单分散磁性纳米颗粒的制备及生物高分子在其上的组装

磁性纳米颗粒因其潜在的生物医学应用价值而成为纳米生物材料领域研究的前沿。本文综述了单分散磁性纳米颗粒的制备方法以及生物高分子在磁性纳米颗粒上的组装的研究进展。     

纳米镍-铁合金/膨胀石墨复合材料的制备、表征及其电磁屏蔽性能

The composites with nano-particles of Ni-Fe alloys dispersed on the nano-layers of expanded graphite (EG) were prepared by the impregnation of EG with ethanol solutions of nickel and iron acetates， followed by drying and reduction in H₂. The square nano-particles of Ni-Fe alloys with particle sizes of mainly 20～40 nm were found to be well spread on the layers of EG. The alloy nano-particles exhibited high shielding effectiveness (SE) for electromagnetic radiations at low frequencies due to their high magnetic conductivity. Since EG is electronically conductive and displayed high SE at high frequencies， the composites exhibited good SE at wide range of frequencies. The electric and magnetic conductivities of the composites could be monitored through regulating the loadings of alloy nano-particles on EG， and it was found that the composites with 20%～40% of the alloys exhibited good SE. Specifically， the composite 27%Ni-3%Fe-EG showed the excellent SE from 66 to 110 dB at the frequencies from 300 kHz to 1.5 GHz.     

LaNi4.7Al0.3单颗粒微电极电化学行为的研究

报道了一种单颗粒微电极制备新方法, 并研究了LaNi4.7Al0.3球形单颗粒微电极的电化学行为.     

反相高效液相色谱法测定3种中成药中的葛根素

 建立了测定小儿清感灵片、步长新脑心通胶囊和感冒清热颗粒 3种中成药中葛根素含量的反相高效液相色谱方法。采用APEXODS色谱柱 ,以醋酸铵缓冲液 (10 0mmol/L ,pH 5 0 ) 甲醇 (体积比为 75∶2 5 )的混合溶液为流动相 ,检测波长为 2 5 0nm ,流速为 0 8mL/min。葛根素在 2mg/L～ 2 0mg/L时其色谱峰面积与质量浓度的线性关系良好 (r =0 9999) ;上述 3种中成药中的葛根素含量分别为 3 48mg/g ,1 0 8mg/ g及 1 5 2mg/ g(蔗糖型 ) ;其加样回收率分别为 99 0 % ,93 4%和 97 5 %。该法简便、快速、专属性强 ,可以作为多种中药制剂中葛根素含量的测定方法。     

停流流动注射—动力学方法多组份同时测定的研究：铁（Ⅱ）,钛（Ⅲ）和…

依据诱导反应原理，提出了同时测定多组份的动力学方法，并以停流流动注射分析研究了Ｆｅ（Ⅱ），Ｔｉ（Ⅲ）及Ｖ（Ⅳ）诱导的Ｃｒ（Ⅵ）－Ｉ＾－反应体系，建立了铁，钛和钒同时测定的条件。对铁，钛和钒测定的线性范围分别为０－２．２μｇ／ｍｌ，０－３．１μｇ／ｍｌ及０－１．８μｇ／ｍｌ，检测限分别为０．０１２，０．０２０和０．０１８μｇ／ｍｌ。     

New Approach to Detecting Phenoxyl Free Radicals Generated in Enzyme Reaction by Stopped-flow Spectrophotometry

Quantification of free radical formation is critical for evaluation and interpretation of many radical-mediated biological processes1-4. Numerous studies have been devoted to the determination of free radicals, but the most of the reports have been focuse…     

Thermal Emulsion Polymerization without any Conventional Initiators and Emulsifiers

Stable poly(styrene-co-sodium styrene sulfonate) (P(St-NaSS) nanoparticles with broader size distribution were synthesized by thermal emulsion polymerization without any conventional initiators and emulsifiers. The obtained polymer nanoparticles have higher ξ potential, and the particle sizes have broad distribution. The stability of polymer particles originated from the addition of small amounts of ionic comonomer, NaSS, which can act as an emulsifier in somewhat. The monomer conversion could reach up to about 28 wt% in 48 h, and did not increase by further polymerization when higher polymerization temperature (120 ℃) was employed. This polymerization system may be give some further understand for mechanism of emulsion polymerization.     

CRYSTALLIZATION AND MECHANICAL PROPERTIES OF POLYPROPYLENE FILLED WITH SiO2 NANOPARTICLES

Oleic acid （OA）-modified SiO2 （OA-m-SiO2） nanoparticles were prepared using surface modification method. Infrared spectroscopy （IR） was used to investigate the structure of the OA-m-SiO2 nanoparticles, and the result showed that OA attached onto the surface of SiO2 nanoparticles through esterification. Effect of OA concentration on the dispersion stability of OA-m-SiO2 in heptane was also studied, and the result indicated that OA-m-SiO2 nanoparticles were dispersed in heptane more stably than the unmodified ones. OA-m-SiO2 nanoparticles can also be dispersed in polypropylene （PP） matrix in nano-scale. The effect of OA-m-SiO2 on crystallization of PP was studied by means of DSC. It was found that the introduction of OA-m-SiO2 resulted in significant increase in the crystallization temperature, crystallization degree and crystallization rate of PP, and OA-m-SiO2 could effectively induce the formation of β-crystal PP. Effect of OA-m-SiO2 content on mechanical properties of PP/OA-m-SiO2 nanocomposites was also studied. The results show that OA-m-SiO2 can significantly improve the mechanical properties of PP.     

纳米二氧化锆在甲醇合成催化剂Cu/Ga2O3/ZrO2中的作用

The introduction of mesoporous nanosize zirconia to the catalyst for methanol synthesis dedicates the nanosized catalyst and mesoporous duplicated properties. The catalyst bears the larger surface area, larger mesoporous volume and more uniform diameter, more surface metal atoms and oxygen vacancies than the catalyst prepared with the conventional coprecipitation method. The modification of microstructure and electronic effect could result in the change of the reduced chemical state and decrease of reducuction temperature of copper, donating the higher activity and methanol selectivity to the catalyst. The results of methanol synthesis demonstrate that the Cu^＋ is the optimum active site. Also, the interaction between the copper and zirconia shows the synergistic effect to fulfil the methanol synthesis.     

压力流驱动电色谱分析方法及其若干色谱行为

压力流驱动电色谱分析方法是一种新型色谱技术。它组合了ＨＰＬＣ和电泳两种技术，为分离提供了更多可控制的因素。介绍了压力流驱动电色谱的装置和毛细管电色谱柱的装置方法，从理论上讨论了影响电色谱分离的因素并用实验数据加以证明。最后尝试性地将电色谱法用于测定香蕉样品中萨索啉（Ｓａｌｓｏｌｉｎｏｌ）等的含量。