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岩溶地基土洞塌陷评价及处理 总被引:1,自引:0,他引:1
地下水(地表水)产生的渗透潜蚀作用、崩解作用等是土洞形成和发展的重要原因。对工程实例中的土洞,采用极限平衡法和压力拱分析法进行了稳定性判别。在土洞中充填砼,然后采用压力灌浆,灌浆所采用的水灰比为1∶1~1∶1.5,灌浆压力一般为0.15~0.30 MPa,地基处理效果好。 相似文献
213.
在线衍生化吹扫捕集-气相色谱/质谱分析水中的五氯酚 总被引:1,自引:0,他引:1
建立了通过乙酸酐衍生化-吹扫捕集-气相色谱/质谱分析水中五氯酚的新方法,探讨了吹扫时间、样品池温度、离子强度以及衍生化试剂的加入量等条件对捕集效果的影响。结果表明:采用吹扫时间25min、样品池温度60℃、离子强度20%氯化钠以及衍生化试剂的量200μl等条件对水中的五氯酚有较好的捕集效果,用于水中五氯酚的测定,结果满意。 相似文献
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This paper aims to identify the main driving force for changes of total primary energy consumption in Beijing during the period of 1981-2005. Sectoral energy use was investigated when regional economic structure changed significantly. The changes of total primary energy consumption in Beijing are decomposed into production effects, structural effects and intensity effects using the additive version of the logarithmic mean Divisia index (LMDI) method. Aggregate decomposition analysis showed that the major contributor of total effect was made by the production effect followed by the intensity effect, and the structural effect was relatively insignificant. The total and production effects were all positive. In contrast, the structural effect and intensity effect were all negative. Sectoral decomposition investigation indicated that the most effective way to slow down the growth rate of total primary energy consumption (TPEC) was to reduce the production of the energy-intensive industrial sectors and improving industrial energy intensity. The results show that in this period, Beijing's economy has undergone a transformation from an industrial to a service economy. However, the structures of sectoral energy use have not been changed yet, and energy demand should be increasing until the energy-intensive industrial production to be reduced and energy intensity of the region reaches a peak. As sequence energy consumption data of sub-sectors are not available, only the fundamental three sectors are considered: agriculture, industry and service. However, further decomposition into secondary and tertiary sectors is definitely needed for detailed investigations. 相似文献
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基于长江流域区域1956-2011年50年气象资料和同期太平洋海温资料,采用Z指数、EOF、REOF、SVD分析等方法,探讨长江流域春季和夏季旱涝特征及其旱涝事件与极端海温异常之间的关联性,得出以下结论。1REOF的Z指数春夏季节旱涝空间分区特征显示,春季前6个模态的累计方差贡献率能够达到61.2%,收敛速度较平缓,夏季前6个模态累积方差贡献率更低,只有52.1%。2前冬太平洋海温的变化与长江流域旱涝的态势呈显著相关关系,春季海温场与长江流域旱涝Z指数场的SVD第一模态显示,长江流域的东北区的旱涝与厄尔尼诺显著相关,当赤道东太平洋海温升高,西太平洋海温降低时,长江流域东北地区偏涝,而长江流域的西部地区偏旱,反之亦然。3夏季海温场与长江流域旱涝Z指数场的SVD第一模态,表明太平洋海温分布主要呈现南北向的分布,当赤道中东太平洋海温偏高,北太平洋海温偏低时,长江流域夏季中部地区偏涝。反之亦然。第二模态,全球海温呈现厄尔尼诺类型的分布,中东太平洋是负相关,而在西太平洋为显著负相关。 相似文献
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Norfloxacin (NOR), an ionizable antibiotic frequently used in the aquaculture industry, has aroused public concern due to its persistence, bacterial resistance, and environmental ubiquity. Therefore, we investigated the photolysis of different species of NOR and the impact of a ubiquitous component of natural water — dissolved organic matter (DOM), which has a special photochemical activity and normally acts as a sensitizer or inhibiter in the photolysis of diverse organics; furthermore, scavenging experiments combined with electron paramagnetic resonance (EPR) were performed to evaluate the transformation of NOR in water. The results demonstated that NOR underwent direct photolysis and self-sensitized photolysis via hydroxyl radical (·OH) and singlet oxygen (1O2) based on the scavenging experiments. In addition, DOM was found to influence the photolysis of different NOR species, and its impact was related to the concentration of DOM and type of NOR species. Photolysis of cationic NOR was photosensitized by DOM at low concentration, while zwitterionic and anionic NOR were photoinhibited by DOM, where quenching of UOH predominated according to EPR experiments, accompanied by possible participation of excited triplet-state NOR and 1O2. Photo-intermediate identification of different NOR species in solutions with/without DOM indicated that NOR underwent different photodegradation pathways including dechlorination, cleavage of the piperazine side chain and photooxidation, and DOM had little impact on the distribution but influenced the concentration evolution of photolysis intermediates. The results implied that for accurate ecological risk assessment of emerging ionizable pollutants, the impact of DOM on the environmental photochemical behavior of all dissociated species should not be ignored. 相似文献
220.
Xi Yang Ping Xie Yunzhen Yu Hong Shen Xuwei Deng Zhimei Ma Peili Wang Min Tao Yuan Niu 《环境科学学报(英文版)》2015
We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures (24, 28 and 32°C). Gas chromatography–mass spectrometry was applied to measure off-flavor compounds dimethyl sulfide (DMS), dimethyl trisulfide (DMTS), 2-methylisoborneol, geosmin (GEO) and β-cyclocitral. During the lag phase of co-cultured M. aeruginosa (first 15 days), P. pseudoalcaligenes significantly increased the production of DMS, DMTS and β-cyclocitral at all three temperatures. In the exponential phase of co-cultured M. aeruginosa (after 15 days), M. aeruginosa became the main factor on off-flavors in the co-culture system, and β-cyclocitral turned to the highest off-flavor compound. These results also indicated that DMS, DMTS and β-cyclocitral were the main off-flavor compounds in our M. aeruginosa/P. pseudoalcaligenes co-culture system. Univariate analysis was applied to investigate the effects of M. aeruginosa and P. pseudoalcaligenes on the production of off-flavors. The results demonstrated that both M. aeruginosa and P. pseudoalcaligenes could increase the production of DMS and DMTS, while β-cyclocitral was mainly determined by M. aeruginosa. Our results also provide some insights into understanding the relationship between cyanobacteria and heterotrophic bacteria. 相似文献