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171.
文章以新常态下经济社会新特点、新方向为出发点,分析了经济增速放缓、结构转型等对资源环境的新影响以及环境管理的新需求,并从释放政策潜力、激活市场活力、提高创新能力3方面,提出了我国环境政策发展的新思路与建议。  相似文献   
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173.
Nocturnal chemistry can play an important role in determining the initial morning conditions for daytime chemistry in urban areas. However, the impact on daytime O3 levels is difficult to assess as the suppression of vertical trace gas transport leads to highly altitude dependent nocturnal chemistry, in particular with respect to the removal and conversion of nitrogen oxides (NOx) and volatile organic compounds (VOC). One-dimensional (1-D) chemical transport model calculations for different nighttime vertical stabilities and different ozone formation regimes (i.e. NOx- vs. VOC-sensitive) were performed assuming a 1000 m high daytime boundary layer and a growing nocturnal boundary layer reaching 200 m height at the end of the night. Exclusion of NO3 chemistry from the model leads to daytime O3 concentration changes from ?4% to +16% for different O3 sensitivities. In all cases strong nocturnal vertical concentration profiles of NOx, O3, NO3 and N2O5 and a dependence of these profiles on vertical stability were found at night. The nocturnal NOx loss averaged over the lowest 1000 m changes by 9–24% for different vertical stabilities and ozone sensitivities. The impact of nocturnal vertical stability leads to 7–12% difference in O3 concentration in the morning and ~0–2.5% in the afternoon.  相似文献   
174.
利用化工污染物能抑制荧光素酶催化发光反应这一特性,对水质中6种化工化合物分别进行毒性测试,建立一种快速检测水质中化工污染物毒性的生物学方法。实验结果表明,对苯二酚、4-氨基酚、苯胺、氯仿、盐酸邻联甲苯胺和硫柳汞的EC50值分别为:5.563、10.225、20.236、38.432、8.827和0.6 mg/L,6种污染物毒性大小依次为:硫柳汞>对苯二酚>盐酸邻联甲苯胺>4-氨基酚>苯胺>氯仿,相关系数>0.95。该方法为进一步研究基于荧光素酶反应体系检测水质中化工污染物综合毒性的生物传感器方法奠定基础。  相似文献   
175.
The ozone pollution at ground level in rural and urban areas has been a long-standing problem in the world. This paper focuses on estimating self-affined nature of nonlinearity of ground-level peak ozone time series, which is analyzed by two nonlinear fractal statistical methods, including R/S analysis and BDS test. To explore the underlying structure of ozone observations at ground level and improve the forecasting capacity in urban region, practical implementation was assessed by a case study via collecting and analyzing the monitoring data at Chaojhou and Zenwu in the Kaohsiung metropolitan region, Taiwan. Based on R/S analysis, the time series can be identified as persistent and long-memory processes with Hurst exponents of both about 0.75. In addition, the V statistics specifies possible fluctuation cycle lengths of 32, 170, and 420 day simultaneously. Such results are consistent with the regional meteorological conditions leading to help characterize the regional scale ozone behavioral trend. Furthermore, the BDS test results confirm a strong nonlinearity of both time series associated with these two cities. Yet in both cases, nonlinearity implies chaos. The R/S analysis and BDS test provide strong evidence for nonlinearity and fractality of ozone time series due to noisy chaos, and we could not rule out the possibility of deterministic chaos in tropospheric ozone system.  相似文献   
176.
● Cu addition enhances CH3OH oxidation and alleviates its inhibitory effect on SCR. ● Cu addition improves the activation of SCR reactants in the presence of methanol. ● Damaged structure by more Cu addition decreases specific surface area and acidity. ● Excessive Cu addition would lead to the narrowing of SCR temperature window. Simultaneously removal of NOx and VOCs over NH3-SCR catalysts have attracted lots of attention recently. However, the presence of VOCs would have negative effect on deNOx efficiency especially at low temperature. In this study, copper modification onto Sb0.5CeZr2Ox (SCZ) catalyst were performed to enhance the catalytic performance for simultaneous control of NOx and methanol. It was obtained that copper addition could improve the low-temperature activity of both NOx conversion and methanol oxidation, where the optimal catalyst (Cu0.05SCZ) exhibited a deNOx activity of 96% and a mineralization rate of 97% at 250 °C, which are around 10% higher than that of Cu free sample. The characterization results showed that copper addition could obviously enhance the redox capacity of the catalysts. As such, the inhibition effect of methanol incomplete oxidation on NO adsorption and NH3 activation were then lessened and the conversion of surface formamide species were also accelerated, resulting in the rising of NOx conversion at low temperature. However, excessive copper addition would damage the Sb-Ce-Zr oxides solid solution structure owing to Cu-Ce strong interactions, decreasing the surface area and acidity. Meanwhile, due to easier over-oxidation of NH3 with more Cu addition, the temperature window for NOx conversion would become quite narrow. These findings could provide useful guidelines for the synergistic removal of VOCs over SCR catalyst in real application.  相似文献   
177.
通过深入研究常见化学品在不同物料输送泵输送过程中的污染物排放规律,模拟实际生产过程中物料输送的形式,设计并搭建了系数测定试验装置,探索并选择甲苯、二甲苯、甲醇和盐酸在该试验装置中的取样、计量和监测方法。经过长期的现场实测,形成了4种常见化学品在典型的5种类型的泵输送过程中的污染物排放系数。根据试验结果,计算总结得知,在三类釜前泵输送过程中,污染物排放系数从小到大排序为二甲苯、盐酸、甲苯、甲醇;在两类真空泵输送过程中,污染物排放系数从小到大排序为二甲苯、甲苯、盐酸、甲醇。  相似文献   
178.
The development and formation of chemical elements in soil are affected not only by parent material, climate, biology, and topology factors, but also by human activities. As the main elements supporting life on earth system, the C, N, P, S cycles in soil have been altered by human activity through land-use change, agricultural intensification, and use of fossil fuels. The present study attempts to analyze whether and how a connection can be made between macroscopical control and microcosmic analysis, to estimate the impacts of human activities on C, N, P, S elements in soil, and to determine a way to describe the spatial relationship between C, N, P, S in soil and human activities, by means of landscape geochemical theories and methods. In addition, the disturbances of human activities on C, N, P, S are explored through the analysis of the spatial relationship between human disturbed landscapes and element anomalies, thereby determining the diversified rules of the effects. The study results show that the rules of different landscapes influencing C, N, P, S elements are diversified, and that the C element is closely related to city landscapes; furthermore, the elements N, P, and S are shown to be closely related to river landscapes; the relationships between mine landscapes and the elements C, N, P, S are apparent; the relationships between the elements C, N, P, S and road landscapes are quite close, which shows that road landscapes have significant effects on these elements. Therefore, the conclusion is drawn that the response mechanism analysis of human disturbance and soil chemical element aggregation is feasible, based on the landscape geochemical theories and methods. The spatial information techniques, such as remote sensing and geographic information systems, are effective for research on soil element migration.  相似文献   
179.
Rapid land use change has taken place in many coastal regions of China such as the Zhujiang Delta over the past two decades due to accelerated industrialization and urbanization. In this paper, land use change dynamics were investigated by the combined use of satellite remote sensing, geographic information systems (GIS), and stochastic modelling technologies. The results indicated that there has been a notable and uneven urban growth and a tremendous loss in cropland between 1989 and 1997. The land use change process has shown no sign of becoming stable. The study demonstrates that the integration of satellite remote sensing and GIS was an effective approach for analyzing the direction, rate, and spatial pattern of land use change. The further integration of these two technologies with Markov modelling was found to be beneficial in describing and analyzing land use change process.  相似文献   
180.
通过观测和研究 ,得出风沙区农田防护林带的走向与主风方向的交角 ,不能小于 45° ,主林带间距 15 0m——— 2 0 0m ,副林带间距 2 3 0m——— 70 0m ,林带结构以疏透结构为最好 ,主林带一般由主林木 5— 6行组成 ,副林带由 2— 3行组成 ,再在迎风面和背风面配置 1行— 2行灌木和针叶树  相似文献   
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