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851.
852.
膜污染是厌氧膜生物反应器(anaerobic membrane bioreactor,AnMBR)产业化应用面临的最大挑战.本研究构建新型微生物电催化(bio-electrochemical systems,BES)-AnMBR组合反应器,以探究纳米零价铁(nano-zero-valent iron,nZVI)投加对BES-AnMBR组合系统膜污染削减和甲烷产生等性能的影响.结果表明,BES-AnMBR组合系统运行稳定,COD去除率一直维持在95%左右.nZVI投加量(以VS计)为0.1 g ·g-1时,运行性能最佳,跨膜压差(transmembrane pressure,TMP)较对照组降低28.1%,膜通量亦有轻微增加;甲烷产量为81.3 mL ·g-1(以CODremoved计),较对照组提高了12.1%.胞外聚合物(extracellular polymeric substance,EPS)变化和膜阻过滤分析表明,nZVI可以加强EPS分解,促进膜表面无机和有机富铁结垢层形成,改善膜污染分布特征,从而显著缓解膜污染.本研究将丰富传统AnMBR的基础理论,为污泥处理与资源化利用提供了新视角. 相似文献
853.
基于灰色-马尔可夫藕合模型的区域建设用地需求预测 总被引:1,自引:0,他引:1
建设用地需求的中长期准确预测是当前土地资源规划和利用的重点和难点。本文将灰色和马尔可夫两种预测模型相结合,建立灰色-马尔可夫藕合模型,以广东省揭阳市为例,对1997到2010年间主要建设用地规模进行了需求预测,同时与其它几种常规的预测方法进行了比较。结果表明,人文驱动力相关预测法误差相对较大,其中国内生产总值(GDP)相关法准确度要优于人口相关法。趋势线法计算简单,预测准确度也相对较高,但只适于短期预测。灰色预测法精确度较高,计算需要模型的支持、专业性强。灰色-马尔可夫预测法由于是对灰色预测的偏离值进行了纠正,因而准确度最高。尽管该方法需要大量数据的支持,计算量大,但仍是值得推荐的高准确度的区域建设用地的专业预测方法。 相似文献
854.
Influence of iron, nickel and cobalt on biogas production during the anaerobic fermentation of fresh residual biomass 总被引:2,自引:0,他引:2
We have investigated the dependence of the rate of the production of biogas upon the concentration of nickel, cobalt and iron at sub-toxic concentration and monitored its composition as amount of hydrogen, methane and carbon dioxide. The distribution of the added metals between the liquid and solid phase has also been monitored.
The results of our investigations show that the addition of any of the listed metals to the sludge may cause the production of a higher amount of biogas and influence the methane or carbon dioxide percentage. Conversely, the effect on the hydrogen production depends upon the metal added, the age of the active sludge used, and its adaptation to the susbtrate. As a general feature, during the acidogenesis phase, nickel reduces, while iron increases, the percentage of dihydrogen in the biogas, while cobalt has no influence. 相似文献
The results of our investigations show that the addition of any of the listed metals to the sludge may cause the production of a higher amount of biogas and influence the methane or carbon dioxide percentage. Conversely, the effect on the hydrogen production depends upon the metal added, the age of the active sludge used, and its adaptation to the susbtrate. As a general feature, during the acidogenesis phase, nickel reduces, while iron increases, the percentage of dihydrogen in the biogas, while cobalt has no influence. 相似文献
855.
新型甲醛被动式检气管的研制 总被引:5,自引:0,他引:5
新研制的甲醛被动式检气管是建立在气体分子扩散和化学吸收原理基础上的,检气管内的惰性担体上浸渍了对甲醛特效的希夫试剂。当管内进入甲醛气体时,即发生显色反应,检气管的显色长度的平方与甲醛浓度及采样时间的乘积成线性关系。检出下限为0.015mg#L(采样5h),它集采样与分析为一体,结构简单,不需动力,便于携带和操作方便,应用于检测某厂刨花板车间和制胶车间的甲醛气体,与传统的注射器采样比色分析法对比,结 相似文献
856.
细菌Rieske型非血红素铁加氧酶研究进展 总被引:2,自引:2,他引:2
细菌Rieske型非血红素铁加氧酶是催化芳香化合物好氧降解第一步反应的酶,能够激发好氧环境下大量芳香或取代芳香化合物的生物降解,同时还可作为有机化合物的合成子.这是一类新型且丰富的酶资源,在受污环境的生物修复方面有着巨大的潜力,并且符合“绿色化学”的要求.本文综述了该类酶的分类、晶体结构、作用机理及其基因改造等最新研究进展. 图4表1参17 相似文献
857.
Hu Y Li JH Zhu YG Huang YZ Hu HQ Christie P 《Environmental geochemistry and health》2005,27(2):169-176
A pot experiment was carried out in a greenhouse to investigate the sequestration of As in iron plaques on root surface of
three rice (Oryza sativa L.) cultivars. Phosphate (P) fertilization increased both plant biomass and tissue P concentrations significantly, indicating
that the soils used in this study was highly P-deficient. Results from this study confirmed that low P supply improved the
formation of iron plaque on rice roots. As a consequence, arsenic (As) concentrations in DCB-extracts with no P addition were
significantly higher than those with P fertilization. Arsenic was highly sequestrated in iron plaque; arsenic concentration
in iron was up to nearly 120 mg kg−1, while arsenic concentrations in roots were just several mg kg−1. Both arsenic and phosphate concentrations in iron plaque were highly positively correlated with the amounts of iron plaque
(DCB-extractable Fe). Contrary to normal understanding that increasing P supply could reduced As accumulation in plants, results
from the present study showed that P fertilization did not inhibit the As uptake by plants (As accumulation in aboveground),
which was probably due to the fact that iron plaque formation was improved under low P conditions, thus leading to more As
sequestration in the iron plaque. Thus results obtained in this study indicated that the iron plaque may inhibit the transfer
of As from roots to shoots, and thus alter the P–As interaction in plant As uptake processes. 相似文献
858.
Rulon W. Clark 《Behavioral ecology and sociobiology》2005,59(2):258-261
A thorough understanding of communication requires an evaluation of both the signaler and receiver. Most analyses of prey–predator communication are incomplete because they examine only the behavior of the prey. Predators in these systems may be understudied because they are perceived as less tractable research subjects, due to their more cryptic hunting behaviors and secretive lifestyles. For example, research on interactions between rodents and rattlesnakes has focused on the behavior of rodent signalers, while responses of snakes have been virtually unexamined. Rattlesnakes are ambush predators, and capture rodents by waiting at foraging sites for long periods of time. In this study, I take advantage of the sedentary nature of this foraging strategy and use fixed videography to record natural encounters between timber rattlesnakes (Crotalus horridus) and their prey. Three different prey species were found to exhibit conspicuous visual displays to snakes, both when snakes were actively foraging, and when they were basking. After receiving displays, foraging snakes left their ambush sites and moved long distances before locating subsequent ambush sites, indicating that they responded to displays by abandoning attempts to ambush prey in the vicinity of signalers. This study represents the first quantitative analysis of the response of free-ranging snakes to signals from their prey, and elucidates a technique by which such quantitative data can be more easily obtained. 相似文献
859.
860.
原子吸收法测定水中铁的不确定度分析 总被引:6,自引:0,他引:6
通过对原子吸收法测定水中铁的不确定度的分析,找出了导致不确定度的因素。对测量不确定度进行计算和评定,结果表明,影响其测量不确定度的主要因素是标准曲线精密度以及仪器漂移。 相似文献