Based on observed data from Tanggu District in Tianjin, a back-propagation neural network (BPNN) model was introduced to predict possible land subsidence due to exploitation of groundwater. According to model estimati...Based on observed data from Tanggu District in Tianjin, a back-propagation neural network (BPNN) model was introduced to predict possible land subsidence due to exploitation of groundwater. According to model estimation under various hypothetical extraction scenarios, patterns of land subsidence at Tanggu District were studied and discussed.The predicted average background land subsidence rate of Tanggu is 9.47 mm/a.The significance of contribution of aquifers to land subsidence descends in order of units Ⅳ,Ⅲ,Ⅴ,Ⅱ.Land subsidence tends to deteriorate with the increase in total extraction rate.展开更多
Particulate matter （PMlo and PM2.5） concentrations were monitored during the November 2008 by using the filter samples collected day and night from three sites in Tanggu District at Tianjin Binhai New Area, China. T...Particulate matter （PMlo and PM2.5） concentrations were monitored during the November 2008 by using the filter samples collected day and night from three sites in Tanggu District at Tianjin Binhai New Area, China. The mean concentrations of PM2.5 and PMlo rank in the order of urban （150 ug/m3 for PM2.5 and 197 ug/m3 for PM10） 〉 industrial （32 ug/m3 for PM2.5 and 170 ug/m3 for PM10） 〉 suburb area （27 ug/m3 for PM2.5 and 59 ug/m3 for PM10）. Sixteen polycyclic aromatic hydrocarbons （PAHs） were analyzed in PMlo and PM2.5 samples. Concentrations of total PAHs in PM2.5 and PMlo are in the range of 8.47- 113.94ng/m3 with average of 62.88ng/m3 and 21.07- 118.23 ng/m3 with average of 73.42 ng/m3, respectively. The light ring PAils （2-4 rings） are dominant in both PM2.5 and PMlo during sampling time compares with the heavy ring （5-6 rings） PAHs. The relationship of PAHs and PM2.5 （r = 0.689, p 〈 0.05） is stronger than PAHs and PMlo （r = 0.570, p 〈 0.05）, illustrating PAHs tend to adsorb in PM2.5. In addition, principal component analysis was applied to find the source of PAHs. Three principal factors representing three types of PAHs sources in Tanggu District are extracted, which were coke production, pyrogenic sources and vehicular source.展开更多
基金Supported by Tianjin Land Subsidence Controlling Office(No.kJ/095).
文摘Based on observed data from Tanggu District in Tianjin, a back-propagation neural network (BPNN) model was introduced to predict possible land subsidence due to exploitation of groundwater. According to model estimation under various hypothetical extraction scenarios, patterns of land subsidence at Tanggu District were studied and discussed.The predicted average background land subsidence rate of Tanggu is 9.47 mm/a.The significance of contribution of aquifers to land subsidence descends in order of units Ⅳ,Ⅲ,Ⅴ,Ⅱ.Land subsidence tends to deteriorate with the increase in total extraction rate.
文摘Particulate matter （PMlo and PM2.5） concentrations were monitored during the November 2008 by using the filter samples collected day and night from three sites in Tanggu District at Tianjin Binhai New Area, China. The mean concentrations of PM2.5 and PMlo rank in the order of urban （150 ug/m3 for PM2.5 and 197 ug/m3 for PM10） 〉 industrial （32 ug/m3 for PM2.5 and 170 ug/m3 for PM10） 〉 suburb area （27 ug/m3 for PM2.5 and 59 ug/m3 for PM10）. Sixteen polycyclic aromatic hydrocarbons （PAHs） were analyzed in PMlo and PM2.5 samples. Concentrations of total PAHs in PM2.5 and PMlo are in the range of 8.47- 113.94ng/m3 with average of 62.88ng/m3 and 21.07- 118.23 ng/m3 with average of 73.42 ng/m3, respectively. The light ring PAils （2-4 rings） are dominant in both PM2.5 and PMlo during sampling time compares with the heavy ring （5-6 rings） PAHs. The relationship of PAHs and PM2.5 （r = 0.689, p 〈 0.05） is stronger than PAHs and PMlo （r = 0.570, p 〈 0.05）, illustrating PAHs tend to adsorb in PM2.5. In addition, principal component analysis was applied to find the source of PAHs. Three principal factors representing three types of PAHs sources in Tanggu District are extracted, which were coke production, pyrogenic sources and vehicular source.
