高纯度液体环氧树脂的结构表征及固化动力学

采用柱分离法对液态双酚A环氧树脂E51进行分离，得到分子量为340的单组分环氧树脂，并对其进行了IR、NMR和ESI-MS表征。研究了E51环氧树脂及单组分环氧树脂与DDS的固化反应动力学，采用DSC测定了E51环氧树脂和单组分环氧树脂与DDS固化体系的固化反应表观活化能，分别为134.85和152.15kJ/mol。通过对2种体系固化产物的T_g分析，结果表明E51/DDS固化产物的T_g比单组分环氧树脂/DDS固化产物的T_g低约10℃，分别为202.2和212.4℃。     

用作环氧树脂固化剂的有机含氮化合物

环氧树脂是一类很重要的化工原料.它只有与固化剂反应后才能产生有实用性能的材料.能使环氧树脂固化的固化剂种类很多,其中含氮有机化合物最多、最重要.本文系统地总结了用作环氧树脂的固化剂中的含氮有机化合物的品种和性能,对胺类固化环氧树脂的反应机理、固化反应速度、以及固化产物的性能也作了介绍.     

玻璃钢缠绕气瓶用环氧树脂固化动力学研究

制备了以环氧树脂为基体,甲基六氢苯酐为固化剂,咪唑为促进剂的环氧树脂体系。采用非等温差示扫描法(DSC)研究了环氧树脂/甲基六氢苯酐体系的固化过程,得出了升温速率对固化体系DSC曲线的影响。引用Kissinger理论,确定了固化反应的动力学参数以及固化反应动力学模型。     

环氧树脂对其固化物性能影响的研究

通过观察试验和测定试验,研究了不同环氧树脂对其固化物的表面质量、力学性能和热性能,测定了固化物的抗压强度、抗弯强度、抗冲击强度、负荷变形温度和维卡软化温度.试验结果表明:当F-51、甲基四氢苯酐、铝粉三者用量的质量比为100∶85∶150时,环氧树脂F-51、甲基四氢苯酐环氧固化体系所得固化物的性能优于环氧树脂E-44、甲基四氢苯酐环氧固化体系所得固化物的性能.     

环氧大豆油/环氧树脂丙烯酸酯的合成及其性能研究

以可再生资源的大豆油衍生物环氧大豆油(ESO)为基体,可以制备环氧大豆油丙烯酸酯(AESO),但该低聚物所成UV固化膜附着力不佳,力学性能较差.文中利用环氧树脂优良的粘接性能和力学性能来改善纯环氧大豆油丙烯酸酯固化膜的这些不足.首先将环氧大豆油和环氧树脂混合,利用丙烯酸对环氧基接枝制备了环氧大豆油/环氧树脂丙烯酸酯(AESO-EA)低聚物,进一步在光引发剂Doracur1173的引发下共聚得到环氧大豆油丙烯酸酯/环氧树脂丙烯酸酯UV固化膜.通过拉伸性能测试、铅笔硬度测试、附着力和冲击性能的测试对固化膜进行了性能分析.测试结果表明,引入了环氧树脂后的固化膜性能显著提高.通过比较分析,当环氧树脂E-44的添加量为环氧大豆油质量的6%左右时,UV固化膜整体性能最佳.     

气相氨固化环氧树脂及涂料开发成功

气相氨与环氧树脂进行固化反应并在工业上应用,国内外的文献中未见有报导。杭州油墨油漆厂于1968年10月在实验室中发现了气相氨可以固化环氧树脂的新现象,设想到新的固化剂和工艺技术有可能解决国内酒类食品的卫生防腐蚀难题,据此该厂探讨了气相氨与环氧树脂固化成膜机理,进行了气     

丙烯酸酯改性己二胺固化剂对环氧树脂性能的影响

利用丙烯酸酯类对己二胺进行改性,作为环氧树脂的室温固化剂。利用红外光谱分析了固化剂的氨解变化,讨论了改性固化剂对环氧树脂固化反应产物的拉伸、弯曲、冲击等性能的影响。实验结果表明,丙烯酸酯改性的己二胺固化剂可以在室温下固化环氧树脂,所得的环氧树脂具有较好的力学性能。     

水性环氧树脂涂膜固化的FTIR法

采用傅立叶变换红外光谱仪研究了水性环氧树脂涂膜的固化过程,得到不同固化温度下交联固化程度随时问的变化规律:水性环氧涂膜在固化前期属于动力学控制阶段,固化速率较高,固化程度随时间增加较快;固化后期属于扩散控制阶段,固化反应程度随时间的延长而增加缓慢.结果表明:此水性环氧树脂涂料体系的固化反应表观活化能为56.082 kJ/mol,室温下具有较快的固化反应速度.     

环氧树脂的韧性固化剂的合成

用酸酐与一系列不同相对分子质量的柔性链剂聚物合成了环氧树脂的韧性固化剂。该韧性固化剂，在固化后的环氧树脂网络中，通过化学链引入了柔性链，与普通固化剂固化的环氧树脂相比，其韧性等机械强都有一定程度的提高。     

含羟基马来酰亚胺固化邻甲酚醛环氧树脂

合成N-对羟基苯基马来酰亚胺,并将其用作固化剂固化邻甲酚醛环氧树脂.采用DSC方法研究了HPM固化邻甲酚醛环氧树脂反应的固化反应动力学.对固化产物的热分析结果表明:N-对羟基苯基马来酰亚胺是非常良好的耐热固化剂,可明显提高邻甲酚醛环氧树脂的耐热性能,固化产物的起始热分解温度为338℃,分解10%时的温度为386℃,700℃时的残留百分量为49%.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has