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991.
992.
DynamicsimulationandmodelingofPCPtransportbetweensedimentandwaterLiTie,YeChangming,LeiZhifangResearchCenterforEcoEnviro... 相似文献
993.
水资源动态完全成本定价的理论探讨 总被引:7,自引:0,他引:7
在辨析水资源价值涵义的基础上 ,阐述水资源动态完全成本定价模型 ;并从不同层次分析了它为何能使水资源可持续利用得以实现 ;最后提出了应用该模型尚需进一步解决的问题 相似文献
994.
内蒙古农牧交错带农业灾情及其动态变化研究 总被引:2,自引:0,他引:2
本文选择我国北方典型易灾、多灾、重灾的区域--内蒙古农牧交错带,通过一系列反映农业灾情的指标,分析了本区农业灾情的现状及空间分布规律,总结出农业灾情的4种主要类型。利用产量偏差率这一指标,用模糊聚类分析方法,进行灾情过程一致性分区,讨论了农业灾情的动态变化规律及区域分界,揭示出不同的区域在减产年出现的时段、减产程度、对应的致灾因子等方面具有不同的特点。 相似文献
995.
《环境科学学报(英文版)》2023,35(3):499-512
Understanding the aerosol vertical characterization is of great importance to both climate and atmospheric environment. This study investigated the variations of aerosol profiles over eight regions of interest in China after clean air policy (2013-2019) and discussed the drivers of the vertical aerosol structure, using observations from active satellite measurements (CALIPSO). From the annual variation, the amplitude of extinction coefficient profiles showed a decreasing trend with fluctuations, and the maximum was 0.21 km−1 in Beijing-Tianjin-Hebei (JJJ). For regions suffered from air pollution, the variation was greatest below 0.45 km, while it was between 1-1.5 km for Sichuan Basin. The correlation coefficient between the relative humidity (RH) and the extinction coefficient indicated that the increase of RH inhibited the decrease of the extinction coefficient in the Yangtze River Delta. In most regions, the main aerosol subtypes were polluted dust and polluted continental, but they were coarser in JJJ and North West. The frequency of concurrency of dust and polluted dust aerosols decreased in JJJ, but polluted continental aerosols occurred more frequently. Further, the aerosol extinction coefficient profiles under different pollution conditions showed that it changed most during heavy pollution periods in JJJ, especially in 2017, with a significant aerosol loading between ∼700 and 1200 m. The atmospheric reanalysis data revealed that the weak convergence at low level and the divergence at high level supported the upward transport of aerosols in 2017. Overall, the differences in divergence allocation, RH, and wind filed were the main meteorological drivers. 相似文献
996.
997.
研究了絮凝-DAF工艺的化学因素和颗粒特征。PAC类絮凝剂的碱化度B值越高,其荷电量和立体结构越显著,絮凝-DAF工艺的除浊效果越好;但除了絮凝剂的电中和能力外,其形成絮体的结构特征也对絮凝-DAF工艺有影响。随着投药量、絮凝搅拌强度和时间的增加,絮体都分别会趋于某一极值尺寸而后逐渐变小,且较大粒度的密实絮体才是与微气泡作用效果最好的絮体。此外,增加絮凝搅拌强度和延长时间都可能有利于水中颗粒的去除,且DAF出水中粒径越大的颗粒含量越少,其中大于15μm的颗粒极少,但2-4μm的颗粒数目时常多于原水。 相似文献
998.
关银霞 《安全.健康和环境》2020,(2):1-5
从微波等离子体发生及应用研究两个方面综述微波等离子体技术及研究进展,先从微波激励气体放电工作原理及能量传递方式两方面介绍微波等离子体技术,在此基础上,结合实验结果及现有研究成果对微波等离子体的发射光谱特性及温度特性进行论述。在微波等离子体应用研究方面,归纳总结了电子回旋共振微波等离子体、表面波等离子体、谐振腔微波等离子体等几种典型的微波等离子体技术及其特点,结合在薄膜沉积、废气处理、微量元素检测等方面的应用研究现状,对微波等离子体技术存在的问题及发展趋势进行了分析和展望。 相似文献
999.
Cheng Hongguang Qi Ye Pu Xiao Gong Li 《Frontiers of Environmental Science & Engineering in China》2007,1(4):448-453
Environmental impact assessment (EIA) system has been established in China since 1973. In present EIA cases, there are four
participants in general: governments, enterprises, EIA organizations and the public. The public has held responsible for both
social costs and social duties. The public supervises social costs produced by enterprises discharging pollutant in EIA. However
public participation is mostly deputized by governments, which severely weaken the independence of the public as one participant
in EIA. In this paper, EIA refers to the different attitudes of the participants whose optional strategies may be described
by a proper game model. According to disfigurements in EIA, three sides (governments, enterprises, and EIA organizations)
dynamic iterative game theory, dynamic game theory of incomplete information, and perfect Bayesian equilibrium theory to analyze
the reciprocity relation among governments, EIA organizations and enterprises. The results show that in a short period, economic
benefit is preponderant over social benefit. Governments and enterprises both do not want to take EIA to reveal social costs.
EIA organizations’ income comes from enterprises and the collusions are built between them to vindicate economic benefit.
In a long run, social benefit loss caused by environmental pollution must be recuperated sooner or later and environmental
deterioration will influence the achievements of economic benefit, so both governments and enterprises are certain to pursue
high social benefit and willing to take EIA, helpful to increase private benefit. EIA organizations will make fair assessment
when their economic benefit are ensured. At present, the public as silent victims can not take actual part in EIA. The EIA
system must be improved to break the present equilibrium of three sides, bringing the public to the equilibrium to exert public
supervision. 相似文献
1000.
辽宁省降水化学组份分析 总被引:2,自引:0,他引:2
对辽宁省1991~1995年期间五城市降水中的化学组份进行了八种离子分析,研究了其时空分布,组成特征及变化规律.得出辽宁省存在降水污染的结论 相似文献