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AN Zhen WANG Zhenyu LI Fengmin TIAN Zhijia HU Hongying 《Frontiers of Environmental Science & Engineering》2008,2(3):297
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
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评价一个建筑的环境性能的好坏,必须充分考虑它的生命周期中的每一个阶段。建立了建筑物的生命周期清单分析模型,并对某钢结构建筑和某混凝土建筑的生命周期清单分析结果进行了比较,结果表明,单从结构的生命周期清单分析结果,钢结构建筑相对于混凝土结构建筑有着较大的优越性,单位面积的建材生命周期环境排放仅为混凝土结构建筑的1/2左右,但是结构在建筑的整个生命周期里面只不到10%的比例,比例最大的是建筑使用阶段,影响建筑使用阶段空调能耗的主要因素是外围护结构的材料和形式,因此优化外围护结构的热工性能是当前我国建筑节能最主要的问题。 相似文献
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Zhijia Miao Wei Zeng Shuying Wang Yongzhen Peng Guihua Cao Dongchen Weng Guisong Xue Qing Yang 《环境科学学报(英文版)》2014,26(2):264-273
Temperature is an important physical factor, which strongly influences biomass and metabolic activity. In this study, the effects of temperature on the anoxic metabolism of nitrite(NO-2) to nitrous oxide(N2O) by polyphosphate accumulating organisms, and the process of the accumulation of N2O(during nitrite reduction), which acts as an electron acceptor, were investigated using 91% ± 4% Candidatus Accumulibacter phosphatis sludge. The results showed that N2O is accumulated when Accumulibacter first utilize nitrite instead of oxygen as the sole electron acceptor during the denitrifying phosphorus removal process. Properties such as nitrite reduction rate, phosphorus uptake rate, N2O reduction rate, and polyhydroxyalkanoate degradation rate were all influenced by temperature variation(over the range from 10 to 30°C reaching maximum values at 25°C). The reduction rate of N2O by N2O reductase was more sensitive to temperature when N2O was utilized as the sole electron acceptor instead of NO2, and the N2O reduction rates, ranging from 0.48 to 3.53 N2O-N/(hr·g VSS), increased to 1.45 to 8.60 mg N2O-N/(hr·g VSS). The kinetics processes for temperature variation of 10 to 30°C were(θ1 = 1.140–1.216 and θ2= 1.139–1.167). In the range of 10°C to 30°C, almost all of the anoxic stoichiometry was sensitive to temperature changes. In addition, a rise in N2O reduction activity leading to a decrease in N2O accumulation in long term operations at the optimal temperature(27°C calculated by the Arrhenius model). 相似文献