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951.
应用紫外诱变技术,将1株从湟水河北川河段水源中分离得到的氨氮降解菌,置于5℃下胁迫培养,筛选出1株氨氮降解率较高的诱变菌YB-6,同时将其应用于城市生活污水的氨氮处理,进行遗传稳定性试验。通过对诱变菌的接种量、反应时间和p H单因素试验的研究,确定了试验菌株在水样中氨氮降解的最佳条件。结果表明:紫外诱变的最佳处理时间为30 s,在5℃条件下,诱变菌株YB-6对生活污水的氨氮降解率达到50%以上,且具有遗传稳定性;并确定了试验菌株YB-6最佳降解条件为:接种量为15%,反应时间为60 h,p H为10.0,在5℃下,对生活污水的氨氮降解率达到68.62%。 相似文献
952.
Ahmed Elsayed Raya K. AL-Dadah Saad Mahmoud Waseem Kaialy 《International Journal of Green Energy》2018,15(5):277-285
Commercially available adsorption cooling systems use water/silica gel, water/zeolite and ammonia/ chloride salts working pairs. The water-based pairs are limited to work above 0°C due to the water high freezing temperature, while ammonia has the disadvantage of being toxic. Ethanol is a promising refrigerant due to its low freezing point (161 K), nontoxicity, zero ozone depletion, and low global warming potential. Activated carbon (AC) is a porous material with high degree of porosity (500–3000 m2/g) that has been used in wide range of applications. Using Dynamic Vapour Sorption (DVS) test facility, this work characterizes the ethanol adsorption of eleven commercially available activated carbon materials for cooling at low temperature of ?15°C. DVS adsorption results show that Maxsorb has the best performance in terms of ethanol uptake and adsorption kinetics compared to the other tested materials. The Maxsorb/ethanol adsorption process has been numerically modeled using computational fluid dynamics (CFD) and simulation results are validated using the DVS experimental measurements. The validated CFD simulation of the adsorption process is used to predict the effects of adsorbent layer thickness and packing density on cycle uptake for evaporating temperature of ?15°C. Simulation results show that as the thickness of the Maxsorb adsorbent layer increases, its uptake decreases. As for the packing density, the amount of ethanol adsorbed per plate increases with the packing density reaching maximum at 750 kg/m3. This work shows the potential of using Maxsorb/ethanol in producing low temperature cooling down to ?15°C with specific cooling energy reaching 400 kJ/kg. 相似文献
953.
954.
21世纪充满着挑战,当世界上还有许多国家需要解决基本的生存问题之时,又要面对过去因单一的经济利益驱动而过度开发带来的环境问题、温室效应问题、资源危机问题等,人类要继续发展下去,就必须面对并尽可能解决这些问题。就解决温室效应问题而引出的低碳消费话题进行了一次调查问卷。调研获得的相关数据的结论,有助于南京市政府职能部门采取相应政策和措施,这样就可以引导南京市居民树立低碳消费理念,使南京市居民实施低碳消费行为。 相似文献
955.
A. Ebel H. Feldmann H.J. Jakobs M. Memmesheimer D. Offermann V. Kuell B. Schler 《Ecological modelling》2009,217(3-4):240
Transport of atmospheric trace gases during a blocking event in the troposphere and lower stratosphere (UTLS) in August 1997 is studied. Considering the frequency of such events it is obvious that they play a significant role for climate and air chemistry and thus the atmospheric environment. The event has been selected because a unique set of composition observations carried out by the CRISTA (Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere) instrument in the UTLS was available for the period of blocking. The regional European Atmospheric Dispersion (EURAD) model system was used for a detailed analysis focusing on ozone and CFC 11 (CFCl3, Freon) distributions and their temporal and spatial variability. The combination of the CRISTA data and a regional transport chemistry model enabled a unique analysis of transport behaviour of a blocking. This developed an Ω-structure with a deep cut-off low at the western flank of the blocking high and a trough with highly perturbed trace gas fields on the eastern side. Tropopause heights varied intensively and were bended down to rather low levels in the cut-off low and folds appearing in the eastern trough. Results of artificial tracer experiments are presented which show that polluted air from lower tropospheric levels and – in this case – lower latitudes as well as the North American continent may be lifted up to the UTLS in the anticyclonic part of the Ω-block and transported from there over large distances in streamers. Quasi-periodic variations of CFC 11 flux divergence indicate dynamical coupling of the different domains of the block. 相似文献
956.
低碳化已成为物流未来发展的趋势,物流发达国家已经推进了低碳化进程并形成了可供借鉴的经验.综观中国物流业,低碳政策与法规不健全、低碳管理能力还有待提高、低碳技术尚需进一步研发、低碳意识和低碳人才培养要加强.在诸多因素制约下,只有政府、物流企业及相关协会组织、教育机构和社会各界共同努力,保持科学发展的态度、积极研发和掌握低碳物流新技术、培养合格的物流人才进行管理,才能将物流业低碳化早日实现. 相似文献
957.
Michele Jeanette Sanders Laura Miller Shonil A. Bhagwat Jesse Marije Anne van der Grient Alex David Rogers 《Conservation biology》2020,34(1):113-124
A key obstacle to conservation success is the tendency of conservation professionals to tackle each challenge individually rather than collectively and in context. We sought to prioritize barriers to conservation previously described in the conservation literature. We undertook an online survey of 154 practitioners from over 70 countries to ascertain the most important barriers to conservation they faced. We used statistical analyses to identify the key impediments to conservation success and to examine whether these were affected by organizational attributes. Twenty-one barriers were identified. The importance ascribed to those was influenced by continent of operation and organization size, but not by organization age or autonomy (from larger parent organizations). We found the most important barriers to consider when undertaking conservation action were wider issues (e.g., population growth, consumerism, favoring development, and industrial-scale activity), operating environment (e.g., lack of political will, ineffective law enforcement, weak governments, corruption, safety and security), community attributes (e.g., dynamics, conflicts, and education levels), and the way conservation is undertaken (overconfidence, lack of funding, and externally set agendas). However, we advise against applying a one-size-fits-all approach. We propose that conservationists account for the complex socioecological systems they operate in if they are to achieve success. 相似文献
958.
959.
5种水生植物去污抗逆能力的试验研究 总被引:21,自引:2,他引:19
在实验室人工模拟太湖地区初春较寒冷的气象条件下,对5种能越冬的水生植物(伊乐藻、微齿眼子菜、竹叶眼子菜、石菖蒲和水芹菜)在不同营养条件下去除氮磷的效果和一些反映其抗逆能力的生理生化指标进行了系统的对比研究.结果表明:这5种植物均能较好地吸收水中的营养物质,其中以水芹菜和微齿眼子菜的脱氮除磷效果最好;5种植物体内脯氨酸含量均与水体营养物质的质量浓度呈正相关,相同试验条件下,水芹菜和微齿眼子菜体内脯氨酸的积累倍数最高,表明二者的抗逆能力也较强;但当水体营养物质的质量浓度超过一定限值后,5种植物的生物量增长率均随水体营养等级的增高而下降.水芹菜和微齿眼子菜可作为构成双层次群落结构(FAMS)的优选植物种类,用于修复太湖地区富营养化水体. 相似文献
960.
北京市交通路口大气颗粒物污染特征研究(Ⅰ)——大气颗粒物污染特征及其影响因素 总被引:14,自引:4,他引:10
研究了北京市典型交通路口大气颗粒物的污染特征及影响因素.于2000年6月在北京市主要交通路口之一的崇文门路口,采集了大气中不同粒径的颗粒物样品,并进行了颗粒物质量浓度、离子浓度和元素质量浓度的分析,同时进行了样品采集期间机动车流量调查.研究结果表明,6月5日大气颗粒物污染严重.6月6日0∶10-3∶50,ρ(PM2.5)达到最高值.崇文门路口的大气颗粒物污染水平与机动车流量之间无明显的对应关系.交通来源颗粒物是影响交通路口污染水平的首要因素,颗粒物中Al,Ca,Fe和Mg等元素主要来自机动车行驶载带的道路可扬尘,而Cu,Pb等元素主要来自机动车的排放.还指出了今后进行该类研究的主要方向和技术思路. 相似文献