Considerable progress has been achieved in friction stir welding （FSW） of steels in every aspect of tool fab- rication, microstructure control and properties evaluation in the past two decades. With the development ...Considerable progress has been achieved in friction stir welding （FSW） of steels in every aspect of tool fab- rication, microstructure control and properties evaluation in the past two decades. With the development of reliable welding tools and precise control systems, FSW of steels has reached a new level of technical maturity. High-quality, long welds can be produced in many engineering steels. Compared to traditional fusion welding, FSW exhibits unique advantages producing joints with better properties. As a result of active control of the welding temperature and/or cooling rate, FSW has the capability of fabricating steel joints with excellent toughness and strength. For example, unfavorable phase transformations that usu- ally occur during traditional welding can be avoided and favorable phase fractions in advanced steels can be maintained in the weld zone thus avoiding the typical property degradations associated with fusion welding. If phase transformations do occur during FSW of thick steels, optimization of microstructure and properties can be attained by controlling the heat input and post-weld cooling rate.展开更多
What is already known about this topic?The World Health Organization set a 2030 target of 70%cervical cancer screening coverage for women aged 35–45 years.Coverage stood at 37%in China in 2015.What is added by this r...What is already known about this topic?The World Health Organization set a 2030 target of 70%cervical cancer screening coverage for women aged 35–45 years.Coverage stood at 37%in China in 2015.What is added by this report?In 2018–2019,China’s cervical cancer screening coverage reached 43.4%in women aged 35–44 years and 36.8%in women aged 35–64 years.Screening coverage was still lower in rural areas as well as central and western regions;large variations existed across provincial-level administrative divisions.What are the implications for public health practice?National and local policy and financial support should be maintained for cervical cancer screening,along with more targeted health education and outreach efforts and strengthened accessibility of health services in the rural areas and central and western regions.展开更多
Introduction:Foodborne diseases are a growing public health problem and have caused a large burden of disease in China.This study analyzed epidemiological characteristics of foodborne diseases in China in 2020 to prov...Introduction:Foodborne diseases are a growing public health problem and have caused a large burden of disease in China.This study analyzed epidemiological characteristics of foodborne diseases in China in 2020 to provide a scientific basis for prevention and control measures.Methods:Data were collected from 30 of 31 provincial-level administrative divisions(PLADs)in the mainland of China,excluding Xizang(Tibet)Autonomous Region,via the National Foodborne Disease Outbreaks Surveillance System・The number and proportion of outbreaks,illnesses,hospitalizations,deaths by setting,pathogen-food category pairs and etiology were calculated.Results:In 2020,7,073 foodborne disease outbreaks were reported,resulting in 37,454 illnesses and 143 deaths.Among the identified pathogens,microbial pathogens were the most common confirmed etiology,accounting for 41.7%of illnesses.Poisonous mushrooms caused the largest proportion of outbreaks(58.0%)and deaths(57.6%).For venues where foodborne disease outbreaks occur,household had the highest number of outbreaks(4,140)and deaths(128),and catering service locations caused the largest proportion of illnesses(59.9%).Outbreaks occurring between June and September accounted for 62.8%of total outbreaks.Conclusions:Foodborne disease outbreaks mainly occurred in households・Microbial pathogens remained the top cause of outbreak-associated illnesses.Poisonous mushrooms were ranked the top cause of deaths in private homes in China.The supervision and management of food safety and health education should be strengthened to reduce the burden of foodborne diseases・Publicity should be increased to reduce the incidence of mushroom poisonings in families,and supervision and management of food should be strengthened to reduce microbial contamination.展开更多
What is already known on this topic?Aerosol transmission was one route for the spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and usually occurred in confined spaces.What is added by this report?...What is already known on this topic?Aerosol transmission was one route for the spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and usually occurred in confined spaces.What is added by this report?Aerosol transmission was found to exist between handshake buildings,i.e.,buildings with extremely close proximity that formed relatively enclosed spaces.Transmission was mainly affected by the airflow layout caused by switching air conditioners on and off as well as opening and closing doors and windows.What are the implications for public health practice?Centralized isolation and home isolation in handshake buildings creates a risk of SARS-CoV-2 aerosol transmission under certain conditions.Attention should be paid to the influence of air distribution layout on aerosol diffusion in isolation wards,and disinfection of isolation venues should be strengthened.展开更多
Designing a material with multiple desired properties is a great challenge,especially in a complex material system.Here,we propose a material design strategy to simultaneously optimize multiple targeted properties of ...Designing a material with multiple desired properties is a great challenge,especially in a complex material system.Here,we propose a material design strategy to simultaneously optimize multiple targeted properties of multi-component Co-base superalloys via machine learning.The microstructural stability,γ′solvus temperature,γ′volume fraction,density,processing window,freezing range,and oxidation resistance were simultaneously optimized.展开更多
文摘Considerable progress has been achieved in friction stir welding （FSW） of steels in every aspect of tool fab- rication, microstructure control and properties evaluation in the past two decades. With the development of reliable welding tools and precise control systems, FSW of steels has reached a new level of technical maturity. High-quality, long welds can be produced in many engineering steels. Compared to traditional fusion welding, FSW exhibits unique advantages producing joints with better properties. As a result of active control of the welding temperature and/or cooling rate, FSW has the capability of fabricating steel joints with excellent toughness and strength. For example, unfavorable phase transformations that usu- ally occur during traditional welding can be avoided and favorable phase fractions in advanced steels can be maintained in the weld zone thus avoiding the typical property degradations associated with fusion welding. If phase transformations do occur during FSW of thick steels, optimization of microstructure and properties can be attained by controlling the heat input and post-weld cooling rate.
文摘What is already known about this topic?The World Health Organization set a 2030 target of 70%cervical cancer screening coverage for women aged 35–45 years.Coverage stood at 37%in China in 2015.What is added by this report?In 2018–2019,China’s cervical cancer screening coverage reached 43.4%in women aged 35–44 years and 36.8%in women aged 35–64 years.Screening coverage was still lower in rural areas as well as central and western regions;large variations existed across provincial-level administrative divisions.What are the implications for public health practice?National and local policy and financial support should be maintained for cervical cancer screening,along with more targeted health education and outreach efforts and strengthened accessibility of health services in the rural areas and central and western regions.
基金Supported by The National Key Research and Development Program of China(Grant number 2017YFC1601502).
文摘Introduction:Foodborne diseases are a growing public health problem and have caused a large burden of disease in China.This study analyzed epidemiological characteristics of foodborne diseases in China in 2020 to provide a scientific basis for prevention and control measures.Methods:Data were collected from 30 of 31 provincial-level administrative divisions(PLADs)in the mainland of China,excluding Xizang(Tibet)Autonomous Region,via the National Foodborne Disease Outbreaks Surveillance System・The number and proportion of outbreaks,illnesses,hospitalizations,deaths by setting,pathogen-food category pairs and etiology were calculated.Results:In 2020,7,073 foodborne disease outbreaks were reported,resulting in 37,454 illnesses and 143 deaths.Among the identified pathogens,microbial pathogens were the most common confirmed etiology,accounting for 41.7%of illnesses.Poisonous mushrooms caused the largest proportion of outbreaks(58.0%)and deaths(57.6%).For venues where foodborne disease outbreaks occur,household had the highest number of outbreaks(4,140)and deaths(128),and catering service locations caused the largest proportion of illnesses(59.9%).Outbreaks occurring between June and September accounted for 62.8%of total outbreaks.Conclusions:Foodborne disease outbreaks mainly occurred in households・Microbial pathogens remained the top cause of outbreak-associated illnesses.Poisonous mushrooms were ranked the top cause of deaths in private homes in China.The supervision and management of food safety and health education should be strengthened to reduce the burden of foodborne diseases・Publicity should be increased to reduce the incidence of mushroom poisonings in families,and supervision and management of food should be strengthened to reduce microbial contamination.
文摘What is already known on this topic?Aerosol transmission was one route for the spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and usually occurred in confined spaces.What is added by this report?Aerosol transmission was found to exist between handshake buildings,i.e.,buildings with extremely close proximity that formed relatively enclosed spaces.Transmission was mainly affected by the airflow layout caused by switching air conditioners on and off as well as opening and closing doors and windows.What are the implications for public health practice?Centralized isolation and home isolation in handshake buildings creates a risk of SARS-CoV-2 aerosol transmission under certain conditions.Attention should be paid to the influence of air distribution layout on aerosol diffusion in isolation wards,and disinfection of isolation venues should be strengthened.
基金We gratefully acknowledge the financial support of National Key Research and Development Program of China(2016YFB0700505 and 2017YFB0702902)Guangdong Province Key Area R&D Program(2019B010940001)Scientific and Technological Innovation Foundation of Shunde Graduate School,USTB(BK19BE030).
文摘Designing a material with multiple desired properties is a great challenge,especially in a complex material system.Here,we propose a material design strategy to simultaneously optimize multiple targeted properties of multi-component Co-base superalloys via machine learning.The microstructural stability,γ′solvus temperature,γ′volume fraction,density,processing window,freezing range,and oxidation resistance were simultaneously optimized.
