Hydrogen fuel cell ships are one of the key solutions to achieving zero carbon emissions in shipping.Multi-fuel cell stacks(MFCS)systems are frequently employed to fulfill the power requirements of high-load power equ...Hydrogen fuel cell ships are one of the key solutions to achieving zero carbon emissions in shipping.Multi-fuel cell stacks(MFCS)systems are frequently employed to fulfill the power requirements of high-load power equipment on ships.Compared to single-stack system,MFCS may be difficult to apply traditional energy management strategies(EMS)due to their complex structure.In this paper,a two-layer power allocation strategy for MFCS of a hydrogen fuel cell ship is proposed to reduce the complexity of the allocation task by splitting it into each layer of the EMS.The first layer of the EMSis centered on the Nonlinear Model Predictive Control(NMPC).The Northern Goshawk Optimization(NGO)algorithm is used to solve the nonlinear optimization problem in NMPC,and the local fine search is performed using sequential quadratic programming(SQP).Based on the power allocation results of the first layer,the second layer is centered on a fuzzy rule-based adaptive power allocation strategy(AP-Fuzzy).The membership function bounds of the fuzzy controller are related to the aging level of the MFCS.The Particle Swarm Optimization(PSO)algorithm is used to optimize the parameters of the residual membership function to improve the performance of the proposed strategy.The effectiveness of the proposed EMS is verified by comparing it with the traditional EMS.The experimental results show that the EMS proposed in this paper can ensure reasonable hydrogen consumption,slow down the FC aging and equalize its performance,effectively extend the system life,and ensure that the ship has good endurance after completing the mission.展开更多
Given the global lack of effective analysis methods for the impact of design parameter tolerance on performance deviation in the vehicle proof-of-concept stage,it is difficult to decompose performance tolerance to des...Given the global lack of effective analysis methods for the impact of design parameter tolerance on performance deviation in the vehicle proof-of-concept stage,it is difficult to decompose performance tolerance to design parameter tolerance.This study proposes a set of consistency analysis methods for vehicle steering performance.The process of consistency analysis and control of automotive performance in the conceptual design phase is proposed for the first time.A vehicle dynamics model is constructed,and the multi-objective optimization software Isight is used to optimize the steering performance of the car.Sensitivity analysis is used to optimize the design performance value.The tolerance interval of the performance is obtained by comparing the original car performance value with the optimized value.With the help of layer-by-layer decomposition theory and interval mathematics,automotive performance tolerance has been decomposed into design parameter tolerance.Through simulation and real vehicle experiments,the validity of the consistency analysis and control method presented in this paper are verified.The decomposition from parameter tolerance to performance tolerance can be achieved at the conceptual design stage.展开更多
Objective To preliminarily assess the biocompatibility and durability of the TruDelta TM transcatheter mitral valve replacement(TMVR)system.Methods Six adult sheep were divided into 3 groups based on the duration of f...Objective To preliminarily assess the biocompatibility and durability of the TruDelta TM transcatheter mitral valve replacement(TMVR)system.Methods Six adult sheep were divided into 3 groups based on the duration of follow-up:30 days(n=1),90 days(n=3)and 180 days(n=2).The TruDelta^(TM)TMVR system was implanteddthrougah transapical approach under transesophageal echocardiographic guidance.The operability of the TMVR system was evaluated using an instrument performance evaluation scale(consisting of 39 items),with scores ranging from 1(worst)to 10(best)assigned by the operator.Echocardiography was conducted preoperatively,immediately after surgery,and at 30,90,and 180 days post-implantation.At the last followup time point,the intervention mitral valve membrane and major organs were dissected for observation.The artificial valves were taken for hematoxylin eosin(HE)staining and observed under a scanning electron microscope.Results All six procedures were successfully completed using 29S size TruDelta^(TM)TMVR device.At the final follow-up,echocardiogram demonstrated good valve function without obvious paravalvular leakage,with a transvalvular gradient of(7.8±3.2)mmHg(1 mmHg=0.133 kPa)and a mitral valve orifice area of(1.8±0.2)cm^(2).Autopsy findings revealed no structural valve failure and almost complete endothelialization(>75%)with 90 to 180 days.Both HE staining and scanning electron microscopy confirmed optimal endothelialization of the valve stent.Conclusion The preclinical animal study indicates that the TruDeltarm device exhibits favorable biocompatibility and durability.展开更多
基金supported by the National Key R&D Program of China(2022YFB4301403).
文摘Hydrogen fuel cell ships are one of the key solutions to achieving zero carbon emissions in shipping.Multi-fuel cell stacks(MFCS)systems are frequently employed to fulfill the power requirements of high-load power equipment on ships.Compared to single-stack system,MFCS may be difficult to apply traditional energy management strategies(EMS)due to their complex structure.In this paper,a two-layer power allocation strategy for MFCS of a hydrogen fuel cell ship is proposed to reduce the complexity of the allocation task by splitting it into each layer of the EMS.The first layer of the EMSis centered on the Nonlinear Model Predictive Control(NMPC).The Northern Goshawk Optimization(NGO)algorithm is used to solve the nonlinear optimization problem in NMPC,and the local fine search is performed using sequential quadratic programming(SQP).Based on the power allocation results of the first layer,the second layer is centered on a fuzzy rule-based adaptive power allocation strategy(AP-Fuzzy).The membership function bounds of the fuzzy controller are related to the aging level of the MFCS.The Particle Swarm Optimization(PSO)algorithm is used to optimize the parameters of the residual membership function to improve the performance of the proposed strategy.The effectiveness of the proposed EMS is verified by comparing it with the traditional EMS.The experimental results show that the EMS proposed in this paper can ensure reasonable hydrogen consumption,slow down the FC aging and equalize its performance,effectively extend the system life,and ensure that the ship has good endurance after completing the mission.
文摘Given the global lack of effective analysis methods for the impact of design parameter tolerance on performance deviation in the vehicle proof-of-concept stage,it is difficult to decompose performance tolerance to design parameter tolerance.This study proposes a set of consistency analysis methods for vehicle steering performance.The process of consistency analysis and control of automotive performance in the conceptual design phase is proposed for the first time.A vehicle dynamics model is constructed,and the multi-objective optimization software Isight is used to optimize the steering performance of the car.Sensitivity analysis is used to optimize the design performance value.The tolerance interval of the performance is obtained by comparing the original car performance value with the optimized value.With the help of layer-by-layer decomposition theory and interval mathematics,automotive performance tolerance has been decomposed into design parameter tolerance.Through simulation and real vehicle experiments,the validity of the consistency analysis and control method presented in this paper are verified.The decomposition from parameter tolerance to performance tolerance can be achieved at the conceptual design stage.
文摘Objective To preliminarily assess the biocompatibility and durability of the TruDelta TM transcatheter mitral valve replacement(TMVR)system.Methods Six adult sheep were divided into 3 groups based on the duration of follow-up:30 days(n=1),90 days(n=3)and 180 days(n=2).The TruDelta^(TM)TMVR system was implanteddthrougah transapical approach under transesophageal echocardiographic guidance.The operability of the TMVR system was evaluated using an instrument performance evaluation scale(consisting of 39 items),with scores ranging from 1(worst)to 10(best)assigned by the operator.Echocardiography was conducted preoperatively,immediately after surgery,and at 30,90,and 180 days post-implantation.At the last followup time point,the intervention mitral valve membrane and major organs were dissected for observation.The artificial valves were taken for hematoxylin eosin(HE)staining and observed under a scanning electron microscope.Results All six procedures were successfully completed using 29S size TruDelta^(TM)TMVR device.At the final follow-up,echocardiogram demonstrated good valve function without obvious paravalvular leakage,with a transvalvular gradient of(7.8±3.2)mmHg(1 mmHg=0.133 kPa)and a mitral valve orifice area of(1.8±0.2)cm^(2).Autopsy findings revealed no structural valve failure and almost complete endothelialization(>75%)with 90 to 180 days.Both HE staining and scanning electron microscopy confirmed optimal endothelialization of the valve stent.Conclusion The preclinical animal study indicates that the TruDeltarm device exhibits favorable biocompatibility and durability.
