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
目的分析1990—2019亚洲主要国家及全球宫颈癌疾病负担,为制定宫颈癌防控策略提供科学依据。方法收集1990—2019年全球疾病负担研究(global burden of disease,GBD)数据,利用发病、死亡、伤残调整寿命年(disability-adjusted life years...目的分析1990—2019亚洲主要国家及全球宫颈癌疾病负担,为制定宫颈癌防控策略提供科学依据。方法收集1990—2019年全球疾病负担研究(global burden of disease,GBD)数据,利用发病、死亡、伤残调整寿命年(disability-adjusted life years,DALY)等指标定量评估宫颈癌的疾病负担情况,采用估计百分百变化(estimated annual percent change,EAPC)分析疾病负担时间变化趋势。结果1990—2019年,全球宫颈癌标化发病率从7.64/10万下降至6.81/10万,标化死亡率从4.46/10万降低至3.40/10万,标化DALY率从139.98/10万下降至107.20/10万,年平均降低分别为0.39%、0.96%、0.94%(EAPC<0,P<0.05)。亚洲主要国家中,中国的标化发病率从4.20/10万上升至5.53/10万,平均每年增长1.63%(EAPC>0,P>0.05)。中国宫颈癌的死亡数从2.64万增加到5.34万,相对增长1.02倍,全球及亚洲主要国家标化死亡率、标化DALY率均呈逐年下降趋势,而中国未出现下降趋势。相关分析显示,发病率与社会人口指数(socio-demographic index,SDI)无明显相关性(ρ=-0.13,P=0.11),死亡率与SDI呈负相关(ρ=-0.74,P<0.001),DALY与SDI也呈负相关(ρ=-0.77,P<0.001)。结论中国宫颈癌的标化发病率、死亡率逐年增加,疾病负担呈上升趋势,应积极采取科学有效的防控措施,降低宫颈癌疾病负担。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.
文摘目的分析1990—2019亚洲主要国家及全球宫颈癌疾病负担,为制定宫颈癌防控策略提供科学依据。方法收集1990—2019年全球疾病负担研究(global burden of disease,GBD)数据,利用发病、死亡、伤残调整寿命年(disability-adjusted life years,DALY)等指标定量评估宫颈癌的疾病负担情况,采用估计百分百变化(estimated annual percent change,EAPC)分析疾病负担时间变化趋势。结果1990—2019年,全球宫颈癌标化发病率从7.64/10万下降至6.81/10万,标化死亡率从4.46/10万降低至3.40/10万,标化DALY率从139.98/10万下降至107.20/10万,年平均降低分别为0.39%、0.96%、0.94%(EAPC<0,P<0.05)。亚洲主要国家中,中国的标化发病率从4.20/10万上升至5.53/10万,平均每年增长1.63%(EAPC>0,P>0.05)。中国宫颈癌的死亡数从2.64万增加到5.34万,相对增长1.02倍,全球及亚洲主要国家标化死亡率、标化DALY率均呈逐年下降趋势,而中国未出现下降趋势。相关分析显示,发病率与社会人口指数(socio-demographic index,SDI)无明显相关性(ρ=-0.13,P=0.11),死亡率与SDI呈负相关(ρ=-0.74,P<0.001),DALY与SDI也呈负相关(ρ=-0.77,P<0.001)。结论中国宫颈癌的标化发病率、死亡率逐年增加,疾病负担呈上升趋势,应积极采取科学有效的防控措施,降低宫颈癌疾病负担。
