power based on a new concept of a virtual power generator.The spatial smoothing effect of wind power is analyzed first.Next,the virtual power generator method of a wind farm cluster is defined and established.Then,the hierarchical coordinated dispatch mode is compared with an existing wind power dispatch mode for individual wind farms.Finally,the proposed concept is implemented on a simulation case to demonstrate applicability and effectiveness.展开更多
A detailed three-dimensional mechanistic model of a large-scale solid oxide fuel cell(SOFC) unit running on partially pre-reformed methane is developed. The model considers the coupling effects of chemical and electro...A detailed three-dimensional mechanistic model of a large-scale solid oxide fuel cell(SOFC) unit running on partially pre-reformed methane is developed. The model considers the coupling effects of chemical and electrochemical reactions, mass transport, momentum and heat transfer in the SOFC unit. After model validation, parametric simulations are conducted to investigate how the methane pre-reforming ratio affects the transport and electrochemistry of the SOFC unit. It is found that the methane steam reforming reaction has a "smoothing effect", which can achieve more uniform distributions of gas compositions, current density and temperature among the cell plane. In the case of 1500 W/m^2 power density output, adding 20% methane absorbs 50% of internal heat production inside the cell, reduces the maximum temperature difference inside the cell from 70 K to 22 K and reduces the cathode air supply by 75%, compared to the condition of completely pre-reforming of methane. Under specific operating conditions, the pre-reforming ratio of methane has an optimal range for obtaining a good temperature distribution and good cell performance.展开更多
In this note,we study the Cauchy problem of the linear spatially homogeneous Landau equation with soft potentials.We prove that the solution to the Cauchy problem enjoys the analytic regularizing effect of the time va...In this note,we study the Cauchy problem of the linear spatially homogeneous Landau equation with soft potentials.We prove that the solution to the Cauchy problem enjoys the analytic regularizing effect of the time variable with an L2 initial datum for positive time.So that the smoothing effect of Cauchy problem for the linear spatially homogeneous Landau equation with soft potentials is similar to the heat equation.展开更多
基金supported by the Natural Science Foundation of Hubei Province,China (2022CFB444)the Key Laboratory of Mathematical Modelling and High Performance Computing of Air Vehicles (NUAA)+1 种基金supported by the NSFC (12031006)the Fundamental Research Funds for the Central Universities of China.
文摘In this work,we study the linearized Landau equation with soft potentials and show that the smooth solution to the Cauchy problem with initial datum in L^(2)(ℝ^(3))enjoys an analytic regularization effect,and that the evolution of the analytic radius is the same as the heat equations.
文摘In this work, we study the smoothing effect of Cauchy problem in Sobolev space for the spatially homogeneous Landau equation in the Maxwellian case. We obtain a precise estimate with respect to time variable, which implies the ultra-analytic effect of weak solutions.
基金Supported by Natural Science Foundation of China(1077107410771139)+1 种基金Supported by the NSF of Wenzhou University(2007L024)Supported by the NSF of Zhejiang Province(Y6080077)
文摘This paper studies the long time behavior of solutions to the Navier-Stokes equations with linear damping on R^2. The authors prove the existence of L^2-global attractor and Hi-global attractor by showing that the corresponding semigroup is asymptotically compact. Thereafter, they establish that the two attractors are the same and thus reveal the asymptotic smoothing effect of the solutions.
基金the NSFC(No.12031006)and the Fundamental Research Funds for the Central Universities of China.
文摘In this work,we study the Cauchy problem of the spatially homogeneous Landau equation with hard potentials in a close-to-equilibrium framework.We prove that the solution to the Cauchy problem enjoys the analytic regularizing effect of the time variable with an L^(2)initial datum for positive time.So that the smoothing effect of the Cauchy problem for the spatially homogeneous Landau equation with hard potentials is exactly same as heat equation.
文摘In this paper, we study the Gevrey class regularity for solutions of the spatially homogeneous Landau equations in the hard potential case and the Maxwellian molecules case.
文摘This paper is devoted to the long time behavior of the solution to the initial boundary value problems for a class of the Kirchhoff wave equations with nonlinear strongly damped terms: . Firstly, in order to prove the smoothing effect of the solution, we make efficient use of the analytic property of the semigroup generated by the principal operator of the equation in the phase space. Then we obtain the regularity of the global attractor and construct the approximate inertial manifold of the equation. Finally, we prove that arbitrary trajectory of the Kirchhoff wave equations goes into a small neighbourhood of the approximate inertial manifold after large time.
文摘This paper presents the influences of plasma layer on the oscillatory flow inarterial stenosis. The analysis demonstrates that the existence of the plasma layer mayobviously change the characteristics of flow such as velocity-profiles, longitudinalimpedance and pressure gradient, but hardly change the phase of longitudinalimpedance and pressure gradient. Besides. such influences vary with a and degree ofstenosis. These analyses have Special physiological significance in blood circulationsystem.
基金The Specialized Research Fund for the Doctoral Program of Higher Education under contract No.20120041130002the National Key Project of Science and Technology under contract No.2011ZX 05056-001-02the Fundamental Research Funds for the Central Universities under contract No.DUT14ZD220
文摘Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides.Currently, commercial calculation programs such as BING have limitations in simulating underwater soil movements. All of these processes can be consistently simulated through a smoothed particle hydrodynamics(SPH) depth integrated model. The basis of the model is a control equation that was developed to take into account the effects of soil consolidation and erosion. In this work, the frictional rheological mode has been used to perform a simulation study of submarine landslides. Time-history curves of the sliding body's velocity, height,and length under various conditions of water depth, slope gradient, contact friction coefficient, and erosion rate are compared; the maximum sliding distance and velocity are calculated; and patterns of variation are discussed.The findings of this study can provide a reference for disaster warnings and pipeline route selection.
文摘Wind electricity power has fluctuation, and accurate and reasonable wind electricity power prediction is very important for solving wind electricity network and combination. This paper takes an analysis of a lot of actual data of a certain wind electricity field. Through wavelet neural network and time series method rolling, it can predict the overall power of wind electricity field. The result shows that for the original data of sampling time length and large sampling frequency, the model constructed by this paper has very good prediction effect. Because of the fan installation position, wind electricity fan flow effect and other random factor influence, wind electricity field overall power and single unit power distribution have difference. Through comparing with the time series parameters, it puts forward that single wind electricity unit power has smooth effect for overall power of wind electricity field. Finally, it summarizes the prediction effect and puts forward some reasonable suzestions for wind electricity network troblems.
文摘Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable simulation but also for discrete variable simulation. In this paper, the X Oilfield in the western South China Sea is taken as an example to compare the sequential indicator simulation method and the Indicator Kriging interpolation method. The results of the final comparison show that the results of the lithofacies model established by the Indicator Kriging deterministic interpolation method are overly smooth, and its coincidence rate with the geological statistical results is not high, thus cannot well reflect the heterogeneity of the underground reservoir, while the simulation results of the lithofacies model established by the sequential indicator stochastic simulation method can fit well with the statistical law of the well, which has eliminated the smoothing effect of Kriging interpolation, thus can better reflect the heterogeneity of the underground reservoir. Therefore, the sequential indicator simulation is more suitable for the characterization of sand bodies and the study of reservoir heterogeneity.
基金supported by National Natural Science Foundation of China(Grant No.11701578)supported by National Natural Science Foundation of China(Grant No.12031006)+1 种基金the Fundamental Research Funds for the Central UniversitiesSouth-Central Minzu University(Grant No.CZT20007)。
文摘In this work,we study the Cauchy problem of the nonlinear spatially homogeneous Landau equation with hard potentials in a close-to-equilibrium framework.We prove that the solution to the Cauchy problem with the initial datum in L^(2)enjoys an analytic regularizing effect,and the evolution of the analytic radius is the same as that of heat equations.
基金Natural Science Foundation of China under grant numbers 10471047 and 10471086Zhejiang Province Natural Science Foundation with item M103043Natural Science Foundation of Guangdong Province of China under grant No.004020077
文摘This paper discusses the Cauchy problem of elliptic-elliptic-type Davey-Stewartson systems with zero-order dissipation on R^2. Making use of the Fourier spectral projector, together with a long time comparison between the solutions to the Davey-Stewartson systems and to an auxiliary problem, we prove that the global attractor in H^1 (R^2) for the addressed Davey-Stewartson systems is a compact subset of H^2(R^2), and thus reveal the asymptotic smoothing effect of the solutions for the systems.
基金the Fundamental Research Funds for the Central Universities of China,South-Central University for Nationalities(No.CZT20007)the Natural Science Foundation of China(No.11701578).
文摘Based on the spectral decomposition for the linear and nonlinear radially symmetric homogeneous non-cutoff Landau operators under the hard potentialγ=2 in perturbation framework,we prove the existence and Gelfand-Shilov smoothing effect for solution to the Cauchy problem of the symmetric homogenous Landau equation with small initial datum.
基金Project supported by the National Natural Science Foundation of China(No.11101188)
文摘The smoothness of the solutions to the full Landau equation for Fermi-Dirac particles is investigated.It is shown that the classical solutions near equilibrium to the Landau-Fermi-Dirac equation have a regularizing effects in all variables (time,space and velocity),that is,they become immediately smooth with respect to all variables.
文摘Objective: To study the effect of Aloe emodin (AE), an active ingredient of Rhubarb,on the kinetics of proliferation of smooth muscular cells (SMCs) cultured in vitro after rabbit iliac arterial injury. Methods: Forty-eight hours after de-endothelialization (balloon endothelial denudation), the iliac arteries of the Japanese white rabbits were isolated and the smooth muscle cells were cultured primarily.AE was added to culture medium containing 10% fetal calf serum (FCS ). The cultures were pulse-labeled with 3H-TdR and TdR uptake into VSMC were measured and the cell cycle of the cultures were analyzed by using flow cytometer. Results: Compared with control, when the concentration gradient ranged from 10 - 1 to 10-5 g/L, the amount (cpm,count per minute) of 3H-TdR uptake into SMCs has significant differences (P < 0. 05 )and 10 -1 and 10 -2 g/L AE showed strong inhibitory effects on TdR uptake into VSMC and the percentage of inhibition [% inhibition =(cpm without AE-cpm with AE)/cpm without AE] was more than 90%. AE displayed concentration dependent inhibitory effects. The percentage of cells in G0/G1 phase was increased, but the percentage of cells in S phase was decreased in AE group, the transition of SMC cycle phase from G0 to S was blocked.Conclusion: AE is a strong inhibitor to the proliferation of SMCs and the pharmacological action of AE may reduce SMC proliferation in vivo and decrease intimal hyperplasia of restenosis.Original article on CJIM(Chin) 1998; 18(7): 420
文摘The effects of hypoxic endothelial cell conditioned medium (HECCM) on proliferation and collagen synthesis of cultured porcine pulmonary arterial smooth muscle cells (PASMCs) were studied by 3H-thymidine (3H-TdR) and 3H-proline incorporations, image analysis for determination of DNA content and colorimetric assay using MTT, and the inhibitory effects of radix salviae miltiorrhizae (RSM) on them were also investigated. The results showed that HECCM could induce enhancement of the enzymatic activity of mitochondria, increase of the nucleic DNA content and increases of the 3H-TdR and 3H-proline incorporations in PASMCs. The 3H-proline incorporation in PASMCs cultured in HECCM was 1.83 times as much as that cultured in normoxic endothelial cell conditioned medium (NECCM). Compared with the control, Chinese herb medicine RSM could inhibit the proliferation of PASMCs cultured in HECCM and decrease the 3H-prolinc incorporation in PASMCs cultured in both HECCM and NECCM (P< 0.001). However, RSM had no ef fects on the nucleic DNA content and 3H-TdR incorporation into DNA of PASMCs cultured in NECCM. It suggests that hypoxia may stimulate the endothelia to synthesize and secrete some cytokines which can stimulate the proliferation and the synthesis of collagen of PASMCs and RSM can inhibit this process.
基金supported in part by Chinese National Key Technologies R&D Program(2013BAA01B03)National Natural Science Foundation of China(51190101)industrial project of State Grid Corporation of China(No.NY71-13-043).
文摘China has made many strides in large-scale development and centralized integration of wind power in recent years.The wind power penetration of some regions has reached a high level,which brings significant challenges for power system dispatch due to the inherent variability and uncertainty of wind resources.To increase the dispatch capabilities of wind power generation,the spatial smoothing effect among adjacent wind farms needs to be fully utilized.This paper presents the concept of hierarchical coordinated dispatch for wind power based on a new concept of a virtual power generator.The spatial smoothing effect of wind power is analyzed first.Next,the virtual power generator method of a wind farm cluster is defined and established.Then,the hierarchical coordinated dispatch mode is compared with an existing wind power dispatch mode for individual wind farms.Finally,the proposed concept is implemented on a simulation case to demonstrate applicability and effectiveness.
基金financially supported by the National Natural Science Foundation of China(Grant No.51776108,No.51476092)
文摘A detailed three-dimensional mechanistic model of a large-scale solid oxide fuel cell(SOFC) unit running on partially pre-reformed methane is developed. The model considers the coupling effects of chemical and electrochemical reactions, mass transport, momentum and heat transfer in the SOFC unit. After model validation, parametric simulations are conducted to investigate how the methane pre-reforming ratio affects the transport and electrochemistry of the SOFC unit. It is found that the methane steam reforming reaction has a "smoothing effect", which can achieve more uniform distributions of gas compositions, current density and temperature among the cell plane. In the case of 1500 W/m^2 power density output, adding 20% methane absorbs 50% of internal heat production inside the cell, reduces the maximum temperature difference inside the cell from 70 K to 22 K and reduces the cathode air supply by 75%, compared to the condition of completely pre-reforming of methane. Under specific operating conditions, the pre-reforming ratio of methane has an optimal range for obtaining a good temperature distribution and good cell performance.
基金supported by the NSFC(No.12031006)the Fundamental Research Funds for the Central Universities of China.
文摘In this note,we study the Cauchy problem of the linear spatially homogeneous Landau equation with soft potentials.We prove that the solution to the Cauchy problem enjoys the analytic regularizing effect of the time variable with an L2 initial datum for positive time.So that the smoothing effect of Cauchy problem for the linear spatially homogeneous Landau equation with soft potentials is similar to the heat equation.