In the presence of an applied uniform magnetic field Bo, the properties of 2-dimensional （2D） magnetosonic solitary waves of relativistic amplitude in the plasma containing electron, light ions He^＋, and heavy ion...In the presence of an applied uniform magnetic field Bo, the properties of 2-dimensional （2D） magnetosonic solitary waves of relativistic amplitude in the plasma containing electron, light ions He^＋, and heavy ions O＋ are presented. In the weakly relativistic limit, a Kadomtsev Petviashvili （KP） equation is derived by reductive perturbation method. We give the N-soliton solution of the KP equation and find dromion solutions of a potential of the physical field. The interaction law of the dromions is obtained, which shows there is no exchange of energy, momentum, and angular momentum before and after interaction of the dromions except for phase shifts.展开更多
The free electron gas in a uniform magnetic field at low temperature is restudied. The grand partition function previously obtained by Landau＇s quantitative calculation contains three parts, which are all approximate...The free electron gas in a uniform magnetic field at low temperature is restudied. The grand partition function previously obtained by Landau＇s quantitative calculation contains three parts, which are all approximate. An improved calculation is presented, in which two of the three parts are obtained in exact forms. A simple remedy for Landau and Lifshitz＇s qualitative calculation in the textbook is also given, which turns the qualitative result into the same one as obtained by the improved quantitative calculation. The chemical potential is solved approximately and the thermodynamic quantities are caiculated explicitly in both a weak field and a strong field. The thermodynamic quantities in a strong field obtained here contain both non-oscillating and oscillating corrections to the corresponding results derived from Landau＇s grand partition function. In particular, Landau＇s grand partition function is not sufficiently accurate to yield our nonzero results for the specific heat and the entropy. An error in the Laplace-transform method for the problem is corrected. The results previously obtained by this method are also improved.展开更多
To simulate the nonlinear behavior of ferroelectric structures and devices under non-uniform electromechanical loadings,a domain-switching embedded electromechanical finite element method is developed in this paper.Fo...To simulate the nonlinear behavior of ferroelectric structures and devices under non-uniform electromechanical loadings,a domain-switching embedded electromechanical finite element method is developed in this paper.Following continuum assumption,the electromechanical behavior of each representative material point can be obtained by averaging the behavior of the local corresponding microstructure,e.g.42 domains used in this work.A new Double Gibbs free energy criterion for domain-switching is proposed to ensure the convergence and stability of the simulations on ferroelectrics under non-uniform field.Several computational examples are given to demonstrate that this nonlinear finite element method can yield reasonable and stable simulation results which can be used to explain some experimental results and assist the design of ferroelectric devices.展开更多
This paper reports a cell trapping and patterning method using dielectric-pattern-assisted negative dielectrophoresis (dnDEP) that can achieve high-density cell arrays and complicated cell patterns.The dnDEP device co...This paper reports a cell trapping and patterning method using dielectric-pattern-assisted negative dielectrophoresis (dnDEP) that can achieve high-density cell arrays and complicated cell patterns.The dnDEP device consists of two planar metal electrodes and a patterned dielectric layer sandwiched in-between.The dielectric patterns generate non-uniform electric fields when an ac voltage is applied on the two electrodes,and the interaction of polarizable cells and the non-uniform electric fields imposes negative DEP forces on the cells,pushing them to the patterns in the dielectric layer.Using this dnDEP device,human lymphoma cells were successfully patterned in high-density microwell arrays and stellate structures.Thanks to the three-dimensional configuration and the small distance between the electrodes,cell trapping and patterning can be implemented with a voltage of 10 V.This dnDEP device has the advantages of simple configuration,low actuating voltage,and the compatibility with high conductivity physiological media for cell culturing.展开更多
基金Supported by National Natural Science Foundation of China under Grant No. 10747109the Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20070008001
文摘In the presence of an applied uniform magnetic field Bo, the properties of 2-dimensional （2D） magnetosonic solitary waves of relativistic amplitude in the plasma containing electron, light ions He^＋, and heavy ions O＋ are presented. In the weakly relativistic limit, a Kadomtsev Petviashvili （KP） equation is derived by reductive perturbation method. We give the N-soliton solution of the KP equation and find dromion solutions of a potential of the physical field. The interaction law of the dromions is obtained, which shows there is no exchange of energy, momentum, and angular momentum before and after interaction of the dromions except for phase shifts.
基金Supported by the National Natural Science Foundation of China under Grant No.10675174
文摘The free electron gas in a uniform magnetic field at low temperature is restudied. The grand partition function previously obtained by Landau＇s quantitative calculation contains three parts, which are all approximate. An improved calculation is presented, in which two of the three parts are obtained in exact forms. A simple remedy for Landau and Lifshitz＇s qualitative calculation in the textbook is also given, which turns the qualitative result into the same one as obtained by the improved quantitative calculation. The chemical potential is solved approximately and the thermodynamic quantities are caiculated explicitly in both a weak field and a strong field. The thermodynamic quantities in a strong field obtained here contain both non-oscillating and oscillating corrections to the corresponding results derived from Landau＇s grand partition function. In particular, Landau＇s grand partition function is not sufficiently accurate to yield our nonzero results for the specific heat and the entropy. An error in the Laplace-transform method for the problem is corrected. The results previously obtained by this method are also improved.
基金supported by the National Natural Science Foundation of China(Grant Nos. 10702034,10732050,90816006 and 10820101048)the National Basic Research Program of China(Grant Nos.2007CB936803 and 2010CB832701)
文摘To simulate the nonlinear behavior of ferroelectric structures and devices under non-uniform electromechanical loadings,a domain-switching embedded electromechanical finite element method is developed in this paper.Following continuum assumption,the electromechanical behavior of each representative material point can be obtained by averaging the behavior of the local corresponding microstructure,e.g.42 domains used in this work.A new Double Gibbs free energy criterion for domain-switching is proposed to ensure the convergence and stability of the simulations on ferroelectrics under non-uniform field.Several computational examples are given to demonstrate that this nonlinear finite element method can yield reasonable and stable simulation results which can be used to explain some experimental results and assist the design of ferroelectric devices.
基金supported in part by the National Natural Science Foundation of China (Grant No. 60871006)
文摘This paper reports a cell trapping and patterning method using dielectric-pattern-assisted negative dielectrophoresis (dnDEP) that can achieve high-density cell arrays and complicated cell patterns.The dnDEP device consists of two planar metal electrodes and a patterned dielectric layer sandwiched in-between.The dielectric patterns generate non-uniform electric fields when an ac voltage is applied on the two electrodes,and the interaction of polarizable cells and the non-uniform electric fields imposes negative DEP forces on the cells,pushing them to the patterns in the dielectric layer.Using this dnDEP device,human lymphoma cells were successfully patterned in high-density microwell arrays and stellate structures.Thanks to the three-dimensional configuration and the small distance between the electrodes,cell trapping and patterning can be implemented with a voltage of 10 V.This dnDEP device has the advantages of simple configuration,low actuating voltage,and the compatibility with high conductivity physiological media for cell culturing.
