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141.
The objectives of this study are to design an optimal electro-enhanced permeable reactive barrier (E2PRB) system for the remediation
of trichloroethylene (TCE)-contaminated water using zero valent iron (ZVI) and direct current (DC) and to investigate the
mechanisms responsible for TCE degradation in different ZVI-DC configurations. A series of column experiments was conducted
to evaluate the effect of different arrangements of electrodes and ZVI barriers in the column on the TCE removal capacity
(RC). In twelve different combinations of ZVI and/or DC application in the test columns, the rate of reductive dechlorination
of TCE was improved up to six times with simultaneous application of ZVI and DC compared to that using ZVI only. The most
effective arrangement of electrode and ZVI for TCE removal was the column set with ZVI and a cathode installed at the down
gradient. Based on the electrokinetic study for the column systems with only DC input, single acid front movement could explain
different RCs. An enhanced dechlorination rate of TCE using E2PRB systems, compared to a conventional PRB system, was observed,
and is considered to be attributed to more electron sources: (1) external DC, (2) electrolysis of water, (3) oxidation of
ZVI, (4) oxidation of dissolved Fe2+, (5) oxidation of molecular hydrogen at the cathode, and (6) oxidation of Fe2+ in mineral precipitates. Each of these electron sources was evaluated for their potential influencing the TCE RC through
the electron competition model and energy consumption. A strong correlation between the quantity of electrons generated, RC,
and the energy-effectiveness was found. 相似文献
142.
本文对沿海地带北方区段环渤海地区的国际、国内环境及其战略地位进行了分析，并对其目前的国际贸易与国际合作现状和问题，以及加强其国际竞争地位的策略进行了重点论述。 相似文献
143.
144.
对中国当前营销型城市增长策略的检讨 总被引：1，自引：0，他引：1
在经济全球化、市场化和分权化所营造的激烈竞争环境中，中国许多城市政府都以促进经济增长为目标而采取了多种多样的城市营销策略，城市治理方式由传统的规制型向企业型转变。城市政府甚至演变为超级企业。文章从制度经济学的角度揭示了在城市营销过程中，地方政府和投资者结成了促进增长的利益联盟和城市增长机器，在获得表象经济增长和城市面貌巨变的同时．却带来了广泛而严峻的经济、社会与空间负效应。文章认为，必须摈弃增长型城市营销中官商结盟的纯功利模式．采取内生的、可持续的城市营销战略，推进城市政府从单一目标的“增长型政府”向综合目标的“发展型政府”的转变。 相似文献
145.
146.
为应对后疫情时代及地缘政治影响下石油贸易新格局, 保障新时代、新格局下中国石油安全, 本文以全球石油贸易新格局为背景, 对中国、俄罗斯、印度、沙特阿拉伯四国石油贸易进行建模。由于沙特阿拉伯与中国、印度石油贸易长期处于安全、稳定状态, 本次实验运用演化博弈理论对中国与印度的能源竞争以及中国与俄罗斯的能源合作进行定量分析。研究结果表明: 1)印度持续增加俄罗斯石油进口将对我国石油安全造成威胁, 在印度对俄罗斯的石油进口占比达到16.5%时, 将改变四国石油贸易结构, 成为我国的重要威胁。2)俄罗斯出口意愿对结果产生直接影响, 在俄罗斯出口意愿持续降低时, 仿真结果产生变化, 对我国石油安全造成威胁。在世界石油贸易格局变化后的新时代, 本研究对保障中国石油安全有重要意义。 相似文献
147.
Abstract. Direct evidence for interspecific competition between Tetrachthamalus oblitteratus and Tetraclita squamosa is provided. Tetrachthamalus oblitteratus is smothered and eliminated from the main midlittoral zone by encrusting Tetraclita. The disjunct distribution of Tetrachthamalus can be explained by elimination through competitive exclusion. 相似文献
148.
149.
Abstract. Over 120 species, including epizoites, endolithic organisms, and an epiflora are associated with the gastropod shells inhabited by the hermit crabs Paguristes oculatus and Pagurus cuanensis in the North Adriatic Sea (Gulf of Trieste). The symbiotic organisms include members of three trophic levels - primary producers (rhodophytes), primary consumers (active and passive filter feeders), and secondary consumers (carnivorous species). Many of the invertebrates show a preferred distribution on the shells. The shells are a mobile substratum for a specific community. They are a sediment- and predator-free surface, and for their size are extremely stable substrates in terms of both time and orientation.
The hermit crab microbiocoenosis is a dynamic phenomenon that can be studied as a functional unit. The symbionts are responsible for two simultaneous processes - a constructive and a destructive process on the shells. Shell deterioration is due primarily to biological processes, not to mechanical destruction. The more frequently occurring species were classified according to their role in reinforcing or weakening shell structure. These developments are related to hermit crab activity. Epizoites grow through several shell changes by hermit crabs, and a number of forms are capable of surviving the final deposition of the shells. 相似文献
The hermit crab microbiocoenosis is a dynamic phenomenon that can be studied as a functional unit. The symbionts are responsible for two simultaneous processes - a constructive and a destructive process on the shells. Shell deterioration is due primarily to biological processes, not to mechanical destruction. The more frequently occurring species were classified according to their role in reinforcing or weakening shell structure. These developments are related to hermit crab activity. Epizoites grow through several shell changes by hermit crabs, and a number of forms are capable of surviving the final deposition of the shells. 相似文献
150.
为探讨UV-B辐射对海洋生态系统的影响，研究了短期(2d)UV-B辐射对金藻8701、小新月菱形藻和亚心形扁藻3种藻单养的敏感性比较以及长期(21d)UV-B辐射对3种藻混养的种间竞争性平衡的影响。实验表明，(1)UV-B条件下。单养和混养情况下，最敏感的藻是金藻8701，小新月菱形藻次之，亚心形扁藻最不敏感；(2)增强的UV-B为对UV-B具有高耐受力的亚心形扁藻提供了竞争优势，使种间竞争平衡向着有利于亚心形扁藻的方向发展，到第21天，UV-B辐射(2．88J／m^2，5．76J／m^2)的处理组中，亚心形扁藻成为优势种。 相似文献