A new solar coupling regeneration system is proposed in order to improve the reliability of solar desiccant regeneration system.The new system makes comprehensively use of the solar energy and can also be appropriate ...A new solar coupling regeneration system is proposed in order to improve the reliability of solar desiccant regeneration system.The new system makes comprehensively use of the solar energy and can also be appropriate for energy-storage in a night operation mode when the electric power supply is at its valley.Comparison of the performance of the new system,the solar thermal regeneration system and the solar electrodialysis regeneration system are made and the influential factors of the performance of the new system are investigated.The results reveal that the new system will be more energy efficient than the solar thermal regeneration system and the solar electrodialysis regeneration system.展开更多
Based on the second integrable ease of known two-dimensional Hamiltonian system with a quartie potentiM, we propose a 4 × 4 matrix speetrM problem and derive a hierarchy of coupled KdV equations and their Hamilto...Based on the second integrable ease of known two-dimensional Hamiltonian system with a quartie potentiM, we propose a 4 × 4 matrix speetrM problem and derive a hierarchy of coupled KdV equations and their Hamiltonian structures. It is shown that solutions of the coupled KdV equations in the hierarchy are reduced to solving two compatible systems of ordinary differentiM equations. As an application, quite a few explicit solutions of the coupled KdV equations are obtained via using separability for the second integrable ease of the two-dimensional Hamiltonian system.展开更多
The structural-acoustic coupling model for isotropic thin elastic plate was extended to honeycomb sandwich plate(HSP) by applying Green function method.Then an equivalent circuit model of the weakly-strongly coupled s...The structural-acoustic coupling model for isotropic thin elastic plate was extended to honeycomb sandwich plate(HSP) by applying Green function method.Then an equivalent circuit model of the weakly-strongly coupled system was proposed.Based on that,the estimation formulae of the coupled eigenfrequency were derived.The accuracy of the theoretical predictions was checked against experimental data,with good agreement achieved.Finally,the effects of HSP design parameters on the system coupling degree,the acoustic cavity eigenfrequency,and sound pressure response were analyzed.The results show that mechanical and acoustical characteristics of HSP can be improved by increasing the thickness of face sheet and reducing the mass density of material.展开更多
Earthquake is a kind of sudden and destructive random excitation in nature.It is significant to determine the probability distribution characteristics of the corresponding dynamic indicators to ensure the safety and t...Earthquake is a kind of sudden and destructive random excitation in nature.It is significant to determine the probability distribution characteristics of the corresponding dynamic indicators to ensure the safety and the stability of structures when the intensive seismic excitation,the intensity of which is larger than 7,acts in train-bridge system.Firstly,the motion equations of a two-dimensional train-bridge system under the vertical random excitation of track irregularity and the vertical seismic acceleration are established,where the train subsystem is composed of 8 mutually independent vehicle elements with 48 degrees of freedom,while the single-span simple supported bridge subsystem is composed of 102D beam elements with 20 degrees of freedom on beam and 2 large mass degrees of freedom at the support.Secondly,Monte Carlo method and pseudo excitation method are adopted to analyze the statistical parameters of the system.The power spectrum density of random excitation is used to define a series of non-stationary pseudo excitation in pseudo excitation method and the trigonometric series of random vibration history samples in Monte Carlo method,respectively solved by precise integral method and Newmark-βmethod through the inter-system iterative procedure.Finally,the results are compared with the case under the weak seismic excitation,and show that the samples of vertical acceleration response of bridge and the offload factor of train obeys the normal distribution.In a high probability,the intensive earthquakes pose a greater threat to the safety and stability of bridges and trains than the weak ones.展开更多
It is shown that the Kronecker product can be applied to construct a new integrable coupling system of soliton equation hierarchy in this paper. A direct application to the Burgers spectral problem leads to a novel so...It is shown that the Kronecker product can be applied to construct a new integrable coupling system of soliton equation hierarchy in this paper. A direct application to the Burgers spectral problem leads to a novel soliton equation hierarchy of integrable coupling system. It indicates that the Kronecker product is an efficient and straightforward method to construct the integrable couplings.展开更多
We report a theoretic study on the inverse spin-Hall effect （ISHE） in a two-terminal nano-device that consists of a two-dimensional electron gas （2DEG） with Rashba spin-orbit coupling （RSOC） and two ideal leads....We report a theoretic study on the inverse spin-Hall effect （ISHE） in a two-terminal nano-device that consists of a two-dimensional electron gas （2DEG） with Rashba spin-orbit coupling （RSOC） and two ideal leads. Based on a two-site toy model and Keldysh Green＇s function method, we derive an analytic result of ISHE, which shows clearly that a nonzero transverse charge current stems from the combined effect of the RSOC, the spin bias, and its spin polarization direction in spin space. Our further numerical calculations in a larger system other than two-site lattice model demonstrate that the transverse charge current, dependent on the strength of the RSOC, the Fermi energy of the system, as well as the system size, can exhibit oscillating behavior and even reverse its sign due to Rashba spin precession. These properties may be helpful for eficient detection of the spin current （spin bias） by measuring the transverse charge current in a spin-orbital coupling system.展开更多
We present an approximate analytical solution to periodically driven two-level system in the weak-coupling regime. The analytical solution is in good agreement with the exact numerical solution in resonance and near r...We present an approximate analytical solution to periodically driven two-level system in the weak-coupling regime. The analytical solution is in good agreement with the exact numerical solution in resonance and near resonance cases when Ω 〈 0.3ωa with Ω and ωa denoting the Rabi and transition frequencies respectively.展开更多
Kondo transport properties through a Kondo-type quantum dot （QD） with a side-coupled triple-QD structure are systematically investigated by using the non-equilibrium Green＇s function method. We firstly derive the f...Kondo transport properties through a Kondo-type quantum dot （QD） with a side-coupled triple-QD structure are systematically investigated by using the non-equilibrium Green＇s function method. We firstly derive the formulae of the current, the linear conductance, the transmission coefficient, and the local density of states. Then we carry out the analytical and numerical studies and some universal conductance properties are obtained. It is shown that the number of the conductance valleys is intrinsically determined by the side-coupled QDs and at most equal to the number of the QDs included in the side-coupled structure in the asymmetric limit. In the process of forming the conductance valleys, the side-coupled QD system plays the dominant role while the couplings between the Kondo-type QD and the side-coupled structure play the subsidiary and indispensable roles. To testify the validity of the universal conductance properties, another different kinds of side-coupled triple-QD structures are considered. It should be emphasized that these universal properties axe applicable in understanding this kind of systems with arbitrary many-QD side structures.展开更多
Under barometric pressure, groundwater flow in well-aquifer systems is a kind of hydromechanical coupling problem. Applying the flux boundary conditions on borehole wall and water pressure equilibrium conditions insid...Under barometric pressure, groundwater flow in well-aquifer systems is a kind of hydromechanical coupling problem. Applying the flux boundary conditions on borehole wall and water pressure equilibrium conditions inside and outside the borehole wall under barometric pressure （BP）, an analytic solution to well-water level changes has been proposed in this paper. The formulation shows that the BP coefficients increase with time and tend to BP constant. The Change of BP coefficients over time depends only on the ratio of transmissivity （T） to the well radius squared （ r2, ） , and has nothing to do with the change in BP. The BP constant only relates to aquifer loading efficiency （B）, and has nothing to do with the aquifer transmissivity and well radius. The BP coefficients＇ change over time in the analytic formulation is consistent with the analysis of measured data from the Nanxi wells. Based on the BP coefficient changes over time, a parameter estimation method is suggested and discussed in its application to the estimation of the aquifer BP constant （or B） and transmissivity by using the Nanxi well data.展开更多
This paper considers finite-time χ-consensus problem for a multi-agent system with firstorderindividual dynamics and switching interaction topologies.Several distributed finite-time consensusrules are constructed for...This paper considers finite-time χ-consensus problem for a multi-agent system with firstorderindividual dynamics and switching interaction topologies.Several distributed finite-time consensusrules are constructed for multi-agent dynamics in a unified way with the help of Lyapunovfunction and graph theory as well as homogeneity.Time-invariant non-smooth forms of finite-timeneighbor-based controllers are proposed and a numerical example is shown for illustration.展开更多
In fluid dynamics, plasma physics and nonlinear optics, Korteweg-de Vries (KdV)-type equations are used to describe certain phenomena. In this paper, a coupled KdV-modified KdV system is investigated. Based on the Bel...In fluid dynamics, plasma physics and nonlinear optics, Korteweg-de Vries (KdV)-type equations are used to describe certain phenomena. In this paper, a coupled KdV-modified KdV system is investigated. Based on the Bell polynomials and symbolic computation, the bilinear form of such system is derived, and its analytic N-soliton solutions are constructed through the Hirota method. Two types of multi-soliton interactions are found, one with the reverse of solitonic shapes, and the other, without. Both the two types can be considered elastic. For a pair of solutions to such system, u and v, with the number of solitons N even, the soliton shapes of u stay unvaried while those of v reverse after the interaction; with N odd, the soliton shapes of both u and v keep unchanged after the interaction.展开更多
An analytical model is presented to study vertical dynamic response of the ballastless track on long-span plate-truss cable-stayed bridges based on an explicit dynamic analysis method.In the model,the train,ballastles...An analytical model is presented to study vertical dynamic response of the ballastless track on long-span plate-truss cable-stayed bridges based on an explicit dynamic analysis method.In the model,the train,ballastless track and bridge are treated as a coupled vibration system with interaction.By simulating the dynamic process of the system,this paper discusses the distribution law of dynamic responses of the bridge deck and the bed slab.It shows the necessity of a base plate for the ballastless track on the long-span plate-truss cable-stayed bridge.Comparison of the influence of different train speeds and stiffness of the elastic vibration-damping pad on the dynamic responses of the bridge deck and the bed slab is also made.The reasonable stiffness value of elastic vibration-damping pad is proposed.展开更多
基金Project(51036001)supported by the National Natural Science Foundation of ChinaProject(2011BAJ03B05)supported by the National Science and Technology Pillar Program during the 12th Five-Year Plan Period of China
文摘A new solar coupling regeneration system is proposed in order to improve the reliability of solar desiccant regeneration system.The new system makes comprehensively use of the solar energy and can also be appropriate for energy-storage in a night operation mode when the electric power supply is at its valley.Comparison of the performance of the new system,the solar thermal regeneration system and the solar electrodialysis regeneration system are made and the influential factors of the performance of the new system are investigated.The results reveal that the new system will be more energy efficient than the solar thermal regeneration system and the solar electrodialysis regeneration system.
基金the Funds for Basic Research Project under Grant Nos.06XJC033 and 2008Bl10003
文摘Based on the second integrable ease of known two-dimensional Hamiltonian system with a quartie potentiM, we propose a 4 × 4 matrix speetrM problem and derive a hierarchy of coupled KdV equations and their Hamiltonian structures. It is shown that solutions of the coupled KdV equations in the hierarchy are reduced to solving two compatible systems of ordinary differentiM equations. As an application, quite a few explicit solutions of the coupled KdV equations are obtained via using separability for the second integrable ease of the two-dimensional Hamiltonian system.
基金Project(51105375)supported by the National Natural Science Foundation of ChinaProject(CSTC2010BB8204)supported by Chongqing Natural Science Foundation,China
文摘The structural-acoustic coupling model for isotropic thin elastic plate was extended to honeycomb sandwich plate(HSP) by applying Green function method.Then an equivalent circuit model of the weakly-strongly coupled system was proposed.Based on that,the estimation formulae of the coupled eigenfrequency were derived.The accuracy of the theoretical predictions was checked against experimental data,with good agreement achieved.Finally,the effects of HSP design parameters on the system coupling degree,the acoustic cavity eigenfrequency,and sound pressure response were analyzed.The results show that mechanical and acoustical characteristics of HSP can be improved by increasing the thickness of face sheet and reducing the mass density of material.
基金Project(52178101) supported by the National Natural Science Foundation of China。
文摘Earthquake is a kind of sudden and destructive random excitation in nature.It is significant to determine the probability distribution characteristics of the corresponding dynamic indicators to ensure the safety and the stability of structures when the intensive seismic excitation,the intensity of which is larger than 7,acts in train-bridge system.Firstly,the motion equations of a two-dimensional train-bridge system under the vertical random excitation of track irregularity and the vertical seismic acceleration are established,where the train subsystem is composed of 8 mutually independent vehicle elements with 48 degrees of freedom,while the single-span simple supported bridge subsystem is composed of 102D beam elements with 20 degrees of freedom on beam and 2 large mass degrees of freedom at the support.Secondly,Monte Carlo method and pseudo excitation method are adopted to analyze the statistical parameters of the system.The power spectrum density of random excitation is used to define a series of non-stationary pseudo excitation in pseudo excitation method and the trigonometric series of random vibration history samples in Monte Carlo method,respectively solved by precise integral method and Newmark-βmethod through the inter-system iterative procedure.Finally,the results are compared with the case under the weak seismic excitation,and show that the samples of vertical acceleration response of bridge and the offload factor of train obeys the normal distribution.In a high probability,the intensive earthquakes pose a greater threat to the safety and stability of bridges and trains than the weak ones.
基金supported by the Research Work of Liaoning Provincial Development of Education under Grant No. 2008670
文摘It is shown that the Kronecker product can be applied to construct a new integrable coupling system of soliton equation hierarchy in this paper. A direct application to the Burgers spectral problem leads to a novel soliton equation hierarchy of integrable coupling system. It indicates that the Kronecker product is an efficient and straightforward method to construct the integrable couplings.
基金Supported by National Natural Science Foundation of China under Grant No.10704016National Natural Science Foundation of Jiangsu Province under Grant No.BK2007100New Teacher Fund of Ministry of Education of China under Grant No.20070286036
文摘We report a theoretic study on the inverse spin-Hall effect （ISHE） in a two-terminal nano-device that consists of a two-dimensional electron gas （2DEG） with Rashba spin-orbit coupling （RSOC） and two ideal leads. Based on a two-site toy model and Keldysh Green＇s function method, we derive an analytic result of ISHE, which shows clearly that a nonzero transverse charge current stems from the combined effect of the RSOC, the spin bias, and its spin polarization direction in spin space. Our further numerical calculations in a larger system other than two-site lattice model demonstrate that the transverse charge current, dependent on the strength of the RSOC, the Fermi energy of the system, as well as the system size, can exhibit oscillating behavior and even reverse its sign due to Rashba spin precession. These properties may be helpful for eficient detection of the spin current （spin bias） by measuring the transverse charge current in a spin-orbital coupling system.
基金The project supported by the Postdoctoral Science Foundation of China under Grant Nos.20060408878 and 2007RS4015Key Science Research Foundation of the Education Ministry of China,Natural Science Foundation of Hunan Province of China under Grant No.05JJ40007Key Science Research Foundation of the Education Department of Hunan Province under Grant No.07A057
文摘We present an approximate analytical solution to periodically driven two-level system in the weak-coupling regime. The analytical solution is in good agreement with the exact numerical solution in resonance and near resonance cases when Ω 〈 0.3ωa with Ω and ωa denoting the Rabi and transition frequencies respectively.
基金Supported by the National Nature Science Foundation of China under Grant Nos.10604005 and 10974015 the Program for New Century Excellent Talents in University under Grant No.NCET-08-0044
文摘Kondo transport properties through a Kondo-type quantum dot （QD） with a side-coupled triple-QD structure are systematically investigated by using the non-equilibrium Green＇s function method. We firstly derive the formulae of the current, the linear conductance, the transmission coefficient, and the local density of states. Then we carry out the analytical and numerical studies and some universal conductance properties are obtained. It is shown that the number of the conductance valleys is intrinsically determined by the side-coupled QDs and at most equal to the number of the QDs included in the side-coupled structure in the asymmetric limit. In the process of forming the conductance valleys, the side-coupled QD system plays the dominant role while the couplings between the Kondo-type QD and the side-coupled structure play the subsidiary and indispensable roles. To testify the validity of the universal conductance properties, another different kinds of side-coupled triple-QD structures are considered. It should be emphasized that these universal properties axe applicable in understanding this kind of systems with arbitrary many-QD side structures.
基金supported by special funds for Public Welfare Scientific Research of Ministry of Science and Technology,PRC(200808055)Scientific Research Project of Education Department,Hebei Province(Z2009104),China
文摘Under barometric pressure, groundwater flow in well-aquifer systems is a kind of hydromechanical coupling problem. Applying the flux boundary conditions on borehole wall and water pressure equilibrium conditions inside and outside the borehole wall under barometric pressure （BP）, an analytic solution to well-water level changes has been proposed in this paper. The formulation shows that the BP coefficients increase with time and tend to BP constant. The Change of BP coefficients over time depends only on the ratio of transmissivity （T） to the well radius squared （ r2, ） , and has nothing to do with the change in BP. The BP constant only relates to aquifer loading efficiency （B）, and has nothing to do with the aquifer transmissivity and well radius. The BP coefficients＇ change over time in the analytic formulation is consistent with the analysis of measured data from the Nanxi wells. Based on the BP coefficient changes over time, a parameter estimation method is suggested and discussed in its application to the estimation of the aquifer BP constant （or B） and transmissivity by using the Nanxi well data.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.60874018,60736022, and60821091
文摘This paper considers finite-time χ-consensus problem for a multi-agent system with firstorderindividual dynamics and switching interaction topologies.Several distributed finite-time consensusrules are constructed for multi-agent dynamics in a unified way with the help of Lyapunovfunction and graph theory as well as homogeneity.Time-invariant non-smooth forms of finite-timeneighbor-based controllers are proposed and a numerical example is shown for illustration.
基金Supported by the National Natural Science Foundation of China under Grant No. 60772023the Fundamental Research Funds for the Central Universities of China under Grant No. 2011BUPTYB02+1 种基金the Open Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications)the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No. 200800130006, Chinese Ministry of Education
文摘In fluid dynamics, plasma physics and nonlinear optics, Korteweg-de Vries (KdV)-type equations are used to describe certain phenomena. In this paper, a coupled KdV-modified KdV system is investigated. Based on the Bell polynomials and symbolic computation, the bilinear form of such system is derived, and its analytic N-soliton solutions are constructed through the Hirota method. Two types of multi-soliton interactions are found, one with the reverse of solitonic shapes, and the other, without. Both the two types can be considered elastic. For a pair of solutions to such system, u and v, with the number of solitons N even, the soliton shapes of u stay unvaried while those of v reverse after the interaction; with N odd, the soliton shapes of both u and v keep unchanged after the interaction.
基金supported by the National Natural Science Foundation of China(Grant No.NNSF-U1334201)the National Basic Research Program of China("973"Project)(Grant No.2013CB036206)the Sichuan Province Youth Science and Technology Innovation Team(Grant No.2015TD0004)
文摘An analytical model is presented to study vertical dynamic response of the ballastless track on long-span plate-truss cable-stayed bridges based on an explicit dynamic analysis method.In the model,the train,ballastless track and bridge are treated as a coupled vibration system with interaction.By simulating the dynamic process of the system,this paper discusses the distribution law of dynamic responses of the bridge deck and the bed slab.It shows the necessity of a base plate for the ballastless track on the long-span plate-truss cable-stayed bridge.Comparison of the influence of different train speeds and stiffness of the elastic vibration-damping pad on the dynamic responses of the bridge deck and the bed slab is also made.The reasonable stiffness value of elastic vibration-damping pad is proposed.
