A new element tracer technique has firstly been established to estimate the contributions of mineral aerosols from both inside and outside Beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to disting...A new element tracer technique has firstly been established to estimate the contributions of mineral aerosols from both inside and outside Beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside Beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in Beijing, of which mineral aerosol accounted for 32%―67% of total suspended particles (TSP), 10%―70% of fine particles (PM2.5), and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside Beijing contributed 62% (38%―86%) of the total mineral aerosols in TSP, 69% (52%―90%) in PM10, and 76% (59%―93%) in PM2.5 in spring, and 69% (52%―83%), 79% (52%―93%), and 45% (7%―79%) in TSP, PM10, and PM2.5, respectively, in winter, while only ～20% in summer and autumn. The sources from outside Beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in Beijing. The contributions from outside Beijing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.展开更多
For a long time,most studies about pyrite have focused on sediments while only a few have focused on pyrite in water.In this study,a method that combines the scanning electron microscopy(SEM)and the energy dispersive ...For a long time,most studies about pyrite have focused on sediments while only a few have focused on pyrite in water.In this study,a method that combines the scanning electron microscopy(SEM)and the energy dispersive X-ray spectrometry(EDS)was used to compare pyrite particles suspended in water to those in associated bottom sediments,both obtained from the mixing zone of the Yangtze Estuary.It was found that the pyrite particles in the two media have similar morphologies and size distributions.The particle morphology mainly includes two types,single crystal and aggregate,and the particle size mainly ranges from 0.5 to 2μm.The pyrite particles in water exhibit an increase in relative content towards the sea,and their transport and deposit processes are mainly affected by hydrodynamic conditions.It is concluded that the pyrite particles in the suspended matter mainly derived from the resuspension of sediments,which are products of the early diagenesis.Precursor minerals may appear during the formation of pyrite,but are generally restricted by the diagenetic environment and local microenvironment.展开更多
Rahughat Hydroelectric Project is an ROR （run of river） project with the installed capacity of 40 MW. The suspended sediment study was carried out in 2008 and 2015 AD. The present study is concentrated on the study ...Rahughat Hydroelectric Project is an ROR （run of river） project with the installed capacity of 40 MW. The suspended sediment study was carried out in 2008 and 2015 AD. The present study is concentrated on the study carried out in 2015 AD. The suspended sediment samples were collected in the headworks site and its analysis was done in Hydro Lab Pvt. Ltd. Concentration analysis, PSD （particle size distribution） analysis and mineral content analysis were carried out. The minimum and maximum sediment concentration is 54 PPM and 3,759 PPM respectively. The PSD analysis shows that 52% of the suspended sediment contained sand fraction and 48% is fine sediments. The mineral content analysis shows presence of quartz, feldspar, mica, kyanite, garnet, carbonates, chlorite, clay and some fragments of shale, phyllite and slate with few unidentified sediments. The proposed desander in RGHEP is designed to settle particles of size 0.2 mm and above. The sediments lesser than 0.2 mm size that reach the turbine may affect the loss of turbine material due to erosion.展开更多
Severe damage to suspended ceilings of metal grids and lay-in panels was observed in public buildings during the 2013 M7.0 Lushan earthquake in China. Over the past several years, suspended ceilings have been widely u...Severe damage to suspended ceilings of metal grids and lay-in panels was observed in public buildings during the 2013 M7.0 Lushan earthquake in China. Over the past several years, suspended ceilings have been widely used practice in public buildings throughout China, including government offices, schools and hospitals. To investigate the damage mechanism of suspended ceilings, a series of three-dimensional shake table tests was conducted to reproduce the observed damage. A full-scale reinforced concrete frame was constructed as the testing frame for the ceiling, which was single-story and infilled with brick masonry walls to represent the local construction of low-rise buildings. In general, the ceiling in the tests exhibited similar damage phenomena as the field observations, such as higher vulnerability of perimeter elements and extensive damage to the cross runners. However, it exhibited lower fragility in terms of peak ground/roof accelerations at the initiation of damage. Further investigations are needed to clarify the reasons for this behavior.展开更多
基金the National Natural Science Foundation of China(Grant Nos.29837190,30230310,20077004&20477004)Beijing Natural Science Foundation(Grant Nos.8991002 , 8041003)+3 种基金the special fund for the doctoral s tudy of the Education Ministry of China(20010027017)“100-talent Project of CAS(dust transport)”,LAPCThe Institute of Atmospheric Phys ics,CAS the Swedish International Development Cooperation Agency(SIDA)through the Asian Regional Research Program on Environmental Technology(ARRPET)at the Asian Institute of Technology.
文摘A new element tracer technique has firstly been established to estimate the contributions of mineral aerosols from both inside and outside Beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside Beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in Beijing, of which mineral aerosol accounted for 32%―67% of total suspended particles (TSP), 10%―70% of fine particles (PM2.5), and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside Beijing contributed 62% (38%―86%) of the total mineral aerosols in TSP, 69% (52%―90%) in PM10, and 76% (59%―93%) in PM2.5 in spring, and 69% (52%―83%), 79% (52%―93%), and 45% (7%―79%) in TSP, PM10, and PM2.5, respectively, in winter, while only ～20% in summer and autumn. The sources from outside Beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in Beijing. The contributions from outside Beijing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.
基金the National Natural Science Foundation of China(NSFC)who organized the public survey cruise in the Yangtze River Estuary in March 2015,with special thanks to the crew of the R/V Run Jiang No.1 for kindly assisting in sediment sampling on the cruiseThis study was funded by the NSFC(No.41676036)and the National Key R&D Program of China(No.2016YFA0600904).
文摘For a long time,most studies about pyrite have focused on sediments while only a few have focused on pyrite in water.In this study,a method that combines the scanning electron microscopy(SEM)and the energy dispersive X-ray spectrometry(EDS)was used to compare pyrite particles suspended in water to those in associated bottom sediments,both obtained from the mixing zone of the Yangtze Estuary.It was found that the pyrite particles in the two media have similar morphologies and size distributions.The particle morphology mainly includes two types,single crystal and aggregate,and the particle size mainly ranges from 0.5 to 2μm.The pyrite particles in water exhibit an increase in relative content towards the sea,and their transport and deposit processes are mainly affected by hydrodynamic conditions.It is concluded that the pyrite particles in the suspended matter mainly derived from the resuspension of sediments,which are products of the early diagenesis.Precursor minerals may appear during the formation of pyrite,but are generally restricted by the diagenetic environment and local microenvironment.
文摘Rahughat Hydroelectric Project is an ROR （run of river） project with the installed capacity of 40 MW. The suspended sediment study was carried out in 2008 and 2015 AD. The present study is concentrated on the study carried out in 2015 AD. The suspended sediment samples were collected in the headworks site and its analysis was done in Hydro Lab Pvt. Ltd. Concentration analysis, PSD （particle size distribution） analysis and mineral content analysis were carried out. The minimum and maximum sediment concentration is 54 PPM and 3,759 PPM respectively. The PSD analysis shows that 52% of the suspended sediment contained sand fraction and 48% is fine sediments. The mineral content analysis shows presence of quartz, feldspar, mica, kyanite, garnet, carbonates, chlorite, clay and some fragments of shale, phyllite and slate with few unidentified sediments. The proposed desander in RGHEP is designed to settle particles of size 0.2 mm and above. The sediments lesser than 0.2 mm size that reach the turbine may affect the loss of turbine material due to erosion.
基金Research fund for earthquake engineering of China Earthquake Administration(201508023)a project of the National Science&Technology Support Program during the Twelfth Five-year Plan Period of China(2015BAK17B03)a general program of National Natural Science Foundation of China(51578515)
文摘Severe damage to suspended ceilings of metal grids and lay-in panels was observed in public buildings during the 2013 M7.0 Lushan earthquake in China. Over the past several years, suspended ceilings have been widely used practice in public buildings throughout China, including government offices, schools and hospitals. To investigate the damage mechanism of suspended ceilings, a series of three-dimensional shake table tests was conducted to reproduce the observed damage. A full-scale reinforced concrete frame was constructed as the testing frame for the ceiling, which was single-story and infilled with brick masonry walls to represent the local construction of low-rise buildings. In general, the ceiling in the tests exhibited similar damage phenomena as the field observations, such as higher vulnerability of perimeter elements and extensive damage to the cross runners. However, it exhibited lower fragility in terms of peak ground/roof accelerations at the initiation of damage. Further investigations are needed to clarify the reasons for this behavior.
文摘目的探究50 Hz 1.8 m T正弦交变电磁(sinusoidal electromagnetic fields,SEMFs)是否能抑制尾吊(hind-limb suspension,HLS)所致大鼠的骨量丢失。方法 30只雌性SD大鼠(180±10)g,分为3组,每组10只,分别为对照组、HLS组和HLS+SEMFs组。除对照组外,HLS组和HLS+SEMFs组大鼠进行尾吊,之后,HLS+SEMFs组大鼠每天进行1.5 h 50 Hz1.8 m T正弦交变电磁场干涉。4 w后处死全部大鼠,对各组大鼠进行重要脏器的器官指数计算和病理学观察、离体骨密度检测、骨生物力学分析和骨形态计量学分析以及Micro-CT扫描。结果实验期间各组大鼠的体重及重要脏器的器官指数差异无统计学意义(P>0.05),脏器病理学观察未见异常变化;骨密度结果显示,SEMFs有效提高股骨和椎骨的离体骨密度;生物力学实验表明,SEMFs减轻了HLS引起的股骨和椎骨力学性能的降低。此外,SEMFs能增加骨钙素(osteocalcin,OC)含量,并且对抗酒石酸酸性磷酸酶5b(tartrate-resistant acid phosphatase 5b,TRACP-5b)具有一定的抑制作用;Micro-CT结果显示,SEMFs部分抑制HLS造成的松质骨骨微结构的减少,相比HLS组,骨小梁数、骨小梁厚度、骨小梁面积显著升高,且分离度下降;骨组织形态学分析同样表明SEMFs改善了松质骨骨微结构的恶化。结论 50 Hz 1.8 m T SEMFs能抑制HLS所致大鼠的骨量丢失,其可能机制是具有抑制骨吸收和提高骨形成的双重活性,这将为电磁场治疗骨质疏松症的临床应用提供依据。
