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441.
拳文通过对硫化碱企业粉尘及二氧化硫污染治理技术进行探索,并结合企业实际,初步对硫化碱短旋转窑炉的粉尘及二氧化硫进行综合治理,取得了一定的成效。  相似文献   
442.
汽车发动机超声清洗废水中含有有机油、表面活性剂等物质,呈黑色,COD较高,较难处理。本实验采用化学絮凝法对其进行处理,取得了良好的效果。实验结果表明,在pH 7.2~8.2范围内,向样品中投入PAC400 mg/L,PAM50 mg/L,氯化钙200 mg/L时,处理效果明显,COD去除率达到96.7%。  相似文献   
443.
东北老工业基地不同土地利用类型土壤重金属污染特点   总被引:1,自引:0,他引:1  
以东北老工业基地北部城市群为例,对其重点区域及周边的不同土地利用类型中Hg,Pb,Cr,Zn4种元素进行测定分析,利用单因子污染评价和多因子污染评价方法进行评价。结果表明,4种元素在不同利用类型土壤中,汞和铅在土壤中的迁移能力较弱,且汞元素在土壤中积累程度不高,只是在个别区域其含量有所波动;铅在农田和工业用地土壤中都有一定的积累,但向其他利用类型土壤的迁移效果不明显;铬在个别区域的旱田,蔬菜地中的积累略高,并迁移威胁到了其周围的林地土壤;锌在某些地区的工业用地,旱田,蔬菜地的污染程度相比其他几种元素污染更为严重。  相似文献   
444.
Veterinary antibiotics can enter the environment due to the common practice of land application of manure from treated animals. The environmental fate of tetracyclines in swine manure after composting and field application remains largely unknown. This study analyzed the concentrations of tetracyclines in manure, manure-based compost and compost amended soil in selected swine farms from Beijing, Jiaxing and Putian, China to determine the dilution effects of antibiotics when released into the soil environment. The results demonstrate that residues of antibiotics were detected in all samples and chlortetracycline as well as its degradation products should be regarded critically concerning their potential ecotoxicity. Application of manure-based compost to soil could reduce the possible risk posed by antibiotic contamination, but the trigger value of 100 μupg/kg was still exceeded in soil samples (776.1 μupg/kg dw) from Putian City after application of compost. Field studies such as the present one can help to improve the routine administration of antibiotic-containing composted manure.  相似文献   
445.
谈地磁观测中的温度效应   总被引:1,自引:0,他引:1  
地磁场各要素的绝对数值是通过基线值来确定的,而基线值又与温度相关,是一条大致随温度变化的曲线。本文选取通海、贵阳、邵阳、天水等地磁台的基线值资料,计算各分量基线值与记录室温度的相关系数,判定基线值与温度之间的相关关系,掌握在不同记录室温度条件下,温度变化对地磁基线值以及地磁观测仪器的影响程度。以供其他地磁台站新建、改造观测记录室时借鉴。  相似文献   
446.
民国初年,我国救灾的成效方面存在着相当的不足,并直接引起连带性恶性效果。影响民国初年救灾成效不佳的原因主要可以归纳为三点,即:施政重点倾斜、社会动荡不安、政府救灾功能减弱等。  相似文献   
447.
● Fe3O4 NPs increased the biomass and chlorophyll content of hemp clones. ● Fe3O4 NPs penetrated and were internalized by root cells. ● Fe3O4 NPs induced the alteration of metabolite profiles in hemp leaves. ● The psychoactive compound THC in hemp leaves was significantly down-regulated. We investigated the effect of iron oxide nanoparticles (Fe3O4 NPs, ~17 nm in size) on the phenotype and metabolite changes in hemp (Cannabis sativa L.), an annual crop distributed worldwide. Hemp clones were grown in hydroponic cultures with Fe3O4 NPs (50, 100, 200, or 500 mg/L) for four weeks. TEM and ICP-MS were used to determine Fe3O4 NPs uptake and translocation. LC-MS-based metabolomics was employed to explore the deep insight into the effect of Fe3O4 NPs on hemp plants. The results revealed that plant growth enhanced gradually with increasing concentrations of given NPs up to 200 mg/L, which improved the fresh weight and dry weight by 36.13% and 74.68%, respectively, compared to the control. Even at a high dose (500 mg/L), Fe3O4 NPs promoted plant growth, including increased biomass and tissue length. NPs significantly increased the iron and chlorophyll content in plant tissues Increased catalase activity and reduced hydrogen peroxide content in hemp leaves suggested that the Fe3O4 NPs activated the defense system. TEM showed that NPs were abundantly attached to the cell wall and dispersed throughout the root cells. Metabolomics revealed that Fe3O4 NPs induced metabolic reprogramming in hemp leaves, including the up-regulation of carbohydrates and organic acids, and down-regulation of antioxidants, especially tetrahydrocannabinol (THC). The significantly up-regulated metabolites, including peonidin and 2-hydroxycinnamic acid, could be involved in photosynthesis in hemp plants. These results demonstrate the potential of Fe3O4 NPs for promoting hemp growth and decreasing the THC content at low doses.  相似文献   
448.
贯彻化学物质的全生命周期环境风险管理理念,加强新污染物治理,深入打好污染防治攻坚战,是促进经济社会发展全面绿色转型的重要内容。以欧洲化学品可持续战略为主线,分析欧盟与化学品相关的环境管理战略与行动计划,从化学品的安全可持续设计、环境零化学污染、化学物质风险评估机制和风险管理方法等方面进行研究,通过问题总结、差距比对,分析提出对我国开展化学品环境管理工作的启示,对推动精准治污、科学治污、依法治污,促进生态文明建设,有重要借鉴意义。  相似文献   
449.

Semi-coking wastewater contains a rich source of toxic and refractory compounds. Three-dimensional electro-Fenton (3D/EF) process used CuFe2O4 as heterocatalyst and activated carbon (AC) as particle electrode was constructed for degrading semi-coking wastewater greenly and efficiently. CuFe2O4 nanoparticles were prepared by coprecipitation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy disperse spectroscopy (EDS). Factors like dosage of CuFe2O4, applied voltage, dosage of AC and pH, which effect COD removal rate of semi-coking waste water were studied. The results showed that COD removal rate reached to 80.9% by 3D/EF process at the optimum condition: 4 V, 0.3 g of CuFe2O4, 1 g of AC and pH?=?3. Trapping experiment suggesting that hydroxyl radical (?OH) is the main active radical. The surface composition and chemical states of the fresh and used CuFe2O4 were analyzed by XPS indicating that Fe, Cu, and O species are involved into the 3D/EF process. Additionally, anode oxidation and the adsorption and catalysis of AC are also contributed to the bleaching of semi-coking waste water. The possible mechanisms of 3D/EF for degrading semi-coking waste water by CuFe2O4 heterocatalyst were proposed.

  相似文献   
450.
泥石流危险等级评价的模糊数学方法   总被引:12,自引:1,他引:12  
本文在文献[1]泥石流危险度研究的基础上.提出泥石流危险性评价的模糊数学方法。文中首先根据有关资料建立了评定因子的隶属函数以及各因子在评定泥石流危险性中权重的模糊子集,并在此基础上运用模糊综合评判技术提出了确定泥石流危险等级模糊向量的方法。  相似文献   
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