The axial field hybrid permanent magnet memory machine(AFHPM-MM)employs a hybrid permanent magnet excitation combining NdFeB and AlNiCo,achieving high torque density and a wide flux adjustment range.A separated stator...The axial field hybrid permanent magnet memory machine(AFHPM-MM)employs a hybrid permanent magnet excitation combining NdFeB and AlNiCo,achieving high torque density and a wide flux adjustment range.A separated stator structure is adopted to enhance its antidemagnetization capability.To analyze the contributions of AlNiCo and NdFeB to the induced electromotive force(EMF)in the AFHPM-MM,a frozen permeability-based induced EMF calculation method is proposed.Theoretical analysis reveals that the conventional method exhibits substantial errors in calculating the AlNiCo-induced EMF,primarily attributed to its failure to adequately account for the dynamic magnetization characteristic discrepancies of AlNiCo under varying magnetization states.Through the analysis of magnetization variations in AlNiCo during the flux adjustment process under different magnetization states,an improved induced EMF calculation method is proposed.Comparative results indicate that,during the flux enhancement process,the average calculation error of the AlNiCo-induced EMF is reduced from 19.84%to 2.09%,whereas during the flux weakening process,the error is reduced from 3.87%to 1.67%.The proposed method achieves accurate induced EMF calculation for the AFHPM-MM.展开更多
The energy term corresponding to the first order of the strain in Taylor series expansion of the energy with respect to strain is always ignored when high-pressure elastic constants are calculated. Whether the modus o...The energy term corresponding to the first order of the strain in Taylor series expansion of the energy with respect to strain is always ignored when high-pressure elastic constants are calculated. Whether the modus operandi would affect the results of the high-pressure elastic constants is still unsolved. To clarify this query, we calculate the high-pressure elastic constants of tantalum and rhenium when the energy term mentioned above is considered and neglected, respectively.Results show that the neglect of the energy term corresponding to the first order of the strain indeed would influence the veracity of the high-pressure elastic constants, and this influence becomes larger with pressure increasing. Therefore, the energy term corresponding to the first-order of the strain should be considered when the high-pressure elastic constants are calculated.展开更多
Viscosity of natural gas is a basic and important parameter,of theoretical and practical significance in the domain of natural gas recovery,transmission and processing.In order to obtain the accurate viscosity data ef...Viscosity of natural gas is a basic and important parameter,of theoretical and practical significance in the domain of natural gas recovery,transmission and processing.In order to obtain the accurate viscosity data efficiently at a low cost,a new model and its corresponding functional relation are derived on the basis of the relationship among viscosity,temperature and density derived from the kinetic theory of gases.After the model parameters were optimized using a lot of experimental data,the diagram showing the variation of viscosity along with temperature and density is prepared,showing that:①the gas viscosity increases with the increase of density as well as the increase of temperature in the low density region;②the gas viscosity increases with the decrease of temperature in high density region.With this new model,the viscosity of 9 natural gas samples was calculated precisely.The average relative deviation between these calculated values and 1539 experimental data measured at 250e450 K and 0.10e140.0 MPa is less than 1.9%.Compared with the 793 experimental data with a measurement error less than 0.5%,the maximum relative deviation is less than 0.98%.It is concluded that this new model is more advantageous than the previous 8 models in terms of simplicity,accuracy,fast calculation,and direct applicability to the CO_(2) bearing gas samples.展开更多
The accurate dissociation energy and equilibrium geometry of the ball state of ^7LiH molecule is calculated using a symmetry-adapted-cluster configuration-interaction method in full active space. And the calculated re...The accurate dissociation energy and equilibrium geometry of the ball state of ^7LiH molecule is calculated using a symmetry-adapted-cluster configuration-interaction method in full active space. And the calculated results are 0.2580 eV and 0.1958 nm for the dissociation energy and equilibrium geometry, respectively. The whole potential energy curve for the b^3∏ state is also calculated over the internuclear separation range from about 0.10 to 0.54 nm. The results are fitted by the Murrell-Sorbie function. It is found that the Murrell-Sorbie function form, which is mainly used to fit the ground-state potential energy function, is well suitable for the excited triplet b^3∏ state. The vertical excitation energy from the ground state to the b^3∏ state is calculated to be 4.233 eV. Based on the analytic potential energy function, the harmonic frequency of 610.88 cm^-1 about this state is firstly estimated. Compared with other theoretical results, this work is the most complete effort to deal with the analytic potential energy function and the harmonic frequency of this state.展开更多
Materials science is currently at the forefront of technological development,which enables remarkable advancements in various aspects of our society.For the past few decades,multiscale computational simulations rangin...Materials science is currently at the forefront of technological development,which enables remarkable advancements in various aspects of our society.For the past few decades,multiscale computational simulations ranging from accurate first principles calculation and atomistic molecular dynamics to mesoscopic and macroscopic continuum models have been essential tools for understanding,predicting,and ultimately designing materials with desired properties.展开更多
基金The National Natural Science Foundation of China(No.52107039)the Fujian Provincial Natural Science Foundation for Youth(No.2021J05133)the Key Project of the National Natural Science Foundation of China(No.51937002)。
文摘The axial field hybrid permanent magnet memory machine(AFHPM-MM)employs a hybrid permanent magnet excitation combining NdFeB and AlNiCo,achieving high torque density and a wide flux adjustment range.A separated stator structure is adopted to enhance its antidemagnetization capability.To analyze the contributions of AlNiCo and NdFeB to the induced electromotive force(EMF)in the AFHPM-MM,a frozen permeability-based induced EMF calculation method is proposed.Theoretical analysis reveals that the conventional method exhibits substantial errors in calculating the AlNiCo-induced EMF,primarily attributed to its failure to adequately account for the dynamic magnetization characteristic discrepancies of AlNiCo under varying magnetization states.Through the analysis of magnetization variations in AlNiCo during the flux adjustment process under different magnetization states,an improved induced EMF calculation method is proposed.Comparative results indicate that,during the flux enhancement process,the average calculation error of the AlNiCo-induced EMF is reduced from 19.84%to 2.09%,whereas during the flux weakening process,the error is reduced from 3.87%to 1.67%.The proposed method achieves accurate induced EMF calculation for the AFHPM-MM.
基金supported by the National Natural Science Foundation of China(Grant No.11274235)the Young Scientist Fund of the National Natural Science Foundation of China(Grant No.11104190)the Doctoral Education Fund of Education Ministry of China(Grant Nos.20100181110086 and 20110181120112)
文摘The energy term corresponding to the first order of the strain in Taylor series expansion of the energy with respect to strain is always ignored when high-pressure elastic constants are calculated. Whether the modus operandi would affect the results of the high-pressure elastic constants is still unsolved. To clarify this query, we calculate the high-pressure elastic constants of tantalum and rhenium when the energy term mentioned above is considered and neglected, respectively.Results show that the neglect of the energy term corresponding to the first order of the strain indeed would influence the veracity of the high-pressure elastic constants, and this influence becomes larger with pressure increasing. Therefore, the energy term corresponding to the first-order of the strain should be considered when the high-pressure elastic constants are calculated.
文摘Viscosity of natural gas is a basic and important parameter,of theoretical and practical significance in the domain of natural gas recovery,transmission and processing.In order to obtain the accurate viscosity data efficiently at a low cost,a new model and its corresponding functional relation are derived on the basis of the relationship among viscosity,temperature and density derived from the kinetic theory of gases.After the model parameters were optimized using a lot of experimental data,the diagram showing the variation of viscosity along with temperature and density is prepared,showing that:①the gas viscosity increases with the increase of density as well as the increase of temperature in the low density region;②the gas viscosity increases with the decrease of temperature in high density region.With this new model,the viscosity of 9 natural gas samples was calculated precisely.The average relative deviation between these calculated values and 1539 experimental data measured at 250e450 K and 0.10e140.0 MPa is less than 1.9%.Compared with the 793 experimental data with a measurement error less than 0.5%,the maximum relative deviation is less than 0.98%.It is concluded that this new model is more advantageous than the previous 8 models in terms of simplicity,accuracy,fast calculation,and direct applicability to the CO_(2) bearing gas samples.
基金This work was supported by the National Natural Science Foundation of China (No. 10574039)Henan Innovation Fund for University Prominent Research Talents (No. 2006KYCX002).
文摘The accurate dissociation energy and equilibrium geometry of the ball state of ^7LiH molecule is calculated using a symmetry-adapted-cluster configuration-interaction method in full active space. And the calculated results are 0.2580 eV and 0.1958 nm for the dissociation energy and equilibrium geometry, respectively. The whole potential energy curve for the b^3∏ state is also calculated over the internuclear separation range from about 0.10 to 0.54 nm. The results are fitted by the Murrell-Sorbie function. It is found that the Murrell-Sorbie function form, which is mainly used to fit the ground-state potential energy function, is well suitable for the excited triplet b^3∏ state. The vertical excitation energy from the ground state to the b^3∏ state is calculated to be 4.233 eV. Based on the analytic potential energy function, the harmonic frequency of 610.88 cm^-1 about this state is firstly estimated. Compared with other theoretical results, this work is the most complete effort to deal with the analytic potential energy function and the harmonic frequency of this state.
文摘Materials science is currently at the forefront of technological development,which enables remarkable advancements in various aspects of our society.For the past few decades,multiscale computational simulations ranging from accurate first principles calculation and atomistic molecular dynamics to mesoscopic and macroscopic continuum models have been essential tools for understanding,predicting,and ultimately designing materials with desired properties.
