In this study, Ce1-xSmxO2-x/2 ceramics were synthesized by sol-gel route and solid state sintering method. The phase structure was analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, a...In this study, Ce1-xSmxO2-x/2 ceramics were synthesized by sol-gel route and solid state sintering method. The phase structure was analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy. The morphologies of the synthesized powders and the corresponding bulk samples were observed using scanning electron microscopy (SEM). Their thermal diffusivities and thermal expansion coefficients were measured by the laser-flash method and the pushing-rod method, respectively. Results show that pure Ce1-xSmxO2-x/2 powders with single fluorite structure are synthesized successfully, and their microstructures of the corresponding bulk samples are very dense. With the increase of Sm2O3 content, their thermal expansion coefficients decrease due to the higher electro-negativity of Sm3+ ions as compared with that of Ce4+ ions. Their thermal conductivities at 1000 degrees C lie in the range of 1.62-2.02 W/(m.K) due to the phonon scattering caused by the substituted atoms and oxygen vacancies. The Ce1-xSmxO2-x/2 ceramics can be used as ceramic candidates for novel thermal barrier coatings (TBCs).展开更多
Although numerous studies have investigated premature deaths attributable to temperature,effects of temperature on years of life lost(YLL)remain unclear.We estimated the relationship between temperatures and YLL,and q...Although numerous studies have investigated premature deaths attributable to temperature,effects of temperature on years of life lost(YLL)remain unclear.We estimated the relationship between temperatures and YLL,and quantified the YLL per death caused by temperature in China.We collected daily meteorological and mortality data,and calculated the daily YLL values for 364 locations(2013–2017 in Yunnan,Guangdong,Hunan,Zhejiang,and Jilin provinces,and 2006–2011 in other locations)in China.A time-series design with a distributed lag nonlinear model was first employed to estimate the location-specific associations between temperature and YLL rates(YLL/100,000 population),and a multivariate meta-analysis model was used to pool location-specific associations.Then,YLL per death caused by temperatures was calculated.The temperature and YLL rates consistently showed U-shaped associations.A mean of 1.02(95%confidence interval:0.67,1.37)YLL per death was attributable to temperature.Cold temperature caused 0.98 YLL per death with most from moderate cold(0.84).The mean YLL per death was higher in those with cardiovascular diseases(1.14),males(1.15),younger age categories(1.31 in people aged 65–74 years),and in central China(1.34)than in those with respiratory diseases(0.47),females(0.87),older people(0.85 in people R75 years old),and northern China(0.64)or southern China(1.19).The mortality burden was modified by annual temperature and temperature variability,relative humidity,latitude,longitude,altitude,education attainment,and central heating use.Temperatures caused substantial YLL per death in China,which was modified by demographic and regional characteristics.展开更多
基金The authors would like to thank the financial support from the National Natural Science Foundation of China，the Scientific and Technological Projects of Henan Province，the Program for Science & Technology Innovation Talents in Universities of Henan Province，the Postaldoctoral Research Sponsorship in Henan Province
文摘In this study, Ce1-xSmxO2-x/2 ceramics were synthesized by sol-gel route and solid state sintering method. The phase structure was analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy. The morphologies of the synthesized powders and the corresponding bulk samples were observed using scanning electron microscopy (SEM). Their thermal diffusivities and thermal expansion coefficients were measured by the laser-flash method and the pushing-rod method, respectively. Results show that pure Ce1-xSmxO2-x/2 powders with single fluorite structure are synthesized successfully, and their microstructures of the corresponding bulk samples are very dense. With the increase of Sm2O3 content, their thermal expansion coefficients decrease due to the higher electro-negativity of Sm3+ ions as compared with that of Ce4+ ions. Their thermal conductivities at 1000 degrees C lie in the range of 1.62-2.02 W/(m.K) due to the phonon scattering caused by the substituted atoms and oxygen vacancies. The Ce1-xSmxO2-x/2 ceramics can be used as ceramic candidates for novel thermal barrier coatings (TBCs).
基金We thank Professor Antonio Gasparrini for providing assistance during statistical analysis.This work was supported by the National Key Research and Development Program of China(2018YFA0606200)Guangzhou Science and Technology Project(201704020194)+3 种基金and the Guangdong Health Innovation Platform.The funders were not involved in the research and preparation of the article,including study designcollection,analysis,and interpretation of datawriting of the articleand the decision to submit it for publication.
文摘Although numerous studies have investigated premature deaths attributable to temperature,effects of temperature on years of life lost(YLL)remain unclear.We estimated the relationship between temperatures and YLL,and quantified the YLL per death caused by temperature in China.We collected daily meteorological and mortality data,and calculated the daily YLL values for 364 locations(2013–2017 in Yunnan,Guangdong,Hunan,Zhejiang,and Jilin provinces,and 2006–2011 in other locations)in China.A time-series design with a distributed lag nonlinear model was first employed to estimate the location-specific associations between temperature and YLL rates(YLL/100,000 population),and a multivariate meta-analysis model was used to pool location-specific associations.Then,YLL per death caused by temperatures was calculated.The temperature and YLL rates consistently showed U-shaped associations.A mean of 1.02(95%confidence interval:0.67,1.37)YLL per death was attributable to temperature.Cold temperature caused 0.98 YLL per death with most from moderate cold(0.84).The mean YLL per death was higher in those with cardiovascular diseases(1.14),males(1.15),younger age categories(1.31 in people aged 65–74 years),and in central China(1.34)than in those with respiratory diseases(0.47),females(0.87),older people(0.85 in people R75 years old),and northern China(0.64)or southern China(1.19).The mortality burden was modified by annual temperature and temperature variability,relative humidity,latitude,longitude,altitude,education attainment,and central heating use.Temperatures caused substantial YLL per death in China,which was modified by demographic and regional characteristics.
