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41.
Increased urbanization has caused problems such as increasing water consumption and the continuous deterioration of the groundwater environment. It is necessary to consider the groundwater quality in the water resource optimization system and increase the rate of reclaimed water development to reduce the amount of groundwater exploitation and achieve sustainable development of water resources. This study used the Daxing District, a region of Beijing’s southern plain, as an example to evaluate water quality by analyzing water quality data of surface and groundwater from 2012 to 2016 and actual water-use schemes from 2006 to 2016. Three groundwater extraction modes were set up based on NO3–N concentrations, water resources were optimized under three extraction modes, and water resource optimization schemes were determined based on the improved connection entropy. The results show that (1) the surface water quality was poor, and the proportion of V4 type water in the indexes of NH3–N and chemical oxygen demand (COD) was the largest. The surface water can only be used for agricultural irrigation. The pollution sources contributing most to NH3–N and COD were domestic and agricultural pollution sources. (2) The groundwater quality was good. The NO3–N index was primarily type I–III water, accounting for 95.20% of the total samples. Severe NH3–N pollution areas were mainly in the northern region, and most regional groundwater can be used for various purposes. (3) Taking 2016 as an example, three groundwater exploitation modes were set to optimize water resource allocation, and the results showed that the rate of groundwater development and NO3–N pollution decreased significantly after optimization. (4) Connection entropy is an evaluation method that combines connection numbers and entropy, including identify, difference, and opposition entropy. As connection entropy being a kind of complete entropy, which can reflect the difference of the system in different states, based on the improved connection entropy, the connection entropies of optimal water resource allocation and actual water-use schemes were calculated. The connection entropy of groundwater exploitation mode 3 was less than that of groundwater exploitation modes 1 and 2 and actual water-use schemes from 2006 to 2016. Therefore, exploitation mode 3’s water resource optimization scheme was recommended. In the paper, satisfactory results have been obtained. As a kind of complete entropy, connection entropy has great research value in dealing with complex hydrological problems. This study’s research methods and outcomes can provide methodological and theoretical lessons for water management in freshwater-deficient areas. 相似文献
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模糊综合评判法在台州市地表水评价中的应用 总被引:1,自引:0,他引:1
应用模糊综合评判法,以长潭等9个水库为研究对象,对台州地区水质进行厂评价:结果表明,台州地区总体水质较好,除东湖属Ⅳ类水外,其它全为Ⅲ类,适合人们生存及生产需要。根据评价提出了相心的建议 相似文献
44.
Ingestion of water is a major route of human exposure to environmental contaminants. There have been numerous studies exploring the different compounds present in drinking water, with recent attention drawn to a new class of emerging contaminants: endocrine-disrupting compounds (EDCs). EDCs encompass a broad range of physio-chemically diverse compounds; from naturally occurring to manmade. Environmentally, EDCs are found as mixtures containing multiple classes at trace amounts. Human exposure to EDCs, even at low concentrations, is known to lead to adverse health effects. Therefore, the ability to evaluate EDC contamination with a high degree of sensitivity and accuracy is of the utmost importance. This review includes (i) discussion on the perceived and actual risks associated with EDC exposure (ii) regulatory actions that look to limit EDC contamination (iii) analytical methods, including sample preparation, instrumentation and bioassays that have been advanced and employed for multiclass EDC identification and quantitation. 相似文献
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梳理任务可用度的基本模型,构建装置执行任务的过程类型和时间模型图,体现任务时限和修复时限的要求,以此给出装置单次任务可用性评价模型 ;选用曲线拟合和拟合优度检验方法,考虑修复对任务影响程度差异及其发生概率,建立装置多次任务可用性评价模型、评价方法及分析步骤,为系统地开展惯性约束聚变激光装置可用性评价提供一般模型和方法。通过对神光-Ⅲ原型装置使用可靠性数据处理和分析,验证提出的模型和分析方法的正确性和经济性。研究成果将直接应用于神光-Ⅲ主机装置的可靠性工程建设中。 相似文献
47.
Among all the bio‐metals, zinc and copper derivatives of ONS donor thiosemicarbazone have aroused great interest because of their potential biological applications. Multisubstituted thiosemicarbazone ligand H2dspt (3,5‐dichlorosalicylaldehyde‐N4‐phenylthiosemicarbazone) derived new ternary complexes like [Zn(dspt)(phen)]?DMF ( 1 ) and [Cu(dspt)(phen)]?DMF ( 2 ), and another thiosemicarbazone, H2dsct (3,5‐dichlorosalicylaldehyde‐N4‐cyclohexylthiosemicarbazone), derived [Cu(dsct)(bipy)]?DMF ( 3 ). These complexes have been characterized by elemental analysis (CHNS), Fourier transform infrared (FT‐IR), ultraviolet–visible (UV–Vis) and proton nuclear magnetic resonance (1H‐NMR) spectra. The structures of the complexes were obtained by single‐crystal X‐ray diffraction analysis. Compounds 1 and 2 got crystallized in the monoclinic P21/c space group. The complexes showed interesting supramolecular interaction, which in turn stabilizes the complexes. The ground state electronic configurations of the complexes were studied using the B3LYP/LANL2DZ basis set, and ESP plots of complexes were investigated. The interaction of the complexes with calf thymus DNA (CT‐DNA) was studied using absorption and fluorescence spectroscopic methods. A UV study of the interaction of the complexes with calf thymus DNA (CT‐DNA) has shown that the complexes can effectively bind to CT‐DNA, and [Cu(dspt)(phen)]·DMF ( 2 ) exhibited the highest binding constant to CT‐DNA (Kb = 3.7 × 104). Fluorescence spectral studies also indicated that Complex 2 binds relatively stronger with CT DNA through intercalative mode, exhibiting higher binding constant (Kq = 4.7 × 105). The DNA cleavage result showed that the complexes are capable of cleaving the DNA without the help of any external agent. Molecular docking studies were carried out to understand the binding of complexes with the molecular target DNA. Complex 2 exhibited the highest cytotoxicity against human breast cancer cell line MD‐MBA‐231 (IC50 = 23.93 μg/mL) as compared to Complex 1 (IC50 = 44.40 μg/mL) . 相似文献
48.
研究采用视频分析法,利用NVivo软件,以东芝杯教学技能创新大赛的化学组选手为对象,从教学理念、教学情境、实验设计和教学手段等4个维度,评价卓越职前化学教师课堂教学的创新能力。结果发现:教学理念新颖,但具体落实尚有不足;情境创设生动,但主题与学生的联系不够紧密;实验设计别致,但在水平上还有提升空间;教学技术手段先进,但还需要深度融合。研究为创新型卓越化学教师的培养提供了启示。 相似文献
49.
在乙醇胺-水混合溶液中采用水热处理硫酸铜的方法制备了多结构的铜树枝晶;采用X射线粉末衍射仪、扫描电子显微镜、透射电子显微镜分析了所得样品的结构和形貌;采用牛津杯法评价了其对金黄葡萄球菌、枯草芽孢杆菌、大肠杆菌和绿脓杆菌的抗菌性能.结果表明,铜树枝晶由一个长的一级中心主干和许多高度对称分布在主干两侧的二级分支结构构成,且形貌均匀;反应温度、反应时间以及溶剂组成对铜树枝晶的形貌有很大影响.与此同时,铜树枝晶表现出选择性的抗菌行为,对金黄葡萄球菌、枯草芽孢杆菌和绿脓杆菌更有效. 相似文献
50.
基于多元评价理论,在“中学化学微格教学”课程中先后尝试进行了如下改革:增加“自评”“组评”环节,调整“自评”“组评”和“师评”的权重,编制并逐年完善了“微格教学评分表(1.0/2.0/3.0)”,基本建立了评价目标多元、评价标准多元、评价主体多元、评价方式多元的多元评价体系。 相似文献