In a neutron-proton system, the matrix elements of the generators for SO(8) × SO(8) symmetry areconstructed explicitly, and with these matrix elements the low-lying excitation spectra obtained by diagonalization ...In a neutron-proton system, the matrix elements of the generators for SO(8) × SO(8) symmetry areconstructed explicitly, and with these matrix elements the low-lying excitation spectra obtained by diagonalization arepresented. The excitation spectra for SO(7) nuclei Pd and Ru isotopes and SO(6) r-soft rotational nuclei Xe, Ba, andCe isotopes are calculated, and comparison with the experimental results is carried out.展开更多
In order to investigate the dynamic behavior of non-conservative systems,the Lie symmetries and conserved quantities of fractional Birkhoffian dynamics based on quasi-fractional dynamics model are proposed and studied...In order to investigate the dynamic behavior of non-conservative systems,the Lie symmetries and conserved quantities of fractional Birkhoffian dynamics based on quasi-fractional dynamics model are proposed and studied.The quasi-fractional dynamics model here refers to the variational problem based on the definition of RiemannLiouville fractional integral(RLFI),the variational problem based on the definition of extended exponentially fractional integral(EEFI),and the variational problem based on the definition of fractional integral extended by periodic laws(FIEPL).First,the fractional Pfaff-Birkhoff principles based on quasi-fractional dynamics models are established,and the corresponding Birkhoff’s equations and the determining equations of Lie symmetry are obtained.Second,for fractional Birkhoffian systems based on quasi-fractional models,the conditions and forms of conserved quantities are given,and Lie symmetry theorems are proved.The Pfaff-Birkhoff principles,Birkhoff’s equations and Lie symmetry theorems of quasi-fractional Birkhoffian systems and classical Birkhoffian systems are special cases of this article.Finally,some examples are given.展开更多
The top-charm associated production with the effects from both B- and L-violating interactions in TeV scale photon-proton collisions is investigated in the framework of minimal supersymmetric standard model. Within t...The top-charm associated production with the effects from both B- and L-violating interactions in TeV scale photon-proton collisions is investigated in the framework of minimal supersymmetric standard model. Within the bounds on the relevant R-parity violating couplings, the total cross section will reach the order of 10 fb in some parts of the parameter space.展开更多
A maximally generalized Yang-Mills model, which contains, besides the vector part Vμ, also an axial-vector part Aμ, a scalar part S, a pseudoscalar part P, and a tensor part Tμv, is constructed and the dynamical br...A maximally generalized Yang-Mills model, which contains, besides the vector part Vμ, also an axial-vector part Aμ, a scalar part S, a pseudoscalar part P, and a tensor part Tμv, is constructed and the dynamical breaking of gauge symmetry in the model is also discussed. It is shown, in terms of the Nambu Jona-Lasinio mechanism, that the gauge symmetry breaking can be realized dynamically in the maximally generalized Yang-Mills model. The combination of the maximally generalized Yang-Mills model and the NJL mechanism provides a way to overcome the difficulties related to the Higgs field and the Higgs mechanism in the usual spontaneous symmetry breaking theory.展开更多
A four-bar linkage mechanism with links fabricated from symmetric laminates was studied. The mass matrix of the beam dement was obtained in light of the mass distribution characteristics of composite materials. The st...A four-bar linkage mechanism with links fabricated from symmetric laminates was studied. The mass matrix of the beam dement was obtained in light of the mass distribution characteristics of composite materials. The stiffness matrix of the beam element was derived from the constitutive equations of each layer and the relationship between the strain distribution and the node displacement of the beam element. The specific damping capacity of the beam element was analyzed according to the strain distribution of the beam element and the strain energy dissipation caused by vibration in each direction of each layer; and the damping coefficients were obtained according to the principle that the total energy dissipation of the beam element was equal to the work done by the equivalent damping force during a cycle of vibration, from which the damping matrix of the dynamic equations was obtained. Using the finite element method, the dynamic analytic model of the mechanism was obtained. The dynamic responses and natural frequency of the mechanism were obtained by simulation, respectively, and those of the simulation obtained by the proposed model were analyzed and compared with the results obtained by the conventional model. The work provides theoretical basis to a certain extent for the further research on nonlinear vibration characteristics and optimum design of this kind of mechanism.展开更多
The stent was a major breakthrough in the treatment of atherosclerotic vascular disease. The permanent vascular implant of a stent, however, changes the intra-stent blood flow hemodynamics. There is a growing consensu...The stent was a major breakthrough in the treatment of atherosclerotic vascular disease. The permanent vascular implant of a stent, however, changes the intra-stent blood flow hemodynamics. There is a growing consensus that the stent implant may change the artery wall shear stress distribution and hence lead to the restenosis process. Computational fluid dynamics (CFD) has been widely used to analyze hemodynamics in stented arteries. In this paper, two CFD models (the axisymmetric model and the 3-D stent model) were developed to investigate the effects of strut geometry and blood rheology on the intra-stent hemodynamics. The velocity profile, flow recirculation, and wall shear stress distribution of various stent strut geometries were studied. Results show strong correlations between the intra-stent hemodynamics and strut geometry. The intra-stent blood flow is very sensitive to the strut height and fillet size. A round strut with a large fillet size shows 36% and 34% reductions in key parameters evaluating the restenosis risk for the axisymmetric model and the 3-D stent model, respectively. This suggests that electrochemical polishing, a surface-improving process during stent manufacturing, strongly influences the hemodynamic behavior in stented arteries and should be controlled precisely in order to achieve the best clinical outcome. Rheological effects on the wall shear stress are minor in both axisymmetric and 3-D stent models for the vessel diameter of 4 mm, with Newtonian flow simulation tending to give more conservative estimates ofrestenosis risk. Therefore, it is reasonable to simulate the blood flow as a Newtonian flow in stented arteries using the simpler axisymmetric model. These findings will provide great insights for stent design optimization for potential restenosis improvement.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
文摘In a neutron-proton system, the matrix elements of the generators for SO(8) × SO(8) symmetry areconstructed explicitly, and with these matrix elements the low-lying excitation spectra obtained by diagonalization arepresented. The excitation spectra for SO(7) nuclei Pd and Ru isotopes and SO(6) r-soft rotational nuclei Xe, Ba, andCe isotopes are calculated, and comparison with the experimental results is carried out.
基金supported by the National Natural Science Foundation of China (Nos.11972241,11572212 and 11272227)the Natural Science Foundation of Jiangsu Province(No. BK20191454)。
文摘In order to investigate the dynamic behavior of non-conservative systems,the Lie symmetries and conserved quantities of fractional Birkhoffian dynamics based on quasi-fractional dynamics model are proposed and studied.The quasi-fractional dynamics model here refers to the variational problem based on the definition of RiemannLiouville fractional integral(RLFI),the variational problem based on the definition of extended exponentially fractional integral(EEFI),and the variational problem based on the definition of fractional integral extended by periodic laws(FIEPL).First,the fractional Pfaff-Birkhoff principles based on quasi-fractional dynamics models are established,and the corresponding Birkhoff’s equations and the determining equations of Lie symmetry are obtained.Second,for fractional Birkhoffian systems based on quasi-fractional models,the conditions and forms of conserved quantities are given,and Lie symmetry theorems are proved.The Pfaff-Birkhoff principles,Birkhoff’s equations and Lie symmetry theorems of quasi-fractional Birkhoffian systems and classical Birkhoffian systems are special cases of this article.Finally,some examples are given.
文摘The top-charm associated production with the effects from both B- and L-violating interactions in TeV scale photon-proton collisions is investigated in the framework of minimal supersymmetric standard model. Within the bounds on the relevant R-parity violating couplings, the total cross section will reach the order of 10 fb in some parts of the parameter space.
基金The project supported by Nationai Naturai Science Foundation of China under Grant No. 10275008
文摘A maximally generalized Yang-Mills model, which contains, besides the vector part Vμ, also an axial-vector part Aμ, a scalar part S, a pseudoscalar part P, and a tensor part Tμv, is constructed and the dynamical breaking of gauge symmetry in the model is also discussed. It is shown, in terms of the Nambu Jona-Lasinio mechanism, that the gauge symmetry breaking can be realized dynamically in the maximally generalized Yang-Mills model. The combination of the maximally generalized Yang-Mills model and the NJL mechanism provides a way to overcome the difficulties related to the Higgs field and the Higgs mechanism in the usual spontaneous symmetry breaking theory.
基金Projects(50175031, 50565001) supported by the National Natural Science Foundation of China project (2003203) supported by the New Century Ten Hundred and Thousand Talent Project Special Foundation of Guangxi+1 种基金 project(0542005) supported by Guangxi Science Foundation project(205119) supported by the Key Project of Chinese Ministry of Education
文摘A four-bar linkage mechanism with links fabricated from symmetric laminates was studied. The mass matrix of the beam dement was obtained in light of the mass distribution characteristics of composite materials. The stiffness matrix of the beam element was derived from the constitutive equations of each layer and the relationship between the strain distribution and the node displacement of the beam element. The specific damping capacity of the beam element was analyzed according to the strain distribution of the beam element and the strain energy dissipation caused by vibration in each direction of each layer; and the damping coefficients were obtained according to the principle that the total energy dissipation of the beam element was equal to the work done by the equivalent damping force during a cycle of vibration, from which the damping matrix of the dynamic equations was obtained. Using the finite element method, the dynamic analytic model of the mechanism was obtained. The dynamic responses and natural frequency of the mechanism were obtained by simulation, respectively, and those of the simulation obtained by the proposed model were analyzed and compared with the results obtained by the conventional model. The work provides theoretical basis to a certain extent for the further research on nonlinear vibration characteristics and optimum design of this kind of mechanism.
文摘The stent was a major breakthrough in the treatment of atherosclerotic vascular disease. The permanent vascular implant of a stent, however, changes the intra-stent blood flow hemodynamics. There is a growing consensus that the stent implant may change the artery wall shear stress distribution and hence lead to the restenosis process. Computational fluid dynamics (CFD) has been widely used to analyze hemodynamics in stented arteries. In this paper, two CFD models (the axisymmetric model and the 3-D stent model) were developed to investigate the effects of strut geometry and blood rheology on the intra-stent hemodynamics. The velocity profile, flow recirculation, and wall shear stress distribution of various stent strut geometries were studied. Results show strong correlations between the intra-stent hemodynamics and strut geometry. The intra-stent blood flow is very sensitive to the strut height and fillet size. A round strut with a large fillet size shows 36% and 34% reductions in key parameters evaluating the restenosis risk for the axisymmetric model and the 3-D stent model, respectively. This suggests that electrochemical polishing, a surface-improving process during stent manufacturing, strongly influences the hemodynamic behavior in stented arteries and should be controlled precisely in order to achieve the best clinical outcome. Rheological effects on the wall shear stress are minor in both axisymmetric and 3-D stent models for the vessel diameter of 4 mm, with Newtonian flow simulation tending to give more conservative estimates ofrestenosis risk. Therefore, it is reasonable to simulate the blood flow as a Newtonian flow in stented arteries using the simpler axisymmetric model. These findings will provide great insights for stent design optimization for potential restenosis improvement.
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.