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621.
622.
采用硫/沸石固定床反应器去除水中硝酸盐。实验结果表明,在硫/沸石固定床反应器内通过自养反硝化作用能使水体中硝酸盐得到有效的去除。在硫与沸石的体积比为1∶2,水力停留时间为2 h,进水COD为50 mg/L时,出水硝酸盐去除率可达到95%以上;不外加碳源,总氮的去除率仍可达80%以上;在不投加CaCO3的情况下,出水pH可始终保持7.0;温度对该反应器硝酸盐的去除率影响不大,进水水温为12℃时总氮(TN)去除率仍可达91.1%。 相似文献
623.
高精度管道泄漏监测报警定位系统是基于管理中心平台上集成了次声波泄漏监测定位技术、最新的卫星定位技术和通讯技术为一体的管道泄漏监测系统.通过在孤东采油厂原油外输线的研发应用,能够准确的监测到原油管线泄漏点,为打击盗油行为,提供了有力保障. 相似文献
624.
合肥市的环城水体没有天然补给水源,极易引起水体污染,开展生态补水工程很有必要。由于水资源紧缺,拟采用中水补水。选用一维河道稳态水质模型及均匀混合水质模型研究了不同量的生态补水对银河、包河、雨花塘水体影响,以及流动后对南淝河亳州路桥一长江路桥段的影响,评估了生态补水工程的可行性,最终确定了最佳的生态补水量。 相似文献
625.
626.
Allelopathic inhibition on red tide microalgae Skeletonema costatum by five macroalgal extracts 总被引:1,自引:0,他引:1
Zhen An Zhenyu Wang Fengmin Li Zhijia Tian Hongying Hu 《Frontiers of Environmental Science & Engineering in China》2008,2(3):297-305
This study aims to identify effective antialgal allelochemicals from marine macroalgae that inhibit the growth of red tide
microalgae. Practically, new algicidal agents were developed to control red tide. The growth inhibitory effects of 5 marine
macroalgae Porphyra tenera, Laminaria japonica, Ulva pertusa, Enteromorpha clathrata, and Undaria pinnatifida on Skeletonema costatum were evaluated by adding crude seawater extracts of macroalgal dry tissue into the culture medium containing S. costatum. The half-effective concentrations at 120 h (EC50, 120 h) of the seawater extracts were 0.6, 0.9, 1.0, 1.0, and 4.7 g/L for the five macroalgae above, respectively. E. clathrata, L. japonica and U. pertusa showed strong allelopathic effect on the growth of S. costatum. There have been no previous reports with regard to the allelopathic effects of the former two macroalgae so far. The possible
allelochemicals of 21 compounds of the E. clathrata were detected using Gas chromatography-mass spectrometry (GC-MS) analysis. Unsaturated fatty acids, acrylic acid (C3H4O2), and linolenic acid (C18H30O2) were the most likely allelochemicals in E. clathrata. 相似文献
627.
Abstract The aim of this article is to develop a structural equation model to assess key factors of residents’ support for hosting mega event based on previous literature. The model consisted of five latent constructs and eight path hypotheses. A survey was conducted in Shanghai before 2010 World Expo. It was found that the support for mega events is affected directly and/or indirectly by four determinants factors: perceived benefits, perceived costs, personal benefits and community attachment, and support relies heavily on perceived benefits rather than costs. This study contributes to the existing body of knowledge in an attempt to understand local residents’ support for a mega event in different economic and cultural settings. 相似文献
628.
Menghong Hu Youji Wang Sau Ting Tsang Siu Gin Cheung Paul K. S. Shin 《Marine Biology》2011,158(7):1591-1600
Energy budget is one of the most studied parameters in aquatic animals under environmental challenge. To examine how prolonged
starvation would affect their energy budget, respiration rate (RR), ammonia excretion rate (ER), oxygen consumption to ammonia–nitrogen
excretion (O:N) ratio and scope for growth (SfG) representing the balance between energy intake and metabolic output, two
Asian horseshoe crab species, Tachypleus tridentatus and Carcinoscorpius rotundicauda, were investigated in two feeding regimes (fed and starved) over a period of 7 weeks. No significant effects of species and
time course, as well as their interaction, on absorption efficiency were observed in the fed treatments. For both species,
RR and ER of the starved treatments significantly decreased, while their O:N ratio significantly increased during the experiment.
However, such values for the fed treatments remained relatively stable over the study period. A rapid reduction in SfG was
only apparent in the first week of the starved treatments for both species; thereafter, their SfG remained relatively constant.
In the fed treatments, SfG of T. tridentatus was significantly lower than that of C. rotundicauda throughout the experiment. In general, C. rotundicauda showed a greater decrease in SfG under starvation than T. tridentatus, suggesting that they may have a more competitive life-history strategy for adjusting to poor nutritional conditions. 相似文献
629.
Anping Zhang Xuemei Xie Jing Ye Chunmian Lin Xiaoyan Hu 《Environmental Chemistry Letters》2011,9(3):369-373
In recent years, the stereoselective toxicity of chiral organophosphorus pesticides has received increasing attention from
environmental toxicology scientists. In an attempt to explore the stereoselective effects of chiral organophosphorus pesticides
on non-target organisms and enzymes, this work investigated the stereoselective toxicity and inhibition of malathion, malaoxon
and isomalathion on Daphnia magna and on acid α-naphthyl acetate esterase extracted from wheat flour, respectively. Toxicity differences were observed between
the two enantiomers of malathion and malaoxon and among the four stereoisomers of isomalathion in the LC50 values on D. magna and the IC50 values on acid α-naphthyl acetate esterase. Enantiomers with (R)-configuration in all the tested compounds showed
higher toxicity to D. magna than their (S)-forms and racemic forms. Racemic malaoxon and isomalathion showed the strongest inhibition on acid α-naphthyl
acetate esterase compared to their respective enantiomers and stereoisomers. 相似文献
630.