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排序方式: 共有3226条查询结果,搜索用时 31 毫秒
1.
Fu Li Chen Yi Yang Xinyi Yang Zuyao Liu Sha Pei Lei Feng Baixiang Cao Ganxiang Liu Xin Lin Hualiang Li Xing Ye Yufeng Zhang Bo Sun Jiufeng Xu Xiaojun Liu Tao Ma Wenjun 《Environmental science and pollution research international》2019,26(20):20137-20147
Environmental Science and Pollution Research - Fetal growth has been demonstrated to be an important predictor of perinatal and postnatal health. Although the effects of maternal exposure to air... 相似文献
2.
When accounting the CO2 emissions responsibility of the electricity sector at the provincial level in China,it is of great significance to consider the scope of both producers’ and the consumers’ responsibility,since this will promote fairness in defining emission responsibility and enhance cooperation in emission reduction among provinces.This paper proposes a new method for calculating carbon emissions from the power sector at the provincial level based on the shared responsibility principle and taking into account interregional power exchange.This method can not only be used to account the emission responsibility shared by both the electricity production side and the consumption side,but it is also applicable for calculating the corresponding emission responsibility undertaken by those provinces with net electricity outflow and inflow.This method has been used to account for the carbon emissions responsibilities of the power sector at the provincial level in China since 2011.The empirical results indicate that compared with the production-based accounting method,the carbon emissions of major power-generation provinces in China calculated by the shared responsibility accounting method are reduced by at least 10%,but those of other power-consumption provinces are increased by 20% or more.Secondly,based on the principle of shared responsibility accounting,Inner Mongolia has the highest carbon emissions from the power sector while Hainan has the lowest.Thirdly,four provinces,including Inner Mongolia,Shanxi,Hubei and Anhui,have the highest carbon emissions from net electricity outflow- 14 million t in 2011,accounting for 74.42% of total carbon emissions from net electricity outflow in China.Six provinces,including Hebei,Beijing,Guangdong,Liaoning,Shandong,and Jiangsu,have the highest carbon emissions from net electricity inflow- 11 million t in 2011,accounting for 71.44% of total carbon emissions from net electricity inflow in China.Lastly,this paper has estimated the emission factors of electricity consumption at the provincial level,which can avoid repeated calculations when accounting the emission responsibility of power consumption terminals(e.g.construction,automobile manufacturing and other industries).In addition,these emission factors can also be used to account the emission responsibilities of provincial power grids. 相似文献
3.
Damianovic MH Saia FT Moraes EM Landgraf D Rezende MO Vazoller RF Foresti E 《Journal of environmental science and health. Part. B》2007,42(1):45-52
Wastewater samples from an anaerobic reactor were extracted with hexane and derivatized with diazomethane (method 1) and with acetic anidride (method 2). Gas chromatography with electron-capture detection (ECD) was employed for separating the parent compound and intermediates trichlorophenols (TCP) and dichlorophenols (DCP) which originated from the penta chlorophenol (PCP) degradation process. The relations between concentrations of PCP, TCP and DCP areas were linear in the range of concentrations of 0.2 to 8 mg/L and 0.025 mg/L to 5 mg/L for methods 1 and 2, respectively. The repeatability of the extraction methods was satisfactory, with variation coefficients lower than 11%. For method 1, at the fortification level of 0.2 mg/L, recovery of PCP, TCP, and DCP was 112%, 74% and 45%, respectively. For method 2, the corresponding recovery values at the fortification level of 0.1 mg/L were 91%, 93% and 103%, respectively. Storage of the frozen samples did not alter their PCP determination properties. The chromatographic methods adapted for chlorophenol determination in wastewater were suitable with relatively simple manipulation techniques. The obtained results were reproducible and allowed identification of intermediates formed during the PCP degradation process. 相似文献
4.
A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass
Tao S Liu YN Lang C Wang WT Yuan HS Zhang DY Qiu WX Liu JM Liu ZG Liu SZ Yi R Ji M Liu XX 《Environmental pollution (Barking, Essex : 1987)》2008,156(2):435-441
A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test. 相似文献
5.
不同轮作模式下作物根际土壤养分及真菌群落组成特征 总被引:10,自引:8,他引:2
为研究宁夏中部干旱带不同轮作模式下土壤养分及真菌群落组成的特征,以谷子轮作大豆(MRG)、轮作籽粒苋(MRA)、轮作藜麦(MRQ)及谷子连作(CK)为对象,测定了土壤养分含量,并利用Illumina MiSeq高通量测序平台测定了土壤真菌的ITS变异区序列.结果表明,不同轮作模式对土壤养分的影响存在差异.3种轮作模式下土壤pH和电导率均有所下降,土壤全氮、全钾、全磷和有机质含量均上升,OTUs数和α多样性指数均高于连作.真菌群落组成研究结果显示,子囊菌门(Ascomycota)为4种模式下的优势菌群.聚类分析显示MRA和MRG的真菌属组成最为相似,其次是MRQ,CK与3种轮作模式相差较大.相关性分析显示,土壤养分与几种优势真菌属呈显著相关性(P<0.05或P<0.01),土壤全氮、全钾、硝态氮和有机质含量是影响土壤真菌群落最主要的因子.主成分分析(PCA)表明,MRG轮作模式优于MRA和MRQ模式.综上所述,轮作提高了真菌群落多样性指数,改变了土壤真菌群落结构,改善了土壤肥力状况,其中以谷子与大豆轮作效果最佳,建议将谷豆轮作作为中部干旱带杂粮产业中主要的轮作模式之一进行推广. 相似文献
6.
Peng Du Jianguo Liu Huaqiao Gui Jiaoshi Zhang Tongzhu Yu Jie Wang Yin Cheng Yihuai Lu Yawei Yao Qiang Fu ChihChieh Chen 《环境科学学报(英文版)》2020,32(1):238-249
PM_(2.5) separator directly affects the accuracy of PM_(2.5) sampling.The specification testing and evaluation for PM_(2.5) separator is particularly important,especially under China's wide variation of terrain and climate.In this study,first a static test apparatus based on polydisperse aerosol was established and calibrated to evaluate the performance of the PM_(2.5) separators.A uniform mixing chamber was developed to make particles mix completely.The aerosol concentration relative standard deviations of three test points at the same horizontal chamber position were less than 0.57%,and the particle size distribution obeyed logarithmic normal distribution with an R~2 of 0.996.The flow rate deviation between the measurement and the set point flow rate agreed to within ± 1.0% in the range of -40 to 50℃.Secondly,the separation,flow and loading characteristics of three cyclone separators(VSCC-A,SCC-A and SCC112) were evaluated using this system.The results showed that the 50% cutoff sizes(D_(50)) of the three cyclones were 2.48,2.47 and 2.44 μm when worked at the manufacturer's recommended flow rates,respectively.The geometric standard deviation(GSD) of the capture efficiency of VSCCA was 1.23,showed a slightly sharper than SCC-A(GSD = 1.27),while the SCC112 did not meet the relevant indicator(GSD = 1.2 ± 0.1) with a GSD = 1.44.The flow rate and loading test had a great effect on D_(50),while the GSD remained almost the same as before.In addition,the maintenance frequency under different air pollution conditions of the cyclones was summarized according to the loading test. 相似文献
7.
根据材料类型和点阵结构,对点阵夹层结构进行了分类简述,并从静态、动态力学性能上,分析了各类点阵夹层结构的优缺点。简要叙述了设计过程中,综合考虑材料、结构以及功能等影响因素,针对不同使用工况的要求,可对各影响因素进行匹配设计,以实现传热特性、电磁波屏蔽特性、声学特性等不同的功能性需求。然后介绍了复合点阵夹层结构(嵌锁组装、模具热压成形、穿插编织)和金属点阵夹层结构(冲压成形、挤压线切割、拉伸网折叠、搭接拼装、熔模铸造以及增材制造)的主要制造工艺。最后提出如何将设计因子与多目标进行匹配及优化设计,是轻质高强点阵夹层结构的重点研究方向,轻质高强点阵夹层结构将朝多材料及多结构复合方向发展,开发新的制造工艺,提高费效比,是点阵夹层结构材料需解决的问题。 相似文献
8.
为了提高落后地区旅游开发的质量,分别从低碳环保旅游以及生态旅游两方面,研究环保因素对落后地区旅游开发的促进作用。提出低碳环保旅游,并分析低碳环保对落后地区旅游业可持续发展的意义,在落后地区旅游开发中实施低碳饮食、低碳住宿、低碳交通以及低碳能源的旅游开发模式。对中国落后地区生态旅游现状和意义实施研究,分析生态旅游对落后地区旅游开发的促进作用。最终给出了落后地区实现生态旅游开发的建议,构建落后地区低碳环保的新型生态旅游模式,实现落后地区旅游的可持续发展。 相似文献
9.
Analysis of pollutant levels in central Hong Kong applying neural network method with particle swarm optimization 总被引:6,自引:0,他引:6
Air pollution has emerged as an imminent issue in modernsociety. Prediction of pollutant levels is an importantresearch topic in atmospheric environment today. For fulfillingsuch prediction, the use of neural network (NN), and inparticular the multi-layer perceptrons, has presented to be acost-effective technique superior to traditional statisticalmethods. But their training, usually with back-propagation (BP)algorithm or other gradient algorithms, is often with certaindrawbacks, such as: 1) very slow convergence, and 2) easilygetting stuck in a local minimum. In this paper, a newlydeveloped method, particle swarm optimization (PSO) model, isadopted to train perceptrons, to predict pollutant levels, andas a result, a PSO-based neural network approach is presented. The approach is demonstrated to be feasible and effective bypredicting some real air-quality problems. 相似文献
10.
The reduction of SO2 by the addition of ammonia gas has been studied in a 2 m high fluidized bed combustor having a 30 cm static bed height and a freeboard height of 170 cm. Ammonia gas was injected at 52 cm above the distributor where the temperature is ca. 700° C by an uncooled stainless steel tube injector. Experiments were carried out to investigate the effects of amminia gas injection on sulphur dioxide emissions at unstaged conditions of: (i) excess air level, (ii) NH3:SO2 molar ratio, (iii) fluidizing velocity and (iv) bed height.A maximum reduction of 75% in SO2 emissions was found at 40% excess air, at an NH3:SO2 molar ratio of 5.4. The onset of SO2 reduction occurred at an NH3:SO2 ratio of 1.5 However, the most effective ratio was found to be between 3 and 5. Fluidizing velocity and bed height were also found to have significant influence on SO2 reduction.It is difficult to determine how the SO2 reduction varied with operating conditions. When ammonia is added in the main combustor zone, the temperature is much higher than that required for the occurrence of sulphur dioxide-ammonia and sulphur trioxide-ammonia reactions. However, this paper points out the significance of ammonia addition in the reduction of sulphur dioxide. 相似文献