纳氏试剂比色法测定水体中氨氮常见问题与解决办法

纳氏试剂光度法是测定水中氨氮的国家标准方法,该法具有操作简单、灵敏的优点。但在实际工作中有许多因素影响纳氏试剂光度法对水中氨氮的测定结果,根据实际工作经验,对试剂等可能影响氨氮测定结果的有关因素及注意事项进行了研究和探讨,并提出了相应的解决方法。只要切实做好监测过程中的每一个环节,严格按照程序进行,就能保证纳氏试剂光度法测定水中氨氮分析结果的准确性。     

Comparing results of cultured and uncultured biological methods used in biological phosphorus removal

Increasing attention has been paid to phosphate-accumulating organisms(PAOs)for their important role in biological phosphorus removal.In this study,microbial communities of PAOs cultivated under different carbon sources(sewage,glucose,and sodium acetate) were investigated and compared through culture-dependent and culture-independent methods,respectively.The results obtained using denaturing gradient gel electrophoresis(DGGE)of polymerase chain reaction-amplified 16S rDNA fragments revealed that the diversity of bacteria in a sewage-fed reactor(1#)was much higher than in a glucose-fed one(2#)and a sodium acetate-fed one(3#);there were common PAOs in three reactors fed by different carbon sources.Five strains were separated from three systems by using a phosphate- rich medium;they were from common bacteria isolated and three isolates could not be found in DGGE profile at all.Two isolates had good phosphorus removal ability.When the microbial diversity was studied,the molecular biological method was better than the culture-dependent one.When phosphorus removal characteristics were investigated,culture-dependent approach was more effective. Thus a combination of two methods is necessary to have a comprehensive view of PAOs.     

欧洲大气颗粒物标准及监测体系

以欧洲环境空气质量及清洁空气指令为基础,从标准限值、监测点位布设、监测方法等多个方面,对欧洲大气颗粒物标准及监测体系进行了综合阐述。由极限值、目标值、暴露浓度限值、评价上限和下限等构成的标准限值体系协同作用,将欧洲大气颗粒物浓度控制在一定范围内;大气颗粒物监测点位布设方法遵循基本布设原则和最少点位数及AEI计算要求的详细规定;在颗粒物监测方法上,参比方法和等效方法并存,近年多种方法的应用情况也有所变化。通过对欧洲大气颗粒物标准及监测体系的综述,以期为中国大气颗粒物监测管理提供先进思路和技术参考。     

土壤中全氮分析方法的研究进展

土壤中的氮是衡量土壤肥力的主要指标之一。基于对国内外文献的调研,系统地归纳了现阶段土壤中全氮分析方法(凯氏法、红外光谱技术、杜马斯燃烧法)的原理和应用。对不同的测定方法进行比较,总结不同分析方法的优缺点。提出自动化分析、高灵敏度、高准确度、低成本、便捷的检测技术是土壤中全氮分析的重要发展方向。     

An improved grey wolf optimizer algorithm for identification and location of gas emission

Identification of the leakage of hazardous gases plays an important role in the environment protection, human health and safety of industry production. However, lots of current optimization algorithms, such as particle swarm optimization (PSO) and Grey Wolf Optimizer (GWO), suffer from poor global optimization capability and estimation accuracy. In this work, a hybrid differential evolutionary and GWO (DE-GWO) algorithm is proposed. Tested by simulation cases and Prairie Grass emission experimental data, DE-GWO shows higher estimation accuracy than GWO. Compared with the other four optimization algorithms, DE-GWO exhibits finer robust stability under different population sizes, fewer iterations, as well as higher estimation accuracy with fewer search agents. Importantly, simulation results demonstrate that DE-GWO is more suitable to apply in the scene with a small number of sensors. Therefore, the proposed in this paper outperforms other optimization algorithms for the gas emission inverse problem. DE-GWO can provide reliable estimation towards gas emission identification and positioning, which shows huge potential as the data analysis module of real-time monitoring and early warning system.     

沿海设施环境适应性试验和评价方法研究进展

概述了沿海设施所服役的腐蚀环境分类，主要分为海洋大气、浪花飞溅区及海水浸泡区，并对其暴露于大气和不同海洋环境位置的环境适应性试验评估方法进行了系统的总结分析。海洋大气环境模拟采用干湿交替加速腐蚀法，或建立户外大气暴露试验台开展试验；海水飞溅区试验通过实验室建海水冲刷试验装置进行模拟试验，或在实际环境中建立腐蚀试验中心开展试验；海水浸泡环境模拟通过海洋工程深水试验池开展试验。本研究对于开展海洋环境钢结构设施的防护性能考核评估具有重要意义，对沿海设施的环境适应评估方法发展具有指导意义。