Owing to perfect impermeability,dynamics stability,flexible and efficient operation mode and strong adjustment,underground salt cavern natural gas storage is especially adapted to be used for short-term dispatch.Based...Owing to perfect impermeability,dynamics stability,flexible and efficient operation mode and strong adjustment,underground salt cavern natural gas storage is especially adapted to be used for short-term dispatch.Based on characteristics of gas flow and heat transfer,dynamic mathematic models were built to simulate the injection and withdrawal performance of underground salt cavern gas storage.Temperature and pressure variations of natural gas in gas storage were simulated on the basis of building models during withdrawal operation,and factors affecting on the operation of gas storage were also analyzed.Therefore,these models can provide theore-tic foundation and technology support for the design,building and operation of salt cavern gas storage.展开更多
The system of mixture of single lane and double lane is studied by a cellular automata model, which is developed by us based on the Nagel and Schreckenberg＇s models. We justify that the model can reach a stable state...The system of mixture of single lane and double lane is studied by a cellular automata model, which is developed by us based on the Nagel and Schreckenberg＇s models. We justify that the model can reach a stable states quickly. The density distributions of the stable state is presented for several cases, which illustrate the manner of the congestion. The relationship between the outflow rate and the total number of vehicles and that between the outflow rate and the density just before the bottleneck are both given. Comparing with the relationship that occurring in the granular flow, we conclude that the transition from the free traffic flow to the congested traffic flow can also be attributed to the abrupt variation through unstable flow state, which can naturally explain the discontinuities and the complex time variation behavior observed in the traffic flow experiments.展开更多
We study non-topological, charged planar walls （Q-walls） in the context of a particle physics model with supersymmetry broken by low-energy gauge mediation. Analytical properties are derived within the fiat-potentia...We study non-topological, charged planar walls （Q-walls） in the context of a particle physics model with supersymmetry broken by low-energy gauge mediation. Analytical properties are derived within the fiat-potential approximation for the flat-direction raising potential, while a numerical study is performed using the fall two-loop supersymmetric potential. We analyze the energetics of finite-size Q-walls and compare them to Q-balls, non-topological solitons possessing spherical symmetry and arising in the same supersymmetric model. This allows us to draw a phase diagram in the charge-transverse length plane, which shows a region where Q-wall solutions are energetically favored over Q-balls. However, due to their finiteness, such finite-size Q-walls are dynamically unstable and decay into Q-balls in a time which is less than their typical scale-length.展开更多
We consider an epidemical model within soclally interacting mobile individuals to study the behaviors of steady states of epidemic propagation in 2D networks. Using mean-field approximation and large scale simulations...We consider an epidemical model within soclally interacting mobile individuals to study the behaviors of steady states of epidemic propagation in 2D networks. Using mean-field approximation and large scale simulations, we recover the usual epidemic behavior with critical thresholds δc and pc below which infectious disease dies out. For the population density δ far above δc it is found that there is linear relationship between contact rate λ and the population density δ in the main. At the same time, the result obtained from mean-field approximation is compared with our numerical result, and it is found that these two results are similar by and large but not completely the same.展开更多
The impulsive motion of a dynamically stabilized robot—Gyrover, which is a single-wheel gyroscopically stabilized robot is studied. A method based on the D’Alembert-Lagrange principle is proposed to develop the impu...The impulsive motion of a dynamically stabilized robot—Gyrover, which is a single-wheel gyroscopically stabilized robot is studied. A method based on the D’Alembert-Lagrange principle is proposed to develop the impulsive dynamic model of the single wheel robot. This method that can be used to find ways to investigate a single wheel mobile robot rolling on a rough terrain is tested using the experimental platform Gyrover. The conditions of falling over without actuators are addressed. Simulations that validate the analysis are provided as well.展开更多
According to the chemical kinetic model of lysogeny/lysis switch in Escherichia coli （E. coil） infected by bacteriophage A, the entropy production rates of steady states are calculated. The resuits show that the lys...According to the chemical kinetic model of lysogeny/lysis switch in Escherichia coli （E. coil） infected by bacteriophage A, the entropy production rates of steady states are calculated. The resuits show that the lysogenic state has lower entropy production rate than lyric state, which provides an explanation on why the lysogenic state of A phage is so stable. We a/so notice that the entropy production rates of both lysogenic state and lyric state are lower than that of saddle-point and bifurcation state, which is consistent with the principle of minimum entropy production for living organism in nonequilibrium stationary state. Subsequently, the relations between CI and Cro degradation rates at two bifurcations and the changes of entropy production rate with CI and Cro degradation are deduced. The theory and method can be used to calculate entropy change in other molecular network.展开更多
A mathematical model is presented in order to describe the dynamics of polygamous populations, bearing in mind single individuals of both sexes and the development of reproductive groups. In this context, the descript...A mathematical model is presented in order to describe the dynamics of polygamous populations, bearing in mind single individuals of both sexes and the development of reproductive groups. In this context, the description leads us to consider positive homogeneous dynamical systems, establishing conditions for the stationary state existence and its local stability. A fourth pre-reproductive stage was considered, i.e. males and females spend part of their lives before being in condition to reproduce, as a first step to consider more general models. Finally, we parametrized the proposed model using southern elephant seal data, to analyze the direct applicability to a real population.展开更多
基金Sponsored by the National Natural Science Foundation of China (Grant No. 50676025)National Great Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Technology of China During the 11th Five-year Plan (Grand No.2006BAB03B09)
文摘Owing to perfect impermeability,dynamics stability,flexible and efficient operation mode and strong adjustment,underground salt cavern natural gas storage is especially adapted to be used for short-term dispatch.Based on characteristics of gas flow and heat transfer,dynamic mathematic models were built to simulate the injection and withdrawal performance of underground salt cavern gas storage.Temperature and pressure variations of natural gas in gas storage were simulated on the basis of building models during withdrawal operation,and factors affecting on the operation of gas storage were also analyzed.Therefore,these models can provide theore-tic foundation and technology support for the design,building and operation of salt cavern gas storage.
基金supported by National Natural Science Foundation of China under Grant Nos. 10674157 and 10875166
文摘The system of mixture of single lane and double lane is studied by a cellular automata model, which is developed by us based on the Nagel and Schreckenberg＇s models. We justify that the model can reach a stable states quickly. The density distributions of the stable state is presented for several cases, which illustrate the manner of the congestion. The relationship between the outflow rate and the total number of vehicles and that between the outflow rate and the density just before the bottleneck are both given. Comparing with the relationship that occurring in the granular flow, we conclude that the transition from the free traffic flow to the congested traffic flow can also be attributed to the abrupt variation through unstable flow state, which can naturally explain the discontinuities and the complex time variation behavior observed in the traffic flow experiments.
文摘We study non-topological, charged planar walls （Q-walls） in the context of a particle physics model with supersymmetry broken by low-energy gauge mediation. Analytical properties are derived within the fiat-potential approximation for the flat-direction raising potential, while a numerical study is performed using the fall two-loop supersymmetric potential. We analyze the energetics of finite-size Q-walls and compare them to Q-balls, non-topological solitons possessing spherical symmetry and arising in the same supersymmetric model. This allows us to draw a phase diagram in the charge-transverse length plane, which shows a region where Q-wall solutions are energetically favored over Q-balls. However, due to their finiteness, such finite-size Q-walls are dynamically unstable and decay into Q-balls in a time which is less than their typical scale-length.
基金The project supported by National Natural Science Foundation of China under Grant No. 50272022 and the Sunshine Foundation of Wuhan City under Grant No. 20045006071-40
文摘We consider an epidemical model within soclally interacting mobile individuals to study the behaviors of steady states of epidemic propagation in 2D networks. Using mean-field approximation and large scale simulations, we recover the usual epidemic behavior with critical thresholds δc and pc below which infectious disease dies out. For the population density δ far above δc it is found that there is linear relationship between contact rate λ and the population density δ in the main. At the same time, the result obtained from mean-field approximation is compared with our numerical result, and it is found that these two results are similar by and large but not completely the same.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences ( No. KGCX2-YW-152 No. KGCX2-YW-156)+2 种基金Key Laboratory of Robotics and Intelligent System,Guangdong Province( No. 2009A060800016) Shenzhen Fundamental Research Program( No. JC200903170431A)China Postdoctoral Science Foundation( No. 20090460532)
文摘The impulsive motion of a dynamically stabilized robot—Gyrover, which is a single-wheel gyroscopically stabilized robot is studied. A method based on the D’Alembert-Lagrange principle is proposed to develop the impulsive dynamic model of the single wheel robot. This method that can be used to find ways to investigate a single wheel mobile robot rolling on a rough terrain is tested using the experimental platform Gyrover. The conditions of falling over without actuators are addressed. Simulations that validate the analysis are provided as well.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11047180,90403010,and 200408020102Scientific Research Startup Foundation of University of Electronic Science and Technology of China
文摘According to the chemical kinetic model of lysogeny/lysis switch in Escherichia coli （E. coil） infected by bacteriophage A, the entropy production rates of steady states are calculated. The resuits show that the lysogenic state has lower entropy production rate than lyric state, which provides an explanation on why the lysogenic state of A phage is so stable. We a/so notice that the entropy production rates of both lysogenic state and lyric state are lower than that of saddle-point and bifurcation state, which is consistent with the principle of minimum entropy production for living organism in nonequilibrium stationary state. Subsequently, the relations between CI and Cro degradation rates at two bifurcations and the changes of entropy production rate with CI and Cro degradation are deduced. The theory and method can be used to calculate entropy change in other molecular network.
文摘A mathematical model is presented in order to describe the dynamics of polygamous populations, bearing in mind single individuals of both sexes and the development of reproductive groups. In this context, the description leads us to consider positive homogeneous dynamical systems, establishing conditions for the stationary state existence and its local stability. A fourth pre-reproductive stage was considered, i.e. males and females spend part of their lives before being in condition to reproduce, as a first step to consider more general models. Finally, we parametrized the proposed model using southern elephant seal data, to analyze the direct applicability to a real population.
