自制固相微萃取装置-气相色谱法测定空气中痕量苯

采用自制的固相微萃取(SPME)装置结合气相色谱仪(GC)对室内空气中痕量苯进行定性和定量的分析。阐述了固相微萃取法的原理和定量的机理;对影响SPME的因素(空气柱、萃取时间、解吸时间和温度)进行了讨论;对所建立的方法进行了系统评价,结果表明:建立的方法具有良好的线性关系(相关系数R=0.9998),检出限为0.01mg/L,3个含量点的相对标准偏差在允许的范围7%以内,回收率为98.18%。     

A tool for estimating the contribution of water-soluble organic compounds to the particle mass and condensational growth in the atmosphere

In this theoretical investigation, we elucidated several factors governing the ability of organic, water-soluble vapours to participate into either the secondary organic aerosol formation or particle condensational growth in the atmosphere. The corresponding requirements for physico-chemical properties of the vapour were estimated. These estimates were also compared with the properties of several difunctional carboxylic acids identified in the atmosphere. Our analysis indicates that while many of the considered compounds are expected to contribute to the total particle mass in the atmosphere, their role in particle condensational growth process remains uncertain. This uncertainty emerges from the fact that the saturation ratio of an organic vapour does not alone determine its ability to act as a “nonvolatile” compound. Instead, the hygroscopic and chemical properties of the vapour, as well as the particle pH and size, have also to be taken into account.     

Optimization of Headspace Solid Phase Microextraction Procedure for Trace Analysis of Toluene

This study describes optimization of headspace solid phase microextraction followed by gas chromatography equipped with a flame ionization detector for toluene at trace level in spiked urine. The parameters affecting the extraction and gas chromatographic determination of analytes were studied: extraction time and temperature; desorption time and temperature; addition of NaCl; and pH, volume and agitation of the sample. Optimized headspace extraction was carried out at 30 °C for 6 min in the presence of 0.2 g-m^-1of NaCl in the sample solution. Also, sample volume and sample pH were optimized at 5 ml and 7 (neutral pH), respectively. Desorption of the analytes was carried out at 250 °C for 60 s. The optimized procedure was validated with 3 different pools of spiked urine; it showed good reproducibility over 6 consecutive days and 6 within-day experiments. The study also determined the accuracy, linearity and detection limits of this method.     

用固相萃取-HPLC法测定水质中杀菌剂多菌灵的方法研究

用固相萃取法萃取水和废水中的多菌灵,取浓缩纯化后的有机相直接进样到高效液相色谱仪,用二极管矩阵检测器检测,根据保留时间外标法定量.     

铁(Ⅲ)-草酸盐配合物的光化学性质及其对天然水相中有机物光降解的作用

本文综述了天然水相（大气水相、地表水等）中Ｆｅ（Ⅲ）－草酸盐配合物的含量与分布、光化学性质、对天然水相中有机物的降解、及其在废水光化学处理中的应用研究及前景。     

Kinetic Study of Naphthalene Biodegradation in Aerobic Slurry Phase Microcosms for the Optimisation of the Process

The research was focused on the slurry-phase biodegradation of naphthalene. The biodegradation process was optimised with preliminary experiments in slurry aerobic microcosms. From soil samples collected on a contaminated site, a Pseudomonas putida strain, called M8, capable to degrade naphthalene was selected. Microcosms were prepared with M8 strain by mixing non-contaminated soil and mineral M9 medium. Different experimental conditions were tested varying naphthalene concentration, soil:water ratio and inoculum density. The disappearance of hydrocarbon, the production of carbon dioxide, and the ratio of total heterotrophic and naphthalene-degrading bacteria were monitored at different incubation times. The kinetic equation that best fitted the disappearance of contaminant with time was determined. The results showed that the isolated strain enhanced the biodegradation rate with respect to the natural biodegradation.     

Direction of pressure wave propagation during combustion-induced rapid phase transition

In the work presented in this paper, the propagation direction of the pressure waves generated during combustion-induced Rapid Phase Transition (cRPT) was investigated. To this end, explosion tests were performed for CH₄/O₂/N₂/CO₂ mixtures in a tubular reactor. Ignition was provided at the top or at the bottom of the vessel. Pressure time histories were recorded by two transducers positioned one at the top and the other one at the bottom.Results have shown that the preferential direction for the pressure waves is that of the flame propagation. When the cRPT phenomenon is weak, an over-adiabatic pressure peak (of around 10–20 bar) can be measured by only one transducer and, in particular, by the transducer far away from the ignition point. Conversely, when the cRPT phenomenon becomes severe, over-adiabatic peaks (as high as 250 bar) can be detected even by the other transducer. Such peaks are the result of separate cRPT events that occur very close to the transducers and, thus, are not damped along the vessel length. In spite of the fact that the upward flame propagation is faster, the cRPT phenomenon is more severe in the case of downward flame propagation.     

Synthesis of TiO2 visible light catalysts with controllable crystalline phase and morphology from Ti-bearing electric arc furnace molten slag

TiO₂ visible light catalysts with different crystalline phases and morphologies were synthesized from titanium-bearing electric arc furnace molten slag (Ti-bearing EAF slag) by using a simple acidolysis process. The effects of the pH of the HCl solution, liquid to solid ratio (R_L/S, HCl solution to the residue ratio, mL/g) and acidolysis time on the micro-morphology and crystalline phase of as-prepared TiO₂ photocatalysts were systematically investigated. The results indicated that with decreasing pH in the HCl solution and increasing R_L/S, the crystalline phase and micro-morphology of the obtained TiO₂ nanostructures tended to transform from anatase type TiO₂ with spherical nanoparticle structures to rutile type TiO₂ with needle-like nanorod structures. The acidolysis time had little influence on the crystalline phase but great impact on the size of the obtained TiO₂. The growth mechanism of TiO₂ from Ti-bearing EAF slag during the acidolysis process was also discussed. In addition, the influence of R_L/S on the photocatalytic properties of the synthesized nanostructured TiO₂ was studied. The results showed that the photodegradation efficiency for Rhodamine B solution could reach 91.00% in 120 min when the R_L/S was controlled at 50:1.     

不同阻燃剂的聚氨酯泡沫材料阴燃特性研究

为了解添加不同阻燃剂的聚氨酯泡沫材料的阴燃特性,对聚氨酯泡沫材料一半干燥一半采用添加Mg Cl2、防老剂、质量分数为10%的水三种情况进行阻燃处理。各次实验结果表明,添加Mg Cl2的材料阻燃效果较好,温度传播到含有添加剂的材料时,由于材料的阻燃性吸附阻止氧气的传播导致没有发生阴燃向有焰火的转化;当传播到有防老剂材料时,由于防老剂的阻氧导致氧气量缓慢减少,在接触后的前期由于氧气量变化缓慢导致气相反应的出现,随着氧气量减少,阴燃结束;当传播到含水材料时,温度出现下降同时阴燃传播速度变慢,但是阴燃仍然能够维持,最后由于氧气的大量进入转化为有焰火。     

相移吸收二元性算法用于X射线混合衬度定量显微CT的可行性研究

本文采用相移吸收二元性（PAD）相位恢复算法来实现混合衬度样品内部不同密度组分的定量成像,采用数字模拟和实验研究验证该方法的可行性.模拟结果表明,对于三种不同材料其重构误差均小于1%,且误差值随材料折射率的增大而减小.利用上海光源X射线成像线站开展了实验研究,结果表明用单距PAD相位恢复算法可获取样品的定量信息.与模拟结果相比,实验中的重构精度相对较低,环状伪影可能是影响精度的主要原因.模拟和实验研究过程中,均只采用了一组单距投影数据.可以认为,相移吸收二元性算法可用于混合衬度样品的定量信息分析研究.由于剂量相对较低,应可适合于软组织和骨骼同时存在时生物医学样品的定量相衬CT研究.