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431.
ABSTRACT

The leadership dynamics between the European Council, the Council and the Member States in European Union (EU) environmental policy since the 1970s are analysed. The puzzle is that, although the EU was set up as a ‘leaderless Europe’, it is widely seen as an environmental leader, albeit sometimes as a one-eyed leader amongst the blind. While differentiating between leadership types, it is argued that the European Council has the largest structural, the Council the most significant entrepreneurial, and the Member States the most important cognitive and exemplary leadership capacities. Most day-to-day environmental policy measures are negotiated by the Environment Council (in collaboration with the European Parliament). The European Council’s increased interest in high politics climate change issues is largely due to the EU’s global leadership ambitions. Member States have traditionally formed environmental leadership alliances on an ad hoc basis although this may be changing.  相似文献   
432.
离子强度对土壤与沉积物吸附多环芳烃的影响研究   总被引:5,自引:0,他引:5  
罗雪梅  刘昌明 《生态环境》2006,15(5):983-987
以黄河三角洲表层沉积物与湿地土壤为对象,研究了离子强度对菲、苯并[a]芘在土壤和沉积物上吸附行为的影响。结果表明:不同Ca2 离子强度下,土壤与沉积物对菲、苯并[a]芘的吸附速率均较快,48h吸附能够达到平衡,Ca2 离子强度对土壤和沉积物影响程度不同;土壤和沉积物的吸附等温线均呈线形,能较好地符合线性方程,可决系数R2在0.98以上,菲的KD值在24~130mL·g-1之间,苯并[a]芘的KD值在3517~5081mL·g-1;随着体系离子强度的增大,土壤与沉积物对PAHs的吸附能力均降低,而且两者之间的吸附量差距明显降低,表明离子强度对土壤影响程度明显大于沉积物。  相似文献   
433.
氢氧化镁对水溶性阴离子染料废水脱色的研究   总被引:34,自引:0,他引:34  
许坤  贾智萍 《环境化学》1998,17(1):94-99
本文研究了氢氧化镁对水溶性阴离子染料模拟废水的脱色规律及机理。结果表明镁盐法具有优异的脱色效果。例如,染料浓度100mg.l^-1,镁盐投加量1000mg.l^-1用CaO调至PH10.9-11.5十种被研究的水溶性阴离子染料的脱色平均值在99%以上。吸附机理属于离子吸附。  相似文献   
434.
Present biodiversity comprises the evolutionary heritage of Earth's epochs. Lineages from particular epochs are often found in particular habitats, but whether current habitat decline threatens the heritage from particular epochs is unknown. We hypothesized that within a given region, humans threaten specifically habitats that harbor lineages from a particular geological epoch. We expect so because humans threaten environments that dominated and lineages that diversified during these epochs. We devised a new approach to quantify, per habitat type, diversification of lineages from different epochs. For Netherlands, one of the floristically and ecologically best-studied regions, we quantified the decline of habitat types and species in the past century. We defined habitat types based on vegetation classification and used existing ranking of decline of vegetation classes and species. Currently, most declining habitat types and the group of red-listed species are characterized by increased diversification of lineages dating back to Paleogene, specifically to Paleocene-Eocene and Oligocene. Among vulnerable habitat types with large representation of lineages from these epochs were sublittoral and eulittoral zones of temperate seas and 2 types of nutrient-poor, open habitats. These losses of evolutionary heritage would go unnoticed with classical measures of evolutionary diversity. Loss of heritage from Paleocene-Eocene became unrelated to decline once low competition, shade tolerance, and low proportion of non-Apiaceae were accounted for, suggesting that these variables explain the loss of heritage from Paleocene-Eocene. Losses of heritage from Oligocene were partly explained by decline of habitat types occupied by weak competitors and shade-tolerant species. Our results suggest a so-far unappreciated human threat to evolutionary heritage: habitat decline threatens descendants from particular epochs. If the trends persist into the future uncontrolled, there may be no habitats within the region for many descendants of evolutionary ancient epochs, such as Paleogene.  相似文献   
435.
This paper deals with effects of sheep and goat grazing on plant species diversity, species richness and species composition in two important conservation areas of the Western Himalaya; the Valley of Flowers (VOF) National Park and the Great Himalayan National Park (GHNP). The VOF is a completely Protected Area as it is devoid of livestock grazing whereas, 20,000 sheep and goats annually graze in GHNP. Both the National Parks possess sub-alpine and alpine vegetation that is distributed in 13 major habitat types. Present investigations indicate that all the habitat types in VOF are higher in plant species diversity and richness compared to habitat types in GHNP. Similarly, all three eco-climatic zones in VOF are higher in species diversity and richness compared to GHNP. Species diversity also decreases with increasing altitude in both the National Parks. The findings of this study are discussed in the light of the management and conservation of alpine meadows of the Western Himalayas.  相似文献   
436.
以氯化-1-烯丙基-3-乙烯基咪唑离子液体为反应单体,偶氮二异丁腈(AIBN)为引发剂,通过自由基聚合先合成聚离子液体预聚物,并将其与聚偏氟乙烯(PVDF)、聚乙二醇(PEG)进一步共混反应,以制备聚离子液体/PVDF共混铸膜液.然后将该铸膜液在聚丙烯(PP)微孔膜表面进行涂覆成膜,以制备具有互穿网络结构的聚离子液体/PVDF荷电复合膜.采用红外光谱、扫描电镜、Zeta电位计等对复合膜表面的化学结构、形貌及荷电性能等进行分析,并采用水通量测定仪对复合膜的纯水通量及蛋白质和染料的分离性能等进行了研究.结果表明,该复合膜表面具有较好的荷电性能,且随聚离子液体的加入可以有效提高膜的亲水性和抗污染性,复合膜M2的纯水通量可达到101.7 L·m-2·h-1,该膜对溶菌酶和染料罗丹明6G的截留率分别为88.0%和94.1%,该分离膜经清水反冲洗后通量恢复率分别达到72.5%和91.8%.  相似文献   
437.
通过对不同园林绿地类型内空气PM_(2.5)的检测,结果发现:PM_(2.5)浓度日变化规律均呈现早晚高午间低的双峰单谷型趋势。各绿地类型内空气PM_(2.5)浓度10月最低,8月最高。全年空气PM_(2.5)浓度均值从大至小依次为夏季>冬季>春季>秋季。不同天气状况下空气PM_(2.5)浓度的大小排序依次为阴天>晴天>雨天>雨后天晴。复混的植被结构对空气颗粒物的滞尘能力大于单一的植被结构,按滞尘能力大小排序依次为阔叶乔灌草、针叶乔灌草、阔叶乔草、灌木草坪、草坪。  相似文献   
438.
This study aimed to unpack the dynamic proximity effects of a park on residential values in the urban regeneration context: first by the development phase of the park, and second, by specific characteristics of the residential units. The study site is the Dream Forest in Seoul, South Korea, and the study period is from 2006 to 2015. The two-fold multilevel regression analysis suggests that the Dream Forest began exerting proximity effects from the time of site acquisition by the city, which peaked at a 3.7% price increment per 100-meter distance to the park from a prototypical housing unit, soon after the public announcement of the park procurement plan. During construction, inauguration and stabilization, the effect has remained at around 3.0%. The analysis also suggests that the proximity effect applies unevenly to housing units: apartment type or older housing units are more sensitive to the externality effects than their counterparts – multifamily type or newer housing units.  相似文献   
439.
中国煤矿水灾事故不安全动作原因对比研究   总被引:1,自引:0,他引:1  
中国是世界上煤矿水灾事故频发的国家之一,重特大水灾事故时有发生.为了分析事故发生原因并从安全管理方面予以预防,采用事故统计、案例分析和分组对比相结合的方法,以1990-2009年发生的142起煤矿水灾事故为例,对煤矿水灾不安全动作等原因进行了研究,得出了不安全动作类型、不安全动作构成比例及不安全动作的发出者在水灾事故中的特点.结果表明:1)1990-2009年,违章放炮等23小类不安全动作一直存在,16小类不安全动作消失,19小类不安全动作新增;2)1990-1999年占比最大的直接不安全动作是违章指挥,但在2000-2009年,违章放炮却成为新的占比最大的直接不安全动作;3)未采取有效探放水措施和未通过安全审批私自生产在2000-2009年分别处于所有不安全动作占比的第一、二位,且比例逐渐增加;4)高层管理人员发出的不安全动作占比最大,一线员工和班组长发出的直接不安全动作占比大于各自发出的所有不安全动作比例.  相似文献   
440.
了解长江黑沙洲湿地生态系统下不同土地利用方式对大型土壤动物群落的影响,于2013年12月,对长江黑沙洲湿地生境下天然洲麦地(W1)、林地(F1)、棉花地(C1)、芦苇地(R)和黑沙洲麦地(W2)、林地( F2)、棉花地( C2)进行野外调查,共捕获土壤动物602只.统计分析表明,不同土地利用方式下,土壤动物的个体数和类群数均存在着极显著的差异(P<0.01),垂直分布表现出较为明显的表聚性,多样性指数H′和丰富度指数D差异较为显著,土壤动物群落相似性指数均较低.因此,不同土地利用方式对黑沙洲湿地大型土壤动物群落组成与结构特征有一定的影响.  相似文献   
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