In this paper, a novel accelerated test method was proposed to analyze the durability of MEA, considering the actual operation of the fuel cell vehicle. The proposed method includes 7 working conditions： open circuit...In this paper, a novel accelerated test method was proposed to analyze the durability of MEA, considering the actual operation of the fuel cell vehicle. The proposed method includes 7 working conditions： open circuit voltage （OCV）, idling, rated output, overload, idling-rated cycle, idling-overload cycle, and OCV-idling cycle. The experimental results indicate that the proposed method can effectively destroy the MEA in a short time （165 h）. Moreover, the degradation mechanism of MEA was analyzed by measuring the polarization curve, CV, SEM and TEM. This paper may provide a new research direction for improving the durability of fuel cell.展开更多
Nowadays,the construction sector is more and more oriented toward the promotion of sustainability in all its activities.The goal to achieve is the optimization of performances,over the whole life-cycle,with respect to...Nowadays,the construction sector is more and more oriented toward the promotion of sustainability in all its activities.The goal to achieve is the optimization of performances,over the whole life-cycle,with respect to environmental,economic and social requirements.According to the latest advances,the concept of sustainability applied to constructions covers a number of branches such as life-cycle costing,ecology,durability and even structural design.Several procedures and design tools have been implemented in the framework of international research.Indeed the current trend in civil engineering research is moving towards life-time engineering,with the aim to implement integrated methodologies to consider as a whole all the sustainability requirements according to time-dependent multi-performance-based design approaches.Following a general introduction of the concept of sustainability applied to constructions,this paper presents an overview of life-time engineering methodologies according to the current state-of-the-art.In particular the methods currently received by International Standards are discussed.A special focus is devoted to the durability design of metal structures with respect to the degradation phenomena able to impair the structural capacity over time.Finally a proposal towards an integrated approach to life-time engineering design of steel structures and needs for further advances are presented.展开更多
滚动轴承是机械设备中的常见关键部件,准确预测其剩余使用寿命对机械设备的安全稳定运行至关重要。针对目前轴承寿命预测存在的轴承退化特征不明显、模型泛化能力差以及数据长期依赖关系难以捕捉的问题,提出基于时频域信号优化器(Time-F...滚动轴承是机械设备中的常见关键部件,准确预测其剩余使用寿命对机械设备的安全稳定运行至关重要。针对目前轴承寿命预测存在的轴承退化特征不明显、模型泛化能力差以及数据长期依赖关系难以捕捉的问题,提出基于时频域信号优化器(Time-Frequency domain signal Ratio Optimizer,TFRO)的多重膨胀多核时间卷积网络(Multi inflated Multi kernel Time Convolutional Network,Mi-MkTCN)模型。TFRO优化器为了精准记忆重要信息,在每一个时间节点上,将过去信息和当前信息重组,其中过去信息中的重要的时频域特征经过了有比例的分配。Mi-MkTCN利用多重膨胀确保重要特征不丢失,再利用多核时间卷积网络实现对不同尺度特征的提取。最终的消融对比实验验证了改进方法的有效性,模型的平均绝对误差、均方误差及均方根误差指标分别为0.00145、0.05069和0.12045。实验结果表明,所提方法显著提升了轴承剩余使用寿命的预测精度,为轴承剩余使用寿命预测提供了高精度、高鲁棒性的解决方案。展开更多
目的 探究前瞻性护理在预防机械通气患者发生ICU获得性衰弱(intensive care unit-acquired weakness,ICU-AW)中的作用。方法 选取2022年8月—2023年12月于南京医科大学附属南京医院呼吸与危重症医学科收治的67例机械通气患者。按照随机...目的 探究前瞻性护理在预防机械通气患者发生ICU获得性衰弱(intensive care unit-acquired weakness,ICU-AW)中的作用。方法 选取2022年8月—2023年12月于南京医科大学附属南京医院呼吸与危重症医学科收治的67例机械通气患者。按照随机数字表法分为对照组(n=33)和研究组(n=34),对照组接受常规护理,研究组在常规护理的基础上接受前瞻性护理。采用医学研究委员会肌力评分(Medical Research Council Muscle Strength,MRC)比较2组肌力,采用日常生活活动量表(Activity of Daily Living,ADL)及巴氏指数(Barthel Index,BI)量表评估2组日常生活能力。采用焦虑自评量表(Self-Rating Anxiety Scale,SAS)及抑郁自评量表(Self-Rating Depression Scale,SDS)评估患者的焦虑、抑郁状态,统计2组患者的机械通气时间及住院时间。结果 护理前2组患者的MRC评分差异无统计学意义(P>0.05),研究组患者护理前后的MRC得分差值高于对照组,差异具有统计学意义(t=4.082,P<0.001);护理前2组患者的ADL得分差异无统计学意义(P>0.05),研究组患者护理前后ADL评分差值高于对照组,差异具有统计学意义(t=8.906,P<0.001);护理前2组患者的BI评分无统计学意义(P>0.05),研究组患者护理前后BI评分差值高于对照组,差异具有统计学意义(t=2.386,P=0.036);护理前2组患者SAS评分及SDS评分差异均无统计学意义(P>0.05),研究组患者护理前后SAS评分及SDS评分差值均高于对照组,差异具有统计学意义(t=5.064、5.238,P均<0.001);研究组患者机械通气时间低于对照组(t=11.063,P<0.001),研究组患者平均住院时间低于对照组(t=10.169,P<0.001)。结论 前瞻性护理可以有效预防ICU-AW,提高患者自理能力,同时缓解患者焦虑、抑郁心理状态,减少其机械通气时间及住院时间,值得在临床中进一步研究与推广。展开更多
文摘In this paper, a novel accelerated test method was proposed to analyze the durability of MEA, considering the actual operation of the fuel cell vehicle. The proposed method includes 7 working conditions： open circuit voltage （OCV）, idling, rated output, overload, idling-rated cycle, idling-overload cycle, and OCV-idling cycle. The experimental results indicate that the proposed method can effectively destroy the MEA in a short time （165 h）. Moreover, the degradation mechanism of MEA was analyzed by measuring the polarization curve, CV, SEM and TEM. This paper may provide a new research direction for improving the durability of fuel cell.
基金the support from the European Cooperation in the field of Scientific and Technical Research(COST)
文摘Nowadays,the construction sector is more and more oriented toward the promotion of sustainability in all its activities.The goal to achieve is the optimization of performances,over the whole life-cycle,with respect to environmental,economic and social requirements.According to the latest advances,the concept of sustainability applied to constructions covers a number of branches such as life-cycle costing,ecology,durability and even structural design.Several procedures and design tools have been implemented in the framework of international research.Indeed the current trend in civil engineering research is moving towards life-time engineering,with the aim to implement integrated methodologies to consider as a whole all the sustainability requirements according to time-dependent multi-performance-based design approaches.Following a general introduction of the concept of sustainability applied to constructions,this paper presents an overview of life-time engineering methodologies according to the current state-of-the-art.In particular the methods currently received by International Standards are discussed.A special focus is devoted to the durability design of metal structures with respect to the degradation phenomena able to impair the structural capacity over time.Finally a proposal towards an integrated approach to life-time engineering design of steel structures and needs for further advances are presented.
文摘滚动轴承是机械设备中的常见关键部件,准确预测其剩余使用寿命对机械设备的安全稳定运行至关重要。针对目前轴承寿命预测存在的轴承退化特征不明显、模型泛化能力差以及数据长期依赖关系难以捕捉的问题,提出基于时频域信号优化器(Time-Frequency domain signal Ratio Optimizer,TFRO)的多重膨胀多核时间卷积网络(Multi inflated Multi kernel Time Convolutional Network,Mi-MkTCN)模型。TFRO优化器为了精准记忆重要信息,在每一个时间节点上,将过去信息和当前信息重组,其中过去信息中的重要的时频域特征经过了有比例的分配。Mi-MkTCN利用多重膨胀确保重要特征不丢失,再利用多核时间卷积网络实现对不同尺度特征的提取。最终的消融对比实验验证了改进方法的有效性,模型的平均绝对误差、均方误差及均方根误差指标分别为0.00145、0.05069和0.12045。实验结果表明,所提方法显著提升了轴承剩余使用寿命的预测精度,为轴承剩余使用寿命预测提供了高精度、高鲁棒性的解决方案。
文摘目的 探究前瞻性护理在预防机械通气患者发生ICU获得性衰弱(intensive care unit-acquired weakness,ICU-AW)中的作用。方法 选取2022年8月—2023年12月于南京医科大学附属南京医院呼吸与危重症医学科收治的67例机械通气患者。按照随机数字表法分为对照组(n=33)和研究组(n=34),对照组接受常规护理,研究组在常规护理的基础上接受前瞻性护理。采用医学研究委员会肌力评分(Medical Research Council Muscle Strength,MRC)比较2组肌力,采用日常生活活动量表(Activity of Daily Living,ADL)及巴氏指数(Barthel Index,BI)量表评估2组日常生活能力。采用焦虑自评量表(Self-Rating Anxiety Scale,SAS)及抑郁自评量表(Self-Rating Depression Scale,SDS)评估患者的焦虑、抑郁状态,统计2组患者的机械通气时间及住院时间。结果 护理前2组患者的MRC评分差异无统计学意义(P>0.05),研究组患者护理前后的MRC得分差值高于对照组,差异具有统计学意义(t=4.082,P<0.001);护理前2组患者的ADL得分差异无统计学意义(P>0.05),研究组患者护理前后ADL评分差值高于对照组,差异具有统计学意义(t=8.906,P<0.001);护理前2组患者的BI评分无统计学意义(P>0.05),研究组患者护理前后BI评分差值高于对照组,差异具有统计学意义(t=2.386,P=0.036);护理前2组患者SAS评分及SDS评分差异均无统计学意义(P>0.05),研究组患者护理前后SAS评分及SDS评分差值均高于对照组,差异具有统计学意义(t=5.064、5.238,P均<0.001);研究组患者机械通气时间低于对照组(t=11.063,P<0.001),研究组患者平均住院时间低于对照组(t=10.169,P<0.001)。结论 前瞻性护理可以有效预防ICU-AW,提高患者自理能力,同时缓解患者焦虑、抑郁心理状态,减少其机械通气时间及住院时间,值得在临床中进一步研究与推广。
