This study presents an experimental investigation of the coupled caloric effect driven by dual-fields in metamagnetic alloy ErCo_(2) with strong magneto-structural coupling.Magnetic measurements were conducted under d...This study presents an experimental investigation of the coupled caloric effect driven by dual-fields in metamagnetic alloy ErCo_(2) with strong magneto-structural coupling.Magnetic measurements were conducted under different pressures,revealing that the application of hydrostatic pressure stabilizes a small volume of paramagnetism(PM) phase,resulting in a shift of the phase transition temperature towards the low-temperature region.This shift is opposite to the temperature associated with the magnetic field-driven phase transition.As pressure increases,the metamagnetic transition in ErCo_(2) is suppressed,and the hysteresis disappears.However,the produced cross-coupling caloric effect compensates the decrease in entropy change caused by the disappearance of the metamagnetic transition.As a result,a reversible giant magnetocaloric effect of 46.2 J/(kg·K) without hysteresis is achieved at a pressure of 0.910 GPa.Moreover,we propose that the temperature span of ErCo_(2) can be significantly widened by optimizing the thermodynamic pathway of the magnetic and pressure fields,overcoming the defect of a narrow temperature range.展开更多
This study employed a computational fluid dynamics model with an overset mesh technique to investigate the thrust and power of a floating offshore wind turbine(FOWT)under platform floating motion in the wind–rain fie...This study employed a computational fluid dynamics model with an overset mesh technique to investigate the thrust and power of a floating offshore wind turbine(FOWT)under platform floating motion in the wind–rain field.The impact of rainfall on aerodynamic performance was initially examined using a stationary turbine model in both wind and wind–rain conditions.Subsequently,the study compared the FOWT’s performance under various single degree-of-freedom(DOF)motions,including surge,pitch,heave,and yaw.Finally,the combined effects of wind–rain fields and platform motions involving two DOFs on the FOWT’s aerodynamics were analyzed and compared.The results demonstrate that rain negatively impacts the aerodynamic performance of both the stationary turbines and FOWTs.Pitch-dominated motions,whether involving single or multiple DOFs,caused significant fluctuations in the FOWT aerodynamics.The combination of surge and pitch motions created the most challenging operational environment for the FOWT in all tested scenarios.These findings highlighted the need for stronger construction materials and greater ultimate bearing capacity for FOWTs,as well as the importance of optimizing designs to mitigate excessive pitch and surge.展开更多
The collective dynamic of a fractional-order globally coupled system with time delays and fluctuating frequency is investigated.The power-law memory of the system is characterized using the Caputo fractional derivativ...The collective dynamic of a fractional-order globally coupled system with time delays and fluctuating frequency is investigated.The power-law memory of the system is characterized using the Caputo fractional derivative operator.Additionally,time delays in the potential field force and coupling force transmission are both considered.Firstly,based on the delay decoupling formula,combined with statistical mean method and the fractional-order Shapiro–Loginov formula,the“statistic synchronization”among particles is obtained,revealing the statistical equivalence between the mean field behavior of the system and the behavior of individual particles.Due to the existence of the coupling delay,the impact of the coupling force on synchronization exhibits non-monotonic,which is different from the previous monotonic effects.Then,two kinds of theoretical expression of output amplitude gains G and G are derived by time-delay decoupling formula and small delay approximation theorem,respectively.Compared to G,G is an exact theoretical solution,which means that G is not only more accurate in the region of small delay,but also applies to the region of large delay.Finally,the study of the output amplitude gain G and its resonance behavior are explored.Due to the presence of the potential field delay,a new resonance phenomenon termed“periodic resonance”is discovered,which arises from the periodic matching between the potential field delay and the driving frequency.This resonance phenomenon is analyzed qualitatively and quantitatively,uncovering undiscovered characteristics in previous studies.展开更多
All-solid-state lithium metal batteries represent leading candidates for the next generation of highenergy-density rechargeable batteries.However,the coupled mechanisms governing dendrite growth and crack propagation ...All-solid-state lithium metal batteries represent leading candidates for the next generation of highenergy-density rechargeable batteries.However,the coupled mechanisms governing dendrite growth and crack propagation within solid-state electrolytes(SSEs)remain inadequately understood.To address this knowledge gap,we propose an electrochemical-mechanical coupled phase-field model designed to simulate the complex processes of lithium deposition and crack propagation in SSEs.This framework systematically examines the influence of initial defect characteristics—including morphology,dimensions,and fracture toughness—on dendrite penetration dynamics.Furthermore,it identifies potential initiation pathways for detrimental lithium deposition within the electrolyte bulk.The model also quantifies the critical role of electrolyte elastic modulus and grain boundary orientation in modulating deposition behavior.Notably,simulation results demonstrate concordance with existing experimental observations,thereby establishing a fundamental theoretical framework for understanding failure mechanisms.This work provides crucial mechanistic insights and predictive capabilities to guide the rational design of failure-resistant SSEs for all-solid-state lithium metal batteries.展开更多
When two identical QED cavities driven by the coherent fields are located in a uniform environment, in addition to dissipation, there appears an indirect coupling between the two cavities induced by the background fie...When two identical QED cavities driven by the coherent fields are located in a uniform environment, in addition to dissipation, there appears an indirect coupling between the two cavities induced by the background fields. We investigate the effects of the coherent fields, the dissipation as well as the incoherent coupling on the following dynamical properties of the system： photon transfer, reversible decoherence, and quantum state transfer, etc. We find that the photons in the cavities do not leak completely into the environment due to the collective coupling between the cavities and the enviroment, and the photons are transferred irreversibly from the cavity with more photons to the cavity with less ones due to the incoherent coupling so that they are equally distributed among the two cavities. The coherent field pumping on the two cavities increases the mean photons, complements the revived magnitude of the reversible decoherence, but hinders the quantum state transfer between the two cavities. The above phenomena may find applications in quantum communication and other basic fields.展开更多
Phase transition of hydrogel,which is polymerized by polymer network,can be regarded as the transition of polymer network stability.The stability of the polymer network might be changed when the external environment c...Phase transition of hydrogel,which is polymerized by polymer network,can be regarded as the transition of polymer network stability.The stability of the polymer network might be changed when the external environment changed.This change will lead to the transformation of sensitive hydrogels stability,thus phase transition of hydrogel take place.Here,we present a new free density energy function,which considers the non-gaussianity of the polymer network,chains entanglement and functionality of junctions through adding Gent hyplastic model and Edwards-Vilgis slip-link model to Flory-Huggins theory.A program to calculate the phase transition temperature was written based on new free energy function.Taking PNIPAM hydrogel as an example,the effects of network entanglement on the phase transition temperature of hydrogel were studied by analyzing the microstructure parameters of the hydrogel networks.Analytical results suggest a significant relationship between phase transition temperature and entanglement network.展开更多
This paper gives a numerical study on the flow and temperature fields in an induced plasma reactor, which worked in 0.5 ATM with air as a working gas. We employed a two-dimensional mode of an inductively coupled plas...This paper gives a numerical study on the flow and temperature fields in an induced plasma reactor, which worked in 0.5 ATM with air as a working gas. We employed a two-dimensional mode of an inductively coupled plasma to calculate the temperature and flow field of the reactor as well as the generator. The algorithm is based on the solutions of the two-dimensional continuity, momentum, and energy equations in term of vorticity, stream function and enthalpy. An upwind finite-difference scheme was adopted to solve those equations with appropriate boundary conditions. The computed results show that there is a flat region with little parameter change in the reactor, that the diameter of the region is not much larger than that of the generator and that a deep change of parameter exists in the outer side of the region.展开更多
The two-dimensional elliptical inclusion problems in infinite anisotropic magnetoelectro-elastic solids are considered. Based on the extended Stroh formalism, the technique of conformal mapping and the concept of pert...The two-dimensional elliptical inclusion problems in infinite anisotropic magnetoelectro-elastic solids are considered. Based on the extended Stroh formalism, the technique of conformal mapping and the concept of perturbation, the magneta-electro-elastic fields in both the matrix: and the inclusion are obtained explicitly. The results are of very importance for studying the effective properties of piezoelectric-piezomagnetic composite materials.展开更多
Some extended solution mapping relations of the nonlinear coupled scalar field and the well-known φ^4 model are presented. Simultaneously, inspired by the new solutions of the famous φ^4 model recently proposed by J...Some extended solution mapping relations of the nonlinear coupled scalar field and the well-known φ^4 model are presented. Simultaneously, inspired by the new solutions of the famous φ^4 model recently proposed by Jia, Huang and Lou, five kinds of new localized excitations of the nonlinear coupled scaiar field （NCSF） system are obtained.展开更多
Magnetohydrodynamic(MHD)induction pumps are contactless pumps able to withstand harsh environments.The rate of fluid flow through the pump directly affects the efficiency and stability of the device.To explore the inf...Magnetohydrodynamic(MHD)induction pumps are contactless pumps able to withstand harsh environments.The rate of fluid flow through the pump directly affects the efficiency and stability of the device.To explore the influence of induction pump settings on the related delivery speed,in this study,a numerical model for coupled electromagnetic and flow field effects is introduced and used to simulate liquid metal lithium flow in the induction pump.The effects of current intensity,frequency,coil turns and coil winding size on the velocity of the working fluid are analyzed.It is shown that the first three parameters have a significant impact,while changes in the coil turns have a negligible influence.The maximum increase in working fluid velocity within the pump for the parameter combination investigated in this paper is approximately 618%.As the frequency is increased from 20 to 60 Hz,the maximum increase in the mean flow rate of the working fluid is approximately 241%.These research findings are intended to support the design and optimization of these devices.展开更多
Electrically-excited flux-switching machines are advantageous in simple and reliable structure,good speed control performance,low cost,etc.,so they have arouse wide concerns from new energy field.However,they have muc...Electrically-excited flux-switching machines are advantageous in simple and reliable structure,good speed control performance,low cost,etc.,so they have arouse wide concerns from new energy field.However,they have much lower torque density/thrust density compared with the same type PM machines.To overcome this challenge,electromagnetic-thermal coupled analysis is carried out with respect to water-cooled electrically-excited flux-switching linear machines(EEFSLM).The simulation results indicate that the conventional fixed copper loss method(FCLM)is no longer suitable for high thrust density design,since it is unable to consider the strong coupling between the electromagnetic and thermal performance.Hence,a multi-step electromagnetic-thermal joint optimisation method is proposed,which first ensures the consistency between the electromagnetic and thermal modelling and then considers the effect of different field/armature coil sizes.By using the proposed joint optimisation method,it is found that the combination of relatively large size of field coil and relatively low field copper loss is favourable for achieving high thrust force for the current EEFSLM design.Moreover,the thrust force is raised by 13-15%compared with using the FCLM.The electromagnetic and thermal performance of the EEFSLM is validated by the prototype test.展开更多
In this paper, the marine ship observation data sets in the seventh (October 16-December 4. 1989) and eighth (June 1-July 16, 1990) cruises of PRC -US tropical ocean and global atmosphere (TOGA) joint scientific inves...In this paper, the marine ship observation data sets in the seventh (October 16-December 4. 1989) and eighth (June 1-July 16, 1990) cruises of PRC -US tropical ocean and global atmosphere (TOGA) joint scientific investigation in the tropical western Pacific are used to analyze the elements such as sea surface temperature (SST), surface wind field, fluxes and net heat budget, which are important physical parameters of underlying earth's surface influencing the global mean circulation evolution on seasonal and interannual time scales. These diagnostic analyses are very beneficial to the understanding of the regional climate characteristics and the air-sea interaction mechanism, and the improving of surface flux parameterizations and regional or global climate model.展开更多
Two full 3D steady mathematical models are developed by finite element method （FEM） to calcalate coupled physics fields. the electro-magnetic model is built and solved first and so is the fluid motion model with the...Two full 3D steady mathematical models are developed by finite element method （FEM） to calcalate coupled physics fields. the electro-magnetic model is built and solved first and so is the fluid motion model with the acquired electromagnetic force as source body forces in Navier-Stokes equations. Effects caused by the ferromagnetic shell, busbar system around, and open boundary problem as well as inside induced current were considered in terms of the magnetic field. Furthermore, a new modeling method is found to set up solid models and then mesh them entirely with so-called structuralized grids, namely hex-mesh. Examples of 75kA prebaked cell with two kinds of busbar arrangements are presented. Results agree with those disclosed in the literature and confirm that the coupled simulation is valid. It is also concluded that the usage of these models facilitates the consistent analysis of the electric field to magnetic field and then flow motion to the greater extent, local distributions of current density and magnetic flux density are very much dependent on the cell structure, the steel shell is a shield to reduce the magnetic field and flow pattern is two dimensional in the main body of the metal pad.展开更多
Cylindrical Al-Zn-Mg alloys were processed by electroplastic compression with forced air cooling.Compared to a simple compression process,an unequal intensity of {110} <111> was obtained,and other textures were ...Cylindrical Al-Zn-Mg alloys were processed by electroplastic compression with forced air cooling.Compared to a simple compression process,an unequal intensity of {110} <111> was obtained,and other textures were eliminated by electroplastic compression,that is,electroplastic compression can promote a uniform texture.The various textures formed in different regions along the radial direction under a simple compression process were illuminated by analyzing the relationship between the crystal rotation and stress state.Furthermore,the interaction between the electrons and dislocations was studied in electroplastic compression.The electrons enhanced {110} <111> by promoting slipping of the dislocations when the Burgers vectors of the dislocations were parallel to the drift direction of the electrons.However,the electrons also inhibited crystal rotation by pinning the dislocations with the Burgers vectors perpendicular to the drift direction of the electrons.Therefore,textures other than {110} <111>have difficulty forming under electroplastic compression.The effect of the current energy on the texture(enhancement or attenuation) was in accordance with the law of conservation.The results provided reasonable explanations for the test phenomena.展开更多
With the continuous upgrading of traditional manufacturing industries and the rapid rise of emerging technology fields,the performance requirements for the permanent magnet synchronous motors(PMSMs)have become higher ...With the continuous upgrading of traditional manufacturing industries and the rapid rise of emerging technology fields,the performance requirements for the permanent magnet synchronous motors(PMSMs)have become higher and higher.The importance of fast and accurate electromagnetic thermal coupling analysis of such motors becomes more and more prominent.In view of this,the surfacemounted PMSM(SPMSM)equipped with unequally thick magnetic poles is taken as the main object and its electromagnetic thermal coupling analytical model(ETc AM)is investigated.First,the electromagnetic analytical model(EAM)is studied based on the modified subdomain method.It realizes the fast calculation of key electromagnetic characteristics.Subsequently,the 3D thermal analytical model(TAM)is developed by combining the EAM,the lumped parameter thermal network method(LPTNM),and the partial differential equation of heat flux.It realizes the fast calculation of key thermal characteristics in 3D space.Further,the information transfer channel between EAM and TAM is built with reference to the intrinsic connection between electromagnetic field and temperature field.Thereby,the novel ETcAM is proposed to realize the fast and accurate prediction of electromagnetic and temperature fields.Besides,ETcAM has a lot to commend it.One is that it well accounts for the complex structure,saturation,and heat exchange behavior.Second,it saves a lot of computer resources.It offers boundless possibilities for initial design,scheme evaluation,and optimization of motors.Finally,the validity,accuracy,and practicality of this study are verified by simulation and experiment.展开更多
The energy preserving average vector field （AVF） method is applied to the coupled Schr6dinger-KdV equations. Two energy preserving schemes are constructed by using Fourier pseudospectral method in space direction di...The energy preserving average vector field （AVF） method is applied to the coupled Schr6dinger-KdV equations. Two energy preserving schemes are constructed by using Fourier pseudospectral method in space direction discretization. In order to accelerate our simulation, the split-step technique is used. The numerical experiments show that the non-splitting scheme and splitting scheme are both effective, and have excellent long time numerical behavior. The comparisons show that the splitting scheme is faster than the non-splitting scheme, but it is not as good as the non-splitting scheme in preserving the invariants.展开更多
An analytical method, using sector field inductively coupled plasma mass spectrometry （SF-ICP-MS） for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in e...An analytical method, using sector field inductively coupled plasma mass spectrometry （SF-ICP-MS） for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in electrolytic manganese metal, was described. At the beginning, the samples were decomposed by HNO3 and H2504, and then analyzed by SF-ICP-MS. Most of the spectral interferences could be avoided by measuring in different mass resolution modes. The matrix effects due to the excess of sulfuric acid and Mn were evaluated. Correction of matrix effects was conducted by using the internal standard elements. The optimum condition for the determination was investigated and discussed. The detection limit is in the range of 0.001-0.169 gg/L. The current method is applied to the determination of trace impurities in electrolytic manganese metal. And experiments show that good results can be obtained much faster, more accurately and conveniently by current method.展开更多
To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dime...To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.展开更多
Semiconductor-based electronic devices usually work under multiphysics fields rendering complex electromagnetic-thermo-mechanical coupling.In this work,we develop a penalty function method based on a finite element an...Semiconductor-based electronic devices usually work under multiphysics fields rendering complex electromagnetic-thermo-mechanical coupling.In this work,we develop a penalty function method based on a finite element analysis to tackle this coupling behavior in a metal/semiconductor bilayer plate-the representative unit of semiconductor antenna,which receives strong and pulsed electromagnetic signals.Under these pulses,eddy current is generated,of which the magnitude varies remarkably from one plate to another due to the difference in electrical conductivity.In the concerned system,the metal layer generates much larger current,resulting in the large temperature rise and the nonnegligible Lorentz force,which could lead to delamination and failure of the semiconductor-based electronic device.This study provides theoretical guidance for the design and protection of semiconductor-based electronic devices in complex environments.展开更多
A simple and efficient coupled displacement field method is developed to study the large amplitude free vibration behavior of the moderately thick square plates.A single term trigonometric admissible displacement fiel...A simple and efficient coupled displacement field method is developed to study the large amplitude free vibration behavior of the moderately thick square plates.A single term trigonometric admissible displacement field is assumed for one of the variables,say,the total rotations(in both X,Y directions).Making use of the coupling equation,the spatial variation for the lateral displacement field is derived in terms of the total rotations.The coupled displacement field method makes the energy formulation to contain half the number of unknown independent coefficients,in the case of a square plate,contrary to the conventional RayleighRitz method.The lesser number of undetermined coefficients significantly simplifies the vibration problem.The expressions for the linear and nonlinear fundamental frequency parameters for the all edges simply supported moderately thick square plates are derived.The numerical results obtained from the present formulation are in very good agreement with those obtained from the existing literature.展开更多
基金supported by the National Key R&D Program of China (2021YFB3501202,2021YFB3501204,2019YFA0704900,2020YFA0711500,2023YFA1406003,2022YFB3505201)the National Natural Science Foundation of China (52088101,U23A20550,92263202,22361132534)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB33030200)。
文摘This study presents an experimental investigation of the coupled caloric effect driven by dual-fields in metamagnetic alloy ErCo_(2) with strong magneto-structural coupling.Magnetic measurements were conducted under different pressures,revealing that the application of hydrostatic pressure stabilizes a small volume of paramagnetism(PM) phase,resulting in a shift of the phase transition temperature towards the low-temperature region.This shift is opposite to the temperature associated with the magnetic field-driven phase transition.As pressure increases,the metamagnetic transition in ErCo_(2) is suppressed,and the hysteresis disappears.However,the produced cross-coupling caloric effect compensates the decrease in entropy change caused by the disappearance of the metamagnetic transition.As a result,a reversible giant magnetocaloric effect of 46.2 J/(kg·K) without hysteresis is achieved at a pressure of 0.910 GPa.Moreover,we propose that the temperature span of ErCo_(2) can be significantly widened by optimizing the thermodynamic pathway of the magnetic and pressure fields,overcoming the defect of a narrow temperature range.
基金Supported by the National Natural Science Foundation of China(51679080 and 51379073)the Fundamental Research Funds for the Central Universities(B230205020).
文摘This study employed a computational fluid dynamics model with an overset mesh technique to investigate the thrust and power of a floating offshore wind turbine(FOWT)under platform floating motion in the wind–rain field.The impact of rainfall on aerodynamic performance was initially examined using a stationary turbine model in both wind and wind–rain conditions.Subsequently,the study compared the FOWT’s performance under various single degree-of-freedom(DOF)motions,including surge,pitch,heave,and yaw.Finally,the combined effects of wind–rain fields and platform motions involving two DOFs on the FOWT’s aerodynamics were analyzed and compared.The results demonstrate that rain negatively impacts the aerodynamic performance of both the stationary turbines and FOWTs.Pitch-dominated motions,whether involving single or multiple DOFs,caused significant fluctuations in the FOWT aerodynamics.The combination of surge and pitch motions created the most challenging operational environment for the FOWT in all tested scenarios.These findings highlighted the need for stronger construction materials and greater ultimate bearing capacity for FOWTs,as well as the importance of optimizing designs to mitigate excessive pitch and surge.
基金supported by the Natural Science Foundation of Sichuan Province,China(Youth Science Foundation)(Grant No.2022NSFSC1952).
文摘The collective dynamic of a fractional-order globally coupled system with time delays and fluctuating frequency is investigated.The power-law memory of the system is characterized using the Caputo fractional derivative operator.Additionally,time delays in the potential field force and coupling force transmission are both considered.Firstly,based on the delay decoupling formula,combined with statistical mean method and the fractional-order Shapiro–Loginov formula,the“statistic synchronization”among particles is obtained,revealing the statistical equivalence between the mean field behavior of the system and the behavior of individual particles.Due to the existence of the coupling delay,the impact of the coupling force on synchronization exhibits non-monotonic,which is different from the previous monotonic effects.Then,two kinds of theoretical expression of output amplitude gains G and G are derived by time-delay decoupling formula and small delay approximation theorem,respectively.Compared to G,G is an exact theoretical solution,which means that G is not only more accurate in the region of small delay,but also applies to the region of large delay.Finally,the study of the output amplitude gain G and its resonance behavior are explored.Due to the presence of the potential field delay,a new resonance phenomenon termed“periodic resonance”is discovered,which arises from the periodic matching between the potential field delay and the driving frequency.This resonance phenomenon is analyzed qualitatively and quantitatively,uncovering undiscovered characteristics in previous studies.
基金supported by the National Natural Science Foundation of China(No.52476053,No.22409209)Beijing Natural Science Foundation(No.3242017)。
文摘All-solid-state lithium metal batteries represent leading candidates for the next generation of highenergy-density rechargeable batteries.However,the coupled mechanisms governing dendrite growth and crack propagation within solid-state electrolytes(SSEs)remain inadequately understood.To address this knowledge gap,we propose an electrochemical-mechanical coupled phase-field model designed to simulate the complex processes of lithium deposition and crack propagation in SSEs.This framework systematically examines the influence of initial defect characteristics—including morphology,dimensions,and fracture toughness—on dendrite penetration dynamics.Furthermore,it identifies potential initiation pathways for detrimental lithium deposition within the electrolyte bulk.The model also quantifies the critical role of electrolyte elastic modulus and grain boundary orientation in modulating deposition behavior.Notably,simulation results demonstrate concordance with existing experimental observations,thereby establishing a fundamental theoretical framework for understanding failure mechanisms.This work provides crucial mechanistic insights and predictive capabilities to guide the rational design of failure-resistant SSEs for all-solid-state lithium metal batteries.
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 10175029, 10375039, and 10647007, the Doctoral Education Fund of Ministry of Education, the Research Fund of Nuclear Theory Center of HIRFL of China, and the Science and Technology Foundation of Sichuan Province under Grant No. 02GY029-189
文摘When two identical QED cavities driven by the coherent fields are located in a uniform environment, in addition to dissipation, there appears an indirect coupling between the two cavities induced by the background fields. We investigate the effects of the coherent fields, the dissipation as well as the incoherent coupling on the following dynamical properties of the system： photon transfer, reversible decoherence, and quantum state transfer, etc. We find that the photons in the cavities do not leak completely into the environment due to the collective coupling between the cavities and the enviroment, and the photons are transferred irreversibly from the cavity with more photons to the cavity with less ones due to the incoherent coupling so that they are equally distributed among the two cavities. The coherent field pumping on the two cavities increases the mean photons, complements the revived magnitude of the reversible decoherence, but hinders the quantum state transfer between the two cavities. The above phenomena may find applications in quantum communication and other basic fields.
基金support from the National Natural Science Foundation of China(Grant Nos.11520007,11572109 and 11632005)the Hebei Natural Science Foundation of China(Grant No.A2016201198)technology research in Colleges and Universities of Hebei Province(Grant No.ZD2017006)are gratefully acknowledged。
文摘Phase transition of hydrogel,which is polymerized by polymer network,can be regarded as the transition of polymer network stability.The stability of the polymer network might be changed when the external environment changed.This change will lead to the transformation of sensitive hydrogels stability,thus phase transition of hydrogel take place.Here,we present a new free density energy function,which considers the non-gaussianity of the polymer network,chains entanglement and functionality of junctions through adding Gent hyplastic model and Edwards-Vilgis slip-link model to Flory-Huggins theory.A program to calculate the phase transition temperature was written based on new free energy function.Taking PNIPAM hydrogel as an example,the effects of network entanglement on the phase transition temperature of hydrogel were studied by analyzing the microstructure parameters of the hydrogel networks.Analytical results suggest a significant relationship between phase transition temperature and entanglement network.
文摘This paper gives a numerical study on the flow and temperature fields in an induced plasma reactor, which worked in 0.5 ATM with air as a working gas. We employed a two-dimensional mode of an inductively coupled plasma to calculate the temperature and flow field of the reactor as well as the generator. The algorithm is based on the solutions of the two-dimensional continuity, momentum, and energy equations in term of vorticity, stream function and enthalpy. An upwind finite-difference scheme was adopted to solve those equations with appropriate boundary conditions. The computed results show that there is a flat region with little parameter change in the reactor, that the diameter of the region is not much larger than that of the generator and that a deep change of parameter exists in the outer side of the region.
文摘The two-dimensional elliptical inclusion problems in infinite anisotropic magnetoelectro-elastic solids are considered. Based on the extended Stroh formalism, the technique of conformal mapping and the concept of perturbation, the magneta-electro-elastic fields in both the matrix: and the inclusion are obtained explicitly. The results are of very importance for studying the effective properties of piezoelectric-piezomagnetic composite materials.
基金National Natural Science Foundation of China under Grant Nos.10475055 and 90503006the Scientific Research Fund of the Education Department of Zhejiang Province under Grant No.20040969
文摘Some extended solution mapping relations of the nonlinear coupled scalar field and the well-known φ^4 model are presented. Simultaneously, inspired by the new solutions of the famous φ^4 model recently proposed by Jia, Huang and Lou, five kinds of new localized excitations of the nonlinear coupled scaiar field （NCSF） system are obtained.
文摘Magnetohydrodynamic(MHD)induction pumps are contactless pumps able to withstand harsh environments.The rate of fluid flow through the pump directly affects the efficiency and stability of the device.To explore the influence of induction pump settings on the related delivery speed,in this study,a numerical model for coupled electromagnetic and flow field effects is introduced and used to simulate liquid metal lithium flow in the induction pump.The effects of current intensity,frequency,coil turns and coil winding size on the velocity of the working fluid are analyzed.It is shown that the first three parameters have a significant impact,while changes in the coil turns have a negligible influence.The maximum increase in working fluid velocity within the pump for the parameter combination investigated in this paper is approximately 618%.As the frequency is increased from 20 to 60 Hz,the maximum increase in the mean flow rate of the working fluid is approximately 241%.These research findings are intended to support the design and optimization of these devices.
基金supported in part by Zhejiang Provincial Natural Science Foundation of China under Grant LY21E070002 and LY17E070002。
文摘Electrically-excited flux-switching machines are advantageous in simple and reliable structure,good speed control performance,low cost,etc.,so they have arouse wide concerns from new energy field.However,they have much lower torque density/thrust density compared with the same type PM machines.To overcome this challenge,electromagnetic-thermal coupled analysis is carried out with respect to water-cooled electrically-excited flux-switching linear machines(EEFSLM).The simulation results indicate that the conventional fixed copper loss method(FCLM)is no longer suitable for high thrust density design,since it is unable to consider the strong coupling between the electromagnetic and thermal performance.Hence,a multi-step electromagnetic-thermal joint optimisation method is proposed,which first ensures the consistency between the electromagnetic and thermal modelling and then considers the effect of different field/armature coil sizes.By using the proposed joint optimisation method,it is found that the combination of relatively large size of field coil and relatively low field copper loss is favourable for achieving high thrust force for the current EEFSLM design.Moreover,the thrust force is raised by 13-15%compared with using the FCLM.The electromagnetic and thermal performance of the EEFSLM is validated by the prototype test.
文摘In this paper, the marine ship observation data sets in the seventh (October 16-December 4. 1989) and eighth (June 1-July 16, 1990) cruises of PRC -US tropical ocean and global atmosphere (TOGA) joint scientific investigation in the tropical western Pacific are used to analyze the elements such as sea surface temperature (SST), surface wind field, fluxes and net heat budget, which are important physical parameters of underlying earth's surface influencing the global mean circulation evolution on seasonal and interannual time scales. These diagnostic analyses are very beneficial to the understanding of the regional climate characteristics and the air-sea interaction mechanism, and the improving of surface flux parameterizations and regional or global climate model.
基金the National High Technical Reasearch and Development Programme of China （No. 2003AA327140） the National Natural Science Foundation of China （No. 50374081）.
文摘Two full 3D steady mathematical models are developed by finite element method （FEM） to calcalate coupled physics fields. the electro-magnetic model is built and solved first and so is the fluid motion model with the acquired electromagnetic force as source body forces in Navier-Stokes equations. Effects caused by the ferromagnetic shell, busbar system around, and open boundary problem as well as inside induced current were considered in terms of the magnetic field. Furthermore, a new modeling method is found to set up solid models and then mesh them entirely with so-called structuralized grids, namely hex-mesh. Examples of 75kA prebaked cell with two kinds of busbar arrangements are presented. Results agree with those disclosed in the literature and confirm that the coupled simulation is valid. It is also concluded that the usage of these models facilitates the consistent analysis of the electric field to magnetic field and then flow motion to the greater extent, local distributions of current density and magnetic flux density are very much dependent on the cell structure, the steel shell is a shield to reduce the magnetic field and flow pattern is two dimensional in the main body of the metal pad.
基金financially supported by National Natural Science Foundation of China(51601011,51874023,U1860206)Fundamental Research Funds for the Central UniversitiesRecruitment Program of Global Experts。
文摘Cylindrical Al-Zn-Mg alloys were processed by electroplastic compression with forced air cooling.Compared to a simple compression process,an unequal intensity of {110} <111> was obtained,and other textures were eliminated by electroplastic compression,that is,electroplastic compression can promote a uniform texture.The various textures formed in different regions along the radial direction under a simple compression process were illuminated by analyzing the relationship between the crystal rotation and stress state.Furthermore,the interaction between the electrons and dislocations was studied in electroplastic compression.The electrons enhanced {110} <111> by promoting slipping of the dislocations when the Burgers vectors of the dislocations were parallel to the drift direction of the electrons.However,the electrons also inhibited crystal rotation by pinning the dislocations with the Burgers vectors perpendicular to the drift direction of the electrons.Therefore,textures other than {110} <111>have difficulty forming under electroplastic compression.The effect of the current energy on the texture(enhancement or attenuation) was in accordance with the law of conservation.The results provided reasonable explanations for the test phenomena.
基金supported by the Project of National Natural Science Foundation of China under Grant 52077122。
文摘With the continuous upgrading of traditional manufacturing industries and the rapid rise of emerging technology fields,the performance requirements for the permanent magnet synchronous motors(PMSMs)have become higher and higher.The importance of fast and accurate electromagnetic thermal coupling analysis of such motors becomes more and more prominent.In view of this,the surfacemounted PMSM(SPMSM)equipped with unequally thick magnetic poles is taken as the main object and its electromagnetic thermal coupling analytical model(ETc AM)is investigated.First,the electromagnetic analytical model(EAM)is studied based on the modified subdomain method.It realizes the fast calculation of key electromagnetic characteristics.Subsequently,the 3D thermal analytical model(TAM)is developed by combining the EAM,the lumped parameter thermal network method(LPTNM),and the partial differential equation of heat flux.It realizes the fast calculation of key thermal characteristics in 3D space.Further,the information transfer channel between EAM and TAM is built with reference to the intrinsic connection between electromagnetic field and temperature field.Thereby,the novel ETcAM is proposed to realize the fast and accurate prediction of electromagnetic and temperature fields.Besides,ETcAM has a lot to commend it.One is that it well accounts for the complex structure,saturation,and heat exchange behavior.Second,it saves a lot of computer resources.It offers boundless possibilities for initial design,scheme evaluation,and optimization of motors.Finally,the validity,accuracy,and practicality of this study are verified by simulation and experiment.
基金supported by the National Natural Science Foundation of China(Grant No.91130013)the Open Foundation of State Key Laboratory of HighPerformance Computing of China
文摘The energy preserving average vector field （AVF） method is applied to the coupled Schr6dinger-KdV equations. Two energy preserving schemes are constructed by using Fourier pseudospectral method in space direction discretization. In order to accelerate our simulation, the split-step technique is used. The numerical experiments show that the non-splitting scheme and splitting scheme are both effective, and have excellent long time numerical behavior. The comparisons show that the splitting scheme is faster than the non-splitting scheme, but it is not as good as the non-splitting scheme in preserving the invariants.
基金Project(21075138)supported by the National Natural Science Foundation of ChinaProject(cstc2013jcyjA10088)supported by Chongqing Natural Science Foundation,ChinaProject(KJ121311)supported by Scientific and Technological Research Program of Chongqing Municipal Education Commission,China
文摘An analytical method, using sector field inductively coupled plasma mass spectrometry （SF-ICP-MS） for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in electrolytic manganese metal, was described. At the beginning, the samples were decomposed by HNO3 and H2504, and then analyzed by SF-ICP-MS. Most of the spectral interferences could be avoided by measuring in different mass resolution modes. The matrix effects due to the excess of sulfuric acid and Mn were evaluated. Correction of matrix effects was conducted by using the internal standard elements. The optimum condition for the determination was investigated and discussed. The detection limit is in the range of 0.001-0.169 gg/L. The current method is applied to the determination of trace impurities in electrolytic manganese metal. And experiments show that good results can be obtained much faster, more accurately and conveniently by current method.
文摘To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.
基金the National Natural Science Foundation of China(Grant nos.11772294,11621062)the Fundamental Research Funds for the Central Universities(Grant no.2017QNA4031).
文摘Semiconductor-based electronic devices usually work under multiphysics fields rendering complex electromagnetic-thermo-mechanical coupling.In this work,we develop a penalty function method based on a finite element analysis to tackle this coupling behavior in a metal/semiconductor bilayer plate-the representative unit of semiconductor antenna,which receives strong and pulsed electromagnetic signals.Under these pulses,eddy current is generated,of which the magnitude varies remarkably from one plate to another due to the difference in electrical conductivity.In the concerned system,the metal layer generates much larger current,resulting in the large temperature rise and the nonnegligible Lorentz force,which could lead to delamination and failure of the semiconductor-based electronic device.This study provides theoretical guidance for the design and protection of semiconductor-based electronic devices in complex environments.
基金JNTU-Kakinada for sponsoring the necessary economical support for presenting the paper under TEQIP2the support given by Mallareddy college of engineering and Indian national academy of engineering
文摘A simple and efficient coupled displacement field method is developed to study the large amplitude free vibration behavior of the moderately thick square plates.A single term trigonometric admissible displacement field is assumed for one of the variables,say,the total rotations(in both X,Y directions).Making use of the coupling equation,the spatial variation for the lateral displacement field is derived in terms of the total rotations.The coupled displacement field method makes the energy formulation to contain half the number of unknown independent coefficients,in the case of a square plate,contrary to the conventional RayleighRitz method.The lesser number of undetermined coefficients significantly simplifies the vibration problem.The expressions for the linear and nonlinear fundamental frequency parameters for the all edges simply supported moderately thick square plates are derived.The numerical results obtained from the present formulation are in very good agreement with those obtained from the existing literature.
