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981.
982.
983.
Calculation of the minimum ecological water requirement of an urban river system and its deployment: A case study in Beijing central region 总被引:1,自引:0,他引:1
The minimum ecological water requirements of an urban river system and water deployment are key elements in integrated water resources planning and urban ecological construction. Based on a review of ecological water requirement calculation methods and considering the different ecological functions of an urban river system, the ecological function method was used in this paper to calculate the components of the ecological water requirements of an urban river. An envelope curve-based method was proposed for assessing the minimum ecological water requirements of an urban river system. Water resources deployment strategies designed to meet the minimum ecological water requirements were described. Then, the minimum ecological water requirements of the urban river system in Beijing central region, selected as a case study, were investigated. The key parameters for assessing the minimum ecological water requirement in the Beijing urban river system were determined. Based on the ecological objectives and the current status of the different urban river systems within the Beijing central region, the minimum ecological water requirements were calculated. Different types of water sources, including rainwater, upstream water, and reclaimed water, were deployed to meet the ecological water requirements for the urban river system in the Beijing central region. 相似文献
984.
通过单细胞凝胶电泳技术(彗星试验)研究了苯并[a]芘(B[a]P)对马氏珠母贝(Pinctada martensi)血淋巴细胞DNA的损伤。结果显示,在相同暴露时间内,不同质量浓度的B[a]P均能引起马氏珠母贝血淋巴细胞DNA损伤。4μg.L-1 B[a]P处理组DNA含量、彗尾长度和Olive尾矩均最大,分别为34.39%、281.73和60.31μm。随着暴露时间的延长,彗星尾长明显增加,表现出明显的时间-效应关系,而DNA含量和Olive尾矩没有呈现出规律性变化。此外,在不同的染毒时间内,对照组和各处理组之间均存在显著差异(P<0.05),3个指标具有很好的一致性。研究表明,彗星试验是检测B[a]P对马氏珠母贝血淋巴细胞DNA损伤的一种有效手段,马氏珠母贝血淋巴细胞DNA损伤可作为指示B[a]P污染的一种有效生物标志物用于早期预警监测。 相似文献
985.
Xiuzhen Che Alex English Jia Lu Yongqin David Chen 《Environmental Impact Assessment Review》2011,31(6):561-571
The enactment and implementation of the 2003 EIA Law in China institutionalised the role of plan environmental impact assessment (PEIA). While the philosophy, methodology and mechanisms of PEIA have gradually permeated through the various levels of government with a positive effect on the process and outcome of urban planning, only a few cities in China have so far carried out PEIA as a Strategic Environmental Assessment (SEA)-type procedure. One such case is the southern city of Shenzhen. During the past three decades, Shenzhen has grown from a small town to a large and booming city as China has successfully and rapidly developed its economy by adopting the “reform and open door” policy. In response to the challenges arising from the generally divergent processes of rapid urbanisation, economic transformation and environment protection, Shenzhen has incrementally adopted the SEA concept in developing the city's Master Urban Plan. As such, this paper reviews the effectiveness of PEIA in three ways:
•
as a tool and process for achieving more sustainable and strategic planning; •
to determine the level of integration of SEA within the planning system; and, •
its effectiveness vis-à-vis implementation.
986.
987.
Wei Jia Zhao Kai Zhang Linling Yang Ranran Wang Muxi 《Environmental science and pollution research international》2021,28(15):18850-18869
Environmental Science and Pollution Research - This study proposes a bibliometric measure to visualize and analyze the research status and development trend of carbon offset based on 1,581 articles... 相似文献
988.
Ali Shahzad Xu Yueyue Ma Xiangcheng Jia Qianmin Jia Zhikuan 《Environmental science and pollution research international》2021,28(22):27666-27680
Environmental Science and Pollution Research - Understanding the greenhouse gas emissions mechanism from the agricultural soils is essential to reach an agricultural system with a lower impact on... 相似文献
989.
Junchang Lü Philip J. Currie Li Xu Xingliao Zhang Hanyong Pu Songhai Jia 《Die Naturwissenschaften》2013,100(2):165-175
Oviraptorids are a group of specialized non-avian theropod dinosaurs that were generally one to 8 m in body length. New specimens of baby oviraptorids from the Late Cretaceous of Henan Province are some of the smallest individuals known. They include diagnostic characters such as the relative position of the antorbital fenestra and the external naris, distinct opening in the premaxilla anteroventral to the external naris, antorbital fossa partly bordered by premaxilla posterodorsally, lacrimal process of premaxilla does not contact the anterodorsal process of the lacrimal, parietal almost as long as frontal; in dorsal view, posterior margin forms a straight line between the postzygapophyses in each of the fourth and fifth cervicals; femur longer than ilium. They also elucidate the ontogenetic processes of oviraptorids, including fusion of cranial elements and changes in relative body proportions. Hind limb proportions are constant in oviraptorids, regardless of absolute body size or ontogenetic stage. This suggests a sedentary lifestyle that did not involve the pursuit of similar-sized prey. The functional implications for bite force and therefore dietary preferences are better understood through the study of such small animals. The comparison of the measurements of 115 skeletons indicates that oviraptorids maintain their hind limb proportions regardless of ontogenetic stage or absolute size, which is a pattern seen more commonly in herbivores than in carnivores. This may weakly support the hypothesis that oviraptorids are herbivores rather than active carnivores. 相似文献
990.
Ying Diwen Jia Jinping Zhang Lehua 《Frontiers of Environmental Science & Engineering in China》2007,1(3):305-310
An electrochemical-activated denitrifying biofilm system consisting of activated carbon fiber electrodes immobilized with
denitrifying bacteria film as cathode was studied. A revised model for an electrochemical-activated denitrifying biofilm was
developed and validated by electrochemical analysis of cathodal polarization curves and nitrate consumption rate. The cathodal
polarization curve and nitrate consumption rate were introduced to verify the rate of electrochemical reaction and the activity
of denitrifying bacteria, respectively. It was shown that the denitrification process effectively strengthened the electrochemical
reaction while the electron also intensified denitrification activity. Electron was transferred between electrochemical process
and biological process not only by hydrogen molecule but also by new produced active hydrogen atom. Additionally, a parameter
of apparent exchange current density was deprived from the cathodal polarization curve with high overpotential, and a new
bio-effect current density was defined through statistical analysis, which was linearly dependent to the activity of denitrification
bacteria. Activated carbon fiber (ACF) electrode was also found to be more suitable to the electrochemical denitrifying system
compared with graphite and platinum.
Translated from Environmental Pollution & Control, 2005, 27(7): 501–504 [译自: 环境污染与防治] 相似文献