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481.
Peng Xu Junke Zhang Dongsheng Ji Zirui Liu Guiqian Tang Changsheng Jiang Yuesi Wang 《环境科学学报(英文版)》2018,30(1):16-27
In this study, we performed a highly time-resolved chemical characterization of nonrefractory submicron particles(NR-PM_1) in Beijing by using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer(HR-ToF-AMS). The results showed the average NR-PM_1 mass concentration to be 56.4 ± 58.0 μg/m~3, with a peak at 307.4 μg/m~3. Due to the high frequency of biomass burning in autumn, submicron particles significantly increased in organic content, which accounted for 51% of NR-PM_1 on average. Secondary inorganic aerosols(sulfate + nitrate + ammonium) accounted for 46% of NR-PM_1, of which sulfate,nitrate, and ammonium contributed 15%, 20%, and 11%, respectively. To determine the intrinsic relationships between the organic and inorganic species, we used the positive matrix factorization(PMF) model to merge the high-resolution mass spectra of the organic species and NO+and NO_2~+ions. The PMF analysis separated the mixed organic and nitrate(NO+and NO_2~+) spectra into four organic factors, including hydrocarbon-like organic aerosol(HOA), oxygenated organic aerosol(OOA), cooking organic aerosol(COA), and biomass burning organic aerosol(BBOA), as well as one nitrate inorganic aerosol(NIA) factor. COA(33%) and OOA(30%) contributed the most to the total organic aerosol(OA) mass, followed by BBOA(20%) and HOA(17%). We successfully quantified the mass concentrations of the organic and inorganic nitrates by the NO+and NO2+ions signal in the organic and NIA factors. The organic nitrate mass varied from 0.01-6.8 μg/m~3, with an average of 1.0 ±1.1 μg/m~3, and organic nitrate components accounted for 10% of the total nitrate mass in this observation. 相似文献
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Jie Song Xinyu Fu Ruoniu Wang Zhong-Ren Peng Zongni Gu 《Mitigation and Adaptation Strategies for Global Change》2018,23(5):703-733
Coastal regions worldwide are during the process of rapid urban expansion. However, expanded urban settlements in land-sea interfaces have been faced with unprecedented threats from climate change related hazards. Adaptation to coastal hazards has received increasing attention from city managers and planners. Adaptation and land management practices are largely informed by remote sensing and land change modeling. This paper establishes a framework that integrates land change analysis, coastal flooding, and sea level rise adaptation. Multilayer perceptron neural network, similarity learning, and binary logistic regression were applied to analyze spatiotemporal changes of residential, commercial, and other built-up areas in Bay County, Florida, USA. The prediction maps of 2030 were produced by three models under four policy scenarios that included the population relocation strategy. Validation results reveal that three models return overall acceptable accuracies but generate distinct landscape patterns. Predictions indicate that planned retreat of residents can greatly reduce urban vulnerability to sea level rise induced flooding. While managed realignment of the coast brings large benefits, the paper recommends different mixes of adaptation strategies for different parts of the globe, and advocates the application of reflective land use planning to foster a more disaster resilient coastal community. 相似文献
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采用声电类比的传递矩阵法,本文对消声器插入损失进行了理论探讨,所推导的理论公式准确地反映了整个内燃机排气系统对消声器插入损失的影响,克服了其它学者在研究此问题中的不足,考虑了声源声阻抗对传递损失的影响,对消声器的整体优化设计具有重要的指导意义。 相似文献
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抗生素制药废水的处理 总被引:1,自引:0,他引:1
王强 《辽宁城乡环境科技》2006,26(3):49-51
锦州九泰制药废水属于不易生化类废水,废水量1000m^3/d,污水站总投资140万元。本文阐述了该工程的水质、预处理、生化处理工艺、活性污泥的培养与驯化及运行效果与设计特点。 相似文献
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Ni Liu Yunguo Liu Guangming Zeng Jilai Gong Xiaofei Tan Jun Wen Shaobo Liu Luhua Jiang Meifang Li Zhihong Yin 《环境科学学报(英文版)》2020,32(1):10-23
Five biochars derived from lotus seedpod(LSP) were applied to examine and compare the adsorption capacity of 17β-estradiol(E2) from aqueous solution.The effect of KOH activation and the order of activation steps on material properties were discussed.The effect of contact time,initial concentration,p H,ionic strength and humic acid on E2 adsorption were investigated in a batch adsorption process.Experimental results demonstrated that the pseudo second-order model fitted the experimental data best... 相似文献