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排序方式: 共有2371条查询结果,搜索用时 15 毫秒
1.
介绍了马尔马里克河土坝滑坡的成因,对滑坡进行了分析研究。强调了进行监测对于预测滑坡的重要性。 相似文献
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水库淤积已经成为澳大利亚的一个严重问题,介绍了澳大利亚的水库快速淤积和极端淤积的几个实例,分析了水库完全淤死的原因。大坝和水库应该以冲沙的形式进行系统的管理,在干旱期必须加强流域的水土保持措施。 相似文献
3.
This study aimed at enhancing knowledge on the fate of diclofenac (DF), together with its main human metabolite 4'-hydroxydiclofenac (4'OHDF), during wastewater treatment by using a laboratory-scale membrane bioreactor (MBR). The reactor was fed continuously with non-radiolabelled diclofenac for a one month period prior to a single pulse of a 14C-radiolabelled solution of DF and 4'OHDF. The solution spike contained approximately 25% 4'OHDF and 65% DF, which corresponds to the ratio observed in municipal sewage, as well as traces of two other metabolites. The radioactivity was monitored for a total of twelve days in the various output streams. The calculation of the complete mass balance in the system demonstrated that the major part of the radioactivity left the reactor with the permeate (88.7%), while 2.1% was recovered in the excess sludge. Negligible amounts were recovered in the off-gas traps and on the membranes. Chromatographic analyses of effluent samples, by means of HPLC-MS coupled in parallel to a radiodetector, displayed a different pattern than the one of the spiked solution. It showed the occurrence of three additional metabolites. 相似文献
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跨国界水资源的共享一直是人们主要关心的问题。在很多地区,没有足够的水资源满足人们的用水需求。随着全球气候变暖,人们在水资源的获得、分配和共享等方面面临越来越多的压力和困难。当水资源跨越国界边境时,这些问题会变得更加尖锐。对影响获取水资源的主要因素,以及有助于解决跨国界水资源冲突的跨国界协议或合约的内容进行了介绍和分析。 相似文献
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Afewyearsago,themunicipalorganizationofthecityofAntwerpwas,duetoitsdisastrousfinancialsituation,forcedtoreduceitsPersonnelandtoshrinkitsbudgets.Allnecessaryandpainfuloperationsresultedinalotofcommotionandunrest.Thecitymanagementfounditselfconfrontedwithanumberofexternalandinternalfactors.overtheyears,thedissatisfactionoftheAntwerpcitizenstowardstheaservice-performance"ofthemunicipalorganizationhadgrown.Ingeneral,thepublicliadanextremelynegativeimageofthemunicipalofficial.Moreover,theresultso… 相似文献
8.
在拉丁美洲众多水电项目中,秘鲁的切夫斯工程和奥尔莫斯工程,以及巴拿马奇里基梯级水电站项目进展较为顺利,这些项目因地下开挖及隧洞施工难度大而备受关注.目前切夫斯水电站处于施工前期阶段,奥尔莫斯引水项目近期将完成TBM施工,奇里基梯级水电站项目施工进展则介于前两者之间.介绍了这3个水电项目的施工进展情况. 相似文献
9.
The objective of this study was to investigate if coexisting compounds could affect the fate of pharmaceuticals in surface water under solar irradiation. The degradation of metronidazole (MET) in the presence of different coexisting pharmaceuticals was investigated in batch experiments with exposure to sunlight. Tinidazole, which has a similar structure to MET, was employed as an analogue. The results indicated that the presence of an analogue with a similar photosensitive group to MET could inhibit the photodegradation of MET. In addition, the effect of coexisting pharmaceuticals with different absorption spectra on the degradation of MET was investigated. The results showed that the effect depended on the degree of overlapping absorption spectra between MET and the coexisting pharmaceuticals. The relationship between the degree of the influence and the ultraviolet absorption spectra of coexisting pharmaceuticals found in this study could give guidance in assessing the fate of pharmaceuticals in environmental water. 相似文献
10.
Odourous emissions from sewer networks and wastewater treatment plants (WWTPs) can significantly impact a local population. Sampling techniques such as wind tunnels and flux hood chambers are traditionally used to collect area source samples for subsequent quantification of odour emission rates using dilution olfactometry, however these methods are unsuitable for assessing liquid samples from point sources due to the large liquid volumes required. To overcome this limitation, a gas phase sample preparation method was developed for assessing the total Odour Emission Ability (OEA) from a liquid sample. The method was validated using two volatile organic sulphur compounds (VOSCs), dimethyl-trisulphide (DMTS) and bismethylthiomethane (BMTM) that are frequently detected from sewers and WWTPs and are relatively stable compared with common VOSCs like mercaptan or methyl mercaptan. The recovery rates of DMTS and BMTM were quantified by injecting a known volume of a standard liquid sample into Tedlar bags using a static injection and a dynamic injection methodology. It was confirmed that both dynamic and static injection methods at ambient condition achieved high recovery rates with no need to consider increasing evaporation by elevating the temperature. This method can also be used to assess odour removal effectiveness of liquids by comparing the OEA before and after the treatment tests. Two application examples were presented. 相似文献