Objective:To explore the level of indoor radon concentration especially after recent 3 decades’great economic development in metropolis Beijing,so as to describe the outline of indoor radon level in Beijing.Methods:A...Objective:To explore the level of indoor radon concentration especially after recent 3 decades’great economic development in metropolis Beijing,so as to describe the outline of indoor radon level in Beijing.Methods:A one-year integrated measurement on 800 dwellings was carried out from September 2018 to August 2019.Passive integrated radon cup monitor with CR-39 as an alpha-track detector was adopted for the survey.As a pilot study,measurement scheme was designed in detail.For measurement quality control,the background track density of CR-39 was strictly defined and controlled throughout the operation of the survey.Results:The annual geometric and arithmetic mean of radon concentration of the surveyed are(39.3±12.9)and(42.0±13.7)Bq/m^(3),respectively,varying from(12.1±2.5)to(119.0±7.8)Bq/m^(3).Radon concentration of the ground floor dwellings is obviously higher than that of other floors.No difference of radon level is found among the dwellings of other floors.Higher radon concentration in buildings built after 2010 is obtained compared with buildings built in 1980s,1990s,and 2000s.Conclusions:There is no big change of radon concentration level in dwellings in Beijing area observed in general compared with a previous survey performed more than ten years ago.For high-rise buildings,building materials are suggested to be the main source of indoor radon.For higher radon concentration in buildings built in latest ten years,the change on building materials and indoor ventilation rate are thought to be the causes,further study in detail is needed to clarify.展开更多
针对萨北油田区块内油井配电变压器密集、配电线路纵横交错的问题,研究开发了油井集成优化配电系统,其主要由集成优化配控站、单井集成优化测控装置及监控中心三部分构成。该系统采用目前较为成熟的节能变压器、箱式变电站、微机数据采...针对萨北油田区块内油井配电变压器密集、配电线路纵横交错的问题,研究开发了油井集成优化配电系统,其主要由集成优化配控站、单井集成优化测控装置及监控中心三部分构成。该系统采用目前较为成熟的节能变压器、箱式变电站、微机数据采集控制及远传、低压自动无功补偿的供电技术,比单井变压器配电方式节约有功损耗电量47.5%,平均单井年节电4 200 k Wh,可实现油田生产高效益、低成本的目标。展开更多
文摘Objective:To explore the level of indoor radon concentration especially after recent 3 decades’great economic development in metropolis Beijing,so as to describe the outline of indoor radon level in Beijing.Methods:A one-year integrated measurement on 800 dwellings was carried out from September 2018 to August 2019.Passive integrated radon cup monitor with CR-39 as an alpha-track detector was adopted for the survey.As a pilot study,measurement scheme was designed in detail.For measurement quality control,the background track density of CR-39 was strictly defined and controlled throughout the operation of the survey.Results:The annual geometric and arithmetic mean of radon concentration of the surveyed are(39.3±12.9)and(42.0±13.7)Bq/m^(3),respectively,varying from(12.1±2.5)to(119.0±7.8)Bq/m^(3).Radon concentration of the ground floor dwellings is obviously higher than that of other floors.No difference of radon level is found among the dwellings of other floors.Higher radon concentration in buildings built after 2010 is obtained compared with buildings built in 1980s,1990s,and 2000s.Conclusions:There is no big change of radon concentration level in dwellings in Beijing area observed in general compared with a previous survey performed more than ten years ago.For high-rise buildings,building materials are suggested to be the main source of indoor radon.For higher radon concentration in buildings built in latest ten years,the change on building materials and indoor ventilation rate are thought to be the causes,further study in detail is needed to clarify.
文摘针对萨北油田区块内油井配电变压器密集、配电线路纵横交错的问题,研究开发了油井集成优化配电系统,其主要由集成优化配控站、单井集成优化测控装置及监控中心三部分构成。该系统采用目前较为成熟的节能变压器、箱式变电站、微机数据采集控制及远传、低压自动无功补偿的供电技术,比单井变压器配电方式节约有功损耗电量47.5%,平均单井年节电4 200 k Wh,可实现油田生产高效益、低成本的目标。
