In this paper, a multi-physics simulation model capable of electromagnetic noise prediction is established, and the effectiveness of the established simulation model in predicting and evaluating electromagnetic noise ...In this paper, a multi-physics simulation model capable of electromagnetic noise prediction is established, and the effectiveness of the established simulation model in predicting and evaluating electromagnetic noise is verified. Based on the verified motor model, a rotor step skewing model which can affect electromagnetic noise is proposed, and the influence of the skewing angle on electromagnetic noise is investigated in detail. By studying the spectral characteristics of the low-order radial magnetic force which has a great influence on electromagnetic noise, the distribution of electromagnetic noise characteristics of the permanent magnet synchronous motor(PMSM) with or without the rotor step skewing is compared and analyzed. Therefore, it lays a technological foundation for predicting and suppressing the electromagnetic vibration noise of electric vehicle(EV) driving motor in the electromagnetic design.展开更多
A preliminary study was conducted to outline the laser Raman spectroscopy technique for determination of salinity in the aqueous phase in fluid inclusions. The skewing parameters of the Raman profiles of the calibrat...A preliminary study was conducted to outline the laser Raman spectroscopy technique for determination of salinity in the aqueous phase in fluid inclusions. The skewing parameters of the Raman profiles of the calibration solutions determined were used to derive a calibration curve for the estimation of the equivalent mass fraction NaCl in aqueous solutions. This technique was also verified in the analysis of the natural fluid inclusions from Tongshankou porphyry Cu (Mo) deposit, Hubei Province, China. Although the analyses on the natural fluid inclusions are limited, an acceptable agreement has been reached on the salinities, for most fluid inclusions, determined by the Raman spectroscopy and microthermometry techniques, indicating the reliability of the Raman technique for determination of salinity in fluid inclusion studies.展开更多
When the wing of Oblique Wing Aircraft(OWA) is skewed, the center of gravity, inertia and aerodynamic characteristics of the aircraft all significantly change, causing an undesirable flight dynamic response, affecting...When the wing of Oblique Wing Aircraft(OWA) is skewed, the center of gravity, inertia and aerodynamic characteristics of the aircraft all significantly change, causing an undesirable flight dynamic response, affecting the flying qualities, and even endangering the flight safety. In this study,the dynamic response of an OWA in the wing skewing process is simulated, showing that the threeaxis movements of the OWA are highly coupled and present nonlinear characteristics during the wing skewing. As the roll control efficiency of the aileron decreases due to the shortened control arm in an oblique configuration, the all-moving horizontal tail is used for additional roll and the control allocation is performed based on minimum control energy. Given the properties of pitchroll-yaw coupling and control input and state coupling, and the difficulty of establishing an accurate aerodynamic model in the wing skewing process due to unsteady aerodynamic force, a multi-loop sliding mode controller is formulated by the time-scale separation method. The closed-loop simulation results show that the asymmetric aerodynamics can be balanced and that the velocity and altitude of the aircraft maintain stable, which means that a smooth transition is obtained during the OWA's wing skewing.展开更多
In this paper, an equation for the calculation of the frictional torque of a dry-lubricated tapered roller bearing(TRB) is provided in which the effect of the roller skewing is emphasized. Calculations were performed ...In this paper, an equation for the calculation of the frictional torque of a dry-lubricated tapered roller bearing(TRB) is provided in which the effect of the roller skewing is emphasized. Calculations were performed to investigate the effect of the roller skewing on the torque of dry-lubricated TRB for two representative preload methods, that is, axial force preload and axial displacement preload. The results show that a proper roller skewing angle under axial force preload benefits the reduction of the TRB torque. However, the roller skewing angle should not exceed a certain critical value;otherwise, it will cause a steep rise in the TRB torque. Finally, the critical value of the roller skewing angle as a function of the friction coefficient and cage pocket clearance is presented. The developed torque model provides a tool for the internal design and torque optimization of dry-lubricated TRBs.展开更多
AGC protein kinases play important roles in plant growth and development.Several AGC kinases in Arabidopsis have been functionally characterized.However,the"AGC Other"subfamily,including IRE,IREH1,IRE3 and I...AGC protein kinases play important roles in plant growth and development.Several AGC kinases in Arabidopsis have been functionally characterized.However,the"AGC Other"subfamily,including IRE,IREH1,IRE3 and IRE4,has not been well understood.Here,we reported that ireh1 mutants displayed a root skewing phenotype,which can be enhanced by ire3 mutation.IREH1 and IRE3 were expressed in roots,consistent with their function in controlling root skewing.The fluorescence intensities of the microtubule marker KNpro:EGFP-MBD were decreased in ireh1,ire3 and ireh1 ire3 mutants compared to wild type.The microtubule arrangements in ireh1 and ireh1 ire3 mutants were also altered.IREH1 physically interacted with IRE3 in vitro and in planta.Thus,our findings demonstrate that IREH1 and IRE3 protein kinases play important roles in controlling root skewing,and maintaining microtubule network in Arabidopsis.展开更多
An improved hybrid method combining two dimensional(2D)finite element analysis(FEA)and the analytical method is put forward to calculate the stator winding inductance and synchronous inductance influenced by stator sk...An improved hybrid method combining two dimensional(2D)finite element analysis(FEA)and the analytical method is put forward to calculate the stator winding inductance and synchronous inductance influenced by stator skewing technique.Based on winding function theory(WFT),the improved method proposes two factors to describe variable inductances along the stator skewing angles.Comprehensive simulations are then performed on three interior permanent magnet synchronous machines(IPMSMs),one normal and two skewed machines(half slot and one slot pitch skewing respectively).Extensive experiments are conducted on relevant prototypes with good correlation.Moreover,analysis and comparisons are made as to the influence of different skewing angles on the inductances and torque-speed curves.It is found that Ld increases and Lq decreases by skewing,leading to the reduction of the rotor saliency and maximal torque capability,but increase of the flux weakening capability.展开更多
Double Sided Linear Synchronous Reluctance Motors(DSL-SynRM)are being increasingly used in high force density applications.The force ripples are one of the major issue in machine which is due to nonlinear nature of cu...Double Sided Linear Synchronous Reluctance Motors(DSL-SynRM)are being increasingly used in high force density applications.The force ripples are one of the major issue in machine which is due to nonlinear nature of current in the machines.This paper focuses on the reduction of force ripples for increasing the force density of the motor.In order to reduce the force ripples,DSL-SynRM with a skewed translator is proposed.The proposed structure is designed and developed by using computational magnetic tools.This concept is effective for reduction of the force ripples and improves the force density of the machine.The proposed design has been reduced the percentage of force ripples by 21.62%,improved the force density by 10.32 N/mm³and efficiency by 0.89%.展开更多
A significant negative aspect in the operation of bridge-type cranes are the technical problems associated with wear of the wheels and the crane track,which causes crane skewing.The main causes of crane skewing includ...A significant negative aspect in the operation of bridge-type cranes are the technical problems associated with wear of the wheels and the crane track,which causes crane skewing.The main causes of crane skewing include unevenness of the crane track,unequal loading of the traction drives depending on the position of the crane trolley,slips and different sizes of travel wheels and combinations of these causes.Firstly,this paper presents a design solution that can be used to detect the magnitude of mechanical stress and deformation of the steel structure of the crane,caused by the effects of skewing.The mechanical stress generated by the transverse forces of the deformed geometric shape of the crane bridge structure is recorded by mechanical stress detectors installed in the inner corners of the crane bridge.The resulting electrical signal from element mechanical voltage detectors,loaded by axial forces,can be used for feedback control of separate crane travel drives controlled by frequency converters.Secondly,this paper presents the calculation of the lateral transverse forces according to CSN 270103 and the determination of the values of mechanical stresses of the deformed steel structure of the crane bridge of a two-girder bridge crane using the finite element method in the program MSC.MARC 2019.Finally,this paper presents the structural and strength design of mechanical stress detectors and the conclusions of laboratory tests of axial force loading of mechanical stress detectors on the test equipment.At the same time,it presents records of the measured axial forces acting in the mechanical stress detectors,arising from the deformation and warping of the crane bridge by the known magnitude of the axial force acting on the crossbeam and from the deformation of the crane bridge caused by the crane operating modes.展开更多
In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet s...In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet shape optimization was used first to improve the torque characteristics using two-dimensional finite element analysis（FEA） in a permanent magnet synchronous generator with a common stator. The rotor step skewing technique was then employed to suppress the impacts of mechanical tolerances and defects, which further improved the torque quality of the machine. Comprehensive three-dimensional FEA was used to evaluate accurately the overall effects of stator radial ventilating air ducts and rotor step skewing on torque features. The influences of the radial ventilating ducts in the stator on torque characteristics, such as torque pulsation and average torque in the machine with and without rotor step skewing techniques, were comprehensively investigated using three-dimensional FEA. The results showed that stator radial ventilating air ducts could not only reduce the average torque but also increase the torque ripple in the machine. Furthermore, the torque ripple of the machine under certain load conditions may even be increased by rotor step skewing despite a reduction in cogging torque.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51675324)
文摘In this paper, a multi-physics simulation model capable of electromagnetic noise prediction is established, and the effectiveness of the established simulation model in predicting and evaluating electromagnetic noise is verified. Based on the verified motor model, a rotor step skewing model which can affect electromagnetic noise is proposed, and the influence of the skewing angle on electromagnetic noise is investigated in detail. By studying the spectral characteristics of the low-order radial magnetic force which has a great influence on electromagnetic noise, the distribution of electromagnetic noise characteristics of the permanent magnet synchronous motor(PMSM) with or without the rotor step skewing is compared and analyzed. Therefore, it lays a technological foundation for predicting and suppressing the electromagnetic vibration noise of electric vehicle(EV) driving motor in the electromagnetic design.
文摘A preliminary study was conducted to outline the laser Raman spectroscopy technique for determination of salinity in the aqueous phase in fluid inclusions. The skewing parameters of the Raman profiles of the calibration solutions determined were used to derive a calibration curve for the estimation of the equivalent mass fraction NaCl in aqueous solutions. This technique was also verified in the analysis of the natural fluid inclusions from Tongshankou porphyry Cu (Mo) deposit, Hubei Province, China. Although the analyses on the natural fluid inclusions are limited, an acceptable agreement has been reached on the salinities, for most fluid inclusions, determined by the Raman spectroscopy and microthermometry techniques, indicating the reliability of the Raman technique for determination of salinity in fluid inclusion studies.
基金supported by the National Natural Science Foundation of China (No. 11402010)
文摘When the wing of Oblique Wing Aircraft(OWA) is skewed, the center of gravity, inertia and aerodynamic characteristics of the aircraft all significantly change, causing an undesirable flight dynamic response, affecting the flying qualities, and even endangering the flight safety. In this study,the dynamic response of an OWA in the wing skewing process is simulated, showing that the threeaxis movements of the OWA are highly coupled and present nonlinear characteristics during the wing skewing. As the roll control efficiency of the aileron decreases due to the shortened control arm in an oblique configuration, the all-moving horizontal tail is used for additional roll and the control allocation is performed based on minimum control energy. Given the properties of pitchroll-yaw coupling and control input and state coupling, and the difficulty of establishing an accurate aerodynamic model in the wing skewing process due to unsteady aerodynamic force, a multi-loop sliding mode controller is formulated by the time-scale separation method. The closed-loop simulation results show that the asymmetric aerodynamics can be balanced and that the velocity and altitude of the aircraft maintain stable, which means that a smooth transition is obtained during the OWA's wing skewing.
基金support of the National Natural Science Foundation of China (Nos. 51675120 and U1637206)
文摘In this paper, an equation for the calculation of the frictional torque of a dry-lubricated tapered roller bearing(TRB) is provided in which the effect of the roller skewing is emphasized. Calculations were performed to investigate the effect of the roller skewing on the torque of dry-lubricated TRB for two representative preload methods, that is, axial force preload and axial displacement preload. The results show that a proper roller skewing angle under axial force preload benefits the reduction of the TRB torque. However, the roller skewing angle should not exceed a certain critical value;otherwise, it will cause a steep rise in the TRB torque. Finally, the critical value of the roller skewing angle as a function of the friction coefficient and cage pocket clearance is presented. The developed torque model provides a tool for the internal design and torque optimization of dry-lubricated TRBs.
基金supported by the grants from the National Natural Science Foundation of China (31270330, 91217310, 91017008 and 31171389)the National Basic Research Program of China (2014CB943400)+2 种基金the National Key Research and Development Program of China (2016YFD0100402)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA0801010402)the One-Hundred Talent Project of the Chinese Academy of Sciences to Y.C
文摘AGC protein kinases play important roles in plant growth and development.Several AGC kinases in Arabidopsis have been functionally characterized.However,the"AGC Other"subfamily,including IRE,IREH1,IRE3 and IRE4,has not been well understood.Here,we reported that ireh1 mutants displayed a root skewing phenotype,which can be enhanced by ire3 mutation.IREH1 and IRE3 were expressed in roots,consistent with their function in controlling root skewing.The fluorescence intensities of the microtubule marker KNpro:EGFP-MBD were decreased in ireh1,ire3 and ireh1 ire3 mutants compared to wild type.The microtubule arrangements in ireh1 and ireh1 ire3 mutants were also altered.IREH1 physically interacted with IRE3 in vitro and in planta.Thus,our findings demonstrate that IREH1 and IRE3 protein kinases play important roles in controlling root skewing,and maintaining microtubule network in Arabidopsis.
基金National Natural Science Foundation of China under Grant 51520105010.
文摘An improved hybrid method combining two dimensional(2D)finite element analysis(FEA)and the analytical method is put forward to calculate the stator winding inductance and synchronous inductance influenced by stator skewing technique.Based on winding function theory(WFT),the improved method proposes two factors to describe variable inductances along the stator skewing angles.Comprehensive simulations are then performed on three interior permanent magnet synchronous machines(IPMSMs),one normal and two skewed machines(half slot and one slot pitch skewing respectively).Extensive experiments are conducted on relevant prototypes with good correlation.Moreover,analysis and comparisons are made as to the influence of different skewing angles on the inductances and torque-speed curves.It is found that Ld increases and Lq decreases by skewing,leading to the reduction of the rotor saliency and maximal torque capability,but increase of the flux weakening capability.
文摘Double Sided Linear Synchronous Reluctance Motors(DSL-SynRM)are being increasingly used in high force density applications.The force ripples are one of the major issue in machine which is due to nonlinear nature of current in the machines.This paper focuses on the reduction of force ripples for increasing the force density of the motor.In order to reduce the force ripples,DSL-SynRM with a skewed translator is proposed.The proposed structure is designed and developed by using computational magnetic tools.This concept is effective for reduction of the force ripples and improves the force density of the machine.The proposed design has been reduced the percentage of force ripples by 21.62%,improved the force density by 10.32 N/mm³and efficiency by 0.89%.
文摘A significant negative aspect in the operation of bridge-type cranes are the technical problems associated with wear of the wheels and the crane track,which causes crane skewing.The main causes of crane skewing include unevenness of the crane track,unequal loading of the traction drives depending on the position of the crane trolley,slips and different sizes of travel wheels and combinations of these causes.Firstly,this paper presents a design solution that can be used to detect the magnitude of mechanical stress and deformation of the steel structure of the crane,caused by the effects of skewing.The mechanical stress generated by the transverse forces of the deformed geometric shape of the crane bridge structure is recorded by mechanical stress detectors installed in the inner corners of the crane bridge.The resulting electrical signal from element mechanical voltage detectors,loaded by axial forces,can be used for feedback control of separate crane travel drives controlled by frequency converters.Secondly,this paper presents the calculation of the lateral transverse forces according to CSN 270103 and the determination of the values of mechanical stresses of the deformed steel structure of the crane bridge of a two-girder bridge crane using the finite element method in the program MSC.MARC 2019.Finally,this paper presents the structural and strength design of mechanical stress detectors and the conclusions of laboratory tests of axial force loading of mechanical stress detectors on the test equipment.At the same time,it presents records of the measured axial forces acting in the mechanical stress detectors,arising from the deformation and warping of the crane bridge by the known magnitude of the axial force acting on the crossbeam and from the deformation of the crane bridge caused by the crane operating modes.
基金Project supported by the National Natural Science Foundation of China（No.51377140） the National Basic Research Program（973）of China（No.2013CB035604）
文摘In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet shape optimization was used first to improve the torque characteristics using two-dimensional finite element analysis（FEA） in a permanent magnet synchronous generator with a common stator. The rotor step skewing technique was then employed to suppress the impacts of mechanical tolerances and defects, which further improved the torque quality of the machine. Comprehensive three-dimensional FEA was used to evaluate accurately the overall effects of stator radial ventilating air ducts and rotor step skewing on torque features. The influences of the radial ventilating ducts in the stator on torque characteristics, such as torque pulsation and average torque in the machine with and without rotor step skewing techniques, were comprehensively investigated using three-dimensional FEA. The results showed that stator radial ventilating air ducts could not only reduce the average torque but also increase the torque ripple in the machine. Furthermore, the torque ripple of the machine under certain load conditions may even be increased by rotor step skewing despite a reduction in cogging torque.
