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961.
通过近三年实验室采用亚甲基蓝分光光度法测定硫化物校准曲线制作的一系列原始数据的收集,并通过数理统计方法对校准曲线、-余标准偏差、斜率扩展不确定度、截距扩展不确定度开展了详细讨论,得出亚甲基蓝分光光度法测定硫化物校准曲线斜率(b)参考范围为:0.019 1±0.00044,截距(a)参考值范围:0.003 3±0.005 0.此结果对实验室分析人员判定硫化物项目校准曲线制作是否合格具有一定的参考价值. 相似文献
962.
矿山开采导致大量的氟元素得到释放,进入水体造成氟污染。选取某铀尾矿库区排放水、尾矿库渗滤水及其周边浅层地下水作为研究对象,研究和分析了该铀尾矿库及其周边水系中氟的含量特征与成因。结果表明:研究区尾矿库排放水、尾矿库渗滤水和浅层地下水中氟的浓度平均值分别为30.93、21.27和1.82 mg/L。尾矿库排放水氟的含量均未达到排放要求;周边浅层地下水氟污染严重,超标率达到85.7%。总体而言,尾矿区及其周边水系中氟的含量较高,整体污染严重。而影响水系中氟的含量除人为因素外,还包括p H值、TDS以及当地气候条件等重要因素;水系中的F~-与HCO_3~-、Ca~(2+)以及其它阴、阳离子都在一定程度上呈现正负相关,表明氟的含量也可能受这些阴、阳离子的影响。 相似文献
963.
Lang Liu Yanli Wang Shiyong Du Wenjie Zhang Lujian Hou Sverre Vedal Bin Han Wen Yang Mindong Chen Zhipeng Bai 《环境科学学报(英文版)》2016,28(2):145-153
To investigate the composition and possible sources of particles, especially during heavy haze pollution, a single particle aerosol mass spectrometer (SPAMS) was deployed to measure the changes of single particle species and sizes during October of 2014, in Beijing. A total of 2,871,431 particles with both positive and negative spectra were collected and characterized in combination with the adaptive resonance theory neural network algorithm (ART-2a). Eight types of particles were classified: dust particles (dust, 8.1%), elemental carbon (EC, 29.0%), organic carbon (OC, 18.0%), EC and OC combined particles (ECOC, 9.5%), Na-K containing particles (NaK, 7.9%), K-containing particles (K, 21.8%), organic nitrogen and potassium containing particles (KCN, 2.3%), and metal-containing particles (metal, 3.6%). Three haze pollution events (P1, P2, P3) and one clean period (clean) were analyzed, based on the mass and number concentration of PM2.5 and the back trajectory results from the hybrid single particle Lagrangian integrated trajectory model (Hysplit-4 model). Results showed that EC, OC and K were the major components of single particles during the three haze pollution periods, which showed clearly increased ratios compared with those in the clean period. Results from the mixing state of secondary species of different types of particles showed that sulfate and nitrate were more readily mixed with carbon-containing particles during haze pollution episodes than in clean periods. 相似文献
964.
Xuewen Tao Fuqiang Liu Zhiping Bai Dongyang Wei Xiaopeng Zhang Junfei Wang Jie Gao Xiaowen Sun Baohua Li Chenghui Li Aimin Li 《环境科学学报(英文版)》2016,28(10):34-44
An efficient and profitable separation process was proposed to prepare 5N(the purity of the metal solution reaches 99.999%) high-purity nickel from 3N nickel-solutions using Purolite S984. The adsorption performance of this superior resin, especially its selectivity for metal ions,was explored quantitatively. The maximum adsorption capacity for copper was 2.286 mmol/g calculated by the Langmuir model, which was twice as large as that for nickel. In the binary systems, the adsorption capacity for nickel was decreased by 45%, indicating direct competition for the active sites. The infinite separation factor for copper versus nickel exceeded 300, revealing the feasibility of preparing5N-level high-purity nickel solutions, which was further verified using the 800 BV(bed volume) effluent in the column dynamic process.According to the cost–benefit analysis, purification contributed to a profit of approximately 60,000 USD per cycle, and the investment return period was less than 1/3 years. Density functional theory analysis confirmed that four nitrogen atoms would be involved in the coordination complex and thus a structure involving two five-membered rings could be achieved. The X-ray photoelectron spectra confirmed the involvement of nitrogen atoms,implying a coordination ratio of approximately 1:1. 相似文献
965.
Yaohui Bai 《环境科学学报(英文版)》2016,28(12):129
正On behalf of Dr.X.Chris Le,the Editor-in-Chief of Journal of Environmental Sciences,we congratulate the following reviewers for frequently providing high-quality and timely reviews for Journal of Environmental Sciences.These scientists are the most deserving recipients of the Best Reviewer Awards(2016). 相似文献
966.
967.
Yingyu Zhang Linlin Jing Qingguo Bai Tiezhong Liu 《International journal of occupational safety and ergonomics》2019,25(2):181-193
This study aimed to provide a greater understanding of the systemic factors involved in coal mine accidents and to examine the relationships between the contributing factors across all levels of the system. Ninety-four extraordinarily major coal mine accidents that occurred in China from 1997 to 2011 were analyzed using the human factors analysis and classification system (HFACS). The empirical results showed that the frequencies of unsafe behaviors, inadequate regulation and failure to correct hidden dangers were the highest among five levels, 14 categories and 48 indicators, respectively. The odds ratio technique was applied to quantitatively examine the relationships between contributing factors. Various statistically significant associations were discovered and should receive greater attention in future attempts to develop accident measures. In addition, several strategies concerning the main contributing factors and routes to failure are proposed to prevent accidents from reoccurring in an organization. 相似文献
968.
采用有机溶剂浸取法从烟草废弃物中提取茄尼醇,对萃取溶剂和工艺条件进行了筛选,实验结果表明以石油醚作溶剂,提取时间3h,温度35℃为提取茄尼醇较适宜的条件,茄尼醇提取率达2.8%,溶剂回收率为68.6%。 相似文献
969.
970.
Modeling soil conservation, water conservation and their tradeoffs:A case study in Beijing 总被引:3,自引:0,他引:3
Natural ecosystems provide society with important goods and services. With the rapid increase in human populations and excessive utilization of natural resources, humans frequently enhance the production of some services at the expense of the others. Although the need for tradeoffs between conservation and development is urgent, the lack of efficient methods to assess such tradeoffs has impeded progress. Three land use strategy scenarios (development scenario, plan trend scenario and conservation scenario) were created to forecast potential changes in ecosystem services from 2007 to 2050 in Beijing, China. GIS-based techniques were used to map spatial and temporal distribution and changes in ecosystem services for each scenario. The provision of ecosystem services differed spatially, with significant changes being associated with different scenarios. Scenario analysis of water yield (as average annual yield) and soil retention (as retention rate per unit area) for the period 2007 to 2050 indicated that the highest values for these parameters were predicted for the forest habitat under all three scenarios. Annual yield/retention of forest, shrub, and grassland ranked the highest in the conservation scenario. Total water yield and soil retention increased in the conservation scenario and declined dramatically in the other two scenarios, especially the development scenario. The conservation scenario was the optimal land use strategy, resulting in the highest soil retention and water yield. Our study suggests that the evaluation and visualization of ecosystem services can effectively assist in understanding the tradeoffs between conservation and development. Results of this study have implications for planning and monitoring future management of natural capital and ecosystem services, which can be integrated into land use decision-making. 相似文献