On the basis of the nonlinear stability theorem in the context of Arnol'd's second theorem for the generalized Phillips model,nonlinear saturation of baroclinic instability in the generalized Phillips model is...On the basis of the nonlinear stability theorem in the context of Arnol'd's second theorem for the generalized Phillips model,nonlinear saturation of baroclinic instability in the generalized Phillips model is investigatedThe lower bound on the disturbance energy and potential enstrophy to the nonlinearly unstable basic flow in the generalized Phillips model is presented,which indicates that there may exist an allocation between a nonlinearly unstable basic flow and a growing disturbance展开更多
Axisymmetric Couette-Taylor flow between two concentric rotating cylinders was simulated numerically by the spectral method.First,stream function form of the Navier-Stokes equations which homogeneous boundary conditio...Axisymmetric Couette-Taylor flow between two concentric rotating cylinders was simulated numerically by the spectral method.First,stream function form of the Navier-Stokes equations which homogeneous boundary condition was given by introducing Couette flow.Second,the analytical expressions of the eigenfunction of the Stokes operator in the cylindrical gap region were given and its orthogonality was proved.The estimates of growth rate of the eigenvalue were presented.Finally,spectral Galerkin approximation of Couette-Taylor flow was discussed by introducing eigenfunctions of Stokes operator as basis of finite dimensional approximate subspaces.The existence,uniquence and convergence of spectral Galerkin approximation of nonsingular solution for the steady-state Navier-Stokes equations are proved.Moreover,the error estimates are given.Numerical result is presented.展开更多
In this paper we prove a zero-free region for L-functions LG（z,Х）. As an application, an abstract prime number theorem with sharp error-term for formations is established.
A class of two-degree-of-freedom systems in resonance with an external, parametric excitation is investigated, the existence of the periodic solutions locked to Omega is proved by the use of the method of multiple sca...A class of two-degree-of-freedom systems in resonance with an external, parametric excitation is investigated, the existence of the periodic solutions locked to Omega is proved by the use of the method of multiple scales. This systems can be transformed into the systems of Wiggins under some conditions. A calculating formula which determines the existence of homoclinic orbits of the systems is given.展开更多
The elasticity theory of the dislocation of cubic quasicrystals is developed. The governing equations of anti-plane elasticity dynamics problem of the quasicrystals were reduced to a solution of wave equations by intr...The elasticity theory of the dislocation of cubic quasicrystals is developed. The governing equations of anti-plane elasticity dynamics problem of the quasicrystals were reduced to a solution of wave equations by introducing displacement functions, and the analytical expressions of displacements, stresses and energies induced by a moving screw dislocation in the cubic quasicrystalline and the velocity limit of the dislocation were obtained. These provide important information for studying the plastic deformation of the new solid material.展开更多
Theoretical aspects of variational data assimilation （VDA） for a simple model with both global and local observational data are discussed. For the VDA problems with global observational data, the initial conditions ...Theoretical aspects of variational data assimilation （VDA） for a simple model with both global and local observational data are discussed. For the VDA problems with global observational data, the initial conditions and parameters for the model are revisited and the model itself is modified. The estimates of both error and convergence rate are theoretically made and the vahdity of the method is proved. For VDA problem with local observation data, the conventional VDA method are out of use due to the ill-posedness of the problem. In order to overcome the difficulties caused by the ill-posedness, the initial conditions and parameters of the model are modified by using the improved VDA method, and the estimates of both error and convergence rate are also made. Finally, the validity of the improved VDA method is proved through theoretical analysis and illustrated with an example, and a theoretical criterion of the regularization parameters is proposed.展开更多
On the basis of the nonlinear stability theorem in the context of Arnol's second theorem for the generalized Phillips model, nonlinear saturation of baroclinic instability in the generalized Phillips model is inve...On the basis of the nonlinear stability theorem in the context of Arnol's second theorem for the generalized Phillips model, nonlinear saturation of baroclinic instability in the generalized Phillips model is investigated. By choosing appropriate artificial stable basic flows, the upper bounds on the disturbance energy and potential enstrophy to the nonlinearly unstable basic flow in the generalized Phillips model are obtained, which are analytic completely and without the limitation of infinitesimal initial disturbance.展开更多
The influence of dopant concentration on PZT (54/46) systems doped with lanthanum and/or niobium is studied. The sintering kinetics is presented for 1 wt% of the dopant used to find the main mechanism which drives thi...The influence of dopant concentration on PZT (54/46) systems doped with lanthanum and/or niobium is studied. The sintering kinetics is presented for 1 wt% of the dopant used to find the main mechanism which drives this process. The results were compared with a phenomenological model for viscous sintering and solid state sintering. The exponent obtained for viscous sintering in PZTN, PLZT and PLZTN were 0.05, 0.01, and 0.23 respectively, which indicate that the process is reactive liquid in all cases. In the other hand, the exponent obtained for solid state sintering were 6.61, 5.68, and 1.23 respectively, and prevalence Ost-wald ripening and coalescence process together. Both dopants inhibit the grain growth and accelerate the sintering process, which increases with dopant concentration and the combination of both dopants. Shoro-hod-Olevsky model was applied for explain grain growth evolution, but does not coincide strictly with the applied model, which suggest that the process is very complex.展开更多
The thermal and electrical transport properties of an ideal anyon gas within fractional exclusion statistics are studied. By solving the Boltzmann equation with the relaxation-time approximation, the analytical expres...The thermal and electrical transport properties of an ideal anyon gas within fractional exclusion statistics are studied. By solving the Boltzmann equation with the relaxation-time approximation, the analytical expressions for the thermal and electrical conductivities of a three-dimensional ideal anyon gas are given. The low-temperature expressions for the two conductivities are obtained by using the Sommerfeld expansion. It is found that the Wiedemann–Franz law should be modified by the higher-order temperature terms, which depend on the statistical parameter g for a charged anyon gas. Neglecting the higher-order terms of temperature, the Wiedemann–Franz law is respected, which gives the Lorenz number. The Lorenz number is a function of the statistical parameter g.展开更多
We introduce the notions of a four-angle Hopf quasimodule and an adjoint quasiaction over a Hopf quasigroup H in a,symmetric monoidal category C.li H possesses an adjoint quasiaction,we show that symmetric Yetter-Drin...We introduce the notions of a four-angle Hopf quasimodule and an adjoint quasiaction over a Hopf quasigroup H in a,symmetric monoidal category C.li H possesses an adjoint quasiaction,we show that symmetric Yetter-Drinfeld categories are trivial,and hence we obtain a braided monoidal category equivalence between the category of right Yetter-Drinfeld modules over H and the category of four-angle Hopf modules over H under some suitable conditions.展开更多
Charge transport characteristics of Cd_（0.95）Mn_（0.05）Te：In radiation detectors have been evaluated by combining time resolved current transient measurements with time of flight charge transient measurements.The ...Charge transport characteristics of Cd_（0.95）Mn_（0.05）Te：In radiation detectors have been evaluated by combining time resolved current transient measurements with time of flight charge transient measurements.The shapes of the measured current pulses have been interpreted with respect to a concentration of net positive space-charge, which has resulted in an electric field gradient across the detector bulk.From the recorded current pulses the charge collection efficiency of the detector was found to approach 100%.From the evolution of the charge collection efficiency with applied bias,the electron mobility-lifetime product ofμ_nτ_n =（8.5±0.4）×10^（-4） cm^2/V has been estimated.The electron transit time was determined using both transient current technique and time of flight measurements in the bias range of 100-1900 V.From the dependence of drift velocity on applied electric field the electron mobility was found to beμ_n =（718±55） cm^2/（V·s） at room temperature.展开更多
Corrected explicit-implicit domain decomposition(CEIDD) algorithms are studied for parallel approximation of semilinear parabolic problems on distributed memory processors. It is natural to divide the spatial domain i...Corrected explicit-implicit domain decomposition(CEIDD) algorithms are studied for parallel approximation of semilinear parabolic problems on distributed memory processors. It is natural to divide the spatial domain into some smaller parallel strips and cells using the simplest straightline interface(SI) . By using the Leray-Schauder fixed-point theorem and the discrete energy method,it is shown that the resulting CEIDD-SI algorithm is uniquely solvable,unconditionally stable and convergent. The CEIDD-SI method always suffers from the globalization of data communication when interior boundaries cross into each other inside the domain. To overcome this disadvantage,a composite interface(CI) that consists of straight segments and zigzag fractions is suggested. The corresponding CEIDD-CI algorithm is proven to be solvable,stable and convergent. Numerical experiments are presented to support the theoretical results.展开更多
In this paper, an epidemic model of a vector-borne disease, namely, malaria, is consi- dered. The explicit expression of the basic reproduction number is obtained, the local and global asymptotical stability of the di...In this paper, an epidemic model of a vector-borne disease, namely, malaria, is consi- dered. The explicit expression of the basic reproduction number is obtained, the local and global asymptotical stability of the disease-free equilibrium is proved under certain conditions. It is shown that the model exhibits the phenomenon of backward bifurcation where the stable disease-free equilibrium coexists with a stable endemic equilibrium. Further, it is proved that the unique endemic equilibrium is globally asymptotically stable under certain conditions.展开更多
A novel surface-enhanced Raman scattering(SERS)-active substrate based on Au nanoparticles(AuNPs)-coated silver nanowire(AgNW) is obtained by an effective and simple method. The results show that the hybrid structures...A novel surface-enhanced Raman scattering(SERS)-active substrate based on Au nanoparticles(AuNPs)-coated silver nanowire(AgNW) is obtained by an effective and simple method. The results show that the hybrid structures prepared by this method are powerful SERS-active substrates for the detection of malachite green(MG) molecules with the limit of 1 nmol/L. The excellent enhancing ability mainly comes from two kinds of hot spots. One is from the gaps among the adjacent AuNPs, and the other is the presence of zone between AuNPs and AgNW. In particular, the AuNPs-coated AgNW can be viewed through the objective of the confocal Raman spectrometer due to the length of the AgNW reaches microns, which can improve the repeatability of detection. Moreover, it is of great significance in research of SERS mechanism and application.展开更多
Synchronization of chaotic vertical-cavity surface-emitting lasers （VCSELs） is achieved by external chaotic signal modulation successfully. Simulation indicates that we can get chaos synchronization if the intensity...Synchronization of chaotic vertical-cavity surface-emitting lasers （VCSELs） is achieved by external chaotic signal modulation successfully. Simulation indicates that we can get chaos synchronization if the intensity of external chaotic signal is large enough. First of all, we use direct current modulation to achieve the chaos of VCSELs, and determine the laser＇s chaotic state by analyzing time series of the output and the corresponding power spectrum. And then we achieve synchronization of the two chaotic systems by external chaotic signal parameter modulation. We also find that the larger the modulation intensity is, the easier it is to achieve synchronization for chaotic VCSELs. This approach can also be applied to systems with a number of modulated lasers.展开更多
The transverse mass spectra of protons, pions, kaons, Lambda and Antilambda produced in central nucleus-nucleus collisions at high energies are described by using one-temperature and two-temperature emission pictures....The transverse mass spectra of protons, pions, kaons, Lambda and Antilambda produced in central nucleus-nucleus collisions at high energies are described by using one-temperature and two-temperature emission pictures. The calculated results are compared and found to be in good agreement with the experimental data of the E895, E866 and E917 Collaborations measured in central Au-Au collisions at the Alternating Gradient Synchrotron （AGS） energies and the NA49 Collaboration measured in central Pb-Pb collisions at the Super Proton Synchrotron （SPS） energies. It is demonstrated that the transverse mass distributions of protons, kaons, Lambda and Antilambda, except for Lambda hyperons produced in central Pb-Pb collisions at 158 A GeV, can be described by using the one-temperature emission picture, and for pions, we need to use the two-temperature emission picture.展开更多
This paper describes a new approach to regulate the photoelectric properties of two-dimensional SiC materials.The first-principles pseudo-potential plane wave method is used to calculate the geometric structure,electr...This paper describes a new approach to regulate the photoelectric properties of two-dimensional SiC materials.The first-principles pseudo-potential plane wave method is used to calculate the geometric structure,electronic structure and optical properties of two-dimensional(2D)SiC co-doped by the adjacent elements of C-Si(such as B and N).The results show that:after B-N co-doping,the supercell lattices of 2D SiC are observed obviously deformation near the doped atoms.Meanwhile,the band structures of 2D SiC co-doped by B-N become rich.As the impurity level enters the forbidden band,the band gap decreases,and the distribution of density of states near the Fermi level changes accordingly.The calculation of optical properties shows that the ability to absorb electromagnetic waves of 2D SiC has been enhanced obviously in the low energy range after B-N co-doping.The reason is originated from the transition of the 2p state of B and N.At the same time,the static dielectric constant increases and the peak of reflectivity decreases.The above results indicate that the optoelectronic properties of 2D SiC can be modulated by co-doping B-N.展开更多
文摘On the basis of the nonlinear stability theorem in the context of Arnol'd's second theorem for the generalized Phillips model,nonlinear saturation of baroclinic instability in the generalized Phillips model is investigatedThe lower bound on the disturbance energy and potential enstrophy to the nonlinearly unstable basic flow in the generalized Phillips model is presented,which indicates that there may exist an allocation between a nonlinearly unstable basic flow and a growing disturbance
文摘Axisymmetric Couette-Taylor flow between two concentric rotating cylinders was simulated numerically by the spectral method.First,stream function form of the Navier-Stokes equations which homogeneous boundary condition was given by introducing Couette flow.Second,the analytical expressions of the eigenfunction of the Stokes operator in the cylindrical gap region were given and its orthogonality was proved.The estimates of growth rate of the eigenvalue were presented.Finally,spectral Galerkin approximation of Couette-Taylor flow was discussed by introducing eigenfunctions of Stokes operator as basis of finite dimensional approximate subspaces.The existence,uniquence and convergence of spectral Galerkin approximation of nonsingular solution for the steady-state Navier-Stokes equations are proved.Moreover,the error estimates are given.Numerical result is presented.
文摘In this paper we prove a zero-free region for L-functions LG（z,Х）. As an application, an abstract prime number theorem with sharp error-term for formations is established.
文摘A class of two-degree-of-freedom systems in resonance with an external, parametric excitation is investigated, the existence of the periodic solutions locked to Omega is proved by the use of the method of multiple scales. This systems can be transformed into the systems of Wiggins under some conditions. A calculating formula which determines the existence of homoclinic orbits of the systems is given.
基金Project supported by the National Natural Science Foundation of China (No. 10372016)
文摘The elasticity theory of the dislocation of cubic quasicrystals is developed. The governing equations of anti-plane elasticity dynamics problem of the quasicrystals were reduced to a solution of wave equations by introducing displacement functions, and the analytical expressions of displacements, stresses and energies induced by a moving screw dislocation in the cubic quasicrystalline and the velocity limit of the dislocation were obtained. These provide important information for studying the plastic deformation of the new solid material.
基金Project supported by the National Natural Science Foundation of China(Nos.40675020, 50505005)
文摘Theoretical aspects of variational data assimilation （VDA） for a simple model with both global and local observational data are discussed. For the VDA problems with global observational data, the initial conditions and parameters for the model are revisited and the model itself is modified. The estimates of both error and convergence rate are theoretically made and the vahdity of the method is proved. For VDA problem with local observation data, the conventional VDA method are out of use due to the ill-posedness of the problem. In order to overcome the difficulties caused by the ill-posedness, the initial conditions and parameters of the model are modified by using the improved VDA method, and the estimates of both error and convergence rate are also made. Finally, the validity of the improved VDA method is proved through theoretical analysis and illustrated with an example, and a theoretical criterion of the regularization parameters is proposed.
文摘On the basis of the nonlinear stability theorem in the context of Arnol's second theorem for the generalized Phillips model, nonlinear saturation of baroclinic instability in the generalized Phillips model is investigated. By choosing appropriate artificial stable basic flows, the upper bounds on the disturbance energy and potential enstrophy to the nonlinearly unstable basic flow in the generalized Phillips model are obtained, which are analytic completely and without the limitation of infinitesimal initial disturbance.
文摘The influence of dopant concentration on PZT (54/46) systems doped with lanthanum and/or niobium is studied. The sintering kinetics is presented for 1 wt% of the dopant used to find the main mechanism which drives this process. The results were compared with a phenomenological model for viscous sintering and solid state sintering. The exponent obtained for viscous sintering in PZTN, PLZT and PLZTN were 0.05, 0.01, and 0.23 respectively, which indicate that the process is reactive liquid in all cases. In the other hand, the exponent obtained for solid state sintering were 6.61, 5.68, and 1.23 respectively, and prevalence Ost-wald ripening and coalescence process together. Both dopants inhibit the grain growth and accelerate the sintering process, which increases with dopant concentration and the combination of both dopants. Shoro-hod-Olevsky model was applied for explain grain growth evolution, but does not coincide strictly with the applied model, which suggest that the process is very complex.
基金Supported by the Excellent Doctorial Dissertation Cultivation Grant from Central China Normal University under Grant No.2013YBYB44the Guidance Project of Education Department of Hubei Province under Grant No.B2014024+2 种基金the Scientific and Technological Research Program of Education Department of Hubei Province under Grant Nos.Q20123004 and Q20134401the Greative Teamof Hubei Polytechnic University under Grant No.13xtz05the National Natural Science Foundation of China under Grant Nos.11105039,11275082,11178001,and 51302074
文摘The thermal and electrical transport properties of an ideal anyon gas within fractional exclusion statistics are studied. By solving the Boltzmann equation with the relaxation-time approximation, the analytical expressions for the thermal and electrical conductivities of a three-dimensional ideal anyon gas are given. The low-temperature expressions for the two conductivities are obtained by using the Sommerfeld expansion. It is found that the Wiedemann–Franz law should be modified by the higher-order temperature terms, which depend on the statistical parameter g for a charged anyon gas. Neglecting the higher-order terms of temperature, the Wiedemann–Franz law is respected, which gives the Lorenz number. The Lorenz number is a function of the statistical parameter g.
基金supported by the National Natural Science Foundation of China(Grant No.11871144)the NNSF of Jiangsu Province(No.BK20171348)the Scientific Research Foundation of Nanjing Institute of Technology(No.YKJ202040).
文摘We introduce the notions of a four-angle Hopf quasimodule and an adjoint quasiaction over a Hopf quasigroup H in a,symmetric monoidal category C.li H possesses an adjoint quasiaction,we show that symmetric Yetter-Drinfeld categories are trivial,and hence we obtain a braided monoidal category equivalence between the category of right Yetter-Drinfeld modules over H and the category of four-angle Hopf modules over H under some suitable conditions.
基金supported in part by the Cooperative Research Centre for Biomedical Imaging Development
文摘Charge transport characteristics of Cd_（0.95）Mn_（0.05）Te：In radiation detectors have been evaluated by combining time resolved current transient measurements with time of flight charge transient measurements.The shapes of the measured current pulses have been interpreted with respect to a concentration of net positive space-charge, which has resulted in an electric field gradient across the detector bulk.From the recorded current pulses the charge collection efficiency of the detector was found to approach 100%.From the evolution of the charge collection efficiency with applied bias,the electron mobility-lifetime product ofμ_nτ_n =（8.5±0.4）×10^（-4） cm^2/V has been estimated.The electron transit time was determined using both transient current technique and time of flight measurements in the bias range of 100-1900 V.From the dependence of drift velocity on applied electric field the electron mobility was found to beμ_n =（718±55） cm^2/（V·s） at room temperature.
基金supported by National Natural Science Foundation of China (Grant No. 10871044)
文摘Corrected explicit-implicit domain decomposition(CEIDD) algorithms are studied for parallel approximation of semilinear parabolic problems on distributed memory processors. It is natural to divide the spatial domain into some smaller parallel strips and cells using the simplest straightline interface(SI) . By using the Leray-Schauder fixed-point theorem and the discrete energy method,it is shown that the resulting CEIDD-SI algorithm is uniquely solvable,unconditionally stable and convergent. The CEIDD-SI method always suffers from the globalization of data communication when interior boundaries cross into each other inside the domain. To overcome this disadvantage,a composite interface(CI) that consists of straight segments and zigzag fractions is suggested. The corresponding CEIDD-CI algorithm is proven to be solvable,stable and convergent. Numerical experiments are presented to support the theoretical results.
文摘In this paper, an epidemic model of a vector-borne disease, namely, malaria, is consi- dered. The explicit expression of the basic reproduction number is obtained, the local and global asymptotical stability of the disease-free equilibrium is proved under certain conditions. It is shown that the model exhibits the phenomenon of backward bifurcation where the stable disease-free equilibrium coexists with a stable endemic equilibrium. Further, it is proved that the unique endemic equilibrium is globally asymptotically stable under certain conditions.
基金the BIPT Breeding Project of Outstanding Young Teachers Management Backbone 2013General Program of Science and Technology Development Project of Beijing Municipal Education Commission(No.Z14-007)
文摘A novel surface-enhanced Raman scattering(SERS)-active substrate based on Au nanoparticles(AuNPs)-coated silver nanowire(AgNW) is obtained by an effective and simple method. The results show that the hybrid structures prepared by this method are powerful SERS-active substrates for the detection of malachite green(MG) molecules with the limit of 1 nmol/L. The excellent enhancing ability mainly comes from two kinds of hot spots. One is from the gaps among the adjacent AuNPs, and the other is the presence of zone between AuNPs and AgNW. In particular, the AuNPs-coated AgNW can be viewed through the objective of the confocal Raman spectrometer due to the length of the AgNW reaches microns, which can improve the repeatability of detection. Moreover, it is of great significance in research of SERS mechanism and application.
文摘Synchronization of chaotic vertical-cavity surface-emitting lasers （VCSELs） is achieved by external chaotic signal modulation successfully. Simulation indicates that we can get chaos synchronization if the intensity of external chaotic signal is large enough. First of all, we use direct current modulation to achieve the chaos of VCSELs, and determine the laser＇s chaotic state by analyzing time series of the output and the corresponding power spectrum. And then we achieve synchronization of the two chaotic systems by external chaotic signal parameter modulation. We also find that the larger the modulation intensity is, the easier it is to achieve synchronization for chaotic VCSELs. This approach can also be applied to systems with a number of modulated lasers.
基金Supported by National Natural Science Foundation of China (10975095)Natural Science Foundation of Shanxi Province(2007011005)
文摘The transverse mass spectra of protons, pions, kaons, Lambda and Antilambda produced in central nucleus-nucleus collisions at high energies are described by using one-temperature and two-temperature emission pictures. The calculated results are compared and found to be in good agreement with the experimental data of the E895, E866 and E917 Collaborations measured in central Au-Au collisions at the Alternating Gradient Synchrotron （AGS） energies and the NA49 Collaboration measured in central Pb-Pb collisions at the Super Proton Synchrotron （SPS） energies. It is demonstrated that the transverse mass distributions of protons, kaons, Lambda and Antilambda, except for Lambda hyperons produced in central Pb-Pb collisions at 158 A GeV, can be described by using the one-temperature emission picture, and for pions, we need to use the two-temperature emission picture.
基金the Natural Science Foundation of Guizhou Province of China(No.[2015]2001)the Innovation Team of Anshun University(No.2015PT02)+1 种基金the Doctoral Fund of Anshun University(No.Asxybsjj201503)the Discipline Platform of Anshun University(No.Asxyxkpt201803).
文摘This paper describes a new approach to regulate the photoelectric properties of two-dimensional SiC materials.The first-principles pseudo-potential plane wave method is used to calculate the geometric structure,electronic structure and optical properties of two-dimensional(2D)SiC co-doped by the adjacent elements of C-Si(such as B and N).The results show that:after B-N co-doping,the supercell lattices of 2D SiC are observed obviously deformation near the doped atoms.Meanwhile,the band structures of 2D SiC co-doped by B-N become rich.As the impurity level enters the forbidden band,the band gap decreases,and the distribution of density of states near the Fermi level changes accordingly.The calculation of optical properties shows that the ability to absorb electromagnetic waves of 2D SiC has been enhanced obviously in the low energy range after B-N co-doping.The reason is originated from the transition of the 2p state of B and N.At the same time,the static dielectric constant increases and the peak of reflectivity decreases.The above results indicate that the optoelectronic properties of 2D SiC can be modulated by co-doping B-N.
