Background:An outbreak of 2019 novel coronavirus diseases(COVID-19)in Wuhan,Hubei Province,China has spread quickly nationwide.Here,we report results of a descriptive,exploratory analysis of all cases diagnosed as of ...Background:An outbreak of 2019 novel coronavirus diseases(COVID-19)in Wuhan,Hubei Province,China has spread quickly nationwide.Here,we report results of a descriptive,exploratory analysis of all cases diagnosed as of February 11,2020.Methods:All COVID-19 cases reported through February 11,2020 were extracted from China’s Infectious Disease Information System.Analyses included the following:(1)summary of patient characteristics;(2)examination of age distributions and sex ratios;(3)calculation of case fatality and mortality rates;(4)geo-temporal analysis of viral spread;(5)epidemiological curve construction;and (6)subgroup analysis.Results:A total of 72,314 patient records—44,672(61.8%)confirmed cases,16,186(22.4%)suspected cases,10,567(14.6%)clinically diagnosed cases(Hubei Province only),and 889 asymptomatic cases(1.2%)-contributed data for the analysis.Among confirmed cases,most were aged 30–79 years(86.6%),diagnosed in Hubei(74.7%),and considered mild(80.9%).A total of 1,023 deaths occurred among confirmed cases for an overall case fatality rate of 2.3%.The COVID-19 spread outward from Hubei Province sometime after December 2019,and by February 11,2020,1,386 counties across all 31 provinces were affected.The epidemic curve of onset of symptoms peaked around January 23–26,then began to decline leading up to February 11.A total of 1,716 health workers have become infected and 5 have died(0.3%).Conclusions:COVID-19 epidemic has spread very quickly taking only 30 days to expand from Hubei to the rest of China's Mainland.With many people returning from a long holiday,China needs to prepare for the possible rebound of the epidemic.展开更多
The fire-extinguishing capability of aqueous film-forming foam(AFFF) is usually evaluated by actual fire-fighting test.It is not only costly,but also unfavorably to environment and safety.Therefore,it is of importance...The fire-extinguishing capability of aqueous film-forming foam(AFFF) is usually evaluated by actual fire-fighting test.It is not only costly,but also unfavorably to environment and safety.Therefore,it is of importance to find means to evaluate the performance of AFFF indoor.In this work a simple laboratory method for evaluating the performance of AFFF is proposed,based on the principle of AFFF and our researches on AFFF.It is found that the fire-extinguishing capability of AFFF could be evaluated by five parameters.1) spread ability of AFFF on the oil,2) the spread amount of AFFF on oil,3) foaming ability of AFFF,4) speed of liquid eduction from foam,5) stability of foam.These parameters can be measured easily in common laboratory,by which the fire-extinguishing capability of AFFF can be evaluated without actual fire-extinguishing test.展开更多
基金supported by National Science and Technology Foundation of China(2018ZX10201002-008-002),and by National Nature Science Foundation of China(NSFC,71934002).
文摘Background:An outbreak of 2019 novel coronavirus diseases(COVID-19)in Wuhan,Hubei Province,China has spread quickly nationwide.Here,we report results of a descriptive,exploratory analysis of all cases diagnosed as of February 11,2020.Methods:All COVID-19 cases reported through February 11,2020 were extracted from China’s Infectious Disease Information System.Analyses included the following:(1)summary of patient characteristics;(2)examination of age distributions and sex ratios;(3)calculation of case fatality and mortality rates;(4)geo-temporal analysis of viral spread;(5)epidemiological curve construction;and (6)subgroup analysis.Results:A total of 72,314 patient records—44,672(61.8%)confirmed cases,16,186(22.4%)suspected cases,10,567(14.6%)clinically diagnosed cases(Hubei Province only),and 889 asymptomatic cases(1.2%)-contributed data for the analysis.Among confirmed cases,most were aged 30–79 years(86.6%),diagnosed in Hubei(74.7%),and considered mild(80.9%).A total of 1,023 deaths occurred among confirmed cases for an overall case fatality rate of 2.3%.The COVID-19 spread outward from Hubei Province sometime after December 2019,and by February 11,2020,1,386 counties across all 31 provinces were affected.The epidemic curve of onset of symptoms peaked around January 23–26,then began to decline leading up to February 11.A total of 1,716 health workers have become infected and 5 have died(0.3%).Conclusions:COVID-19 epidemic has spread very quickly taking only 30 days to expand from Hubei to the rest of China's Mainland.With many people returning from a long holiday,China needs to prepare for the possible rebound of the epidemic.
文摘The fire-extinguishing capability of aqueous film-forming foam(AFFF) is usually evaluated by actual fire-fighting test.It is not only costly,but also unfavorably to environment and safety.Therefore,it is of importance to find means to evaluate the performance of AFFF indoor.In this work a simple laboratory method for evaluating the performance of AFFF is proposed,based on the principle of AFFF and our researches on AFFF.It is found that the fire-extinguishing capability of AFFF could be evaluated by five parameters.1) spread ability of AFFF on the oil,2) the spread amount of AFFF on oil,3) foaming ability of AFFF,4) speed of liquid eduction from foam,5) stability of foam.These parameters can be measured easily in common laboratory,by which the fire-extinguishing capability of AFFF can be evaluated without actual fire-extinguishing test.
