高效液相色谱直接光学拆分手性农药(英文)

Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides,indoxacarb,lambda-cyhalothrin,and simeconazole,were studied on cellulose tris-(3,5-dimethylphenyl-carbamate)-coated chiral stationary phase(CDMPC-CSP) using high-performance liquid chromatography under normal phase condition.The effects of chromatographic conditions,such as the mobile phase composition including the concentration and type of alcohol modifiers in hexane,flow rate and column temperature,on enantiomer separation were examined.The thermodynamical mechanism of enantioseparation and chiral recognition mechanism were discussed.Better separation were achieved using 20% n-propanol for indoxacarb,2% iso-butanol for lambda-cyhalothrin,and 20% iso-propanol for simeconazole as modifiers in hexane at 25℃ with the selectivity factor(a) of 1.69,1.82 and 1.70,respectively.The resolution factor(Rs) decreased as the flow rate increased from 0.4 to 1.1 ml·min-1.The retention factor(k’) and selectivity factor for the enantiomers of analytes decreased as temperature increased.The lna-1/T plots for racemic chiral pesticides were linear in the range of 15-35℃ in hexane/iso-propanol and the chiral separation was controlled by enthalpy.Hydrogen bonding,π-π and dipole-dipole interactions between enantiomers and CDMPC-CSP play an important role in chiral identification,and the fitting of the asymmetric portion of solutes in a chiral cavity or channel of the CSP is also important.     

磁场环境中磺基水杨酸再掺杂聚苯胺的性能研究

以磺基水杨酸作为掺杂剂,在磁场环境中对聚苯胺进行再掺杂,探讨了磁场强度、掺杂剂浓度和掺杂时间对再掺杂聚苯胺的导电性、溶解性和热稳定性能的影响,并通过四探针、热重分析（TGA）、紫外可见光谱（uV-Vis）以及X-射线衍射（XRD）对再掺杂聚苯胺性能进行了表征。结果表明：在磁场环境中,由于磁场和掺杂酸对聚苯胺,性能影响的协同效应,导致聚苯胺的电导率、溶解性和热稳定性得到了明显的改善,结晶度也得到了很大提高。与无磁场相比,其电导率从0．5s／cm增加到了3．2s／cm,在二甲苯中的溶解度也从12％提高到23％,热分解温度从220℃提高到320℃。     

球磨MgNi非晶储氢合金电化学性能的研究

采用机械合金化法,制备了MgNi非晶储氢合金。探讨了球磨生成非晶的机制。用SEM和XRD分析了合金的表面形貌和相组成。研究不同的球磨工艺如球料比、球径配比、转速以及球磨时间对合金电极电化学性能的影响。所制备的MgNi非晶合金电极的放电容量最高为450mAh/g,但是容量衰减较快。     

锂离子二次电池的正极材料LiMn2O4的研究进展

讨论了锂离子二次电池正极材料ＬＩｎＭ２Ｏ４的制备、结构、电化学性能及其研究发展趋势。