氯仿(CHCl_(3))和溴仿(CHBr_(3))是两种重要的挥发性卤代烃(Volatile halohydrocarbon,VHCs),可通过光化学作用,引起臭氧层破坏和温室效应,影响全球气候变化。以黄河三角洲湿地的优势物种—盐地碱蓬(Suaeda glauca)为研究对象,采用室内...氯仿(CHCl_(3))和溴仿(CHBr_(3))是两种重要的挥发性卤代烃(Volatile halohydrocarbon,VHCs),可通过光化学作用,引起臭氧层破坏和温室效应,影响全球气候变化。以黄河三角洲湿地的优势物种—盐地碱蓬(Suaeda glauca)为研究对象,采用室内盆栽培养来探究不同浓度氮输入水平(CK,对照,6.0 g N m^(-2) a^(-1);1.5N0,低氮处理,9.0 g N m^(-2) a^(-1);3.0N0,高氮处理,18.0 g N m^(-2) a^(-1))对盐地碱蓬以及盆栽微生态系统CHCl_(3)、CHBr_(3)通量特征的影响。结果表明,不同氮梯度下盐地碱蓬CHCl_(3)和CHBr_(3)排放通量均呈现出先降后升的趋势,低浓度1.5N0下可以促进盐地碱蓬CHCl_(3)的释放,高浓度3.0N0则抑制;盐地碱蓬CHCl_(3)、CHBr_(3)气体通量的峰值分别出现在枯萎期与苗期,其主要原因是不同氮梯度刺激了气体消耗与产生之间的平衡以及植物各生长期生长因子的改变。由相关性分析可知,盐地碱蓬CHCl_(3)排放通量受多种因子相互作用,植物根长与CHBr_(3)排放之间存在显著相关性,根部越长,CHBr_(3)的排放通量越低。不同氮梯度下盆栽微生态系统内CHCl_(3)、CHBr_(3)排放通量的变化趋势不同,CHCl_(3)通量为先升后降,CHBr_(3)为先降后升,气体通量的最高值与最低值出现在植物不同生长时期,盆栽微生态系统气体排放通量主要受土壤NH^(+)_(4)-N、NO^(-)_(3)-N、以及植物凋落物等交互作用的影响。展开更多
Due to the lipophilicity of carbon nanotubes (CNTs),the carbon nanotubes composite filter for removing oil particles in cooking fumes is synthesized. The composite filter was fabricated by the chemical vapor depositio...Due to the lipophilicity of carbon nanotubes (CNTs),the carbon nanotubes composite filter for removing oil particles in cooking fumes is synthesized. The composite filter was fabricated by the chemical vapor deposition (CVD) method. The filtration characteristics of the resultant filter and the influence of the parameters were investigated. The results show that the filtration efficiency of the CNT filter during the saturation period is 99.92%, which satisfies the high efficiency particulate air (HEPA) standard. Pressure drop increases linearly before saturation and the pressure drop at the saturation stage is only two times that of the initial stage, which is far less than that of conventional glass fiber filters. The efficiency increases by enhancing filtration velocity. Pressure drops in the composite filter at the equilibrium stage are equal under different aerosol concentrations. The increase in concentration can improve the efficiency of composite filters. Therefore, the CNT filter is suitable for decreasing oil particle pollution due to its lower increase ratio of pressure drop and higher efficiency.展开更多
文摘氯仿(CHCl_(3))和溴仿(CHBr_(3))是两种重要的挥发性卤代烃(Volatile halohydrocarbon,VHCs),可通过光化学作用,引起臭氧层破坏和温室效应,影响全球气候变化。以黄河三角洲湿地的优势物种—盐地碱蓬(Suaeda glauca)为研究对象,采用室内盆栽培养来探究不同浓度氮输入水平(CK,对照,6.0 g N m^(-2) a^(-1);1.5N0,低氮处理,9.0 g N m^(-2) a^(-1);3.0N0,高氮处理,18.0 g N m^(-2) a^(-1))对盐地碱蓬以及盆栽微生态系统CHCl_(3)、CHBr_(3)通量特征的影响。结果表明,不同氮梯度下盐地碱蓬CHCl_(3)和CHBr_(3)排放通量均呈现出先降后升的趋势,低浓度1.5N0下可以促进盐地碱蓬CHCl_(3)的释放,高浓度3.0N0则抑制;盐地碱蓬CHCl_(3)、CHBr_(3)气体通量的峰值分别出现在枯萎期与苗期,其主要原因是不同氮梯度刺激了气体消耗与产生之间的平衡以及植物各生长期生长因子的改变。由相关性分析可知,盐地碱蓬CHCl_(3)排放通量受多种因子相互作用,植物根长与CHBr_(3)排放之间存在显著相关性,根部越长,CHBr_(3)的排放通量越低。不同氮梯度下盆栽微生态系统内CHCl_(3)、CHBr_(3)排放通量的变化趋势不同,CHCl_(3)通量为先升后降,CHBr_(3)为先降后升,气体通量的最高值与最低值出现在植物不同生长时期,盆栽微生态系统气体排放通量主要受土壤NH^(+)_(4)-N、NO^(-)_(3)-N、以及植物凋落物等交互作用的影响。
基金The National Natural Science Foundation of China(No.51576043)
文摘Due to the lipophilicity of carbon nanotubes (CNTs),the carbon nanotubes composite filter for removing oil particles in cooking fumes is synthesized. The composite filter was fabricated by the chemical vapor deposition (CVD) method. The filtration characteristics of the resultant filter and the influence of the parameters were investigated. The results show that the filtration efficiency of the CNT filter during the saturation period is 99.92%, which satisfies the high efficiency particulate air (HEPA) standard. Pressure drop increases linearly before saturation and the pressure drop at the saturation stage is only two times that of the initial stage, which is far less than that of conventional glass fiber filters. The efficiency increases by enhancing filtration velocity. Pressure drops in the composite filter at the equilibrium stage are equal under different aerosol concentrations. The increase in concentration can improve the efficiency of composite filters. Therefore, the CNT filter is suitable for decreasing oil particle pollution due to its lower increase ratio of pressure drop and higher efficiency.
