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331.
This paper improves the ecological footprint method by regulating cropland area with cropping index. The results calculated
by the improved method are the area of cropland that human needed, but not of cropping. This study analyzes the ecological
supply/demand of Funing County in China with improved ecological footprint method. It suggested that ecological remainder
per thousand U.S. dollar GDP is regarded as the indicator of regional sustainable development ability and pointed out that
the stockbreeding is the keystone factor that affects the regional ecological footprint. 相似文献
332.
南京市铅锌矿采矿场土壤重金属污染评价及优势植物重金属富集特征 总被引:15,自引:8,他引:7
为了筛选可用于修复土壤重金属污染的植物材料,测定了南京市某铅锌矿采矿场土壤及样地内14种优势植物中Cd、Cr、Cu、Mn、Pb、Zn的含量,并分析了采矿场土壤重金属的污染状况和14种植物对这6种重金属元素的富集和转运能力.结果表明,矿区土壤中Cd、Mn、Zn、Pb的污染最为严重,单因子污染指数分别达到了45.71、11.68、10.40和4.46;样地的内梅罗综合污染指数为33.45,也达到重度污染级别.尽管各种重金属的含量不同,14种优势植物均表现出了较强的重金属耐受能力,其中井栏边草(Pteris multifida)和络石(Trachelospermum jasminoides)对6种重金属均表现出很高的富集能力.所有植物体内Zn含量均超出了正常范围,但仅马唐(Digitaria sanguinalis)对Zn的生物富集系数大于1,其他植物的重金属生物富集系数均小于1.14种植物对重金属的生物转移系数较高,其中菊芋(Helianthus tuberosus)和野菊(Dendranthema indicum)对6种重金属的生物转移系数均大于1.根据植物对重金属的吸收机制,可将14种植物分为3类:富集型植物,如菊芋(H.tuberosus)、野菊(D.indicum)、垂序商陆(Phytolacca americana)、爵床(Justicia procumbens)、马唐(D.sanguinalis)、山莴苣(Sonchus brachyotus)、龙葵(Solanum nigrum)和狗尾草(Setaria viridis);根部囤积型植物,如井栏边草(P.multifida)和络石(T.jasminoides);规避型植物,如一枝黄花(Solidago decurrens)、蛇莓(Duchesnea indica)、青绿苔草(Carex breviculmis)和贯众(Cyrtomium fortunei). 相似文献
333.
Shasha Yuan Mingming Gao Hui M Muhammad Zaheer Afzal Yun-Kun Wang Mingyu Wang Hai Xu Shu-Guang Wang Xin-Hua Wang 《环境科学学报(英文版)》2018,30(5):154-160
Inexact mechanism of aerobic granulation still impedes optimization and application of aerobic granules. In this study, the extended Derjaguin, Landau, Verwey, and Overbeek(XDLVO) theory and physicochemical properties were combined to assess the aggregation ability of sludge during aerobic granulation process qualitatively and quantitatively. Results show that relative hydrophobicity of sludge and polysaccharide content of extracellular polymeric substances(EPS) increased, while electronegativity of sludge decreased during acclimation phase. After 20 days' acclimation, small granules began to form due to high aggregation ability of sludge. Since then, coexisted flocs and granules possessed distinct physicochemical properties during granulation and maturation phase. The relative hydrophobicity decreased while electronegativity increased for flocs, whereas that for granules presented reverse trend. Through analyzing the interaction energy using the XDLVO theory, small granules tended to self-grow rather than self-aggregate or attach of flocs due to poor aggregation ability between flocs and granules during the granulation phase. Besides, remaining flocs were unlikely to self-aggregate owing to poor aggregation ability, low hydrophobicity and high electronegativity. 相似文献
334.
对用2种不同方法合成的4种吸水剂的合成条件及其性能进行研究,对其吸液能力、吸水速度、保水性能、耐盐性能、重复利用性等进行了测试和比较。 相似文献
335.
Holling proposed a four-phase conceptual model of ecosystem dynamics that includes exploitation, conservation, and destructive and renewal components to explain the failure of many natural resource management schemes. The model is drawn as a sideways figure-eight i.e. . There are two dimensions in this model, connectivity (abscissa) and the amount of capital stored in the system (ordinate). This conceptual model has been suggested as a guide to thinking about the impact of climate change on biodiversity, but the two dimensions are insufficient and the alignment of the figure-eight model is problematic when compared with actual data. Kay has adjusted the dimensions of the figure-eight model and renamed the abscissa as exergy stored and the ordinate as exergy consumed. We realign the original figure-eight model, labeling the abscissa as carbon stored and the ordinate as nutrients, such that the relative values of both axes are in qualitative agreement with data from four different studies. This new alignment is then shown to fit relatively well with Holling's original labels. This revision of the figure-eight model brings Holling's model into agreement with observations and provides insight into the linkages between biodiversity and climate change. 相似文献
336.
谈高等学校国家精品课程建设 总被引:3,自引:0,他引:3
徐州师范大学的<画法几何及机械制图>课程在教学体系、教学内容、教学手段、教材建设及实践教学等各方面都进行了深入的研究和探索,取得了一系列的研究成果,2004年被评为国家精品课程.本文根据国家精品课程指标评价体系,结合徐州师范大学<画法几何及机械制图>课程改革与创新的实际,提出了国家精品课程建设的观点和看法,阐述了精品课程建设应加强教师队伍建设等七个方面的工作. 相似文献
337.
唐耀敏 《防灾科技学院学报》2006,8(2):140-142
学生能力的培养是教学活动的中心,本文通过对数学教学过程的总结和分析,就如何培养学生能力问题谈了自己的一些见解,并针对学习能力和理解能力的培养提出了一些措施。 相似文献
338.
CBE教学模式与高职教育模式的比较及应用 总被引:6,自引:0,他引:6
我国现行高职教育模式还没有脱离普通高等教育的学科型教育桎梏,存在不能解决高职教育对理论知识“必需”、“够用”、教与学的矛盾、职业能力的培养等问题.CBE是近年流行于北美的较为成功的职教模式,它能较好地解决我国学科型教育模式运用于高职教育的问题,值得借鉴与应用,本文运用CBE的理论方法对高职园林专业的能力模块和教学计划进行了整合与设计. 相似文献
339.
340.
The understanding of trade-offs between behaviours is fundamental to the study of animal behaviour. Individuals may often be faced with the choice of which of two mutually incompatible behaviours to perform. Here, I present a model investigating the trade-off between two behaviours, where one of the behaviours is crucial to the success of the other. I illustrate the results with examples, considering particularly a trade-off between territorial defence and courtship. I investigate how the ability of an individual to perform the behaviours changes the time or energy allocated to each behaviour. Intuition suggests that the time invested in performing a behaviour should decline as the individuals ability to perform the behaviour increases. Explicit, quantitative modelling suggests that this is not always the case. Instead, we see a pattern where investment in one of the behaviours at first increases and then decreases as the ability to perform the behaviour increases. This finding has implications for the empirical study of trade-offs between behaviours, since it could appear that individual ability has no effect on the trade-off under consideration. I discuss potential methods for distinguishing whether time allocation changes in a counter-intuitive, non-monotonic way with increasing individual ability, or whether there is indeed no effect.Communicated by C. St. Mary 相似文献