Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing (CIP) was applied to fabricate...Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing (CIP) was applied to fabricate porous lithium sodium potassium niobate (Li0.06Na0.5K0.44) NbO3 specimens using a pore-forming method. The morphologies of the CIP-processed specimens were characterized and compared to those of specimens made by from conventional pressing procedures. The effects of the ceramic on the attachment and proliferation of osteoblasts isolated from the cranium of 1-day-old Sprague- Dawley rats were examined by a scanning electron microscopy (SEM) and metbylthiazol tetrazolium (MTT) assay. Results The results showed that CIP enhanced piezoelectricity and biological performance of the niobate specimen, and also promoted an extracellular matrix-like topography of it. In vitro studies showed that the CIP-enhanced material had positive effects on the attachment and proliferation of osteoblasts. Conclusion Niobate ceramic generated by CIP shows a promise for being a piezoelectric composite bone substitute.展开更多
This paper introduces the principle of space vector pulse width modulation (SVPWM), and discusses a method for implementing the SVPWM based on MATLAB/SIMULINK, as well as modeling of AC servo system with permanent m...This paper introduces the principle of space vector pulse width modulation (SVPWM), and discusses a method for implementing the SVPWM based on MATLAB/SIMULINK, as well as modeling of AC servo system with permanent magnet synchronous motor (PMSM). Simulation results show that the model is effective, and the method provides a frame of reference for software and hardware designs which can be applied in high temperature superconducting (HTS) flywheel energy storage system (FESS) and linear motor (LM).展开更多
In this paper, the design optimization of the structural parameters of multilayer conductors in high temperature superconducting (HTS) cable is reviewed. Various optimization methods, such as the particle swarm opti...In this paper, the design optimization of the structural parameters of multilayer conductors in high temperature superconducting (HTS) cable is reviewed. Various optimization methods, such as the particle swarm optimization (PSO), the genetic algorithm (GA), and a robust optimization method based on design for six sigma (DFSS), have been applied to realize uniform current distribution among the multilayer HTS conductors. The continuous and discrete variables, such as the winding angle, radius, and winding direction of each layer, are chosen as the design parameters. Under the constraints of the mechanical properties and critical current, PSO is proven to be a more powerful tool than GA for structural parameter optimization, and DFSS can not only achieve a uniform current distribution, but also improve significantly the reliability and robustness of the HTS cable quality.展开更多
In this paper,the giant magnetoresistance(GMR)multilayer sensor is fabricated with a Wheatstone bridge,and it exhibits excellent performance with a sensitivity of 2.8349 mV/(V/Oe)(1 Oe=79.5775 A·m^-1)and a satura...In this paper,the giant magnetoresistance(GMR)multilayer sensor is fabricated with a Wheatstone bridge,and it exhibits excellent performance with a sensitivity of 2.8349 mV/(V/Oe)(1 Oe=79.5775 A·m^-1)and a saturation field of 26 Oe along the sensitive axis.The GMR sensor is also characterized in a high magnetic field.The sensitivity decreases from 2.8349 mV/(V/Oe)at an angle of 0°to 0.0175 mV/(V/Oe)at an angle of 90°.Then,the sensor is placed in a series of rotating magnetic fields.We propose a model to express the output characteristics of the GMR multilayer sensor.The transfer curves of the sensor can be shown as two exactly symmetrical circles with an increasing radius when the magnetic field increases.The experimental results are consistent with the simulation results of the model.The advantage of this model is that it is simpler and more intuitive.展开更多
A permanent magnet linear synchronous motor (PMLSM) for a high temperature superconducting (HTS) maglev system has been studied, including the motor structure, control strategy, and analysis techniques. Finite ele...A permanent magnet linear synchronous motor (PMLSM) for a high temperature superconducting (HTS) maglev system has been studied, including the motor structure, control strategy, and analysis techniques. Finite element analysis (FEA) of magnetic field is conducted to accurately calculate major motor parameters. Equivalent electrical circuit is used to predict the drive's steady-state characteristics, and a phase variable model is applied to predict the dynamic performance. Preliminary experiment with a prototype has been made to verify the theoretical analysis and the HTS-PM synchronous driving technology.展开更多
Skyrmion, as a quasi-particle structure, has attracted much attention due to its potential applications in future spintronic devices. Artificial skyrmion structure has aroused great interest as it can be stabilized at...Skyrmion, as a quasi-particle structure, has attracted much attention due to its potential applications in future spintronic devices. Artificial skyrmion structure has aroused great interest as it can be stabilized at room temperature, without needing to incorporate materials with Dzyaloshinskii–Moriya interaction(DMI) into it. In this paper, it is found that the artificial skyrmion structure can be realized in CoCrPt/NiFe bilayers by micromagnetic simulations. The critical magnetic field of the core decreases as the diameter of the NiFe soft magnetic layer increases. The artificial skyrmion has excellent topological protection, and the critical magnetic field of plane is about 76 mT(760 Oe, 1 Oe = 79.5775 A·m-1). The external magnetic field plays a key role in determining the core diameter of the skyrmion, and the artificial skyrmion can be realized in CoCrPt/Cu/CoCrPt/NiFe four-layer with a diameter of 13 nm.展开更多
In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux densi...In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.展开更多
The limited treatment options for advanced prostate cancer(PCa)lead to the urgent need to discover new anticancer drugs.Mannose,an isomer of glucose,has been reported to have an anticancer effect on various tumors.How...The limited treatment options for advanced prostate cancer(PCa)lead to the urgent need to discover new anticancer drugs.Mannose,an isomer of glucose,has been reported to have an anticancer effect on various tumors.However,the anticancer effect of mannose in PCa remains unclear.In this study,we demonstrated that mannose inhibits the proliferation and promotes the apoptosis of PCa cells in vitro,and mannose was observed to have an anticancer effect in mice without harming their health.Accumulation of intracellular mannose simultaneously decreased the mitochondrial membrane potential,increased mitochondrial and cellular reactive oxygen species(ROS)levels,and reduced adenosine triphosphate(ATP)production in PCa cells.Mannose treatment of PCa cells induced changes in mitochondrial morphology,caused dysregulated expression of the fission protein,such as fission,mitochondrial 1(FIS1),and enhanced the expression of proapoptotic factors,such as BCL2-associated X(Bax)and BCL2-antagonist/killer 1(Bak).Furthermore,lower expression of mannose phosphate isomerase(MPI),the key enzyme in mannose metabolism,indicated poorer prognosis in PCa patients,and downregulation of MPI expression in PCa cells enhanced the anticancer effect of mannose.This study reveals the anticancer effect of mannose in PCa and its clinical significance in PCa patients.展开更多
The origin of a high mechanical quality in CuO-doped (K, Na)NbO3-based ceramics is addressed by considering the correlations between the lattice positions of Cu ions and the hardening effect in K0.48Na0.52+xNbO3-0....The origin of a high mechanical quality in CuO-doped (K, Na)NbO3-based ceramics is addressed by considering the correlations between the lattice positions of Cu ions and the hardening effect in K0.48Na0.52+xNbO3-0.01CuO ceramics. The Cu ions simultaneously occupy K/Na and Nb sites of these ceramics with x = 0 and 0.02, only occupy the K/Na site of the ceramics with x= -0.02, and mostly form a secondary phase of the ceramics with x = -0.05. The Cu ions lead to the hardening of ceramics with an increase of Ec and Qm by only occupying the K/Na site, together with the formation of double hysteresis loops in un-poled compositions. A defect model is proposed to illuminate the origin of a high Qm value, that is, the domain stabilization is dominated by the content of relatively mobile O2- ions in the ceramics, which has a weak bonding with CUK/Na defects.展开更多
基金supported by the National Natural Science Foundation of China (59972020)
文摘Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing (CIP) was applied to fabricate porous lithium sodium potassium niobate (Li0.06Na0.5K0.44) NbO3 specimens using a pore-forming method. The morphologies of the CIP-processed specimens were characterized and compared to those of specimens made by from conventional pressing procedures. The effects of the ceramic on the attachment and proliferation of osteoblasts isolated from the cranium of 1-day-old Sprague- Dawley rats were examined by a scanning electron microscopy (SEM) and metbylthiazol tetrazolium (MTT) assay. Results The results showed that CIP enhanced piezoelectricity and biological performance of the niobate specimen, and also promoted an extracellular matrix-like topography of it. In vitro studies showed that the CIP-enhanced material had positive effects on the attachment and proliferation of osteoblasts. Conclusion Niobate ceramic generated by CIP shows a promise for being a piezoelectric composite bone substitute.
基金This workis supported by the Chinese High Technology Development Plan Projectunder Grant No. 2007AA03Z208.
文摘This paper introduces the principle of space vector pulse width modulation (SVPWM), and discusses a method for implementing the SVPWM based on MATLAB/SIMULINK, as well as modeling of AC servo system with permanent magnet synchronous motor (PMSM). Simulation results show that the model is effective, and the method provides a frame of reference for software and hardware designs which can be applied in high temperature superconducting (HTS) flywheel energy storage system (FESS) and linear motor (LM).
文摘In this paper, the design optimization of the structural parameters of multilayer conductors in high temperature superconducting (HTS) cable is reviewed. Various optimization methods, such as the particle swarm optimization (PSO), the genetic algorithm (GA), and a robust optimization method based on design for six sigma (DFSS), have been applied to realize uniform current distribution among the multilayer HTS conductors. The continuous and discrete variables, such as the winding angle, radius, and winding direction of each layer, are chosen as the design parameters. Under the constraints of the mechanical properties and critical current, PSO is proven to be a more powerful tool than GA for structural parameter optimization, and DFSS can not only achieve a uniform current distribution, but also improve significantly the reliability and robustness of the HTS cable quality.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFF01010701)the Natural Science Foundation of Zhejiang Province,China(Grant No.LQ17F010004)the National Natural Science Foundation of China(Grant No.61741506)
文摘In this paper,the giant magnetoresistance(GMR)multilayer sensor is fabricated with a Wheatstone bridge,and it exhibits excellent performance with a sensitivity of 2.8349 mV/(V/Oe)(1 Oe=79.5775 A·m^-1)and a saturation field of 26 Oe along the sensitive axis.The GMR sensor is also characterized in a high magnetic field.The sensitivity decreases from 2.8349 mV/(V/Oe)at an angle of 0°to 0.0175 mV/(V/Oe)at an angle of 90°.Then,the sensor is placed in a series of rotating magnetic fields.We propose a model to express the output characteristics of the GMR multilayer sensor.The transfer curves of the sensor can be shown as two exactly symmetrical circles with an increasing radius when the magnetic field increases.The experimental results are consistent with the simulation results of the model.The advantage of this model is that it is simpler and more intuitive.
文摘A permanent magnet linear synchronous motor (PMLSM) for a high temperature superconducting (HTS) maglev system has been studied, including the motor structure, control strategy, and analysis techniques. Finite element analysis (FEA) of magnetic field is conducted to accurately calculate major motor parameters. Equivalent electrical circuit is used to predict the drive's steady-state characteristics, and a phase variable model is applied to predict the dynamic performance. Preliminary experiment with a prototype has been made to verify the theoretical analysis and the HTS-PM synchronous driving technology.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFF01010701)the National Natural Science Foundation of China(Grant No.51332003)the Sichuan Science and Technology Program,China(Grant No.2018G20140)
文摘Skyrmion, as a quasi-particle structure, has attracted much attention due to its potential applications in future spintronic devices. Artificial skyrmion structure has aroused great interest as it can be stabilized at room temperature, without needing to incorporate materials with Dzyaloshinskii–Moriya interaction(DMI) into it. In this paper, it is found that the artificial skyrmion structure can be realized in CoCrPt/NiFe bilayers by micromagnetic simulations. The critical magnetic field of the core decreases as the diameter of the NiFe soft magnetic layer increases. The artificial skyrmion has excellent topological protection, and the critical magnetic field of plane is about 76 mT(760 Oe, 1 Oe = 79.5775 A·m-1). The external magnetic field plays a key role in determining the core diameter of the skyrmion, and the artificial skyrmion can be realized in CoCrPt/Cu/CoCrPt/NiFe four-layer with a diameter of 13 nm.
文摘In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.
基金supported by grants from the National Natural Science Foundation of China(No.82072813)Natural Science Foundation of Guangdong Province(No.2020A1515010473 and No.2018A030313668)China Postdoctoral Science Foundation(No.2020M682666).
文摘The limited treatment options for advanced prostate cancer(PCa)lead to the urgent need to discover new anticancer drugs.Mannose,an isomer of glucose,has been reported to have an anticancer effect on various tumors.However,the anticancer effect of mannose in PCa remains unclear.In this study,we demonstrated that mannose inhibits the proliferation and promotes the apoptosis of PCa cells in vitro,and mannose was observed to have an anticancer effect in mice without harming their health.Accumulation of intracellular mannose simultaneously decreased the mitochondrial membrane potential,increased mitochondrial and cellular reactive oxygen species(ROS)levels,and reduced adenosine triphosphate(ATP)production in PCa cells.Mannose treatment of PCa cells induced changes in mitochondrial morphology,caused dysregulated expression of the fission protein,such as fission,mitochondrial 1(FIS1),and enhanced the expression of proapoptotic factors,such as BCL2-associated X(Bax)and BCL2-antagonist/killer 1(Bak).Furthermore,lower expression of mannose phosphate isomerase(MPI),the key enzyme in mannose metabolism,indicated poorer prognosis in PCa patients,and downregulation of MPI expression in PCa cells enhanced the anticancer effect of mannose.This study reveals the anticancer effect of mannose in PCa and its clinical significance in PCa patients.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China (NSFC Grant Nos. 11305152, 51272164, 50772068 and 50972095) and Foundation of Doctor Training Program in University and College in China (Grant Nos. 20030610035 and 20080610020).
文摘The origin of a high mechanical quality in CuO-doped (K, Na)NbO3-based ceramics is addressed by considering the correlations between the lattice positions of Cu ions and the hardening effect in K0.48Na0.52+xNbO3-0.01CuO ceramics. The Cu ions simultaneously occupy K/Na and Nb sites of these ceramics with x = 0 and 0.02, only occupy the K/Na site of the ceramics with x= -0.02, and mostly form a secondary phase of the ceramics with x = -0.05. The Cu ions lead to the hardening of ceramics with an increase of Ec and Qm by only occupying the K/Na site, together with the formation of double hysteresis loops in un-poled compositions. A defect model is proposed to illuminate the origin of a high Qm value, that is, the domain stabilization is dominated by the content of relatively mobile O2- ions in the ceramics, which has a weak bonding with CUK/Na defects.