Surface 03 production has a highly nonlinear relationship with its precursors. The spatial and temporal heterogeneity of O3-NOx-VOC-sensitivity regimes complicates the control- decision making. In this paper, the indi...Surface 03 production has a highly nonlinear relationship with its precursors. The spatial and temporal heterogeneity of O3-NOx-VOC-sensitivity regimes complicates the control- decision making. In this paper, the indicator method was used to establish the relationship between 03 sensitivity and assessment indicators. Six popular ratios indicating ozone-precursor sensitivity, HCHO/NOy, H2O2/ HNO3, O3/NOy, O3/NOz, O3/HNO3, and H2O2/NOz, were evaluated based on the distribution of NOx- and VOC-sensitive regimes. WRF-Chem was used to study a serious ozone episode in fall over the Pearl River Delta （PRD）. It was found that the south-west of the PRD is characterized by a VOCsensitive regime, while its north-east is NO y-sensitive, with a sharp transition area between the two regimes. All indicators produced good representations of the elevated ozone hours in the episode on 6 November 2009, with H202/HNO3 being the best indicator. The threshold sensitivity levels for HCHO/NOy, H2O2/HNO3, O3/NOy, O3/NOz, O3/HNO3, and H2O2/NOz were estimated to be 0.41, 0.55, 10.2, 14.0, 19.1, and 0.38, respectively. Threshold intervals for the indicators H2O2/HNO3, O3/ NOy, O3/NOz, O3/HNO3, and H202/NOz were able to identify more than 95% of VOC- and NOx-sensitive grids. The ozone episode on 16 November 16 2008 was used to independently verify the results, and it was found that only H2O2/HNO3 and H2O2/NOz were able to differentiate the ozone sensitivity regime well. Hence, these two ratios are suggested as the most appropriate indicators for identifying fall ozone sensitivity in the PRD. Since the species used for indicators have seasonal variation, the utility of those indicators for other seasons should be investigated in the future work.展开更多
The energy absorption characteristics of the lotus-type porous coppers at the strain rate of 10-3 s-1 to N2400 s 1 were systematically investigated. Depending on the relative density and loading rate, the energy absor...The energy absorption characteristics of the lotus-type porous coppers at the strain rate of 10-3 s-1 to N2400 s 1 were systematically investigated. Depending on the relative density and loading rate, the energy absorption capability of the tested samples varied from -20 to -85 MJ m-1, while the energy absorption efficiency fluctuated around N0.6. An energy absorption efficiency curve based approach was proposed for unambiguous identification of the plateau regime, which gave an extension of -0.50 strain range for the presently investigated porous coppers. With detailed observations of cell wall morphologies at various deformation stages, it was suggested that buckling of cell wails was the dominant mechanism mediat- ing the energy absorption in lotus-type porous coppers.展开更多
基金Acknowledgements Financial supports from the Special Fund for Meteorological-scientific Research in the Public Interest of China （No. GYHY201406031）, National Science Foundation for Distinguished Young Scholars （No. 41425020）, National Key Technology Research and Development Program of the Ministry of Science and Technology of China （Grant No. 2014BAC21B02）, Foshan Environmental Protection Bureau Project （GDJAFS 2015046G） are gratefully acknowledged by the authors. We acknowledge Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund （the second phase） and National Supercomputing Center in Guangzhou （NSCC-GZ）. At the same time, we are grateful for Guangzhou Meteorological Service for the Meteorological data, and Guangzhou Environmental Monitoring for air quality observational data.
文摘Surface 03 production has a highly nonlinear relationship with its precursors. The spatial and temporal heterogeneity of O3-NOx-VOC-sensitivity regimes complicates the control- decision making. In this paper, the indicator method was used to establish the relationship between 03 sensitivity and assessment indicators. Six popular ratios indicating ozone-precursor sensitivity, HCHO/NOy, H2O2/ HNO3, O3/NOy, O3/NOz, O3/HNO3, and H2O2/NOz, were evaluated based on the distribution of NOx- and VOC-sensitive regimes. WRF-Chem was used to study a serious ozone episode in fall over the Pearl River Delta （PRD）. It was found that the south-west of the PRD is characterized by a VOCsensitive regime, while its north-east is NO y-sensitive, with a sharp transition area between the two regimes. All indicators produced good representations of the elevated ozone hours in the episode on 6 November 2009, with H202/HNO3 being the best indicator. The threshold sensitivity levels for HCHO/NOy, H2O2/HNO3, O3/NOy, O3/NOz, O3/HNO3, and H2O2/NOz were estimated to be 0.41, 0.55, 10.2, 14.0, 19.1, and 0.38, respectively. Threshold intervals for the indicators H2O2/HNO3, O3/ NOy, O3/NOz, O3/HNO3, and H202/NOz were able to identify more than 95% of VOC- and NOx-sensitive grids. The ozone episode on 16 November 16 2008 was used to independently verify the results, and it was found that only H2O2/HNO3 and H2O2/NOz were able to differentiate the ozone sensitivity regime well. Hence, these two ratios are suggested as the most appropriate indicators for identifying fall ozone sensitivity in the PRD. Since the species used for indicators have seasonal variation, the utility of those indicators for other seasons should be investigated in the future work.
基金financial support from the National Natural Science Foundation of China (Grant No. 50904004)
文摘The energy absorption characteristics of the lotus-type porous coppers at the strain rate of 10-3 s-1 to N2400 s 1 were systematically investigated. Depending on the relative density and loading rate, the energy absorption capability of the tested samples varied from -20 to -85 MJ m-1, while the energy absorption efficiency fluctuated around N0.6. An energy absorption efficiency curve based approach was proposed for unambiguous identification of the plateau regime, which gave an extension of -0.50 strain range for the presently investigated porous coppers. With detailed observations of cell wall morphologies at various deformation stages, it was suggested that buckling of cell wails was the dominant mechanism mediat- ing the energy absorption in lotus-type porous coppers.
