固相微萃取-气相色谱在水中有机污染物测定中的应用

固相微萃取技术是一种新型的无溶剂的样品前处理方法,集取样、萃取、富集、进样于一体,具有无溶剂、可直接进样、操作简便快捷、灵敏的特点。简述了固相微萃取技术原理,综述了SPME与GC联用在水中有机污染物测定中的应用。具体介绍了该技术在苯系物、酚类化合物、多环芳烃、有机氯化物及其它有机污染物分析中的应用,并提出了该技术的发展趋势及应用展望。     

吹扫捕集-气相色谱法同时测定水中的乙醛、丙烯醛和甲醛

研究了吹扫捕集-气相色谱法同时测定水中乙醛、丙烯醛和甲醛的方法并优化了实验条件.实验结果表明,该方法操作简便,灵敏高效,目标化合物的检出限分别为0.037、0.012、0.0006mg/L,相对标准偏差在3.9％ ～15.8％之间,实际水样的加标回收率在73.0％ ～118％之间,能很好满足《地表水环境质量标准》中相关项目的要求.     

北京地区极端温度事件的变化趋势和年代际演变特征

利用北京地区20个气象观测站1978-2007年逐日平均温度资料,分析了近30年北京地区极端温度事件的变化趋势以及年代际空间演变特征。研究结果显示,北京观象台近30年的两次迁站对研究极端温度事件并无太大影响;近10年夏季显著的热岛效应,是城区极端高温事件发生频次明显高于其他地区的重要原因;尽管北京地区冬季平均温度的空间分布形态变化甚微,并始终存在着明显的热岛效应,但城区极端低温事件的发生频次有可能发生了与热岛效应无关的突变过程。     

Chemical absorption of carbon dioxide with asymmetrically heated polytetrafluoroethylene membranes

In this study, the absorption of carbon dioxide using an absorbent composed of 2-amino-2-methyl-L-propanol (AMP) + monoethanolamine (MEA) + piperazine (PZ) in asymmetric and symmetric polytetrafluoroethylene (PTFE) membrane contactors was investigated. Experiments were conducted using various gas flow rates, liquid flow rates, and absorbent blends. CO(2) recovery increased with increasing liquid flow rates. The mean pore size of PTFE membrane reduced via heating treatment. An asymmetric membrane had a better CO(2) recovery than a symmetric membrane. For the asymmetric membrane, placing the smaller pore-size side of the membrane in contact with the liquid phase, reduced the level of wetting of the membrane. The membrane mass transfer coefficient and durability of the PTFE membrane were enhanced by asymmetrically heating.     

榆林气田开发技术研究

针对榆林气田单井产能低、气田稳产能力差和生产中出现的低产低效气井难以正常生产等问题,进行了储层改造工艺技术优化研究.通过本项目的开展,有效地解决了影响气田正常生产和安全供气问题,为子洲-米脂气田的高效开发奠定了技术基础.     

Dispersion modeling approach for quantification of methane emission rates from natural gas fugitive leaks detected by infrared imaging technique

Recently, infrared optical imaging has been applied in the oil and gas industry as a method to detect potential leaks in pipelines, components and equipment. The EPA suggested that this impending technique is considered as a smart gas LDAR (leak detection, monitoring and repair) for its rapid recognition of leaks, accuracy and robustness. In addition, compared to the conventional method using Total Vapor Analyzer (TVA) or gas sniffer, it has several other advantages, such as the ability to perform real-time scanning and remote sensing, ability to provide area measurement instead of point measurement, and provide an image of the gas which is not visible to naked eye. However, there is still some limitation in the application of optical imaging techniques; it does not give any measurement of gas emissions rates or concentrations of the leaking gas. Infrared cameras can recognize a target gas and distinguish the gas from its surrounding up to a certain concentration, namely the minimum detectable concentration. The value of the minimum detectable concentration depends on the camera design, environmental conditions and surface characteristics when the measurement is taken. This paper proposed a methodology to predict gas emissions rates from the size of the dispersed gas plume or cloud to the minimum detectable concentration. The gas emissions rate is predicted from the downwind distance and the height of the cloud at the minimum detectable concentration for different meteorological conditions. Gas release and dispersion from leaks in natural gas pipeline systems is simulated, and the results are presented.     

Comparison of calculated data for the flammability and the oxidation potential according to ISO 10156 with experimentally determined values

The classification of flammable gas mixtures is based on either testing or calculation methods proposed by the revised international standard ISO 10156. This standard is used for classification of physical hazards in Chapters 2.2 and 2.4 of the UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and in the UN Recommendations on Transport of Dangerous Goods (TDG). The test methods of flammability and oxidizing potential in this standard were developed by BAM. Earlier versions of this standard are not based on triangular diagrams and on the reference combustible substance “ethane”. The old material characteristics, especially in case of oxidizing potential, are based mostly on practical experience without any quantifiable test results. First time it is possible to compare experimental results from the CHEMSAFE database with the newly developed calculation method. In this paper the basic principles of the calculation methods are presented and the methods are validated by examples. A comparison of experimental flammability data with classification results gained by the calculation methods of ISO 10156 is demonstrated.     

基于复杂网络和熵的城轨路网运营安全评价模型

针对城市轨道交通的特点以及现有城市轨道交通运营安全评价研究现状,从人、机、环、管4个方面分析影响城市轨道交通路网安全运营的要素及其相互作用关系.在此基础上,基于复杂网络理论构建一个能够描述安全要素耦合作用关系的城市轨道交通路网运营安全层次化网络模型,通过对模型的形式化描述及统计参数分析,采用自底向上、微观和宏观相结合的...     

鱼体中指示性多氯联苯残留量的测定

建立了鱼体中多氯联苯残留量的气相色谱分析方法。结果表明,7种指示性多氯联苯的线性范围为0.001μg/mL-0.20μg/mL。标准添加浓度为1.0μg/kg-10.0μg/kg时,PCB28、PCB52、PCB101、PCB118、PCB138、PCB153和PCB180的回收率均为80%-105%。方法检出限为0.3μg/kg。该方法前处理简便快捷,净化效果好,准确性高。     

气相色谱法和高效液相色谱法测定废水中N，N-二甲基甲酰胺的比较

为比较气相色谱法和高效液相色谱法测定废水中N,N-二甲基甲酰胺是否存在显著性差异,分别使用这两种方法测定N,N-二甲基甲酰胺含量。结果显示,两种方法的精密度、准确度和测定结果无显著性差异,均可作为测定废水中N,N-二甲基甲酰胺的方法。