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781.
选取临水河底部表层沉积物为研究对象,采用地质累积指数、潜在生态危害指数对其重金属污染进行评价。结果表明:沉积物Cr、Cd、Cu、Pb的含量介于203.971~412.363 mg/kg,浓度由高到低依次为Cr>Cu>Pb>Cd;Cd、Cu、Pb的空间变异系数较大,依次为82.8%、65.1%和43.1%,表明这3种重金属可能存在点源污染;Cr的空间变异系数较小,为28.2%,说明该重金属可能存在面源污染。地质累积指数表明:Cd和Cr的污染等级分别为3~5级和1~2级,为中度污染到极强度污染,Cu和Pb无污染。潜在生态危害指数RI值为280.54~879.27,污染程度为中等污染至很强污染。Cd为河流表层沉积物重金属污染的最大贡献者。 相似文献
782.
Profile of the culturable microbiome capable of producing acyl-homoserine lactone in the tobacco phyllosphere 总被引:1,自引:0,他引:1
Bacterial populations coexisting in the phyllosphere niche have important effects on plant health. Quorum sensing (QS) allows bacteria to communicate via diffusible signal molecules, but QS-dependent behaviors in phyllosphere bacterial populations are poorly understood. We investigate the dense and diverse N-acyl-homoserine lactone (AHL)-producing phyllosphere bacteria living on tobacco leaf surfaces via a culture-dependent method and 16S rRNA gene sequencing. Our results indicated that approximately 7.9%-11.7% of the culturable leaf-associated bacteria have the ability to produce AHL based on the assays using whole-cell biosensors. Sequencing of the 16S rRNA gene assigned the AHL-producing strains to two phylogenetic groups, with Gammaproteobacteria (93%) as the predominant group, followed by Alphaproteobacteria. All of the AHL-producing Alphaproteobacteria were affiliated with the genus Rhizobium, whereas the AHL-producing bacteria belonging to the Gammaproteobacteria mainly fell within the genera Pseudomonas, Acinetobacter, Citrobacter, Enterobacter, Pantoea and Serratia. The bioassays of supernatant extracts revealed that a portion of the strains have a remarkable AHL profile for AHL induction activity using the two different biosensors, and one compound in the active extract of a representative isolate, NTL223, corresponded to 3-oxo-hexanoyl-homoserine lactone. A large population size and diversity of bacteria capable of AHL-driven QS were found to cohabit on leaves, implying that cross-communication based AHL-type QS may be common in the phyllosphere. Furthermore, this study provides a general snapshot of a potential valuable application of AHL-producing bacteria inhabiting leaves for their presumable ecological roles in the phyllosphere. 相似文献
783.
Yaru Zhang Jinfeng Bai Jun Xu Xiangyun Zhong Zhenning Zhao Hongchun Liu 《环境科学学报(英文版)》2013,(S1):S190-S195
The stamp-charging coke making process has some advantages of improving the operation environment, decreasing fugitive emission, higher gas collection efficiency as well as less environmental pollution. This article describes the different structure strength and high temperature thermal properties of 4 different types of coke manufactured using a conventional coking process and the stamp-charging coke making process. The 4 kinds of cokes were prepared from the mixture of five feed coals blended by the petrography blending method. The results showed that the structure strength indices of coke prepared using the stamp-charging coke method increase sharply. In contrast with conventional coking process, the stamp-charging process improved the coke strength after reaction but had little impact on the coke reactivity index. 相似文献
784.
Xiangyun Zhong Shiyong Wu Yang Liu Zhenning Zhao Yaru Zhang Jinfeng Bai Jun Xu Bai Xi 《环境科学学报(英文版)》2013,(S1):S186-S189
The evolvement of morphology and structure of the coal with different metamorphic degrees during coking process in the vertical furnace was investigated by infrared Image detector. Moreover, the temperature distribution in the radial direction and the crack formation were also studied in heating process. The results show that the amount of crack and the shrinkage level of char decrease with the coal rank rising. In addition, the initial temperature of crack formation for char increases with the coal rank rising. 相似文献
785.
Zhenning Zhao Jinfeng Bai Jun Xu Yaru Zhang Xiangyun Zhong Hongchun Liu Dekai Yang 《环境科学学报(英文版)》2013,(S1):S118-S121
Long flame coal are abundant and widely distributed in China, but the resource utilization is quite low, the production efficiency is not high. Stamp-charging coke making technology can bend some long flame coal, which can reduce production cost and expand the coking coal resources. The long flame coal of different mass fraction is added into prime coking coal including fat coal from Longhu, 1/3 coking coal from Xinjian and coking coal from Didao in experiment. The swelling pressure is tested on-line detection using pressure sensor in coke making process, and the pores are observed by scanning electron microscopy. The results show that, the swelling pressure first increase and then decrease with the temperature increased and the maximum swelling pressure reduces gradually with mass fraction of the Long flame coal from Shenmu increased in coke making process. The SEM images of resultant coke display that the coke get more and more loose and the amount of pores is increased with mass fraction of the long flame coal from Shenmu increased. The amount pores and the pore diameter both is minimum for coking coal from Didao as prime coking coal under the same fraction of long flame coal. 相似文献
786.
工业园区大气环境影响预测的难点主要在于进入园区项目的不确定性使得预测工作没有较为精准的基础数据。因此,要在充分分析园区定位、产业特征和入园行业的基础上,以宏观与微观相结合的方式进行预测,设立多种情景分析;同时充分分析园区的所在地区的环境承载力,才能对园区建设对大气环境的影响有较为准确的把握。以内蒙古蒙大新能源化工基地为例,简要说明。 相似文献
787.
本文通过多年来的工作实践和管理经验,针对新时期环境监测及污染源监测工作的特殊要求,围绕环境监测站的定位,软、硬件建设及监测数据管理的重要性,从多方面、多角度进行了详尽的阐述,提出了有针对性的对策与建议. 相似文献
788.
789.
790.
Zhang Ziteng Gu Weihua Bai Jianfeng Zhuang Xuning Zhao Jing Zhang Chenglong Wang Jingwei 《Journal of Material Cycles and Waste Management》2022,24(6):2365-2374
Journal of Material Cycles and Waste Management - Monolithic ceramic capacitors (MLCCs) contain a high level of silver. This paper describes a method to recover silver from the waste MLCCs. First,... 相似文献