Concern over the health effects of fine particles in the ambient environment led the U.S. Environmental Protection Agency to develop the first standard for PM2.5 （particulate matter less than 2.5 μm） in 1997. The P...Concern over the health effects of fine particles in the ambient environment led the U.S. Environmental Protection Agency to develop the first standard for PM2.5 （particulate matter less than 2.5 μm） in 1997. The Particle Technology Laboratory at the University of Minnesota has helped to establish the PM2.5 standard by developing many instruments and samplers to perform atmospheric measurements. In this paper, we review various aspects of PM2.5, including its measurement, source apportionment, visibility and health effects, and mitigation. We focus on PM2.s studies in China and where appropriate, compare them with those obtained in the U.S. Based on accurate PM2.5 sampling, chemical analysis, and source apportionment models, the major PM2.5 sources in China have been identified to be coal combustion, motor vehicle emissions, and industrial sources. Atmospheric visibility has been found to correlate well with PM2.s concentration. Sulfate, ammonium, and nitrate carried by PM2.s, commonly found in coal burning and vehicle emissions, are the dominant contributors to regional haze in China. Short-term exposure to PM2.s is strongly associated with the increased risk of morbidity and mortality from cardiovascular and respiratory diseases in China. The strategy for PMzs mitigation must be based on reducing the pollutants from the two primary sources of coal-fired power plants and vehicle emissions. Although conventional Particulate Emission Control Devices （PECD） such as electrostatic precipitators in Chinese coal-fired power plants are generally effective for large particles, most of them may not have high collection efficiency of PM2.5. Baghouse filtration is gradually incorporated into the PECD to increase the PM2.5 collection efficiency. By adopting stringent vehicle emissions standard such as Euro 5 and 6, the emissions from vehicles can be gradually reduced over the years. An integrative approach, from collaboration among academia, government, and industries, can effectively manage and mitigate the PM2.s p展开更多
Combining improved injector, gas line and valve-driving models, a gas chromatograph (GC) equipped with Hydrogen Flame Ionization Detector (FID) and Electron Capture Detector (ECD), can measure CH4, CO2, and N2O simult...Combining improved injector, gas line and valve-driving models, a gas chromatograph (GC) equipped with Hydrogen Flame Ionization Detector (FID) and Electron Capture Detector (ECD), can measure CH4, CO2, and N2O simultaneously in an air sample in four minutes. Test results show that the system has high sensitivity, resolution, and precision; the linear response range of the system meets the requirement of flux measurements in situ. The system is suitable for monitoring fluxes of the main greenhouse gases in a short-plant field since it is easy to use, efficacious, and constant and reliable in collecting data.展开更多
Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportati...Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportation,manufacturing,power generation,and residential.Previously published four case studies on passenger cars,trucks and buses,paper machines and the mining industry were included in our detailed calculations as reference data in our current analyses.The following can be concluded:-In total,～23％ (119 EJ) of the world's total energy consumption originates from tribological contacts.Of that 20％ (103 EJ) is used to overcome friction and 3％ (16 EJ) is used to remanufacture worn parts and spare equipment due to wear and wear-related failures.-By taking advantage of the new surface,materials,and lubrication technologies for friction reduction and wear protection in vehicles,machinery and other equipment worldwide,energy losses due to friction and wear could potentially be reduced by 40％ in the long term (15 years)and by 18％ in the short term (8 years).On global scale,these savings would amount to 1.4％ of the GDP annually and 8.7％ of the total energy consumption in the long term.-The largest short term energy savings are envisioned in transportation (25％) and in the power generation (20％) while the potential savings in the manufacturing and residential sectors are estimated to be ～10％.In the longer terms,the savings would be 55％,40％,25％,and 20％,respectively.-Implementing advanced tribological technologies can also reduce the CO2 emissions globally by as much as 1,460 MtCO2 and result in 450,000 million Euros cost savings in the short term.In the longer term,the reduction can be 3,140 MtCO2 and the cost savings 970,000 million Euros.Fifty years ago,wear and wear-related failures were a major concern for UK industry and their mitigation was considered to be the major contributor to potential economic savings by as much as 95％ in ten years by the development and deployment of new展开更多
A special kind of rice field exists in China that is flooded year-round. These rice fields have substantially large CH4 emissions during the rice-growing season and emit CH4 continuously in the non-rice growing season...A special kind of rice field exists in China that is flooded year-round. These rice fields have substantially large CH4 emissions during the rice-growing season and emit CH4 continuously in the non-rice growing season. CH4 emission factors were used to estimate the CH4 emissions from year-round flooded rice fields during the rice-growing season in China. The CH4 emissions for the year-round flooded rice fields in China for the rice growing season over a total area of 2.66 Mha were estimated to be 2.44 Tg CH…展开更多
遥感卫星的多光谱数据应用于找矿已取得显著成效,2004年7月中国卫星地面站开始提供ASTER(Advanced Space-borne Thermal Emission and Reflection Radiometer,高级星载热发射反照辐射计)数据,因涵盖波长范围宽[VNIR(Visible and Near In...遥感卫星的多光谱数据应用于找矿已取得显著成效,2004年7月中国卫星地面站开始提供ASTER(Advanced Space-borne Thermal Emission and Reflection Radiometer,高级星载热发射反照辐射计)数据,因涵盖波长范围宽[VNIR(Visible and Near Infra-red)、SWIR(Short wave-length Infra-red)、TIR(Thermal Infra-red)]、波段多(14个波段)、性价比合理等因素,ASTER数据的研究迅速发展。长久以来,对覆盖区进行蚀变遥感异常信息提取一直是遥感找矿的关注点之一。笔者等利用ASTER数据对浅覆盖区——包古图斑岩铜矿的Ⅱ号、Ⅴ号斑岩体进行蚀变遥感异常提取,提取的蚀变异常与野外地质情况吻合性好。分别提取了光谱特征谱带差异明显的2组蚀变矿物的异常信息:第一组是蒙脱石、埃洛石、伊利石与绢云母;第二组是方解石、黑云母与绿泥石。提出了需要进一步工作的异常靶区。展开更多
We study a generalized nonlinear KdV system is studied by using the homotopic mapping method. Firstly, a homotopic mapping transform is constructed; secondly, the suitable initial approximation is selected; then the h...We study a generalized nonlinear KdV system is studied by using the homotopic mapping method. Firstly, a homotopic mapping transform is constructed; secondly, the suitable initial approximation is selected; then the homotopic mapping is used. The accuracy of the approximate solution for the solitary wave is obtained. From the obtained approximate solution, the homotopic mapping method exhibits a good accuracy.展开更多
文摘Concern over the health effects of fine particles in the ambient environment led the U.S. Environmental Protection Agency to develop the first standard for PM2.5 （particulate matter less than 2.5 μm） in 1997. The Particle Technology Laboratory at the University of Minnesota has helped to establish the PM2.5 standard by developing many instruments and samplers to perform atmospheric measurements. In this paper, we review various aspects of PM2.5, including its measurement, source apportionment, visibility and health effects, and mitigation. We focus on PM2.s studies in China and where appropriate, compare them with those obtained in the U.S. Based on accurate PM2.5 sampling, chemical analysis, and source apportionment models, the major PM2.5 sources in China have been identified to be coal combustion, motor vehicle emissions, and industrial sources. Atmospheric visibility has been found to correlate well with PM2.s concentration. Sulfate, ammonium, and nitrate carried by PM2.s, commonly found in coal burning and vehicle emissions, are the dominant contributors to regional haze in China. Short-term exposure to PM2.s is strongly associated with the increased risk of morbidity and mortality from cardiovascular and respiratory diseases in China. The strategy for PMzs mitigation must be based on reducing the pollutants from the two primary sources of coal-fired power plants and vehicle emissions. Although conventional Particulate Emission Control Devices （PECD） such as electrostatic precipitators in Chinese coal-fired power plants are generally effective for large particles, most of them may not have high collection efficiency of PM2.5. Baghouse filtration is gradually incorporated into the PECD to increase the PM2.5 collection efficiency. By adopting stringent vehicle emissions standard such as Euro 5 and 6, the emissions from vehicles can be gradually reduced over the years. An integrative approach, from collaboration among academia, government, and industries, can effectively manage and mitigate the PM2.s p
文摘Combining improved injector, gas line and valve-driving models, a gas chromatograph (GC) equipped with Hydrogen Flame Ionization Detector (FID) and Electron Capture Detector (ECD), can measure CH4, CO2, and N2O simultaneously in an air sample in four minutes. Test results show that the system has high sensitivity, resolution, and precision; the linear response range of the system meets the requirement of flux measurements in situ. The system is suitable for monitoring fluxes of the main greenhouse gases in a short-plant field since it is easy to use, efficacious, and constant and reliable in collecting data.
文摘Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportation,manufacturing,power generation,and residential.Previously published four case studies on passenger cars,trucks and buses,paper machines and the mining industry were included in our detailed calculations as reference data in our current analyses.The following can be concluded:-In total,～23％ (119 EJ) of the world's total energy consumption originates from tribological contacts.Of that 20％ (103 EJ) is used to overcome friction and 3％ (16 EJ) is used to remanufacture worn parts and spare equipment due to wear and wear-related failures.-By taking advantage of the new surface,materials,and lubrication technologies for friction reduction and wear protection in vehicles,machinery and other equipment worldwide,energy losses due to friction and wear could potentially be reduced by 40％ in the long term (15 years)and by 18％ in the short term (8 years).On global scale,these savings would amount to 1.4％ of the GDP annually and 8.7％ of the total energy consumption in the long term.-The largest short term energy savings are envisioned in transportation (25％) and in the power generation (20％) while the potential savings in the manufacturing and residential sectors are estimated to be ～10％.In the longer terms,the savings would be 55％,40％,25％,and 20％,respectively.-Implementing advanced tribological technologies can also reduce the CO2 emissions globally by as much as 1,460 MtCO2 and result in 450,000 million Euros cost savings in the short term.In the longer term,the reduction can be 3,140 MtCO2 and the cost savings 970,000 million Euros.Fifty years ago,wear and wear-related failures were a major concern for UK industry and their mitigation was considered to be the major contributor to potential economic savings by as much as 95％ in ten years by the development and deployment of new
文摘A special kind of rice field exists in China that is flooded year-round. These rice fields have substantially large CH4 emissions during the rice-growing season and emit CH4 continuously in the non-rice growing season. CH4 emission factors were used to estimate the CH4 emissions from year-round flooded rice fields during the rice-growing season in China. The CH4 emissions for the year-round flooded rice fields in China for the rice growing season over a total area of 2.66 Mha were estimated to be 2.44 Tg CH…
文摘遥感卫星的多光谱数据应用于找矿已取得显著成效,2004年7月中国卫星地面站开始提供ASTER(Advanced Space-borne Thermal Emission and Reflection Radiometer,高级星载热发射反照辐射计)数据,因涵盖波长范围宽[VNIR(Visible and Near Infra-red)、SWIR(Short wave-length Infra-red)、TIR(Thermal Infra-red)]、波段多(14个波段)、性价比合理等因素,ASTER数据的研究迅速发展。长久以来,对覆盖区进行蚀变遥感异常信息提取一直是遥感找矿的关注点之一。笔者等利用ASTER数据对浅覆盖区——包古图斑岩铜矿的Ⅱ号、Ⅴ号斑岩体进行蚀变遥感异常提取,提取的蚀变异常与野外地质情况吻合性好。分别提取了光谱特征谱带差异明显的2组蚀变矿物的异常信息:第一组是蒙脱石、埃洛石、伊利石与绢云母;第二组是方解石、黑云母与绿泥石。提出了需要进一步工作的异常靶区。
基金Supported by the National Natural Science Foundation of China under Grant No 40676016, the National Basic Research Programme of China under Grant Nos 2003CB415101-03 and 2004CB418304, the Knowledge Innovation Project of Chinese Academy of Sciences under Grant No KZCX3-SW-221, in part by E-Institutes of Shanghai Municipal Education Commission under Grant No E03004.
文摘We study a generalized nonlinear KdV system is studied by using the homotopic mapping method. Firstly, a homotopic mapping transform is constructed; secondly, the suitable initial approximation is selected; then the homotopic mapping is used. The accuracy of the approximate solution for the solitary wave is obtained. From the obtained approximate solution, the homotopic mapping method exhibits a good accuracy.
