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排序方式: 共有1413条查询结果,搜索用时 15 毫秒
51.
We examined long-term data on water chemistry of Lake Rachelsee (Germany) following the changes in acidic depositions in central Europe since 1980s. Despite gradual chemical recovery of Rachelsee, its biological recovery was delayed. In 1999, lake recovery was abruptly reversed by a coincident forest die-back, which resulted in elevated terrestrial export of nitrate and ionic aluminum lasting ~5 years. This re-acidification episode provided unique opportunity to study plankton recovery in the rapidly recovering lake water after the abrupt decline in nitrate leaching from the catchment. There were sudden changes both in lake water chemistry and in plankton biomass structure, such as decreased bacterial filaments, increased phytoplankton biomass, and rotifer abundance. The shift from dominance of heterotrophic to autotrophic organisms suggested their substantial release from severe phosphorus stress. Such a rapid change in plankton structure in a lake recovering from acidity has, to the best of our knowledge, not been previously documented.  相似文献   
52.
微生物电化学技术能同时实现污染物去除和能量回收,但存在污染物去除种类有限及产能效率低的局限,近几年将可再生的太阳能引入微生物电化学技术的微生物-光-电化学耦合技术应运而生。本文简要介绍了微生物-光-电化学耦合技术的发展背景和研究现状,对该技术现有的耦合形式进行分类,并对各种形式的耦合机理进行详细的阐释,最后对其未来的发展进行了展望。  相似文献   
53.
研究了采用柴油低温临界吸收法回收装车挥发油气的效果。实验结果表明:按装车挥发油气中的总烃体积分数为20.88%、装车挥发油气流量为280 m3/h、年运行时间为2 668 h计,装置年回收油气量为291 t,装置年最大运行功率为206.770 MW,装置投资回收期为3 a;处理后净化气中的总烃体积分数为1.24%,排放质量浓度低于25 g/m3,油气回收率达95%。处理后净化气满足GB 20950—2007《储油库大气污染物排放标准》,取得了较好的环保效益和经济效益。  相似文献   
54.
Exergo-economic analysis of the pinch point temperature difference (PPTD) in both evaporator and condenser of sub-critical organic Rankine cycle system (ORCs) are performed based on the first and second laws of thermodynamics. Taking mixture R13I1/R601a as a working fluid and the annual total cost per net output power Z as exergo-economic performance evaluation criterion, the effects of PPTD in evaporator ΔTe, and the PPTD ratio of condenser to evaporator y, on the exergo-economic performance of ORCs are analyzed. Moreover, how some other parameters influence the optimal PPTD in evaporator ΔTe,opt and the optimal PPTD ratio of condenser to evaporator yopt are also discussed. It has been found that the exergo-economic performance of ORCs is remarkably influenced by ΔTe and y, and there exists ΔTe,opt and yopt. In addition, ΔTe,opt and yopt are affected by heat transfer coefficient ratio of condenser to evaporator ß, the temperature of working fluid at dew point in condenser T1a, and composition of R13I1/R601a: larger ß and T1a lead to lower ΔTe,opt and yopt; by contraries, larger mass fraction of R13I1 makes ΔTe,opt and yopt increase, and yopt increases linearly. The effects of the temperature of working fluid at bubble point in evaporator T3a, mass flow rate of exhaust flue gas mg, and inlet temperature of exhaust flue gas Tgi on ΔTe,opt and yopt are very slight. For comparison, three additional working fluids, namely R601a, R245fa, and 0.32R245fa/0.68R601a, are also taken into account.  相似文献   
55.
《组织行为杂志》2017,38(8):1213-1226
This diary study examined within‐person effects of positive work and off‐work experiences on daily work engagement. Assessing the gain cycle assumption of conservation of resources theory, we investigated the relationship of nighttime recovery experiences and subsequent resources including elevated sleep quality and morning positive affect; the relationship of morning positive affect with positive collegial interactions and subsequent work engagement; and the relationship of work engagement with nighttime recovery experiences. Sixty‐nine employees completed 3 daily questionnaires over 5 consecutive working days. Multilevel analyses revealed that sleep quality positively predicted morning positive affect, which in turn predicted work engagement directly and also indirectly through having positive interactions with colleagues. Work engagement positively predicted nighttime recovery experiences, whereas nighttime recovery experiences were not related to sleep quality or morning positive affect the next day. Overall, on days after a good night's sleep, individuals feel more positive, bring this positivity to their workplace, reach out to their workplace colleagues, and are in turn more likely to be engaged in their work. Additionally, on days when individuals experience higher levels of positive collegial interactions at work and in turn higher work engagement, they are likely to enjoy better recovery experiences.  相似文献   
56.
Eradication of introduced mammalian predators from islands has become increasingly common, with over 800 successful projects around the world. Historically, introduced predators extirpated or reduced the size of many seabird populations, changing the dynamics of entire island ecosystems. Although the primary outcome of many eradication projects is the restoration of affected seabird populations, natural population responses are rarely documented and mechanisms are poorly understood. We used a generic model of seabird colony growth to identify key predictor variables relevant to recovery or recolonization. We used generalized linear mixed models to test the importance of these variables in driving seabird population responses after predator eradication on islands around New Zealand. The most influential variable affecting recolonization of seabirds around New Zealand was the distance to a source population, with few cases of recolonization without a source population ≤25 km away. Colony growth was most affected by metapopulation status; there was little colony growth in species with a declining status. These characteristics may facilitate the prioritization of newly predator‐free islands for active management. Although we found some evidence documenting natural recovery, generally this topic was understudied. Our results suggest that in order to guide management strategies, more effort should be allocated to monitoring wildlife response after eradication. Conductores de la Recuperación de Poblaciones de Aves Marinas en Islas de Nueva Zelanda después de la Erradicación de Depredadores  相似文献   
57.
Conflicts between local people's livelihoods and conservation have led to many unsuccessful conservation efforts and have stimulated debates on policies that might simultaneously promote sustainable management of protected areas and improve the living conditions of local people. Many government‐sponsored payments‐for‐ecosystem‐services (PES) schemes have been implemented around the world. However, few empirical assessments of their effectiveness have been conducted, and even fewer assessments have directly measured their effects on ecosystem services. We conducted an empirical and spatially explicit assessment of the conservation effectiveness of one of the world's largest PES programs through the use of a long‐term empirical data set, a satellite‐based habitat model, and spatial autoregressive analyses on direct measures of change in an ecosystem service (i.e., the provision of wildlife species habitat). Giant panda (Ailuropoda melanoleuca) habitat improved in Wolong Nature Reserve of China after the implementation of the Natural Forest Conservation Program. The improvement was more pronounced in areas monitored by local residents than those monitored by the local government, but only when a higher payment was provided. Our results suggest that the effectiveness of a PES program depends on who receives the payment and on whether the payment provides sufficient incentives. As engagement of local residents has not been incorporated in many conservation strategies elsewhere in China or around the world, our results also suggest that using an incentive‐based strategy as a complement to command‐and‐control, community‐ and norm‐based strategies may help achieve greater conservation effectiveness and provide a potential solution for the park versus people conflict.  相似文献   
58.
Climate change adaptation is an important part of addressing climate warming. Inner Mongolia grassland is a sensitive and vulnerable area of climate and an important region for adaptation to climate change. New climate change adaptation approaches with nomadic culture characteristics should be exploded in the context of climate warming. In this paper, the different utilization pattern of grassland in different regions, the different modes of production and management and historical culture were analyzed first in Nenjiang–West Liaohe plain and Ke’erqin region, Inner Mongolia Plateau and Ordos Plateau. Then, nomadic culture on the grassland was discussed from the productivity to biodiversity, from local livestock variety to resource-used system. Finally, new approaches of climate change adaptation with inheriting the essence of nomadic culture were proposed, including protecting biodiversity and using resources reasonably, performing a practice of grazing suspension–rotational grazing system, fencing degenerated grassland to facilitate its growth, founding new farming and husbandry system on the grassland, and establishing an incentive mechanism favorable to grassland and ethical cultural protection.  相似文献   
59.
陈娴  陆金  殷燕  程洁红 《环境工程学报》2014,8(9):4012-4016
焙烧-酸浸法可有效回收电镀污泥中的有价金属,而污泥的热处理特性是决定能否采用焙烧预处理的重要因素。研究了氧化焙烧和还原焙烧对污泥成分和金属浸出性的影响,并对焙烧前后的污泥进行了金属形态分析和X射线衍射(XRD)分析。结果表明,焙烧预处理实现了污泥减量和金属富集;ES1经氧化焙烧后金属浸出率接近原泥,Cu的浸出率达99%;ES2的还原焙烧效果优于氧化焙烧,特别是Cu的浸出率超过97%,XRD分析发现,还原焙烧过程中金属Cu被还原为铁铜合金;2种焙烧均造成了ES3中目标金属Ni的浸出率的降低;金属浸出性的下降与残渣态的形成有关。  相似文献   
60.
反渗透处理稀土氨氮废水试验研究   总被引:4,自引:2,他引:2  
根据稀土冶炼厂排放的碳铵沉淀洗涤废水的水质情况,采用NH4Cl和 NaCl模拟废水进行了反渗透可行性对比实验。模拟实验发现,在相同条件下反渗透对NaCl 较NH4Cl 有着更高的去除率,而NH4Cl 相对NaCl则有着更高的产水速率。实际废水试验结果表明,在恒定操作压力范围内回收率为65%的条件下,NH4Cl浓度为2.85 g/L的碳铵沉淀洗涤废水经反渗透处理其NH4Cl去除率为77.3%,可作为氨氮废水的预处理。对该废水处理成本进行了分析,得出其约为2.7元/m3,比相近浓度氨氮废水的氨吹脱处理成本节省约26%。  相似文献   
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