Electrochemical impedance spectroscopy (EIS) is widely used in fuel cell impedance analysis. However, for ohmic resistance (R Ω), EIS has some disadvantages such as long test period and complex data analysis with equ...Electrochemical impedance spectroscopy (EIS) is widely used in fuel cell impedance analysis. However, for ohmic resistance (R Ω), EIS has some disadvantages such as long test period and complex data analysis with equivalent circuits. Therefore, the current interruption method is explored to measure the value of RΩ in direct methanol fuel cells (DMFC) at different temperatures and current densities. It is found that RΩ decreases as temperature increase, and decreases initially and then increases as current density increases. These results are consistent with those measured by the EIS technique. In most cases, the ohmic resistances with current interruption (R iR ) are larger than those with EIS (R EIS ), but the difference is small, in the range from –0.848% to 5.337%. The errors of R iR at high current densities are less than those of R EIS . Our results show that the R iR data are reliable and easy to obtain in the measurement of ohmic resistance in DMFC.展开更多
The incremental capacity analysis(ICA)technique is notably limited by its sensitivity to variations in charging conditions,which constrains its practical applicability in real-world scenarios.This paper introduces an ...The incremental capacity analysis(ICA)technique is notably limited by its sensitivity to variations in charging conditions,which constrains its practical applicability in real-world scenarios.This paper introduces an ICA-compensation technique to address this limitation and propose a generalized framework for assessing the state of health(SOH)of batteries based on ICA that is applicable under differing charging conditions.This novel approach calculates the voltage profile under quasi-static conditions by subtracting the voltage increase attributable to the additional polarization effects at high currents from the measured voltage profile.This approach's efficacy is contingent upon precisely acquiring the equivalent impedance.To obtain the equivalent impedance throughout the batteries'lifespan while minimizing testing costs,this study employs a current interrupt technique in conjunction with a long short-term memory(LSTM)network to develop a predictive model for equivalent impedance.Following the derivation of ICA curves using voltage profiles under quasi-static conditions,the research explores two scenarios for SOH estimation:one utilizing only incremental capacity(IC)features and the other incorporating both IC features and IC sampling.A genetic algorithm-optimized backpropagation neural network(GABPNN)is employed for the SOH estimation.The proposed generalized framework is validated using independent training and test datasets.Variable test conditions are applied for the test set to rigorously evaluate the methodology under challenging conditions.These evaluation results demonstrate that the proposed framework achieves an estimation accuracy of 1.04%for RMSE and 0.90%for MAPE across a spectrum of charging rates ranging from 0.1 C to 1 C and starting SOCs between 0%and 70%,which constitutes a major advancement compared to established ICA methods.It also significantly enhances the applicability of conventional ICA techniques in varying charging conditions and negates the necessity for separate testing protocols for each charging scenario.展开更多
目的评估新疆地区“药品零差率”政策对心脑血管疾病患者住院费用结构及次均费用的影响,为完善公立医院补偿机制与控费政策提供依据。方法基于新疆某三甲综合公立医院2016年1月-2023年12月心脑血管疾病患者住院费用数据,本研究聚焦次均...目的评估新疆地区“药品零差率”政策对心脑血管疾病患者住院费用结构及次均费用的影响,为完善公立医院补偿机制与控费政策提供依据。方法基于新疆某三甲综合公立医院2016年1月-2023年12月心脑血管疾病患者住院费用数据,本研究聚焦次均住院费用、次均西药费用及费用构成等核心指标,采用间断时间序列分析(Interrupted time series analysis,ITSA)量化了政策带来的费用水平与趋势的即时与长期变化,并结合结构变动度模型揭示了各分项费用的结构变动贡献率。结果与政策实施前比较,实施后次均住院费用短期内显著下降(β_(2)=-12754.66,P<0.05),长期呈缓慢回升趋势(β_(1)+β_(3)=107.40,P<0.05);西药费用占比下降,次均西药费用控制未达显著(P≥0.05)。医院通过增加检查费、化验费等医疗服务性收入(累计贡献率43.87%)弥补药品收入损失,存在将成本从药品转向检查、化验等医疗服务项目的风险。结论“药品零差率”政策短期内降低住院费用,但需深化医疗、医保、医药领域的协同改革,强化疾病诊断相关分组(Diagnosis related groups,DRG)付费、耗材集采等协同措施,遏制隐性成本转移,巩固政策成效。展开更多
基金Supported by the National High Technology Research and Development Program of China （2007AA05Z150） the National Natural Science Foundation of China （50911140287 50973055）
文摘Electrochemical impedance spectroscopy (EIS) is widely used in fuel cell impedance analysis. However, for ohmic resistance (R Ω), EIS has some disadvantages such as long test period and complex data analysis with equivalent circuits. Therefore, the current interruption method is explored to measure the value of RΩ in direct methanol fuel cells (DMFC) at different temperatures and current densities. It is found that RΩ decreases as temperature increase, and decreases initially and then increases as current density increases. These results are consistent with those measured by the EIS technique. In most cases, the ohmic resistances with current interruption (R iR ) are larger than those with EIS (R EIS ), but the difference is small, in the range from –0.848% to 5.337%. The errors of R iR at high current densities are less than those of R EIS . Our results show that the R iR data are reliable and easy to obtain in the measurement of ohmic resistance in DMFC.
基金funded by the Bavarian State Ministry of ScienceResearch and Art(Grant number:H.2-F1116.WE/52/2)。
文摘The incremental capacity analysis(ICA)technique is notably limited by its sensitivity to variations in charging conditions,which constrains its practical applicability in real-world scenarios.This paper introduces an ICA-compensation technique to address this limitation and propose a generalized framework for assessing the state of health(SOH)of batteries based on ICA that is applicable under differing charging conditions.This novel approach calculates the voltage profile under quasi-static conditions by subtracting the voltage increase attributable to the additional polarization effects at high currents from the measured voltage profile.This approach's efficacy is contingent upon precisely acquiring the equivalent impedance.To obtain the equivalent impedance throughout the batteries'lifespan while minimizing testing costs,this study employs a current interrupt technique in conjunction with a long short-term memory(LSTM)network to develop a predictive model for equivalent impedance.Following the derivation of ICA curves using voltage profiles under quasi-static conditions,the research explores two scenarios for SOH estimation:one utilizing only incremental capacity(IC)features and the other incorporating both IC features and IC sampling.A genetic algorithm-optimized backpropagation neural network(GABPNN)is employed for the SOH estimation.The proposed generalized framework is validated using independent training and test datasets.Variable test conditions are applied for the test set to rigorously evaluate the methodology under challenging conditions.These evaluation results demonstrate that the proposed framework achieves an estimation accuracy of 1.04%for RMSE and 0.90%for MAPE across a spectrum of charging rates ranging from 0.1 C to 1 C and starting SOCs between 0%and 70%,which constitutes a major advancement compared to established ICA methods.It also significantly enhances the applicability of conventional ICA techniques in varying charging conditions and negates the necessity for separate testing protocols for each charging scenario.
文摘目的评估新疆地区“药品零差率”政策对心脑血管疾病患者住院费用结构及次均费用的影响,为完善公立医院补偿机制与控费政策提供依据。方法基于新疆某三甲综合公立医院2016年1月-2023年12月心脑血管疾病患者住院费用数据,本研究聚焦次均住院费用、次均西药费用及费用构成等核心指标,采用间断时间序列分析(Interrupted time series analysis,ITSA)量化了政策带来的费用水平与趋势的即时与长期变化,并结合结构变动度模型揭示了各分项费用的结构变动贡献率。结果与政策实施前比较,实施后次均住院费用短期内显著下降(β_(2)=-12754.66,P<0.05),长期呈缓慢回升趋势(β_(1)+β_(3)=107.40,P<0.05);西药费用占比下降,次均西药费用控制未达显著(P≥0.05)。医院通过增加检查费、化验费等医疗服务性收入(累计贡献率43.87%)弥补药品收入损失,存在将成本从药品转向检查、化验等医疗服务项目的风险。结论“药品零差率”政策短期内降低住院费用,但需深化医疗、医保、医药领域的协同改革,强化疾病诊断相关分组(Diagnosis related groups,DRG)付费、耗材集采等协同措施,遏制隐性成本转移,巩固政策成效。
