火灾后钢筋混凝土柱外包钢管加固性能——数值模拟

基于ABAQUS软件进行了外包钢管约束加固火灾后钢筋混凝土柱力学性能的数值模拟,分别建立了受火钢筋混凝土构件的温度场分析模型及加固后构件的三维单元力学分析模型。探讨了钢管屈服强度、名义含钢率、新修复混凝土强度等对外包钢管约束加固火灾后钢筋混凝土柱承载力、刚度及延性的影响规律。结果表明:火灾后钢筋混凝土柱的承载力和刚度都会明显降低,采用外包钢管可对受损伤的钢筋混凝土柱进行修复加固,加固后组合柱受力性能将得到大大改善。分析结果可为有关工程应用提供参考。     

LC-MS/MS method validation for determination of selected neonicotinoids in groundwater for the purpose of a column experiment

The work was carried out to develop and validate a method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) for the simultaneous detection and quantification of five neonicotinoid insecticides: acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam in groundwater samples for the purpose of a further column experiment. This experiment will be used to analyze breakthrough curves of neonicotinoids under a saturated water flow to set transport parameters, where the reliability of the results of chemical analysis plays an important role. The validation was performed in a concentration range from 0.09?µg L^?1 to 100?µg L^?1 using an Infinity 1290 (Agilent, USA) chromatograph coupled with a QTrap 5500 mass spectrometer (Sciex, Canada). The calibration curves were obtained on the basis of the results of six standard solution analyses. Linearity was not lower than 0.998. The limit of detection was set at the lowest concentration which can be determined with an acceptable accuracy and precision. All pesticides had recoveries in the range 85–109% with relative standard deviation values less than 8.1%. The estimated measurement uncertainty did not exceed 30%, so the LC-MS/MS method fits for the intended purpose.     

填料塔中Na2CO3吸收高浓度H2S的传质特性

在填料吸收塔中考察了Na2CO3溶液吸收高浓度H2S气体的气液传质特性。通过测量填料塔进出口气体中H2S浓度计算了Na2CO3溶液吸收高浓度H2S气体的总体积传质系数（KGa）,并研究了进气流速、吸收液流量、吸收温度和吸收液浓度对KGa的影响。结果表明,KGa随Na2CO3浓度、吸收液流量的增加而增加,随吸收温度、进气流速的升高而降低;在高浓度H2S吸收过程中液相传质阻力不能忽略。     

A novel pretreatment approach for fast determination of organochlorine pesticides in biotic samples

Recent studies have focused on enantiomeric behaviors of chiral organochlorine pesticides (OCPs) in biotic matrix because they provide insights into the biotransformation processes of chiral OCPs. In the present paper, a double in-line column chromatographic method was developed to effectively remove the lipid impurity in different biotic samples for clean-up of OCPs. After an initial Soxhlet extraction of OCPs from the biotic samples by a mixture of acetone and dichloromethane (DCM), dimethyl sulfoxide (DMSO) was directly added to the extract, and low boiling point solvents (acetone and DCM) were then evaporated. OCPs remained in DMSO were eluted via column 1 filled with silicon gel, and subsequently passed through column 2 packed with 15% deactivated florisil. This novel method was characterized by significant time and solvent savings. The recovery rates of α -HCH (hexachlorocyclohexane), β -HCH, γ -HCH and δ -HCH were 78.5 ± 3.1%, 72.4 ± 7.7%, 72 ± 4.0% and 70.0 ± 8.7%, respectively, and 92.5 ± 3.8%, 79.7 ± 6.7% and 83.4 ± 6.5% for 1,1-dichloro-2-(2-chlorophenyl)-2-(4- chlorophenyl) ethylene (o,p′-DDE), 1,1-dichloro-2-(2-chlorophenyl)-2-(4-chloro phenyl)ethane (o,p′-DDD) and 1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl) ethane (o,p′-DDT), separately. In addition, the separation efficiencies of the target compounds by both achiral and chiral gas chromatographic columns were satisfactory using the established method. Therefore, the double in-line column chromatography was a useful alternative method for pretreatment of OCPs in different biotic samples.     

NMR成像技术测试煤样渗吸过程中水分变化规律研究

外加水在渗吸过程中可以促进煤体瓦斯解吸,减小煤层瓦斯含量,从而减少瓦斯事故的发生频率。为了研究含瓦斯煤水分分布规律,采用NMR（核磁共振成像）技术,针对不含瓦斯煤进行定量外加水渗吸实验。研究结果表明:型煤中的水分主要受毛细管力和重力作用的影响;在自下向上吸水和自上向下吸水渗吸过程中,毛细管力作用相同,径向方向上水分扩散速度相近,但在轴向方向上的扩散速度具有明显差异,由于重力作用的影响,分别产生抑制和促进作用;水分三向扩散半径与时间符合朗格缪尔函数关系。     

钟市油田井下管柱腐蚀断裂机理与防治

针对钟市油田井下管柱腐蚀现状,通过分析注入水、环空水水化学成分及pH值、细菌等水质指标,结合断裂管柱腐蚀产物成分,研究管柱腐蚀断裂机理。结果表明,钟市油田注入水SO2-4质量浓度高达4 398.2 mg/L,利于硫酸盐还原菌(SRB)繁殖生长,SRB代谢产生H2S导致腐蚀加剧是注水井井下管柱断裂的主要原因。环空注入杀灭环空菌是解决管柱过早腐蚀断裂的有效方法,文章应用的环空保护液杀菌率100%、腐蚀速率0.058 mm/a,现场试验结果达到国家标准要求。     

Transport of bacterial cell (E. coli) from different recharge water resources in porous media during simulated artificial groundwater recharge

• The recharge pond dwelling process induced changes in cell properties. • Cell properties and solution chemistry exerted confounding effect on cell transport. • E. coli cells within different recharge water displayed different spreading risks. Commonly used recharge water resources for artificial groundwater recharge (AGR) such as secondary effluent (SE), river water and rainfall, are all oligotrophic, with low ionic strengths and different cationic compositions. The dwelling process in recharge pond imposed physiologic stress on Escherichia coli (E. coli) cells, in all three types of investigated recharge water resources and the cultivation of E. coli under varying recharge water conditions, induced changes in cell properties. During adaptation to the recharge water environment, the zeta potential of cells became more negative, the hydrodynamic diameters, extracellular polymeric substances content and surface hydrophobicity decreased, while the cellular outer membrane protein profiles became more diverse. The mobility of cells altered in accordance with changes in these cell properties. The E. coli cells in rainfall recharge water displayed the highest mobility (least retention), followed by cells in river water and finally SE cells, which had the lowest mobility. Simulated column experiments and quantitative modeling confirmed that the cellular properties, driven by the physiologic state of cells in different recharge water matrices and the solution chemistry, exerted synergistic effects on cell transport behavior. The findings of this study contribute to an improved understanding of E. coli transport in actual AGR scenarios and prediction of spreading risk in different recharge water sources.     

过硫酸钾脱除气态元素汞的试验研究

在鼓泡塔反应器中,用过硫酸钾(K2S2O8)脱除气态元素汞.试验考察了K2S2O8浓度、吸收温度及催化剂等因素对脱汞效率的影响.结果表明:当K2S2O8在1.0～10.0 mmol/L时,随着浓度的增加,脱汞效率显著升高;AgNO3对K2S2O8脱汞具有显著的催化作用,且0.3 mmol/L AgNO3的催化效果优于0.1 mmol/L AgNO3;CuSO4对K2S2O8除汞也具有催化作用,但催化效果不如AgNO3;AgNO3存在下,低温更有利于汞的脱除.     

胶束电动毛细管色谱测定塑料工业废水中邻苯二甲酸丁苄酯

运用胶束电动毛细管色谱法同时分离测定了水中 5种邻苯二甲酸酯的标准混合物,建立了对实际工业废水样中邻苯二甲酸丁苄酯的定量测定方法。结果表明,30min内 5种邻苯二甲酸酯得到了较好的分离。以峰面积定量,在4～ 5 0mg L的浓度范围内,邻苯二甲酸丁苄酯的标准曲线具有良好的线性相关性,相关系数较好。相对标准偏差<2 6 %,工业废水加标测定,邻苯二甲酸丁苄酯的回收率在 10 4 %～ 10 9%之间     

粉煤灰浸出液入渗土壤过程中的水岩作用研究

为明确粉煤灰浸出液对地下水环境的影响,依据饱水土柱试验,利用质量平衡模型,对比研究了灞桥电厂粉煤灰浸出液和清水入渗土壤过程中的水岩作用.研究表明,虽然粉煤灰浸出液和清水入渗土柱的渗出液水化学特征存在明显差异,但入渗水的水质对渗出液的时间变异性影响较小.矿物的溶解沉淀作用及Ca-Na离子交换等水岩作用对浸出液和清水入渗过程中的化学反应及水化学形成产生重要影响.高浓度的粉煤灰浸出液比清水溶解了土壤中更多的可溶盐,使土壤的渗透系数增大,增加了地下水污染风险.