The increasing emission of primary and gaseous precursors of secondarily formed atmospheric particulate matter due to continuing industrial development and urbanization are leading to an increased public awareness of ...The increasing emission of primary and gaseous precursors of secondarily formed atmospheric particulate matter due to continuing industrial development and urbanization are leading to an increased public awareness of environmental issues and human health risks in China. As part of a pilot study, 12-h integrated fine fraction particulate matter （PM2.5） filter samples were collected to chemically characterize and investigate the sources of ambient particulate matter in Guiyang City, Guizhou Province, southwestern China. Results showed that the 12-h integrated PM2.5 concentrations exhibited a daytime average of 51 ± 22 μg m^-3 （mean -4- standard deviation） with a range of 17-128 μg m^-3 and a nighttime average of 55 ± 32 μg m^-3 with a range of 4-186 μg m^-3. The 24-h integrated PM2.5 concentrations varied from 15 to 157 μg m^-3, with amean value of 53 ± 25 μg m^-3, which exceeded the 24-h PM2.5 standard of 35μg m^-3 set by USEPA, but was below the standard of 75 μg m^-3, set by China Ministry of Environmental Protection. Energy-dispersive X-ray fluorescence spectrometry （XRF） was applied to determine PM2.5 chemical element concentrations. The order of concentrations of heavy metals in PM2.5 were iron （Fe） 〉 zinc （Zn） 〉 manganese （Mn） 〉 lead （Pb） 〉 arsenic （As）〉 chromium （Cr）. The total concentration of 18 chemical elements was 13 ± 2 μg m^-3, accounting for 25% in PM2.5, which is comparable to other major cities in China, but much higher than cities outside of China.展开更多
In China, the technical information currently available both domestically and abroad has been reviewed in an attempt to integrate the technique of ultraviolet air disinfection with Grade Ⅱ filters and develop a steri...In China, the technical information currently available both domestically and abroad has been reviewed in an attempt to integrate the technique of ultraviolet air disinfection with Grade Ⅱ filters and develop a sterile conservation-oriented environment. As detection showed, such a sanitary system of air disinfection, integrated by ultraviolet air disinfection and Grade Ⅱ filters can reach the same standard of cleanliness as a high efficiency particle filter. This system easily satisfies the cleaning of air in hospital wards, surpassing the sterile air standards and the requirements of the National Bacteria Indicator （NBI）. As a result of this system＇s efficiency, resources and running costs can be reduced dramatically. Therefore, revision of the national standards of Structural Technical Specification of the Cleaning Operation Department needs to move forward.展开更多
Constacyclic codes are an important class of linear codes in coding theory.Many optimal linear codes are directly derived from constacyclic codes.In this paper,(1 — uv)-constacyclic codes over the local ring F_p + uF...Constacyclic codes are an important class of linear codes in coding theory.Many optimal linear codes are directly derived from constacyclic codes.In this paper,(1 — uv)-constacyclic codes over the local ring F_p + uF_p + vF_p + uvF_p are studied.It is proved that the image of a(1 — uv)-constacyclic code of length n over F_p + uF_p + vF_p + uvF_p under a Gray map is a distance invariant quasi-cyclic code of index p2 and length p^3n over F_p.Several examples of optimal linear codes over F_p from(1 — uv)-constacyclic codes over F_p + uF_p + vF_p + uvF_p are given.展开更多
基金The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development, partially funded and participated in the research described here through cooperative agreement CR-833232-01 through the U.S. National Science Foundation-National Research Council Research Associateship Awardfunded by the National Key Basic Research Program of China (2013CB430004)the National Natural Science Foundation of China (No. 40773067)
文摘The increasing emission of primary and gaseous precursors of secondarily formed atmospheric particulate matter due to continuing industrial development and urbanization are leading to an increased public awareness of environmental issues and human health risks in China. As part of a pilot study, 12-h integrated fine fraction particulate matter （PM2.5） filter samples were collected to chemically characterize and investigate the sources of ambient particulate matter in Guiyang City, Guizhou Province, southwestern China. Results showed that the 12-h integrated PM2.5 concentrations exhibited a daytime average of 51 ± 22 μg m^-3 （mean -4- standard deviation） with a range of 17-128 μg m^-3 and a nighttime average of 55 ± 32 μg m^-3 with a range of 4-186 μg m^-3. The 24-h integrated PM2.5 concentrations varied from 15 to 157 μg m^-3, with amean value of 53 ± 25 μg m^-3, which exceeded the 24-h PM2.5 standard of 35μg m^-3 set by USEPA, but was below the standard of 75 μg m^-3, set by China Ministry of Environmental Protection. Energy-dispersive X-ray fluorescence spectrometry （XRF） was applied to determine PM2.5 chemical element concentrations. The order of concentrations of heavy metals in PM2.5 were iron （Fe） 〉 zinc （Zn） 〉 manganese （Mn） 〉 lead （Pb） 〉 arsenic （As）〉 chromium （Cr）. The total concentration of 18 chemical elements was 13 ± 2 μg m^-3, accounting for 25% in PM2.5, which is comparable to other major cities in China, but much higher than cities outside of China.
文摘In China, the technical information currently available both domestically and abroad has been reviewed in an attempt to integrate the technique of ultraviolet air disinfection with Grade Ⅱ filters and develop a sterile conservation-oriented environment. As detection showed, such a sanitary system of air disinfection, integrated by ultraviolet air disinfection and Grade Ⅱ filters can reach the same standard of cleanliness as a high efficiency particle filter. This system easily satisfies the cleaning of air in hospital wards, surpassing the sterile air standards and the requirements of the National Bacteria Indicator （NBI）. As a result of this system＇s efficiency, resources and running costs can be reduced dramatically. Therefore, revision of the national standards of Structural Technical Specification of the Cleaning Operation Department needs to move forward.
基金supported by the National Natural Science Foundation of China under Grant No.61370089the Natural Science Foundation of Anhui Province under Grant No.1208085MA14+2 种基金the Natural Science Fund of Education Department of Anhui province under Grant No.KJ2013Z276the Fundamental Research Fundsof Hefei University under Grant No.10KY01ZDthe Key construction discipline Funds of Hefei University under Grant No.2014XK08
文摘Constacyclic codes are an important class of linear codes in coding theory.Many optimal linear codes are directly derived from constacyclic codes.In this paper,(1 — uv)-constacyclic codes over the local ring F_p + uF_p + vF_p + uvF_p are studied.It is proved that the image of a(1 — uv)-constacyclic code of length n over F_p + uF_p + vF_p + uvF_p under a Gray map is a distance invariant quasi-cyclic code of index p2 and length p^3n over F_p.Several examples of optimal linear codes over F_p from(1 — uv)-constacyclic codes over F_p + uF_p + vF_p + uvF_p are given.
