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本文分析研究了油田注汽系统盐析现象及其成因和危害,并根据盐析成因探索了预防注汽盐析方法以减少甚至消除其危害。通过研究确定,采用高压旋流饱和蒸发与低压闪蒸和多效蒸集成技术是预防注汽系统盐析并减少甚至消除盐析及其造成的危害较为有效的方法。 相似文献
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Abstract: Die-offs of cordgrass are pervasive throughout western Atlantic salt marshes, yet understanding of the mechanisms precipitating these events is limited. We tested whether herbivory by the native crab , Sesarma reticulatum , is generating die-offs of cordgrass that are currently occurring on Cape Cod, Massachusetts (U.S.A.), by manipulating crab access to cordgrass transplanted into die-off areas and healthy vegetation. We surveyed 12 Cape Cod marshes to investigate whether the extent of cordgrass die-off on creek banks, where die-offs are concentrated, was related to local Sesarma grazing intensity and crab density. We then used archived aerial images to examine whether creek bank die-off areas have expanded over the past 2 decades and tested the hypothesis that release from predation, leading to elevated Sesarma densities, is triggering cordgrass die-offs by tethering crabs where die-offs are pervasive and where die-offs have not yet been reported. Intensity of crab grazing on transplanted cordgrass was an order of magnitude higher in die-off areas than in adjacent vegetation. Surveys revealed that Sesarma herbivory has denuded nearly half the creek banks in Cape Cod marshes, and differences in crab-grazing intensity among marshes explained >80% of variation in the extent of the die-offs. Moreover, the rate of die-off expansion and area of marsh affected have more than doubled since 2000. Crab-tethering experiments suggest that release from predation has triggered elevated crab densities that are driving these die-offs, indicating that disruption of predator–prey interactions may be generating the collapse of marsh ecosystems previously thought to be exclusively under bottom-up control . 相似文献
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某煤业有限公司清洗锅炉产生的废液中含有大量的铁离子与H^+,具有腐蚀性危险特性,属于危险废物。本工程实例利用酸碱中和及氧化絮凝沉淀的原理,消除了该废酸液的腐蚀性危险特性,同时降低了废酸液中的铁离子以及废酸液的色度、浊度,为后续的深度治理提供了便利。对高含铁废酸液的治理有一定的借鉴意义。 相似文献
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Two species of blue green algae Spirulina platensis and Anacystis nidulans grown in artificial aqueous media were treated with Cu and Cd in concentrations of 0.01, 0.1, 1.0 and 10 ppm to study carbon assimilation and Chlorophyll (Chl) A content. The species were treated with concentrations of 0.1, 0.5, 1.0, 5.0 and 10.0 ppm to study the uptake of metals with exposure time. Carbon assimilation and Chl A content showed responses proportional to the concentration in the general form y = K + n ln C, where C is the concentration of metal in ppm, while in case of uptake the relation was y = KC”; (where C is the molar concentration x 10‐6 of the metal). The n values in case of uptake was found to be < 1 indicating a non‐Langmuir type of sorption. The concentration factors of metals decreased with metal concentration in the medium. 相似文献
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挥发性有机污染物在土壤多孔介质中的有效扩散系数是土壤气相抽提(soil vapor extraction,SVE)传质过程中的一个重要参数.笔者以苯为研究对象,采用土柱扩散试验,对不同含水量条件下挥发苯在细砂介质中的有效扩散系数和扩散规律进行研究.结果表明,对于吸附型矿物含量少的细砂介质,含水量大小在一定程度上影响了挥发苯的扩散过程.含水量在50 g·kg-1时,扩散最快;低于50 g·kg-1时,随含水量增大扩散能力增强;高于50 g·kg-1时,扩散能力则随含水量增大而减弱.同一扩散柱中,随着扩散距离增加,挥发苯的有效扩散系数增大,这可能与其蒸汽分压降低有关. 相似文献
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MARK A. HAYES 《Conservation biology》2009,23(5):1075-1079
Abstract: Some educational psychologists and researchers have argued that there are multiple ways of being intelligent. In the early 1980s, Howard Gardner presented a theory of multiple intelligences by proposing that humans can be described not by a single kind of intelligence, or intelligence quotient score, but rather by a variety of kinds of intelligence. This idea of considering multiple views of intelligence has helped educators look at intelligence from a less rigid, more expansive perspective. I considered how the relatively new concept of naturalistic intelligence, which is the cognitive potential to process information that is exhibited by expert naturalists, might influence the design of undergraduate biology curricula. Naturalistic intelligence can be fostered in undergraduate biology students by emphasizing the need for well-rounded scientific naturalists; developing curricula that involves students in outdoor inquiry-based projects; and helping students learn how to observe both the natural world and their own learning, skills that are essential to developing expert naturalistic knowledge. Professors, graduate students, and administrators can improve the naturalistic intelligence of undergraduate biology students by giving these students opportunities to be involved in outdoor research. Time spent outdoors alone and among people with expertise in natural history, ecology, and conservation biology will have important influences on the knowledge and skills biology undergraduates learn, the careers they pursue, and the contributions they make to conserving Earth's biodiversity. 相似文献