Quantum-classical correspondence is affirmed via performing Wigner function and a classical-quantum chaotic system containing random variables.The classical-quantum system is transformed into a Kolmogorov model for fo...Quantum-classical correspondence is affirmed via performing Wigner function and a classical-quantum chaotic system containing random variables.The classical-quantum system is transformed into a Kolmogorov model for force and energy analysis.Combining different forces,the system is divided into two categories:conservative and non-conservative,revealing the mechanical characteristic of the classical-quantum system.The Casimir power,an analysis tool,is employed to find the key factors governing the orbital trajectory and the energy cycle of the system.Detailed analyses using the Casimir power and an energy transformation uncover the causes of the different dynamic behaviors,especially chaos.For the corresponding classical Hamiltonian system when Planck's constant ?→0,the supremum bound of the system is derived analytically.Difference between the classical-quantum system and the classical Hamiltonian system is displayed through trajectories and energies.Quantum-classical correspondences are further demonstrated by comparing phase portrait,kinetic,potential and Casimir energies of the two systems.展开更多
An atmospheric-pressure plasma jet array specially designed for HTV silicone rubber treatment is reported in this paper. Stable plasma containing highly energetic active particles was uniformly generated in the plasma...An atmospheric-pressure plasma jet array specially designed for HTV silicone rubber treatment is reported in this paper. Stable plasma containing highly energetic active particles was uniformly generated in the plasma jet array. The discharge pattern was affected by the applied voltage. The divergence phenomenon was observed at low gas flow rate and abated when the flow rate increased.Temperature of the plasma plume is close to room temperature which makes it feasible for temperature-sensitive material treatment. Hydrophobicity of contaminated HTV silicone rubber was significantly improved after quick exposure of the plasma jet array, and the effective treatment area reached 120 mm?×?50 mm(length?×?width). Reactive particles in the plasma accelerate accumulation of the hydrophobic molecules, namely low molecular weight silicone chains, on the contaminated surface, which result in a hydrophobicity improvement of the HTV silicone rubber.展开更多
To investigate how the multiphase structures affect the electrical conductivity in semicrystalline polymer composites,herein,an accurate multiphase content calculation method is proposed and verified,which combines am...To investigate how the multiphase structures affect the electrical conductivity in semicrystalline polymer composites,herein,an accurate multiphase content calculation method is proposed and verified,which combines amorphous phase information in broadband dielectric spectroscopy and crystalline phase information in differential scanning calorimetry.Taken aluminium hydroxide(ATH)filled silicone rubber as an example,it is found that the rigid amorphous fraction(RAF)corresponding to the chains constrained by crystals(RAF_(cry))is not linearly increased with crystalline fraction(CF).Compared to non-isothermal crystallisation,RAF caused by ATH/silicone rubber interface(RAF_(int))after isothermal crystallisation at 213 K changes little,while mobile amorphous fraction and RAFcry is attenuated and CF is strengthened.Based on the calculated structures of ATH filled silicone rubber,activation energy of conductivities during cooling is dominated by the thermal transition for conductive ions and shortened distance among the conductive ions through shrunk volumes of the amorphous phase.Our findings deepen the understanding of multiphase content in semi-crystalline polymer composites and its relationship with electrical conductivity,which can be applied in manipulating electrical performance of semi-crystalline polymers by fillers.展开更多
Element doping is an effective method to improve the performance of ZnO varistors.Previous studies mainly focused on the variation of microstructures and Schottky barriers.In this study,the effects of Co dopant on ele...Element doping is an effective method to improve the performance of ZnO varistors.Previous studies mainly focused on the variation of microstructures and Schottky barriers.In this study,the effects of Co dopant on electrical properties are investigated from the aspect of multiscale defect structures,including intrinsic point defects,the heterogeneous interface of depletion/intergranular layers,and interface states at grain boundaries.Combining with analysis of phase composition and energy dispersive spectroscopy,it is found that Co tends to dissolve into ZnO grains when slightly doped.It substitutes Zn2+with the same valence and affects little on densities of donors.Segregation of Co at grain boundaries would result in the formation of spinel phase Co(Co4/3Sb2/3)O4 and transformation of the intergranular phase fromα-Bi2O3 toδ-Bi2O3.Meanwhile,densities of point defects are indirectly affected by oxygen ambient during sintering,resulting in abnormal variation of grain resistivity.And interface states are enhanced,leading to improved barriers at grain boundaries.Therefore,reduced leakage current,enhanced grain resistivity,and improved non-linear coefficient in Co-doped ZnO varistor blocks are understood from the underlying multiple defect structures.This presents a potential approach to explore short-term performance and long-term stability of ZnO varistors from the aspect of defect responses.展开更多
The stability and synchronous performance are usually hard to be improved simultaneously in the biaxial cross-coupling position motion control system.Based on analyzing the characteristics of the cross-coupling contro...The stability and synchronous performance are usually hard to be improved simultaneously in the biaxial cross-coupling position motion control system.Based on analyzing the characteristics of the cross-coupling control system,a robust adaptive cross-coupling control strategy is proposed.To restrict influences of destabilizing factors and improve both of stability and synchronous performance,the strategy forces dual axes to track the same reference model using Narendra adaptive control theory.And then,a robust parameters adaptive law is proposed.The stability analysis of the proposed strategy is conducted by applying Lyapunov stability theory.Related simulations and experiments indicate that the proposed strategy can improve synchronous performance and stability simultaneously.展开更多
Due to the excellent dynamic performance,the Finite Control Set Model Predictive Control has been widely used in various types of converters.However,when Finite Control Set Model Predictive Control is adopted,the swit...Due to the excellent dynamic performance,the Finite Control Set Model Predictive Control has been widely used in various types of converters.However,when Finite Control Set Model Predictive Control is adopted,the switching frequency of converters varies significantly with system operating conditions.Consequently,constant-frequency predictive control strategy has been proposed.Two active voltage vectors and a zero voltage vector are selected within each sampling period.The action time sequence is then calculated.Due to the unsymmetrical distribution of current variation rates around zero,the calculated value of the voltage-vector action time will turn up negative.According to common sense,the voltage-vector action time is greater than or equal to zero.The action time is normally forced to zero whenever a negative value is predicted,resulting in the control failure and performance deterioration.To solve this problem,this paper proposes modified strategy.The modified strategy examines the action time calculated out.When negative action time comes out,the modified strategy reselects the active voltage vector accordingly,instead of forcing the action time to be zero.Optimized action time sequence is further determined by minimizing the cost function.The effectiveness of the modified strategy is clearly verified by experimental tests,and analytical remarks are all founded in practical results.展开更多
A calibration method for the five essential parameters is proposed. Using the calibration results, the three dimensional (3D) reconstruction can be performed directly. The five essential parameters include the distanc...A calibration method for the five essential parameters is proposed. Using the calibration results, the three dimensional (3D) reconstruction can be performed directly. The five essential parameters include the distance between the camera and the projector, the distance between the reference plane and the camera, the fundamental frequency of the fringe pattern, the scale factor from the image coordinates to the world coordinate system in X axis direction and that in Y axis direction. The proposed calibration method is implemented and tested in our 3D reconstruction system. The mean calibration error is found to be 0.0215 mm over a volume of 400 mm (H)×300 mm (V)×500 mm (D). The proposed calibration method is accurate and useful for the 3D reconstruction system.展开更多
This paper presents a mathematical model of three-level voltage PWM rectifier,and derives a power control model from the theory of instantaneous power.In the vector-space,the influences on instantaneous power exercise...This paper presents a mathematical model of three-level voltage PWM rectifier,and derives a power control model from the theory of instantaneous power.In the vector-space,the influences on instantaneous power exercised by all the switching vectors are studied and illustrated separately,then a direct power control(DPC) scheme for three-level PWM rectifier which uses multistage band hysteresis comparator is proposed,and a novel switching table is designed.Meanwhile,the neutralpoint voltage unbalance is inhibited by selecting the redundancy switching states of small voltage vectors.Simulation and experimental results show that the proposed strategy can not only stabilize the DC bus voltage but also realize the unity power factor operation and the balance of neutral-point voltage.Moreover,the proposed method can improve the performance of the three-level rectifier.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61873186 and 11902220)the Natural Science Foundation of Tianjin City of China(Grant No.17JCZDJC38300)+1 种基金the Provincial Foundation for Excellent Young Talents of Colleges and Universities of Anhui Province of China(Grant No.GXYQ2017014)the Anhui University Humanities and Social Sciences Research Project of China(Grant No.SK2019A0116).
文摘Quantum-classical correspondence is affirmed via performing Wigner function and a classical-quantum chaotic system containing random variables.The classical-quantum system is transformed into a Kolmogorov model for force and energy analysis.Combining different forces,the system is divided into two categories:conservative and non-conservative,revealing the mechanical characteristic of the classical-quantum system.The Casimir power,an analysis tool,is employed to find the key factors governing the orbital trajectory and the energy cycle of the system.Detailed analyses using the Casimir power and an energy transformation uncover the causes of the different dynamic behaviors,especially chaos.For the corresponding classical Hamiltonian system when Planck's constant ?→0,the supremum bound of the system is derived analytically.Difference between the classical-quantum system and the classical Hamiltonian system is displayed through trajectories and energies.Quantum-classical correspondences are further demonstrated by comparing phase portrait,kinetic,potential and Casimir energies of the two systems.
基金supported in part by National Natural Science Foundation of China (Grant No. 51677105)Key project of Shenzhen Technology Innovation Plan (JSGG20170412151407005)
文摘An atmospheric-pressure plasma jet array specially designed for HTV silicone rubber treatment is reported in this paper. Stable plasma containing highly energetic active particles was uniformly generated in the plasma jet array. The discharge pattern was affected by the applied voltage. The divergence phenomenon was observed at low gas flow rate and abated when the flow rate increased.Temperature of the plasma plume is close to room temperature which makes it feasible for temperature-sensitive material treatment. Hydrophobicity of contaminated HTV silicone rubber was significantly improved after quick exposure of the plasma jet array, and the effective treatment area reached 120 mm?×?50 mm(length?×?width). Reactive particles in the plasma accelerate accumulation of the hydrophobic molecules, namely low molecular weight silicone chains, on the contaminated surface, which result in a hydrophobicity improvement of the HTV silicone rubber.
基金Natural Science Foundation of Anhui Province,Grant/Award Number:2008085UD11Fundamental Research Funds for the Central Universities,Grant/Award Number:JZ2021HGQB0270Institute of Energy,Hefei Comprehensive National Science Center,Grant/Award Number:19KZS207。
文摘To investigate how the multiphase structures affect the electrical conductivity in semicrystalline polymer composites,herein,an accurate multiphase content calculation method is proposed and verified,which combines amorphous phase information in broadband dielectric spectroscopy and crystalline phase information in differential scanning calorimetry.Taken aluminium hydroxide(ATH)filled silicone rubber as an example,it is found that the rigid amorphous fraction(RAF)corresponding to the chains constrained by crystals(RAF_(cry))is not linearly increased with crystalline fraction(CF).Compared to non-isothermal crystallisation,RAF caused by ATH/silicone rubber interface(RAF_(int))after isothermal crystallisation at 213 K changes little,while mobile amorphous fraction and RAFcry is attenuated and CF is strengthened.Based on the calculated structures of ATH filled silicone rubber,activation energy of conductivities during cooling is dominated by the thermal transition for conductive ions and shortened distance among the conductive ions through shrunk volumes of the amorphous phase.Our findings deepen the understanding of multiphase content in semi-crystalline polymer composites and its relationship with electrical conductivity,which can be applied in manipulating electrical performance of semi-crystalline polymers by fillers.
基金the Natural Science Foundation of China(grant nos.51937008 and 51707177)the National Key Research and Development Program of China(grant no.2018YFB0905802)the State Key Laboratory of Reliability and Intelligence of Electrical Equipment(grant no.EERIKF2019001).
文摘Element doping is an effective method to improve the performance of ZnO varistors.Previous studies mainly focused on the variation of microstructures and Schottky barriers.In this study,the effects of Co dopant on electrical properties are investigated from the aspect of multiscale defect structures,including intrinsic point defects,the heterogeneous interface of depletion/intergranular layers,and interface states at grain boundaries.Combining with analysis of phase composition and energy dispersive spectroscopy,it is found that Co tends to dissolve into ZnO grains when slightly doped.It substitutes Zn2+with the same valence and affects little on densities of donors.Segregation of Co at grain boundaries would result in the formation of spinel phase Co(Co4/3Sb2/3)O4 and transformation of the intergranular phase fromα-Bi2O3 toδ-Bi2O3.Meanwhile,densities of point defects are indirectly affected by oxygen ambient during sintering,resulting in abnormal variation of grain resistivity.And interface states are enhanced,leading to improved barriers at grain boundaries.Therefore,reduced leakage current,enhanced grain resistivity,and improved non-linear coefficient in Co-doped ZnO varistor blocks are understood from the underlying multiple defect structures.This presents a potential approach to explore short-term performance and long-term stability of ZnO varistors from the aspect of defect responses.
基金supported by the National Basic Research Program of China("973"Project)(Grant No.2013CB035600)the National Natural Science Foundation of China(Grant No.51377121)
文摘The stability and synchronous performance are usually hard to be improved simultaneously in the biaxial cross-coupling position motion control system.Based on analyzing the characteristics of the cross-coupling control system,a robust adaptive cross-coupling control strategy is proposed.To restrict influences of destabilizing factors and improve both of stability and synchronous performance,the strategy forces dual axes to track the same reference model using Narendra adaptive control theory.And then,a robust parameters adaptive law is proposed.The stability analysis of the proposed strategy is conducted by applying Lyapunov stability theory.Related simulations and experiments indicate that the proposed strategy can improve synchronous performance and stability simultaneously.
基金supported in part by the National Key Basic Research Program of China ("973" Program) (Grant No. 2013CB035602)the National Natural Science Foundation of China (Grant No. 51107084)the Doctoral Program of Higher Education of China(Grant No. 20100032120081)
文摘Due to the excellent dynamic performance,the Finite Control Set Model Predictive Control has been widely used in various types of converters.However,when Finite Control Set Model Predictive Control is adopted,the switching frequency of converters varies significantly with system operating conditions.Consequently,constant-frequency predictive control strategy has been proposed.Two active voltage vectors and a zero voltage vector are selected within each sampling period.The action time sequence is then calculated.Due to the unsymmetrical distribution of current variation rates around zero,the calculated value of the voltage-vector action time will turn up negative.According to common sense,the voltage-vector action time is greater than or equal to zero.The action time is normally forced to zero whenever a negative value is predicted,resulting in the control failure and performance deterioration.To solve this problem,this paper proposes modified strategy.The modified strategy examines the action time calculated out.When negative action time comes out,the modified strategy reselects the active voltage vector accordingly,instead of forcing the action time to be zero.Optimized action time sequence is further determined by minimizing the cost function.The effectiveness of the modified strategy is clearly verified by experimental tests,and analytical remarks are all founded in practical results.
基金supported by the National Natural Science Foundation of China (Nos.60808020 and No. 61078041)the Tianjin Research Program of Application Foundation and Advanced Technology (No.10JCYBJC07200)
文摘A calibration method for the five essential parameters is proposed. Using the calibration results, the three dimensional (3D) reconstruction can be performed directly. The five essential parameters include the distance between the camera and the projector, the distance between the reference plane and the camera, the fundamental frequency of the fringe pattern, the scale factor from the image coordinates to the world coordinate system in X axis direction and that in Y axis direction. The proposed calibration method is implemented and tested in our 3D reconstruction system. The mean calibration error is found to be 0.0215 mm over a volume of 400 mm (H)×300 mm (V)×500 mm (D). The proposed calibration method is accurate and useful for the 3D reconstruction system.
基金supported by the Key Program of National Natural Science Foundation of China (Grant No. 51037004)the National Natural Science Foundation of China (Grant No. 51077097)the Key Technologies Research and Development Program of Tianjin (Grant No.11ZCKFGX03300)
文摘This paper presents a mathematical model of three-level voltage PWM rectifier,and derives a power control model from the theory of instantaneous power.In the vector-space,the influences on instantaneous power exercised by all the switching vectors are studied and illustrated separately,then a direct power control(DPC) scheme for three-level PWM rectifier which uses multistage band hysteresis comparator is proposed,and a novel switching table is designed.Meanwhile,the neutralpoint voltage unbalance is inhibited by selecting the redundancy switching states of small voltage vectors.Simulation and experimental results show that the proposed strategy can not only stabilize the DC bus voltage but also realize the unity power factor operation and the balance of neutral-point voltage.Moreover,the proposed method can improve the performance of the three-level rectifier.