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61.
水环境中污染物的迁移转化过程模拟和预测是水生态环境健康诊断、预测、预警及控制管理的重要基础。水环境数学模拟已经在国内外有了非常广泛的应用,并且成为国内外学者研究的热点。本文介绍了水环境数学模型的基础研究和应用现状,并提出其发展趋势和国内水质数学模型存在的主要问题。 相似文献
62.
近年来,随着经济的飞速发展,全国各地普遍面临建设用地紧张的局势。文登市在土地节约集约利用方面牢固树立和落实科学发展观,规划用地结构,掌握节约集约的管理方法,创新体制,实现土地资源的优化配制,保护和利用好每寸土地,促进了经济的可持续发展。其方法对促进县级市如何做到节约集约用地促进县域经济发展具有一定的借鉴作用。 相似文献
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64.
Since the 20th century, numerous Quaternary moraine dating methods have emerged, including lichenometric, moraine 14C, quartz sand thermoluminescence (TL), electron spin resonance (ESR), optically stimulated luminescence (OSL) and 10Be, 26A1, 36C1, 3H, 21Ne nuclide dating methods. These dating methods are widely applied to determine moraine ages and have provided a large dataset. Unfortunately each method has its defects. In this paper, we will review these various dating methods and provide some comments. 相似文献
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67.
鲁北平原因超量开采地下水而引发了诸多水环境问题.本文对其分布规律和演化趋势进行了分析,并提出了对策建议. 相似文献
68.
Throughout the world, the coastal zones of many countries are used increasingly for aquaculture in addition to other activities
such as waste disposal. These activities can cause environmental problems and health problems where they overlap. The interaction
between aquaculture and waste disposal, and their relationship with eutrophication are the subjects of this paper.
Sewage discharge without adequate dispersion can lead to nutrient elevation and hence eutrophication which has clearly negative
effects on aquaculture with the potential for toxic blooms. Blooms may be either toxic or anoxia-causing through the decay
process or simply clog the gills of filter-feeding animals in some cases. With the development of aquaculture, especially
intensive aquaculture, many environmental problems appeared, and have resulted in eutrophication in some areas. Eutrophication
may destroy the health of whole ecosystem which is important for sustainable aquaculture.
Sewage discharge may also cause serious public health problems. Filter-feeding shellfish growing in sewage-polluted waters
accumulate micro-organims, including human pathogenic bacteria and viruses, and heavy metal ion, presenting a significant
health risk. Some farmed animals may also accumulate heavy metals from sewage. Bivalves growing in areas affected by toxic
algae blooms may accumulate toxins (such as PSP, DSP) which can be harmful to human beings. 相似文献
69.
WANGHong GUChao-lin 《中国地理科学(英文版)》2002,12(2):152-156
Chinaˊs urban reforms have brought social progress and development,but a comprehensive national system of social welfare(for example,unemployment insurance,pensions,medical care and public housing)for new migrants from rural areas is lacking.One of the most remarkable changes in Chinese cities in the last decade was a change in so-cial“equality“,with the rise of new poverty both in individual communities and some social groups in urban society.Howev-er,there is little social assistance and public infrastructure for the migrants.Governments or communities or individual should pay attention to the control of new urban poverty and new slums.This paper consider that it is necessary to launch a successful policy,which include mainly:1)accommodating urban growth through low-cost investment projects;2)ur-ban economy depends heavily on successful macroeconomic policy;3)to broaden the three channels linking adjustment to the incidence of urban poverty;4)to restructure urban economic based on the high or new technology;5)to coordi-nate relationship between urban economic growth and environment management for sustainable development of Beijingˊs metropolitan fringe. 相似文献
70.
David L. Mary 《Journal of Astrophysics and Astronomy》2005,26(2-3):283-292
We provide a detailed introduction to the main problems arising when analyzing light curves in asteroseismology. Attention
is first paid to the signal model delivered by the pulsating stars and to the noise sources corrupting this model in photometric
observations. The main pitfalls and ambiguities occurring in Fourier analysis are summarized and illustrated. Some classical,
Least Squares (LS) based methods for spectrum analysis are analyzed and commented on from the point of view of ill-posed problems.
The insight that can be gained from such analyses is discussed. 相似文献