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741.
This paper explores and identifies the rules of the unsteady evolution of COD in the upper and middle reaches of Minjiang River through multi-scale analysis on the weekly COD data for the last six years provided by the Water Quality Monitoring Station,Minjiang River Bridge,Leshan City,Sichuan Province.The results of the wavelet analysis indicate that the COD index oscillates alternatively and differently at each time-scale in an oneyear cycle,and the density of COD,subjected to the runoff volume,the effects of Wenchuan Earthquake and agricultural seeding and industrial construction,etc.,is high in winter and spring,mild in summer and autumn. 相似文献
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743.
超声波净化石油污染土壤实验研究 总被引:3,自引:0,他引:3
为研究超声波技术处理石油污染土壤的影响因素,选取了土壤含油量、土水比、土壤类型、超声处理时间和超声功率5个因素进行了具有交互作用的正交实验,并讨论了各因素对土壤中石油污染物清除率的影响。实验结果表明超声波对土壤中石油污染物的净化效果明显,总石油烃(TPH)的清除率在23.0%到77.3%之间,土壤类型对净化效果的影响最为显著,粘土中的TPH清除率显著低于砂土。由超声空化引起的解吸作用和真空抽滤是实验过程中土壤TPH减少的主要途径。研究结果表明超声波技术用于石油污染土壤修复是可行并且有效果的。 相似文献
744.
活性炭纤维载体生物膜法处理洗车废水研究 总被引:2,自引:2,他引:0
为了实现洗车废水的循环使用,进行了以聚丙烯腈基活性炭纤维(PAN-ACF)为生物膜载体处理洗车废水的实验研究。以LAS、COD和NH3-N等指标考察了活性炭纤维生物膜反应器对洗车废水的处理效果。结果表明:在常温下、pH=6.5~7,当进水流量在30 mL/min时,反应器达到最佳运行参数,活性炭纤维载体生物膜法对LAS、COD和NH3-N等的去除率分别达到了97%、80%和60%。出水水质完全达到《生活杂用水水质标准》(CJ/T48-99)中洗车用水主要水质指标的规定。此外,实验表明PAN-ACF作为生物膜载体具有很好的生物亲和性和再生性。 相似文献
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746.
747.
There is growing recognition that teams do not function in a vacuum and that external boundary activities are important predictors of team performance, effectiveness, and knowledge sharing. In the past, researchers have focused on the effects of team composition or task characteristics as antecedents of critical boundary spanning activities. However, less effort has been directed at understanding how antecedents at multiple levels can simultaneously influence boundary spanning behavior in teams. This paper takes stock of over 20 years of research on the topic of team boundary spanning. Adopting a “bracketing” approach etc., we develop a multi‐level theoretical model to guide future research on the determinants of team boundary spanning. This model specifies task‐based, team‐level, and contextual antecedents of team boundary spanning and outlines the contingencies shaping the emergence of effective boundary‐management behavior in teams. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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749.
本文论述了国内外冷却服的发展现状,介绍了3种制冷技术路线,指出了其各自的关键技术,有利于人们对冷却服的发展趋势进一步的了解和认识. 相似文献
750.
Changseok Han Vlassis Likodimos Javed Ali Khan Mallikarjuna N. Nadagouda Joel Andersen Polycarpos Falaras Pablo Rosales-Lombardi Dionysios D. Dionysiou 《Environmental science and pollution research international》2014,21(20):11781-11793
Noble metal Ag-decorated, monodisperse TiO2 aggregates were successfully synthesized by an ionic strength-assisted, simple sol–gel method and were used for the photocatalytic degradation of the antibiotic oxytetracycline (OTC) under both UV and visible light (UV–visible light) irradiation. The synthesized samples were characterized by X-ray diffraction analysis (XRD); UV–vis diffuse reflectance spectroscopy; environmental scanning electron microscopy (ESEM); transmission electron microscopy (TEM); high-resolution TEM (HR-TEM); micro-Raman, energy-dispersive X-ray spectroscopy (EDS); and inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the uniformity of TiO2 aggregates was finely tuned by the sol–gel method, and Ag was well decorated on the monodisperse TiO2 aggregates. The absorption of the samples in the visible light region increased with increasing Ag loading that was proportional to the amount of Ag precursor added in the solution over the tested concentration range. The Brunauer, Emmett, and Teller (The BET) surface area slightly decreased with increasing Ag loading on the TiO2 aggregates. Ag-decorated TiO2 samples demonstrated enhanced photocatalytic activity for the degradation of OTC under UV–visible light illumination compared to that of pure TiO2. The sample containing 1.9 wt% Ag showed the highest photocatalytic activity for the degradation of OTC under both UV–visible light and visible light illumination. During the experiments, the detected Ag leaching for the best TiO2-Ag photocatalyst was much lower than the National Secondary Drinking Water Regulation for Ag limit (0.1 mg L?1) issued by the US Environmental Protection Agency. 相似文献