In this paper, we consider a system of （2＋2）-dimensional nonlinear models by using CK direct method and Hereman-Nuseir method generated by the Janlent-Miodek Hierarchy. We construct some new multiple kink and singu...In this paper, we consider a system of （2＋2）-dimensional nonlinear models by using CK direct method and Hereman-Nuseir method generated by the Janlent-Miodek Hierarchy. We construct some new multiple kink and singular kink solutions of （2＋1）-Dimensional Nonlinear Models with the aid of symbolic computation.展开更多
The energy levels, wave functions and the second-order nonlinear susceptibilities are calculated in GaAs/Al0.2Ga0.8As/Al0.5Ga0.5As asymmetric quantum well （AQW） by using an asymmetric model based on the parabolic an...The energy levels, wave functions and the second-order nonlinear susceptibilities are calculated in GaAs/Al0.2Ga0.8As/Al0.5Ga0.5As asymmetric quantum well （AQW） by using an asymmetric model based on the parabolic and non-parabolic band. The influence of non-parabolicity can not be neglected when analyzing the phenomena in narrow quantum wells and in higher lying subband edges in wider wells. The numerical results show that under double resonance （DR） conditions, the second- order difference frequency generation （DFG） and optical rectification （OR） generation susceptibilities in the AQW reach 2.5019 μm/V and 13.208 μm/V, respectively, which are much larger than those of the bulk GaAs. Besides, we calculate the absorption coefficient of AQW and find out the two pump wavelengths correspond to the maximum absorption, so appropriate pump beams must be selected to generate terahertz （THz） radiation by DFG.展开更多
By means of the classical symmetry method,we investigate two types of the(2+1)-dimensional nonlinearKlein-Gorden equation.For the wave equation,we give out its symmetry group analysis in detail.For the secondtype of t...By means of the classical symmetry method,we investigate two types of the(2+1)-dimensional nonlinearKlein-Gorden equation.For the wave equation,we give out its symmetry group analysis in detail.For the secondtype of the(2+1)-dimensional nonlinear Klein-Gorden equation,an optimal system of its one-dimensional subalgebrasis constructed and some corresponding two-dimensional symmetry reductions are obtained.展开更多
Here we present a cyclicly symmetric non-vacuum spacetime, admitting closed timelike curves(CTCs) which appear after a certain instant of time,i.e.,a time-machine spacetime. The spacetime is asymptotically flat, freef...Here we present a cyclicly symmetric non-vacuum spacetime, admitting closed timelike curves(CTCs) which appear after a certain instant of time,i.e.,a time-machine spacetime. The spacetime is asymptotically flat, freefrom curvature singularities and a four-dimensional extension of the Misner space in curved spacetime. The spacetime is of type Ⅱ in the Petrov classification scheme and the matter field pure radiation satisfy the energy condition.展开更多
All the possible CP-conserving non-linear operators up to the p^4-order in the Lagrangian expansion are analysed here for the left-right symmetric model in the non-linear electroweak chiral context coupled to a light ...All the possible CP-conserving non-linear operators up to the p^4-order in the Lagrangian expansion are analysed here for the left-right symmetric model in the non-linear electroweak chiral context coupled to a light dynamical Higgs. The low energy effects will be triggered by an emerging new physics field content in the nature, more specifically,from spin-1 resonances sourced by the straightforward extension of the SM local gauge symmetry to the larger local group SU(2)_L × SU(2)_R× U(1)_(B-L). Low energy phenomenology will be altered by integrating out the resonances from the physical spectrum, being manifested through induced corrections onto the left handed operators. Such modifications are weighted by powers of the scales ratio implied by the symmetries of the model and will determine the size of the effective operator basis to be used. The recently observed diboson excess around the invariant mass 1.8 TeV–2 TeV entails a scale suppression that suggests to encode the low energy effects via a much smaller set of effective operators.展开更多
Piezoelectric nanogenerators(NGs)have been developed for converting mechanical energy into electric energy using ZnO,GaN,ZnSnO3,and PZT nanowires.Due to the unique polarity and non-central symmetry of the wurtzite str...Piezoelectric nanogenerators(NGs)have been developed for converting mechanical energy into electric energy using ZnO,GaN,ZnSnO3,and PZT nanowires.Due to the unique polarity and non-central symmetry of the wurtzite structure,a composite made of using the conical shaped nanowires are used as a simple,cost-effective,and scalable nanogenerator.Based on the finite element methods,the output voltage of the nanogenerator is modeled numerically.The key factors:the spatial location of nanowires,length and dip angle of nanowires,thickness of NG devices,and the physical properties of the polymer inside NGs,which affect the output voltage are studied.The results provide guidance for optimization the output of piezoelectric nanogenerators.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No. 10647112the Fundamental Research Funds for the Central Universities
文摘In this paper, we consider a system of （2＋2）-dimensional nonlinear models by using CK direct method and Hereman-Nuseir method generated by the Janlent-Miodek Hierarchy. We construct some new multiple kink and singular kink solutions of （2＋1）-Dimensional Nonlinear Models with the aid of symbolic computation.
基金supported by the National Basic Research Program of China (No.2007CB310403)the National Natural Science Foundation of China (Nos.60801017 and 61172010)the Science and Technology Committee of Tianjin (No.11JCYBJC01100)
文摘The energy levels, wave functions and the second-order nonlinear susceptibilities are calculated in GaAs/Al0.2Ga0.8As/Al0.5Ga0.5As asymmetric quantum well （AQW） by using an asymmetric model based on the parabolic and non-parabolic band. The influence of non-parabolicity can not be neglected when analyzing the phenomena in narrow quantum wells and in higher lying subband edges in wider wells. The numerical results show that under double resonance （DR） conditions, the second- order difference frequency generation （DFG） and optical rectification （OR） generation susceptibilities in the AQW reach 2.5019 μm/V and 13.208 μm/V, respectively, which are much larger than those of the bulk GaAs. Besides, we calculate the absorption coefficient of AQW and find out the two pump wavelengths correspond to the maximum absorption, so appropriate pump beams must be selected to generate terahertz （THz） radiation by DFG.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10735030 and 90718041Shanghai Leading Academic Discipline Project under Grant No.B412+1 种基金Program for Changjiang Scholars and Innovative Research Team in University (IRT0734)K.C.Wong Magna Fund in Ningbo University
文摘By means of the classical symmetry method,we investigate two types of the(2+1)-dimensional nonlinearKlein-Gorden equation.For the wave equation,we give out its symmetry group analysis in detail.For the secondtype of the(2+1)-dimensional nonlinear Klein-Gorden equation,an optimal system of its one-dimensional subalgebrasis constructed and some corresponding two-dimensional symmetry reductions are obtained.
文摘Here we present a cyclicly symmetric non-vacuum spacetime, admitting closed timelike curves(CTCs) which appear after a certain instant of time,i.e.,a time-machine spacetime. The spacetime is asymptotically flat, freefrom curvature singularities and a four-dimensional extension of the Misner space in curved spacetime. The spacetime is of type Ⅱ in the Petrov classification scheme and the matter field pure radiation satisfy the energy condition.
基金KITPC financial support during the completion of this work
文摘All the possible CP-conserving non-linear operators up to the p^4-order in the Lagrangian expansion are analysed here for the left-right symmetric model in the non-linear electroweak chiral context coupled to a light dynamical Higgs. The low energy effects will be triggered by an emerging new physics field content in the nature, more specifically,from spin-1 resonances sourced by the straightforward extension of the SM local gauge symmetry to the larger local group SU(2)_L × SU(2)_R× U(1)_(B-L). Low energy phenomenology will be altered by integrating out the resonances from the physical spectrum, being manifested through induced corrections onto the left handed operators. Such modifications are weighted by powers of the scales ratio implied by the symmetries of the model and will determine the size of the effective operator basis to be used. The recently observed diboson excess around the invariant mass 1.8 TeV–2 TeV entails a scale suppression that suggests to encode the low energy effects via a much smaller set of effective operators.
文摘Piezoelectric nanogenerators(NGs)have been developed for converting mechanical energy into electric energy using ZnO,GaN,ZnSnO3,and PZT nanowires.Due to the unique polarity and non-central symmetry of the wurtzite structure,a composite made of using the conical shaped nanowires are used as a simple,cost-effective,and scalable nanogenerator.Based on the finite element methods,the output voltage of the nanogenerator is modeled numerically.The key factors:the spatial location of nanowires,length and dip angle of nanowires,thickness of NG devices,and the physical properties of the polymer inside NGs,which affect the output voltage are studied.The results provide guidance for optimization the output of piezoelectric nanogenerators.
