顶空固相微萃取-气相色谱质谱法测定水体中的苯甲醚

建立了顶空固相微萃取-气相色谱质谱法定性定量检测水中苯甲醚的分析方法。对影响检测结果的因素如萃取头的选择、萃取时间等进行了优化。经过条件优化，方法在1～1 000 μg/L 范围内线性良好，线性相关系数＞0.999，实际水样加标质量浓度分别为10，60，300 μg/L时，加标回收率为85%～120%，相对标准偏差（RSD）为3.95%～6.72%。全扫描模式下，苯甲醚的检出限为0.3 μg/L。实验结果表明，该方法快速、简便、灵敏度高，方法精密度和准确度均能满足水中微量及痕量苯甲醚检测的要求。     

Development and validation of a thermally regulated atmospheric simulation chamber (THALAMOS): A versatile tool to simulate atmospheric processes

Atmospheric simulation chambers, are unique tools for investigating atmospheric processes in the gas and heterogeneous phases. They can provide a controlled yet realistic environment that simulates atmospheric conditions. In the current study, a Teflon atmospheric simulation chamber of 600 L, named THALAMOS (thermally regulated atmospheric simulation chamber) has been developed and cross-validated. THALAMOS can be operated over the temperature range 233 to 373 K under both static and flow conditions. It is equipped with state of the art instrumentation (selective ion flow tube mass spectrometry (SIFT-MS), long path Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), various analyzers) for the in-line monitoring of both reactants and products. THALAMOS was validated by measuring the rate coefficients of well documented reactions, i.e. the reaction of ethanol with OH radicals and the reaction of dichloromethane with Cl atoms, in a wide temperature range. Two different detection techniques were used in parallel, FTIR and SIFT-MS, to internally cross-validate the obtained results. The measured rate coefficients are in excellent agreement, both between each other and with the literature recommended values. Furthermore, the gas phase oxidation of toluene by Cl atoms (kinetics and product yields) was studied in the temperature range of 253 to 333 K. To the best of our knowledge, THALAMOS is a unique facility on national level and among a few smog chambers internationally that can be operated in such a wide temperature range providing the scientific community with a versatile tool to simulate both outdoor and indoor physicochemical processes.     

离子掺杂效应对二氧化锆热稳定性的影响

本文利用X -射线衍射技术及比表面测试 ,研究了La3 、Ce4 、Ti4 掺杂离子对亚稳态t-ZrO2 晶相转变及对t-ZrO2 比表面积的影响。最后发现掺杂离子能有效的提高亚稳态t-ZrO2 的热稳定性能。其中La3 和Ce4 离子能有效的推迟亚稳态t-ZrO2 的晶相转变温度。并发现离子掺杂效应对二氧化锆热稳定性作用大小排列顺序为 :La3 >Ce4 >Ti4 。     

基于系统动力学的企业安全经济效益分析 —以安全教育经济效益子系统为例

为达到企业安全经济效益最大化的目标,运用系统动力学的方法对企业安全经济效益系统进行建模,并对其中的安全教育经济效益子系统进行仿真模拟。实验结果表明:改变系统中的影响因素,安全教育经济效益并没有立即发生变化,而存在一段“延迟阶段”。同时也证明了安全培训人员能力在安全教育经济效益系统中具有最大的影响效果。     

镁离子对氧化亚铁硫杆菌生物合成次生铁矿物的影响

通过摇瓶实验,在Mg2+分别为48,4.8mg/L,其他元素组成与9K液体培养基一致的体系中,采用氧化亚铁硫杆菌A. ferrooxidans催化合成次生铁矿物.考察了Mg2+含量对生物合成次生铁矿物体系pH值、氧化还原电位(ORP)、Fe2+氧化率、总Fe沉淀率、次生铁矿物矿相及矿物晶体尺寸的影响.结果表明,经过48h培养,Mg2+浓度为48,4.8mg/L生物成矿体系pH值分别从原来的2.50降低至2.30,2.19,ORP分别从初始259mV增加至269mV,276mV.两体系Fe2+氧化率培养至第48h均达到100%,然而两体系总Fe沉淀率及矿物形态及却不尽相同.Mg2+浓度为48mg/L生物成矿体系,总Fe沉淀率为23.7%,次生矿物紧密粘附于三角瓶底部.而Mg2+浓度为4.8mg/L生物成矿体系,总Fe沉淀率达到32.2%,次生矿物却均匀分散于溶液中.两体系合成次生铁矿物均为黄铁矾与施氏矿物共存的混合物,Mg2+含量4.8mg/L体系合成黄铁矾单个晶体长度(~1.60μm)约为Mg2+含量48mg/L体系的1.2倍.     

Modeling of Ce（IV） transport through a dispersion flat combined liquid membrane with carrier P507

A mathematical model for the transport of Ce （IV） from hydrochloric acid solutions through dispersion flat combined liquid membrane （DFCLM） with contain 2- ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester （P507） as the carrier, dissolved in kerosene as the membrane solution have been studied. This process of facilitated transport, based on membrane technology, is a variation on the conventional technique of solvent extraction and may be described mathematically using Fick＇s second law. The equations for transport velocity are derived considering the diffusion of P507 and its metallic complexes through the liquid membrane. In this work, the system is considered to be in a transient state, and chemical reaction between Ce（IV） and the carrier to take place only at the solvent-aqueous interfaces. Model concentration profiles are obtained for the Ce（IV）, from which extraction velocities are predicted. The experimental and simulated Ce（IV） extractions showed similar tendencies for a high Ce （IV） concentration and acidity case.The model results indicate that high initial Ce（IV） concentrations and acidity both have detrimental effects on Ce（IV） extraction and stripping. The diffusion coefficient of Ce（IV） in the membrane and the thickness of diffusion layer between feed phase and membrane phase are obtained and the values are 6.31 × 10-8m2·s-1 and 31.2 μm, respectively. The results are in good agreement with experimental results.     

一体化A/O工艺处理生活污水的研究

采用A/O生物接触氧化法处理生活污水,考查了系统的挂膜启动以及水力停留时间(HRT)、进水pH值和进水COD浓度对系统去除有机物及脱氮效果的影响。结果表明:15 d左右挂膜成功;HRT=13 h,COD去除率和氨氮去除率可分别达到96.72%、85.43%;系统具有较好的抗冲击负荷能力,COD去除率最低在70%左右,氨氮去除率均大于65%,最佳的进水COD质量浓度应控制在300~500mg/L;pH值变化对氨氮去除率的影响更加明显,pH值在7~8时,COD去除率大于90%,氨氮去除率达68%~80%。     

热氨融霜过程多相相变流动液击形成机理研究

热氨融霜多相流动液锤诱发的回气总管频现爆管和穿孔腐蚀事故的预防仍是一项技术挑战。基于进口速度突变和瞬态冷凝与汽化相变直接驱动力,建立了描述多相相变流动液击形成过程的理论模型及其数值模拟算法,研究了回气总管热氨蒸汽与深冷液氨多相分层流动液击的形成机理,研究结果表明:在进口流速突变条件下,瞬态冷凝与汽化相变多相流动诱发的液击压强是无相变多相流动液击压强4倍左右,考虑相变驱动是准确预测多相流动液击的理论前提,多相流动液锤压力显多波型大幅脉动波动变化,且随着氨液剩余填充量增加而增大,而深冷液氨区局部液击压力降至液氨的饱和蒸汽压所诱发的空泡溃灭是导致回气总管频现穿孔腐蚀的直接原因。     

High performance liquid chromatographic determination of pesticides in soluble phase and suspended phase in river water

A high performance liquid chromatographic method has been developed to determine pesticides in river water as both dissolved phase and suspended phase. The target pesticides were eight herbicides, asulam, diuron, flazasulfuron, linuron, MCPB, mecoprop, pyrazosulfuron‐ethyl and siduron, and two fungicides, oxine‐copper and thiram. The pesticides in filtered river water were extracted with styrene‐divinylbenzene copolymer and were eluted with acetonitrile. The pesticides on suspended solids were extracted ultrasonically with acetonitrile. Each eluate was concentrated and analyzed by HPLC with multiwavelength detector. Recoveries of the pesticides in the overall procedure of this method were 78–114% for filtered river water and 75–107% for suspended solids. The limits of detection in water and suspended solids ranged from 0.1 to 0.9 μg/L and 1 to 7 μg/g, respectively. Pesticide distribution between soluble phase and suspended phase in river water was measured by this method.     

Effect of selenium on the growth of Lemna minor

The effect of selenium on the vegetative reproduction of cultured Lemna minor was investigated. Cultures were grown for 28 days at a temperature of 23 ± 3°C and under a constant (24 h) light cycle. Growth was monitored every seven days. The growth of L. minor was inhibited at high concentrations (>5mg/L [Se]), but stimulated at low concentrations (0.2—2mg/L [Se]). This stimulation of growth at low selenium concentrations has significant implications for the use of selenium enriched superphosphate fertilisers on selenium deficient pastures.