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991.
根据几十年来武汉东湖水质监测资料和数据 ,在东湖截污工程完成后 ,没有新的污染物进入水体的前提下 ,对东湖水体通过自然净化恢复到健康状态所需要的时间进行了详细的数学推导和科学论证。结果表明 ,在不考虑地泥营养物质的情况下 ,东湖水体通过工业、农业、生活用水以及收获鱼类和高等植物造成的营养物的输出 ,只需要 3a左右的时间就能恢复。然而如果考虑地泥的影响 ,几十年沉积在地泥的营养物质持续向水体中释放 ,然后再通过用水及生物输出 ,东湖水质需要35a以上才能得到恢复。可见 ,截污后东湖在相当长的时间内还将处于富营养化状态 ,地泥是造成东湖长期富营养化的关键。解决东湖污染问题的关键是清除地泥 ,因此得出结论 :挖底泥后引入长江水源来加速东湖水体改善的最佳途径  相似文献   
992.
环境保护是人类共同关注的重大课题,因此,对幼儿进行环境教育是幼儿教育的一项重要内容。在对幼儿进行环境教育的过程中,把环境教育的内容渗透到教学活动过程中,使环境教育既生动直观又充满儿童的情趣,最终让幼儿具有初步的保护环境的意识,养成良好的行为习惯。  相似文献   
993.
对海上污染的来源进行解析,是监督污染源排放的有效手段之一。通过图像灰度处理原理,提出以边缘检测方法来分析示踪凝胶电泳图像的思路,并对Sobel算子和Gauss-Laplace算子进行了详细分析,使用VC++编程实现,给出部分关键软件代码。最终得出Gauss-Laplace算子对于检测凝胶图像边缘效果较佳的结论,为示踪因子凝胶图像分析提供更简易方法。  相似文献   
994.
电子设备的环境应力损伤模型   总被引:2,自引:1,他引:1  
介绍了环境应力损伤模型的基本概念以及电子设备环境应力损伤模型的分类,重点研究在典型环境条件下电子设备的环境应力损伤模型,总结了加速试验和故障机理分析两种试验验证方法。  相似文献   
995.
The free enzyme extracted from WZ-I,which was identified as Fusarium LK.ex Fx,could effectively degrade chlorpyrifos,an organophosphate insecticide.The methods of immobilizing this free enzyme and determined its degradation-related characteristics were investigated.The properties of the immobilized enzyme were compared with those of the free enzyme.The optimal immobilization of the enzyme was achieved in a solution of 30 g/L sodium alginate at 4°C for 4-12 hr.The immobilized enzyme showed the maximal activity at pH 8.0,45°C.The maximum initial rate and the substrate concentration of the immobilized enzyme were less than that of the free enzyme.The immobilized enzyme,therefore,had a higher capacity to withstand a broader range of temperatures and pH conditions than the free enzyme.With varying pH and temperatures,the immobilized enzyme was more active than the free enzyme in the degradation reaction.In addition,the immobilized enzyme exhibited only a slight loss in its initial activity,even after three repeated uses.The results showed that the immobilized enzyme was more resistant to different environmental conditions,suggesting that it was viable for future practical use.  相似文献   
996.
土壤重金属污染与食品安全   总被引:2,自引:0,他引:2  
<正>人们食用的食品主要来源于农产品,农产品质量安全是影响食品安全的首要因素。近几年来,食品安全成了主宰人们日常生活的重要话题。农产品质量安全问题也就成为了人们关注的焦点之一。而农产品的质量与  相似文献   
997.
城市脱水污泥常见的处置方式是焚烧、燃烧发电、堆肥后土地化利用和填埋等。无论采用哪种无害化、资源化处置方法,输送环节都是必不可少的。城市污泥管道输送技术是以管道输送设备为核心,融合城市污泥的预处理和处置工艺的集成化系统。通过对城市污泥的流变特性和输送特性实验测试,其流变方程符合幂定律关系式;通过环管实验拟合出了污泥在管道中的阻力损失与输送距离和输送流量之间的关系,经验证,其理论计算和实际测定基本相符,证明管道输送方式能够成功地应用于城市污泥的远距离输送,为城市污泥管道输送系统的优化设计提供了理论依据。  相似文献   
998.
This paper empirically shows how the uncertainty associated to the absence of a mitigation regime which follows the United Nations Framework Convention on Climate Change Kyoto Protocol (UN FCCC Kyoto Protocol) is affecting investments in abatement activities in the EU electricity sector and, thus, future emissions levels. Based on a survey of EU electric utilities, it identifies the most likely post-Kyoto scenarios considered by them and how they are coping with such uncertainty in their investment decisions. It is found that firms react differently to such uncertainty and adopt different strategies to cope with it, diversifying their emissions control activities. Although most companies foresee post-Kyoto compliance regimes with emissions trading systems, they differ in their perceptions of the form that a post-Kyoto regime could take and are, thus, positioning differently to face such regime. The particular features of each company and the country where they operate affect their perception of the uncertainties, their position regarding a possible post-Kyoto regime and their inclination to carry out mitigation activities. Complying with Kyoto (and, eventually, post-Kyoto) targets significantly influences the investment decisions of European electricity companies. Uncertainty about a post-Kyoto regime may already be affecting investments in mitigation activities in the electricity sector. Therefore, significant progress has to be made in the definition of a post-Kyoto regime. It is urgent to define and agree internationally the emissions reduction objectives and the mitigation instruments that will be accepted for compliance, ensuring continuity of the international emissions trading system foreseen in the Kyoto Protocol.
Pablo del RíoEmail:
  相似文献   
999.
There have been several reports on novel threadlike structures (NTSs) on the surfaces of the internal organs of rats and rabbits since their first observation by Bonghan Kim in 1963. To confirm this novel circulatory function, it is necessary to observe the flow of liquid through the NTS as well as the structurally corroborating channels in the NTS. In this article, we report on the measurement of the flow speed of Alcian blue solution in the NTSs on the organ surfaces of rabbits, and we present electron microscopic images depicting the cribrous cross-section with channels. The speed was measured as 0.3 ± 0.1 mm/s, and the flow distance was up to 12 cm. The flow was unidirectional, and the phase contrast microscopic images showed that the NTSs were strongly stained with Alcian blue. The ultrastructure of the NTSs revealed by cryo-scanning electron microscopy and high-voltage electron microscopy showed that (1) there were cell-like bodies and globular clumps of matter inside the sinus of the channel with thin strands of segregated zones which is a microscopic evidence of the liquid flow, (2) the sinuses have wall structures surrounded with extracellular matrices of collagenous fibers, and (3) there exists a cribriform structure of sinuses. To understand the mechanism for the circulation, a quantitative analysis of the flow speed has been undertaken applying a simplified windkessel model. In this analysis, it was shown that the liquid flow through the NTSs could be due to peristaltic motion of the NTS itself. Baeckkyoung Sung and Min Su Kim contributed equally to this work.  相似文献   
1000.
介绍了内浮顶罐防腐作业时发生的爆炸事故,进行了故障树分析,结合故障树最小割集对基本事件进行了深入分析,表明非防爆喷漆的电火花是这次事故的点火源,提出了防止类似事故的措施。  相似文献   
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