This paper develops a five degrees of freedom（5-DOF） model for aeroengine spindle dual-rotor system dynamic analysis.In this system,the dual rotors are supported on two angular contact ball bearings and two deep gro...This paper develops a five degrees of freedom（5-DOF） model for aeroengine spindle dual-rotor system dynamic analysis.In this system,the dual rotors are supported on two angular contact ball bearings and two deep groove ball bearings,one of the latter-mentioned bearings works as the inter-shaft bearing.Driven by respective motors,the dual rotors have different co-rotating speeds.The proposed model mathematically formulates the nonlinear displacements,elastic deflections and contact forces of bearings with consideration of 5-DOF and coupling of dual rotors.The nonlinear equations of motions of dual rotors with 5-DOF are solved using Runge-Kutta-Fehlberg algorithm.In order to investigate the effect of the introduced 5-DOF and nonlinear dy-namic bearing model,we compare the proposed model with two models：the 3-DOF model of this system only considering three translational degrees of freedom（Gupta,1993,rotational freedom is neglected）;the 5-DOF model where the deep groove ball bearings are simplified as linear elastic spring（Guskov,2007）.The simulation results verify Gupta＇s prediction（1993） and show that the rotational freedom of rotors and nonlinear dynamic model of bearings have great effect on the system dynamic simula-tion.The quantitative results are given as well.展开更多
Wind-induced vibration energy harvesting has a great potential for utilizing wind energy to supply power for low-powered devices.To improve the working performance of energy harvesters effectively,a suitable structura...Wind-induced vibration energy harvesting has a great potential for utilizing wind energy to supply power for low-powered devices.To improve the working performance of energy harvesters effectively,a suitable structural design is crucial.This paper proposes a dual-beam piezo-magneto-elastic wake-induced vibration energy harvesting system to enhance the functional performance of aeroelastic energy harvesters in environments with variable wind speeds.The system contains two piezoelectric beams coupled by magnets(forming upstream and downstream energy harvesters),and each beam is attached with a foam cylinder.A corresponding dynamic model is provided,and output characteristics are obtained at different wind speeds.Results and experimental verification indicate that both upstream and downstream energy harvesters can realize efficient energy harvesting.When the wind speed exceeds a certain critical value,the amplitudes of the system’s displacement and voltage are high.The wind speed threshold value is approximately 1.25 m/s.When the wind speed and magnet spacing are 10.2 m/s and 20 mm,respectively,the output power of the system reaches 4.9×10^(−4)W.Moreover,the wind speed threshold value of the proposed system can be adjusted by an equivalent nonlinear restoring force.展开更多
Acquisition of real-time and accurate vehicle state and parameter information is critical to the research of vehicle dynamic control system.By studying the defects of the former Kalman filter based estimation method,a...Acquisition of real-time and accurate vehicle state and parameter information is critical to the research of vehicle dynamic control system.By studying the defects of the former Kalman filter based estimation method,a new estimating method is proposed.First the nonlinear vehicle dynamics system,containing inaccurate model parameters and constant noise,is established.Then a dual unscented particle filter(DUPF)algorithm is proposed.In the algorithm two unscented particle filters run in parallel,states estimation and parameters estimation update each other.The results of simulation and vehicle ground testing indicate that the DUPF algorithm has higher state estimation accuracy than unscented Kalman filter(UKF)and dual extended Kalman filter(DEKF),and it also has good capability to revise model parameters.展开更多
Sc and Zn were introduced into O3-NaMn_(0.5)Ni_(0.5)O_(2)(NaMN)using the combination of solution combustion and solid-state method.The effect of Sc and Zn dual-substitution on Na^(+) diffusion dynamics and structural ...Sc and Zn were introduced into O3-NaMn_(0.5)Ni_(0.5)O_(2)(NaMN)using the combination of solution combustion and solid-state method.The effect of Sc and Zn dual-substitution on Na^(+) diffusion dynamics and structural stability of NaMN was investigated.The physicochemical characterizations suggest that the introduction of Sc and Zn broaden Na^(+) diffusion channels and weaken the Na—O bonds,thereby facilitating the diffusion of sodium ions.Simulations indicate that the Sc and Zn dual-substitution decreases the diffusion barrier of Na-ions and improves the conductivity of the material.The dual-substituted NaMn_(0.5)Ni_(0.4)Sc_(0.04)Zn_(0.04)O_(2)(Na MNSZ44)cathode delivers impressive cycle stability with capacity retention of 71.2%after 200 cycles at 1C and 54.8%after 400 cycles at 5C.Additionally,the full cell paired with hard carbon anode exhibits a remarkable long-term cycling stability,showing capacity retention of 64.1%after 250 cycles at 1C.These results demonstrate that Sc and Zn dual-substitution is an effective strategy to improve the Na^(+) diffusion dynamics and structural stability of NaMN.展开更多
Flexible ion-conductive materials exhibit intriguing advantages for applications in flexible electronic devices.Currently,the further enhancement of their conductivity within environmental limitations is an urgent dem...Flexible ion-conductive materials exhibit intriguing advantages for applications in flexible electronic devices.Currently,the further enhancement of their conductivity within environmental limitations is an urgent demand for the development of flexible electronic devices,yet remains as a great challenge.Herein,we report a“dual-acid”strategy,via the encapsulation of two acids,H_(3)PW_(12)O_(40)(HPW) and NH_(2)SO_(3)H(SA),with synergistic interaction into poly(vinyl alcohol)-glycerol(PVA-Gly) hydrogel,to achieve polyoxometalate(POM)-based flexible materials with superionic conductivity under various environmental conditions.As a representative example,the prepared PVA-Gly/HPW-SA-20% hydrogel presents an ultrahigh proton conductivity ranging from -30℃(3.33×10^(-2)S cm^(-1)) to room temperature(2.78×10^(-1)S cm^(-1)) under ambient humidity.Moreover,the PVA-Gly/HPW-SA-20% hydrogel exhibits remarkable advantages in anti-freezing,mechanical flexibility and self-adhesiveness,making it a promising multifunctional electrolyte for flexible electronic devices.Both experimental results and molecular dynamics(MD) simulations jointly demonstrate that SA bridges HPW clusters to form a dense proton transport pathway induced by multiple electrostatic and hydrogen bonding interactions between SA and HPW counterparts,which contributes to the high-level proton conductivity of the PVA-Gly/HPW-SA-20% hydrogel.This work provides new insights into the design of POM-based flexible materials with superionic conductivity.展开更多
This work aims to systematically study hydrodynamics and mixing characteristics of non-Newtonian fluid(carboxyl methyl cellulose,CMC)in dual shaft eccentric mixer.Fluid rheology was described by the power law rheologi...This work aims to systematically study hydrodynamics and mixing characteristics of non-Newtonian fluid(carboxyl methyl cellulose,CMC)in dual shaft eccentric mixer.Fluid rheology was described by the power law rheological model.Computational fluid dynamics was employed to simulate the velocity field and shear rate inside the stirred tank.The influence mechanism of the rotational modes,height difference between impellers,impeller eccentricities,and impeller types on the flow field have been well investigated.We studied the performance of different dual-shaft eccentric mixers at the constant power input with its fluid velocity profiles,average shear strain rate,mixing time and mixing energy.The counter-rotation mode shows better mixing performance than co-rotation mode,and greater eccentricity can shorten mixing time on the basis of same stirred condition.To intensify the hydrodynamic interaction between impellers and enhance the overall mixing performance of the dual shaft eccentric mixers,it is critical to have a reasonable combination of impellers and an appropriate spatial position of impellers.展开更多
Energy storage systems(ESSs)operate as independent market participants and collaborate with photovoltaic(PV)generation units to enhance the flexible power supply capabilities of PV units.However,the dynamic variations...Energy storage systems(ESSs)operate as independent market participants and collaborate with photovoltaic(PV)generation units to enhance the flexible power supply capabilities of PV units.However,the dynamic variations in the profitability of ESSs in the electricity market are yet to be fully understood.This study introduces a dual-timescale dynamics model that integrates a spot market clearing(SMC)model into a system dynamics(SD)model to investigate the profit-aware capacity growth of ESSs and compares the profitability of independent energy storage systems(IESSs)with that of an ESS integrated within a PV(PV-ESS).Furthermore,this study aims to ascertain the optimal allocation of the PV-ESS.First,SD and SMC models were set up.Second,the SMC model simulated on an hourly timescale was incorporated into the SD model as a subsystem,a dual-timescale model was constructed.Finally,a development simulation and profitability analysis was conducted from 2022 to 2040 to reveal the dynamic optimal range of PV-ESS allocation.Additionally,negative electricity prices were considered during clearing processes.The simulation results revealed differences in profitability and capacity growth between IESS and PV-ESS,helping grid investors and policymakers to determine the boundaries of ESSs and dynamic optimal allocation of PV-ESSs.展开更多
基金National Natural Science Foundation of China (50575031, 50975033)National Key Technology Research and Development Program (JPPT-115-189)
文摘This paper develops a five degrees of freedom（5-DOF） model for aeroengine spindle dual-rotor system dynamic analysis.In this system,the dual rotors are supported on two angular contact ball bearings and two deep groove ball bearings,one of the latter-mentioned bearings works as the inter-shaft bearing.Driven by respective motors,the dual rotors have different co-rotating speeds.The proposed model mathematically formulates the nonlinear displacements,elastic deflections and contact forces of bearings with consideration of 5-DOF and coupling of dual rotors.The nonlinear equations of motions of dual rotors with 5-DOF are solved using Runge-Kutta-Fehlberg algorithm.In order to investigate the effect of the introduced 5-DOF and nonlinear dy-namic bearing model,we compare the proposed model with two models：the 3-DOF model of this system only considering three translational degrees of freedom（Gupta,1993,rotational freedom is neglected）;the 5-DOF model where the deep groove ball bearings are simplified as linear elastic spring（Guskov,2007）.The simulation results verify Gupta＇s prediction（1993） and show that the rotational freedom of rotors and nonlinear dynamic model of bearings have great effect on the system dynamic simula-tion.The quantitative results are given as well.
基金supported by the National Natural Science Foundation of China(Grant No.52161135106)the Science,Technology and Innovation Commission of Shenzhen Municipality(Grant No.JCYJ201908061536-15091)+4 种基金the International Science and Technology Cooperation Project of Guangdong Province(Grant No.2021A0505030012)the Innovation Capability Support Plan of Shaanxi Province(Grant No.2020KJXX-021)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Grant No.CX2022001)the 111 Project(Grant No.BP0719007)supported by the National Science Centre,Poland under the project SHENG-2(Grant No.2021/40/Q/ST8/00362)。
文摘Wind-induced vibration energy harvesting has a great potential for utilizing wind energy to supply power for low-powered devices.To improve the working performance of energy harvesters effectively,a suitable structural design is crucial.This paper proposes a dual-beam piezo-magneto-elastic wake-induced vibration energy harvesting system to enhance the functional performance of aeroelastic energy harvesters in environments with variable wind speeds.The system contains two piezoelectric beams coupled by magnets(forming upstream and downstream energy harvesters),and each beam is attached with a foam cylinder.A corresponding dynamic model is provided,and output characteristics are obtained at different wind speeds.Results and experimental verification indicate that both upstream and downstream energy harvesters can realize efficient energy harvesting.When the wind speed exceeds a certain critical value,the amplitudes of the system’s displacement and voltage are high.The wind speed threshold value is approximately 1.25 m/s.When the wind speed and magnet spacing are 10.2 m/s and 20 mm,respectively,the output power of the system reaches 4.9×10^(−4)W.Moreover,the wind speed threshold value of the proposed system can be adjusted by an equivalent nonlinear restoring force.
基金Supported by the National Natural Science Foundation of China(10902049)the Chinese Postdoctoral Science Foundation(2012M521073)+3 种基金the Fundamental Research Funds for the Central Universitiesthe Jiangsu Planned Projects for Postdoctoral Research Funds(1302020C)the Nanjing University of Aeronautics and Astronautics Student Innovative Training Program(20120119101535)the Fundation of Graduate Innovation Center in Nanjing University of Aeronautics and Astronautics(kfjj201404)
文摘Acquisition of real-time and accurate vehicle state and parameter information is critical to the research of vehicle dynamic control system.By studying the defects of the former Kalman filter based estimation method,a new estimating method is proposed.First the nonlinear vehicle dynamics system,containing inaccurate model parameters and constant noise,is established.Then a dual unscented particle filter(DUPF)algorithm is proposed.In the algorithm two unscented particle filters run in parallel,states estimation and parameters estimation update each other.The results of simulation and vehicle ground testing indicate that the DUPF algorithm has higher state estimation accuracy than unscented Kalman filter(UKF)and dual extended Kalman filter(DEKF),and it also has good capability to revise model parameters.
基金financial support from the National Natural Science Foundation of China(No.52377220)the Natural Science Foundation of Hunan Province,China(No.kq2208265)。
文摘Sc and Zn were introduced into O3-NaMn_(0.5)Ni_(0.5)O_(2)(NaMN)using the combination of solution combustion and solid-state method.The effect of Sc and Zn dual-substitution on Na^(+) diffusion dynamics and structural stability of NaMN was investigated.The physicochemical characterizations suggest that the introduction of Sc and Zn broaden Na^(+) diffusion channels and weaken the Na—O bonds,thereby facilitating the diffusion of sodium ions.Simulations indicate that the Sc and Zn dual-substitution decreases the diffusion barrier of Na-ions and improves the conductivity of the material.The dual-substituted NaMn_(0.5)Ni_(0.4)Sc_(0.04)Zn_(0.04)O_(2)(Na MNSZ44)cathode delivers impressive cycle stability with capacity retention of 71.2%after 200 cycles at 1C and 54.8%after 400 cycles at 5C.Additionally,the full cell paired with hard carbon anode exhibits a remarkable long-term cycling stability,showing capacity retention of 64.1%after 250 cycles at 1C.These results demonstrate that Sc and Zn dual-substitution is an effective strategy to improve the Na^(+) diffusion dynamics and structural stability of NaMN.
基金supported by the National Natural Science Foundation of China (22071019, 21872021, 21671033)financially supported by the National Natural Science Foundation of China (9237210012, 22073094)+3 种基金the Science and Technology Development Program of Jilin Province (20240602003RC, 20210402059GH)the Program for Young Scholars in Regional Development of Chinese Academy of Sciences (CAS)the essential support of the Network and Computing Center at Changchun Institute of Applied Chemistry, CASthe Computing Center of Jilin Province。
文摘Flexible ion-conductive materials exhibit intriguing advantages for applications in flexible electronic devices.Currently,the further enhancement of their conductivity within environmental limitations is an urgent demand for the development of flexible electronic devices,yet remains as a great challenge.Herein,we report a“dual-acid”strategy,via the encapsulation of two acids,H_(3)PW_(12)O_(40)(HPW) and NH_(2)SO_(3)H(SA),with synergistic interaction into poly(vinyl alcohol)-glycerol(PVA-Gly) hydrogel,to achieve polyoxometalate(POM)-based flexible materials with superionic conductivity under various environmental conditions.As a representative example,the prepared PVA-Gly/HPW-SA-20% hydrogel presents an ultrahigh proton conductivity ranging from -30℃(3.33×10^(-2)S cm^(-1)) to room temperature(2.78×10^(-1)S cm^(-1)) under ambient humidity.Moreover,the PVA-Gly/HPW-SA-20% hydrogel exhibits remarkable advantages in anti-freezing,mechanical flexibility and self-adhesiveness,making it a promising multifunctional electrolyte for flexible electronic devices.Both experimental results and molecular dynamics(MD) simulations jointly demonstrate that SA bridges HPW clusters to form a dense proton transport pathway induced by multiple electrostatic and hydrogen bonding interactions between SA and HPW counterparts,which contributes to the high-level proton conductivity of the PVA-Gly/HPW-SA-20% hydrogel.This work provides new insights into the design of POM-based flexible materials with superionic conductivity.
基金supported by the National Natural Science Foundation of China(22078030,52021004)National Natural Science Foundation of Chongqing(2022NSCQ-LZX0271)+2 种基金Fundamental Research Funds for the Central Universities(2022CDJQY-005)National Key Research and Development Project(2019YFC1905802,2022YFC3901204)Key Project of Independent Research Project of State Key Laboratory of coal mine disaster dynamics and control(2011DA105287-zd201902).
文摘This work aims to systematically study hydrodynamics and mixing characteristics of non-Newtonian fluid(carboxyl methyl cellulose,CMC)in dual shaft eccentric mixer.Fluid rheology was described by the power law rheological model.Computational fluid dynamics was employed to simulate the velocity field and shear rate inside the stirred tank.The influence mechanism of the rotational modes,height difference between impellers,impeller eccentricities,and impeller types on the flow field have been well investigated.We studied the performance of different dual-shaft eccentric mixers at the constant power input with its fluid velocity profiles,average shear strain rate,mixing time and mixing energy.The counter-rotation mode shows better mixing performance than co-rotation mode,and greater eccentricity can shorten mixing time on the basis of same stirred condition.To intensify the hydrodynamic interaction between impellers and enhance the overall mixing performance of the dual shaft eccentric mixers,it is critical to have a reasonable combination of impellers and an appropriate spatial position of impellers.
基金supported by National Natural Science Foundation of China(U2066209)。
文摘Energy storage systems(ESSs)operate as independent market participants and collaborate with photovoltaic(PV)generation units to enhance the flexible power supply capabilities of PV units.However,the dynamic variations in the profitability of ESSs in the electricity market are yet to be fully understood.This study introduces a dual-timescale dynamics model that integrates a spot market clearing(SMC)model into a system dynamics(SD)model to investigate the profit-aware capacity growth of ESSs and compares the profitability of independent energy storage systems(IESSs)with that of an ESS integrated within a PV(PV-ESS).Furthermore,this study aims to ascertain the optimal allocation of the PV-ESS.First,SD and SMC models were set up.Second,the SMC model simulated on an hourly timescale was incorporated into the SD model as a subsystem,a dual-timescale model was constructed.Finally,a development simulation and profitability analysis was conducted from 2022 to 2040 to reveal the dynamic optimal range of PV-ESS allocation.Additionally,negative electricity prices were considered during clearing processes.The simulation results revealed differences in profitability and capacity growth between IESS and PV-ESS,helping grid investors and policymakers to determine the boundaries of ESSs and dynamic optimal allocation of PV-ESSs.
