Fast access to core/shell/shell CdTe/CdSe/ZnO quantum dots via magnetic hyperthermia method

The intrinsic low quantum yield (QY) of type II core shell quantum dots (QDs) composes the limitation for these heterostructured nanomaterials to be used in practical application. Herein, magnetic hyperthermia method is employed to intensify reaction process and facilely synthesize CdTe/CdSe heterostructured QDs with improved optical performance for the first time. The QY of the type II QDs is increased to 49% by further growing an inert ZnO layer. The type I interface between CdSe and ZnO helps confine electrons to the inner structure of the QDs, thus improving the QY. The successful preparation and performance enhancement of the CdTe/CdSe type II QDs via magnetic hyperthermia method demonstrate the great potential of this method for the preparation of other materials. Besides, the red‐emission QDs are used as conversion materials in white light emitting diodes to reveal their promising application in practical illumination. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2614–2621, 2016     

Rheology of polyacrylonitrile‐based precursor polymers produced from controlled (RAFT) and conventional polymerization: Its role in solution spinning

Polymer solutions in dimethyl sulfoxide (DMSO) as a solvent, made from reversible addition fragmentation chain transfer (RAFT)‐mediated polyacrylonitrile (RAFT^¥ PAN) terpolymer with molecular weight (MW) of 260,000 g/mol and dispersity (Ð) of 1.29, behave differently under applied shear stress than polymer solutions made from conventional PAN (Control PAN) with similar MW (258,000 g/mol) but Ð of 2.05 in the same solvent. The unique rheology of RAFT PAN is because of the reduced amount of high MW polymer fractions. Specifically, a 25% (w/v) polymer solution of RAFT PAN had a viscosity of 198 Pas while the equivalent control PAN polymer solution had a viscosity of 968 Pas at a shear rate of 1 s^?1. Also, RAFT PAN polymer solutions had a longer Newtonian plateau than control PAN polymer solutions. This exhibits more liquid character in RAFT PAN polymer solutions than control PAN polymer solutions at same temperature and concentration. In dynamic tests, RAFT PAN polymer solutions gelled slower than their equivalent control PAN polymer solutions because of their longer polymer chain relaxation times. Slow gelling and higher liquid character in RAFT PAN polymer solutions can result in obtaining stronger and finer precursor fibers during wet spinning. Since RAFT PAN polymer solutions exhibit low viscosity and higher liquid character when compared to its equivalent control PAN at same concentration and temperature, these can allow a wider working window for wet spinning and can also allow higher solid content in the polymer solutions that remain easy to wet spin. This is expected to lead to compact and finer fibers with less voids and higher strength. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44273.     

Study on air flow dynamic characteristic of mechanical ventilation of a lung simulator

As an important life support treatment, mechanical ventilation is usually adopted in clinics. With the development of the res-piratory diagnostic and treatment technologies, air flow dynamics of mechanical ventilation is usually referenced in the evaluation of pulmonary status and assessment of respiratory therapy. In order to improve the ventilation efficiency and provide a reference for pulmonary diagnostics, in this paper, a new mathematical model of mechanical ventilation system was set up. Furthermore, a prototype mechanical ventilation system for an artificial simulating lung was designed and experimentally studied. Lastly, in order to improve the ventilation efficiency and provide a reference for pulmonary diagnostics, the air flow dynamics of the mechanical ventilation system was illustrated through simulation and experimental studies. The study can be helpful to the optimization of the mechanical ventilation system.     

陶瓷叠层结构增韧设计的数值模拟及实验研究

本研究尝度将微机作为辅助手段引入仿生陶瓷复合材料的增韧设计。基于多层梁模型,采用有限元数值模拟方法模拟了仿生陶瓷叠层结构的断裂行为和裂纹逐次从硬层基片向弱界面层基片向弱界面层的拐折和扩展。后处理程序显示了三点弯曲试件的裂纹扩展路径,相应的载荷－位移曲线和增韧效应（断裂功大幅度提高）,还进一步分析了叠层陶瓷的韧性和强度受试件几何参数（硬软层层厚比,层数）和材料性能参数（断裂应变,Ｙｏｕｎｇ氏模量比等     

焊接接头系数ф的思考

介绍了换热器格栅管撑的结构,提出了管撑的制造工装和加工工艺。     

无机矿物填料对玻璃钢制品防腐性能的影响研究

本文论述了通过静态浸泡实验 ,观察玻璃钢试样的外观、介质外观变化及试样力学性能的变化 ,研究了制品中加入不同类型、不同比例的无机矿物填料对玻璃钢制品防腐性能和力学性能的影响     

选择性溶剂中的嵌段共聚物胶束

综述了近20年来在选择性溶剂中嵌段聚合物缔合行为的研究进展 ,探讨了胶束结构、表征方法及胶束形成的热力学、动力学和流体力学。     

Covalent incorporation of [70]fullerene into poly(p-methylstyrene) by anionic copolymerization

A soluble non-crosslinked C₇₀-p-methylstyrene (C₇₀-PMS) copolymer was prepared in sodium naphthalene-initiated anionic polymerization reaction. This copolymer exhibits the lower intrinsic viscosity and higher absolute molecular weight compared with linear polystyrene at equal retention time, suggesting that the copolymer possess star-shaped structure. The covalent graftings of multiple poly(p-methylstyrene) (PPMS) chains onto the C₇₀ core result in the marked enhancement of the absorption degree at longer wavelengths, and in the increase of glass transition temperature. Like pure PPMS, C₇₀-PMS copolymer also exhibits the higher solvency in common solvents.     

络合萃取法处理己内酰胺废水

以磷酸三丁酯 (TBP)作为络合剂 ,三氯乙烯为稀释剂 ,研究了相比、络合剂浓度、溶液pH值等条件的改变对络合萃取处理己内酰胺废水效果的影响 ,结果表明 ,在相比为 1∶3(水相体积∶有机相体积 )、络合剂质量分数为 30 %、pH =5的条件下用络合萃取法处理己内酰胺废水的效果较好     

压缩无石棉密封材料的组成和配方设计

针对无石棉密封材料的国产化要求,分析并研究了无石棉密封材料的基本组成,对无石棉密封材料的配方进行了正交设计,获得了具有较好综合性能和推广应用价值的压缩无石棉密封板材。