改性超滤膜技术在水处理中的应用研究进展

膜技术由于其兼具较好的处理效果和较小的环境影响的特点,在水处理领域的应用前景广阔,其中超滤膜因其抗污染能力强、使用寿命长的特点广泛应用于水处理中。本文针对不同的应用场景总结梳理了聚偏氟乙烯超滤膜、TiO₂管式复合超滤膜、聚醚砜超滤膜这三种常见的超滤膜材料的改性方法和改性膜特点,讨论了这些改性膜材料在水处理过程中的应用现状和亟需解决的问题,以期为膜处理技术中的发展和应用提供科学支撑和理论依据。     

MODIFICATION OF CeO2 AND ITS EFFECT ON THE HEAT-RESISTANCE OF SILICONE RUBBER

By means of the wet chemical surface modification,the surface of CeO_2 was modified by vinyltrimethoxysilane (VTMS).Infrared spectroscopy was used to investigate the structure of the modified CeO_2 and the result showed that VTMS has been attached onto the surface of CeO_2.Effect of VTMS concentration on the active index of the modified CeO_2 was also studied,and the result indicated that the active index of the modified CeO_2 increases with the increase of VTMS concentration and the optimal concentratio...     

氯离子加速的铜基芬顿反应用于对多巴胺的比色检测EI北大核心CSCD

基于氯离子加速的铜基芬顿反应构建了一种便捷、快速、无标记的比色分析方法并将其应用于多巴胺(DA)的快速检测。Cl^(-)可以加速Cu^(2+)催化过氧化氢(H_(2)O_(2))产生羟基自由基,进而氧化3,3′,5,5′-四甲基联苯胺(TMB)显色,而DA可以与Cu^(2+)配位,使反应速率减慢。基于此,可以利用检测液的颜色及TMB^(2+)在452 nm处吸光度的变化来实现对DA的检测。DA的浓度在0~10μmol/L及10~50μmol/L范围内与TMB^(2+)在452 nm处的吸光度呈线性相关,检出限为0.5μmol/L。本方法已用于实际样品的检测。     

麻省理工学院开放性数学课程资源的有效利用

美国麻省理工学院(MIT)在全美工科院校排名中连续多年位居第一,其基础学科数学系的课程设置独具风格.本文将简要介绍MIT开放性课程官方网站上目前提供的58门次本科数学课程以及它们之间的依赖关系,提出有效利用这些课程资源的几点建议,以便教师、学生和自学者在使用中参考.     

Ammonium sulfamate flame retarded polyamide 6: Morphology and thermal degradation

<正>The effect of ammonium sulfamate(AS) content on the flame retardancy of polyamide 6(PA6) was studied.It is found that the limiting oxygen index(LOI) of PA6 increases with the increase of AS content and the flame retardancy of PA6 is significantly improved.The morphology of the residues after combustion was examined by means of scanning electron microscopy(SEM).SEM results show that AS facilitates the formation of the intumescent char layer with honeycomb-like structure,which inhibits the transfer of heat and mass,and thus improves the flame retardancy of PA6.The thermal degradation of AS flame retarded PA6 was studied by thermogravimetric analysis(TGA).The Kissinger method was applied to estimate the activation energy(E_a) of the degradation.The activation energy of the thermal degradation of PA6 decreases by adding AS,indicating that AS can promote the degradation of PA6.     

Ir/CeO2催化剂上乙醇水蒸气重整反应的研究

研究了Ir/CeO2催化剂在乙醇水蒸气重整反应中的催化性能.用沉积沉淀法在高比表面的CeO2载体上制备了Ir/CeO2催化剂,采用X射线衍射光谱、程序升温还原和透射电子显微镜对催化剂的晶相组成、还原性能和形貌进行了表征.结果表明,Ir和CeO2之间发生了强烈的相互作用,从而明显改善了Ir粒子的分散.Ir具有优异的C-C键断裂性能,在低温下即可实现乙醇的完全转化,而在高温区具有很好的甲烷重整性能,可获得很高的氢气产率.     

OXIDATIVE POLYMERIZATION BEHAVIOR OF 2,6-DIMETHYLPHENOL IN AQUEOUS MEDIA WITH POTASSIUM FERRICYANIDE

The effects of potassium ferricyanide,sodium n-dodecyl sulfate,sodium hydroxide and temperature on the molecular weight and the yield of poly(2,6-dimethyl-1,4-phenylene oxide)(PPO) synthesized in an aqueous medium were studied.It was found that oxygen in air had little influence on the oxidative polymerization of 2,6-dimethylphenol(DMP) in the aqueous medium,and potassium ferricyanide was only an oxidant during the oxidative polymerization of DMP.Sodium n-dodecyl sulfate could stabilize polymer particles...     

微流控芯片光学检测技术在细胞研究中的应用与进展

重点综述了芯片上细胞培养和实时检测的微系统研究及相应检测方法和技术近年来的进展.总结了多种光学检测方法和技术体系的优缺点及发展趋势,讨论了各种方法技术对细胞研究模型的研究适用范围,探讨各种检测方法和技术对活细胞、单细胞实时无损无标记检测和传感发展前景和研究进展.最后对整个芯片实验室框架下细胞研究及传感微系统的发展方向进行了有益的思路和方法展望.     

液相色谱-质谱联用技术测定无糖食品中果糖、葡萄糖、蔗糖、麦芽糖和乳糖

建立了无糖食品中葡萄糖、果糖、蔗糖、麦芽糖、乳糖的高效液相色谱-串联四极杆质谱联用测定方法.本方法以水提取样品,以Waters Carbohydrate Analysis柱(300 mm×3.9 mm, 10 μm)分离,流动相为水-乙腈(15∶ 85, V/V),电喷雾负离子MRM模式检测.方法的检出限为0.1 g/kg;线性范围为2.5～125.0 mg/L;加标回收率为86.2%～97.7%;相对标准偏差为3.1%～8.7%.     

高职数学教学立体化改革探索

分析高职高等数学教学现状,给出高职高等数学教学立体化改革的探索思路,即分层次的教学模式、合理选取教学内容、因人而异选择教学方法、灵活多样地进行考核以及建立网络辅助教学平台.