固相膜萃取与GC/MS联用测定地下水中痕量半挥发性有机物的野外采样方法研究

C18固相萃取膜适宜处理大体积地下水样现场采样而且易于运输、贮存。利用C18固相膜萃取以及GC／MS联用的方法对地下水中痕量半挥发性有机污染物进行了萃取以及定性、定量分析。优化了固相膜萃取的地下水采样量和浓缩体积。有机氯农药和多环芳烃的平均回收率分别为85％～110．1％、90．3％～115．1％；方法检出限达到10^-9g／L；相对标准偏差均小于15％。本方法用于北京地区地下水中的有机污染物分析，并给出地下水样C18固相膜萃取的GC／MS测定结果。     

Effect of nucleating agent on the structure and properties of polypropylene/poly(ethylene-octene) blends

The effect of the sorbital nucleating agent on properties of the ethylene-octene copolymer (POE) toughened polypropylene (PP) was studied. The results show that the addition of POE increases notched Izod and Charpy impact strength significantly but impair the tensile strength and flexural modulus. As a nucleating agent (1,3,2,4-di(p-methylbenzylidene) sorbitol, DM) was added, the toughness and stiffness of toughed PP increased simultaneously at the same content of POE. This result shows that the toughness and stiffness of toughed PP are in balance. Polarized light microscopy analysis shows that with the addition of POE and nucleating agent, only a low level of PP spherulites were observed.     

某些含二维液晶基元的热致液晶高分子的向列态纹影响构

发现某些含二维液晶基元的热致液晶高分子容易产生反向壁织构与含有高强度有错点（│Ｓ│大于１）的向列态纹影织构。这类液晶高分子的织构与形态学特点与含一维棒状液晶基元的其他液晶高分子不同。     

The Preparation and Characterization of Highly Dispersed PdO over Alumina for Low‐temperature Combustion of Methane

PdO/Al₂O₃ catalysts prepared by glow discharge plasma treatment followed by thermal calcination show a much higher dispersion and a better catalytic activity for methane combustion at relatively low temperatures. The dispersion of palladium active species by such plasma prepared catalysts is 29.7%, 5.4 times higher than that of conventional catalysts. XPS analysis indicates that a surface enrichment of Pd active species (PdO) has been achieved after plasma treatment. The surface atomic composition of PdO of plasma prepared catalysts reaches 10.5%. XRD characterization also confirms a wellcrystallized PdO phase present on the plasma prepared catalyst. The lightoff temperature of the plasma prepared catalyst is 370°C, 50°C lower than that obtained from the conventional catalyst.     

气相色谱法测定阳离子表面活性剂合成体系中脂肪烷基二甲基叔胺

选用HP-NINOWax毛细管色谱柱及氢火焰离子化检测器（FID），采用程序升温，建立了4种脂肪烷基二甲基叔胺的分析方法。结果表明，4种脂肪烷基二甲基叔胺质量浓度在0.005~1.0 g/L范围内，其峰面积与质量浓度有良好的线性关系，相关系数（R²）在0.9996以上。检出限（LODs，信噪比为3）在0.001~0.002 g/L之间，定量限（LOQs，信噪比为10）在0.003~0.005 g/L之间，回收率在90%~130%之间，相对标准偏差为1.3%~6.9%（n=6）。方法的线性范围宽、回收率高、选择性好，可用于叔胺的产品质量分析及生产过程控制分析。利用该方法对阳离子表面活性剂合成反应中十六烷基二甲基叔胺进行监测，结果很好地符合双分子亲核取代反应。该方法比滴定分析法更快速、精确，与液相色谱法相比，不需要进行柱前衍生或者使用色谱-质谱联用仪器。     

THERMODYNAMIC STUDY OF ADSORPTION OF PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTION BY A WATER-COMPATIBLE HYPERCROSSLINKED POLYMERIC ADSORBENT

Equilibrium data for the adsorption of phenolic compounds, i.e., phenol, p-cresol, p-chlorophenol and p-nitrophenol from aqueous solutions by a water-compatible hypercrosslinked polymeric adsorbent (NJ-8) within temperature range of 283-323 K were obtained and correlated with a Freundlich-type of isotherm equation, so that equilibrium constants KF and n were obtained. The capacities of equilibrium adsorption for all the four phenolic compounds on the NJ-8 from aqueous solutions are around 2 times as high as those of Amberlite XAD-4, which may be attributed to the unusual micropore structure and the partial polarity on the network. The values of the enthalpy (always negative) are indicative of an exothermic process, which manifests the adsorption of all the four phenolic compounds on the two polymeric adsorbents to be a process of physical adsorption. The negative values of free energy change show that the solute is more concentrated on the adsorbent than in the bulk solution. The absolute free energy values of adsorption for NJ-8 are always higher than those for Amberlite XAD-4, which indicates that phenolic compounds are preferentially adsorbed on NJ-8. The negative values of the adsorption entropy are consistent with the restricted mobilities of adsorbed molecules of phenolic compounds as compared with the molecules in solution. The adsorption entropy values of phenolic compounds for NJ-8 are lower than those for Amberlite XAD-4, which means the micropores of NJ-8 require more orderly arranged adsorbate.     

Agonist–PPARγ interactions: Molecular modeling study with docking approach

Docking simulation of 18 agonists with the ligand binding pocket (LBP) of PPARγ has been performed. The binding conformations and binding affinities of these agonists were obtained by use of the flexible docking protocol FlexX. Test compound calculations indicated that FlexX can reproduce the binding conformation of the crystal structure (root mean square deviation = 1.43 Å); moreover, the predicted binding affinities correlate well with the activities of these agonists. The interaction model and pharmacophore of PPARγ agonists were derived and the difference in biologic activities of these agonists can be well explained. The PPARγ agonists must have both polar head and the hydrophobic tail, which form hydrogen bonds and hydrophobic contacts with hydrophilic and hydrophobic regions of the LBP of PPARγ, respectively. In addition, a suitable linker is also necessary. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 405–410, 2003     

用于测量农药残留的小麦酯酶的选择

为研制探测农药残留的生物传感器，研究了农药乐果[O,O-二甲基S－（N－甲基胺基甲酰甲戎）二硫代磷酸酯]对各种小麦植物酯酶的抑制，从小麦中提取植物酶，以农药乐果为抑制剂，采用分光光度法研究了乐果对各种小麦酯酶活性的影响；研究显示，不同品种小麦酯酶对农药乐果的敏感度不同，在所研究的品种中，豫麦39和小麦周9对乐果较敏感，研究结果说明了选择小麦酶源的必要性。     

胺甲基化聚丙烯酰胺稀溶液行为的研究——pH值对粘性行为及其絮凝作用的影响

pH值对胺甲基化聚丙烯酰胺(CPAM)稀溶液粘性行为的研究表明:不同的CPAM-H_2O溶液体系(胺化度28.8～38mol％,外加盐浓度0～0.2M)的粘性行为,特性粘数[η]和Huggins常数k′随溶液pH值变化分别是现极大值和极小值;CPAM对有机污泥脱水絮凝作用随溶液pH值变化存在极大值。本文从CPAM电荷的形成、电荷密度的增加以及屏蔽出发讨论了上述两种极限现象。     

Photovoltaic Characteristics of a Naphthylamine Derivative

Organic photovoltaic （OPV） cells were fabricated via vacuum vapor deposition with {4-[2-（3-di-cyanomethylidene-5,5-dimethylcyclohexenyl）vinyl]phenyl}di（1-naphthyl）amine （DNP-2CN） as the electron donor, and fullerene （C60） as the electron acceptor. A thin film （10 nm） of tris（8-quinolinolato）aluminum （Alq3） was adopted as the buffer layer. A device based on this DNP-2CN exhibited an open circuit voltage （Voc） of 370 mV, a short-circuit current density （Jsc） of 0.61 mAocm 2, and a white-light power conversion efficiency （ η） of 0.09% （AM1.5, 75 mW.cm^- 2）.