The emission of N2 is important to remove excess N from lakes, ponds, and wetlands. To investigate the gas emission from water, Gao et al. (2013) developed a new method using a bubble trap device to collect gas samples from waters. However, the determination accuracy of sampling volume and gas component concentration was still debatable. In this study, the method was optimized for in situ sampling, accurate volume measurement and direct injection to a gas chromatograph for the analysis of N2 and other gases. By the optimized new method, the recovery rate for N2 was 100.28% on average; the mean coefficient of determination (R2) was 0.9997; the limit of detection was 0.02%. We further assessed the effects of the new method, bottle full of water, vs. vacuum bag and vacuum vial methods, on variations of N2 concentration as influenced by sample storage times of 1, 2, 3, 5, and 7 days at constant temperature of 15°C, using indices of averaged relative peak area (%) in comparison with the averaged relative peak area of each method at 0 day. The indices of the bottle full of water method were the lowest (99.5%-108.5%) compared to the indices of vacuum bag and vacuum vial methods (119%-217%). Meanwhile, the gas chromatograph determination of other gas components (O2, CH4, and N2O) was also accurate. The new method was an alternative way to investigate N2 released from various kinds of aquatic ecosystems. 相似文献
The emission of N2 is important to remove excess N from lakes, ponds, and wetlands. To investigate the gas emission from water, Gao et al.(2013) developed a new method using a bubble trap device to collect gas samples from waters. However, the determination accuracy of sampling volume and gas component concentration was still debatable. In this study, the method was optimized for in situ sampling, accurate volume measurement and direct injection to a gas chromatograph for the analysis of N2 and other gases. By the optimized new method, the recovery rate for N2 was 100.28% on average; the mean coefficient of determination(R2) was 0.9997; the limit of detection was 0.02%. We further assessed the effects of the new method, bottle full of water, vs. vacuum bag and vacuum vial methods, on variations of N2 concentration as influenced by sample storage times of 1,2, 3, 5, and 7 days at constant temperature of 15°C, using indices of averaged relative peak area(%) in comparison with the averaged relative peak area of each method at 0 day.The indices of the bottle full of water method were the lowest(99.5%–108.5%) compared to the indices of vacuum bag and vacuum vial methods(119%–217%). Meanwhile, the gas chromatograph determination of other gas components(O2, CH4, and N2O) was also accurate. The new method was an alternative way to investigate N2 released from various kinds of aquatic ecosystems. 相似文献
Over the previous two decades, Chinese economic development presented a rapid growth. However, with continuous industrialization and urbanization, China is confronted with great challenges of energy security and environmental issues. These problems are closely related to the current accounting method of economic growth to a certain extent. In order to meet these challenges, it is imperative to establish a green accounting system of economic growth and measure China’s green GDP and its changing trend based on the industrial perspective. Using the System of Environmental Economic Accounting (SEEA) and industry data, this paper estimates China’s green GDP and green value added by industry sectors in 2005, 2007, 2010, 2012, 2015, and 2017. The results reveal the following: First, the ratio of green GDP to traditional GDP gradually increases from 89.85 to 95.83% during 2005–2017, which means that the negative externalities of economic growth of the resource and environment are gradually weakened. Second, the difference between traditional GDP and green GDP during 2005–2017 is about 6.96%, with the carbon emissions accounting for 70.71% of environmental impact. Third, due to more than 80% of the environmental impact coming from three sectors: manufacturing (49.99%), electricity industry (22.63%), and other services (11.37%), these three sectors should be key sectors for energy conservation and emission reduction; fourth, the green GDP of the mining, electricity industries, and manufacturing accounts for the lowest proportion of GDP, which means that the development patterns of these three industries in recent years should be adjusted and optimized step by step.
The influence of a single water molecule on the reaction mechanism and kinetics of hydrogen abstraction from methanol(CH_3OH) by the ClO radical has been investigated using ab initio calculations. The reaction proceeds through two channels: abstraction of the hydroxyl H-atom and methyl H-atom of CH_3OH by ClO, leading to the formation of CH_3O + HOCl(+H_2O) and CH_2OH + HOCl(+H_2O), respectively. In both cases, pre-and post-reactive complexes were located at the entrance and exit channel on the potential energy surfaces. Results indicate that the formation of CH_2OH + HOCl(+H_2O) is predominant over the formation of CH_3O + HOCl(+H_2O),with ambient rate constants of 3.07 × 10-19 and 3.01 × 10~(-23) cm~3/(molecule·sec), respectively, for the reaction without water. Over the temperature range 216.7–298.2K, the presence of water is seen to effectively lower the rate constants for the most favorable pathways by 4–6 orders of magnitude in both cases. It is therefore concluded that water plays an inhibitive role on the CH_3OH + ClO reaction under tropospheric conditions. 相似文献
The interaction between green finance and other factors, such as ecological environment, has been a research hotspot nowadays. Especially, the reasonable guiding of capital into energy conservation and environmental protection industries would greatly affect those factors, so as to the relation between them. This paper aimed to analyze the relationships between green finance, technological progress, and ecological performance quantitatively. The entropy method was used to respectively construct the system of index for green finance and technological progress, and index for ecological performance was measured by the super-SBM model. The panel vector autoregressive (PVAR) model was selected to empirically analyze dynamic relationships based on datasets from 30 provinces in China during 2008–2019 period. The results told that (1) from 2008 to 2019, China’s overall level of green finance, technological progress and ecological performance increased to varying degrees. Spatially, the areas with high-developed green finance greatly coincided with those such as large cities or the eastern coast that had good financial development. The distribution of technological progress index were similar, except some underdeveloped areas with relatively advanced scientific research institutes. The ecological performance, however, was high in the South and low in the north. (2) In the lag for 3 years, the influence of green finance on ecological performance in different regions was all positive for that all the coefficient symbols that passed the significance test were above 0, while that on technological progress was negative first and then positive. And the effects of technological progress on ecological performance were positive in ecological regions and negative in low ecological regions (0.0893 and -0.1211 in the case of three-stage lag respectively). (3) The contribution of green finance to ecological performance was high according to the results of variance decomposition, maintained at about 30%, and that of technological progress increased year by year (from 0.000 to 0.039). Therefore, we proposed to strengthen the development of green finance in underdeveloped regions. The emphasis should be laid on the researches and applications of green technology, the formulation of financing policies in innovation compensation and the establishment of a dynamic monitoring system for the ecological environment.
