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排序方式: 共有1441条查询结果,搜索用时 978 毫秒
831.
832.
Shouliang Huo Chunzi M Beidou Xi Jing Su Fengyu Zan Danfeng Ji Zhuoshi He 《环境科学学报(英文版)》2013,25(10):2014-2022
The trophic status assessment of lakes in different lake regions may provide important and fundamental information for lake trophic state classification and eutrophication control. In this study, a region-specific lake eutrophication assessment standard was established through a frequency distribution method based on chlorophyll-a concentration. The assessment standards under the oligotrophic state for lakes in the Eastern plain, Yungui Plateau, Northeast Plain and Mountain Mongolia-Xinjiang regions are total phosphorus of 0.068, 0.005, 0.011, 0.005 mg/L; total nitrogen of 1.00, 0.16, 0.37, 0.60 mg/L; Secchi depth of 0.60, 8.00, 1.55, 3.00 m; and CODMn of 2.24, 1.00, 5.1 l, 4.00 mg/L, respectively. Moreover, a region-specific comprehensive trophic level index was developed to provide an understandable assessment method for the public. The results indicated that the frequency distribution analysis based on chlorophyll-a combined with trophic level index provided a useful metric for the assessment of the lake trophic status. In addition, the difference of eutrophication assessment standards in different lake regions was analyzed, which suggested that the sensitivities of algae to nutrients and the assessment standard of trophic status possessed significant regional differences for the four lake ecoregions. Lake eutrophication assessment standards would contribute to maximizing the effectiveness of future management strategies, to control and minimize lake eutrophication problems. 相似文献
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834.
日益增长的农村污水设施剩余污泥已成为农村污水治理工作开展面临的新难题,农村剩余污泥适合采用多台污水设施共用车载式剩余污泥脱水设备进行脱水后收运集中处理,而农村道路的宽度和限高以及污水设施与道路间的距离等是主要的限制因素,因此急需研发适合农村作业环境的小型车载式剩余污泥脱水关键技术与设备.本研究的车载式剩余污泥脱水通过主要脱水设备负压运行方式,有效减小设备的尺寸,设备外观尺寸为5.995 m×1.905 m×2.56 m,吸污管道50 m.结果表明:可适应农村的作业环境,满足90%以上的农村小型污水处理设施使用.该设备行驶油耗7.2 L·h-1,工作油耗1.88 L·h-1;脱水后的污泥含水率80%左右.模拟案例表明,车载式剩余污泥脱水设备脱水收运方式比不脱水直接收运方式每台户用小型设施每年可节省污泥收运费103.3元,在一个安装了4400台小型污水设施的农村区域,每年可节省污泥收运费约45.5万元. 相似文献
835.
采用NaBH4超声还原法合成了富含氧空位的MoO2,并通过多种表征方法证明了氧空位的存在.10-MoO2作为助催化剂显著增强了Fe2+/过一硫酸盐体系催化性能,构建的10-MoO2/Fe2+/PMS体系可快速降解四环素(TC),10 min内对TC的降解率接近100%.系统研究了各种影响因素对TC降解效果的影响,探讨了助催化剂的稳定性及该体系的实用性.电化学、铁离子循环及自由基捕获实验的结果表明,由于氧空位(Ovacancy)的存在,降低了MoO2的电阻,增强了电子转移能力,加速了Fe3+/Fe2+循环,提高了活性氧物种的产率,从而增强了Fe2+/PMS类芬顿体系的催化活性.本研究为类芬顿法处理抗生素废水提供了一种新的视角. 相似文献
836.
Ni Lixiao Li Danye Rong Shiyi Su Lili Zhou Wei Wang Peifang Wang Chao Li Shiyin Acharya Kumud 《Environmental science and pollution research international》2017,24(26):21091-21102
Environmental Science and Pollution Research - This paper focuses on the characterization of extracellular polymeric substances (EPS), which are composed of soluble EPS (SL-EPS), loosely bound EPS... 相似文献
837.
838.
Györgyi Bela Taru Peltola Juliette C. Young Bálint Balázs Isabelle Arpin György Pataki Jennifer Hauck Eszter Kelemen Leena Kopperoinen Ann Van Herzele Hans Keune Susanne Hecker Monika Suškevičs Helen E. Roy Pekka Itkonen Mart Külvik Miklós László Corina Basnou Joan Pino Aletta Bonn 《Conservation biology》2016,30(5):990-999
The number of collaborative initiatives between scientists and volunteers (i.e., citizen science) is increasing across many research fields. The promise of societal transformation together with scientific breakthroughs contributes to the current popularity of citizen science (CS) in the policy domain. We examined the transformative capacity of citizen science in particular learning through environmental CS as conservation tool. We reviewed the CS and social‐learning literature and examined 14 conservation projects across Europe that involved collaborative CS. We also developed a template that can be used to explore learning arrangements (i.e., learning events and materials) in CS projects and to explain how the desired outcomes can be achieved through CS learning. We found that recent studies aiming to define CS for analytical purposes often fail to improve the conceptual clarity of CS; CS programs may have transformative potential, especially for the development of individual skills, but such transformation is not necessarily occurring at the organizational and institutional levels; empirical evidence on simple learning outcomes, but the assertion of transformative effects of CS learning is often based on assumptions rather than empirical observation; and it is unanimous that learning in CS is considered important, but in practice it often goes unreported or unevaluated. In conclusion, we point to the need for reliable and transparent measurement of transformative effects for democratization of knowledge production. 相似文献
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840.