Synthesis of polyketone by copolymerization of styrene and CO using carbon nanotube-complex Pd2+ catalyst

The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst(Pd/CNT) for the copolymerization of carbon monoxide(CO) and styrene(ST) towards the formation of polyketone(PK).The Pd/CNT was characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM).The construction and crystallization property of PK were evaluated by Fourier transform infrared spectroscopy(FTIR),13C-nuclear magnetic resonance(NMR) and XRD,respectively.The catalyst showed excellent activity and reusability in promoting the fabrication of PK.It can be recycled 14 times with the highest total catalytic activity of 4 239.64 gPK/(gPd·h) at Pd content of 8.63wt%.The results indicate that the prepared catalyst is effective to catalyze the copolymerization of CO and styrene.     

Use of ionic liquids in recycle of palladium catalysts for synthesis of polyketone

Room temperature ionic liquids as solvents for palladium-catalyzed copolymerization of carbon monoxide and styrene were prepared by reaction of aqueous lead tetrafluoroborate with correspond-ing chloride or bromide salts. The recyclability of palladium composite catalyst in various ionic liquids was investigated.[Pd(bipy)2][BF4]2 showed a lower catalytic activity than [Pd(bipy)2][PF6]2 in similar conditions, although the catalytic activity of each composite catalyst in ionic liquids still existed after 4 successive recycles. It was shown the catalytic activity of palladium composite catalyst was higher than that of the catalyst formed in situ from palladium acetate, 2,2'-bipyridyl, and HA (A=PF6-, BF4-) in ionic liquids. The effects of volume of ionic liquids, reaction time, and the dosage of benzoquinone on the copolymerization were also studied.     

统筹--老名词新观念

论文通过对我们党在不同时期的统筹问题的分析研究，既指出了过去对统筹问题上存在的认识上的片面性和实践中的误区，又阐明了我们党在新的历史时期对统筹问题的新的理论和认识上的发展。从而对统筹问题有了更深层次的理解和认识，有利于帮助人们加深对我们党新提出的“五个统筹”理论认识，增强人们在实践中贯彻执行“五个统筹”发展观的自觉性。     

Improving the Performance of Oilwell Cement by Graft-modified PB Latex

Graft-modified polybutadiene(PB) latex was synthesized and used as an admixture to improve the performance of oilwell cement. Results showed that the addition of latex to pure cement slurry can significantly reduce the fluid loss of the cement slurry. When the dosage was 8%, the fluid loss was only 38 mL, and the fluidity of the cement slurry was improved. With an increasing amount of latex, the fluidity of the cement slurry increased continuously. The toughness of cement was significantly enhanced, whose average elastic modulus was 4.2 GPa. Scanning electron microscopy revealed that the filter cake of the cement slurry with latex was thin and dense, and the surface was coated with a layer of latex film. The microstructure of the cement stone showed a high density, and an interweaving mesh network formed in the cement. The results of cement hydration heat analysis and X-ray diffraction showed that latex inhibited the hydration of cement; the effect was stronger under a larger amount of latex. It is indicated that the graft-modified PB latex has great potential to replace the conventional styrene-butadiene rubber(SBR) latex for cementing in the future.     

论邓小平发展战略观

建国50年来,尤其是改革开放20年,我们取得了举世瞩目的成就。因此有许多经验和教训值得总结。我国正在准备制定“十五”计划和十年远景规划,以实现第二步战略目标。于是对邓小平的发展战略观作比较研究,就具有重要的现实意义。一、在统一中发展唯物辩证法是邓小平的发展战略的方法论基础。毛泽东曾说,邓小平最讲辩证法。在1978年,邓小平在全军政治工作会议上的讲话中专讲实事求是思想。他说:“我们说的做的究竟能不能解决问题,问题解决得不是不正确,关键在于我们是否能够理论联系实际,是否善于总结经验,针对客观现实,采取实事求是的态度,一…     

视频展台的选购和使用

介绍了视频展台的选购原则和使用注意事项，可供同行参考。     

Synthesis and characterization of HDI/MDI-polycarbonate urethanes

A novel polycarbonate urethane was synthesized by the two-stage solution process of diisocyanates with polycarbonate diols(PCDL),in which PCDL,1,4-butanediol(BD) and mixture of 4,4'-methylenediphenyl diisocy-anate and hexamethylene diisocyanate(HDI) were soft segment,chain extender and rigid segment,respectively.The structures were characterized by using FTIR and 1H-NMR.The thermoanalysis and mechanical properties of products were measured by means of DSC,TG and other systems.The result shows that an import...     

《板桥杂记》的刊本与流传

本文系统考察了《板桥杂记》的各种刊本与流传过程。分析了《杂记》的流传与时代及社会风尚变迁的关系,说明《杂记》是一部广泛受欢迎的不朽著作。     

浅谈学校篮球队的训练与管理

在大力推行素质教育、向21世纪进军的今天,学校体育在学校教育过程中占据着一个非常重要的位置。篮球队的群体特点,决定了其管理原则首先是提高整体效应,使球队规范有序地运行,提高整个队伍的凝聚力与战斗力。因此,在篮球队的管理中,必须充分发挥教练员的影响力,发挥队长和骨干队员的作用。本文就中学篮球队的训练与管理谈几点看法,希望对今后的篮球教学有所帮助。     

用示波器显示的电磁振荡演示仪

介绍了阻尼振荡和无阻尼振荡的示波器演示装置的制作方法和使用方法。