反应性单体改性PP/PS共混物的增容作用

制备了聚丙烯/聚苯乙烯(PP/PS)共混物和反应性单体苯乙烯(St)、丙烯酸(AA)及其混合单体改性PP/PS共混物,用扫描电镜(SEM)、偏光显微镜(POM)和动态黏弹谱仪(DMA)研究了反应性单体改性PP/PS共混物的相形态与动态力学行为.结果表明反应性单体St存在增容作用,促进PS在PP中的分散,使分散相PS的粒子尺寸减小.反应性单体AA存在明显的异相成核作用,使PP的球晶尺寸降低.St改性共混物的增容作用比AA改性共混物的明显,而AA改性共混物的异相成核作用比St改性的大.     

EPDM与PP流变性能及其体系形态影响因素分析

EPDM／PP体系各组分材料的流变性能测试表明,两者均为假塑性流体且黏度比大,要比一般聚合物共混物难加工．通过EPDM／PP体系能耗速率数学模型的建立,分析了流场强度、振动强度、相态尺寸、流变参数对体系形态的影响．随着振动强度的增加,共混体系的稳定裕度增大,EPDM为分散相时其粒径必须足够小才能获得高性能制品,改变流场强度和流变参数亦可实现对EPDM／PP体系形态的控制．     

聚丙烯-聚氨酯共混体系的结构与性质

本文对聚丙烯(PP)与热塑性聚氨酯(PU)共混体系的相容性、分散相的形态、熔体的流变性质、共混物的热性质及初生纤维的染色性等作了初步的研究。结果表明,PP与PU为不相容的两相体系,PU以分散相分布于PP基质之中,其尺寸及形状随组成而变;共混物熔体的粘度-组成曲线上呈现一个极小值:当PU含量较低时,共混物的耐热性与纯PP相近;初生纤维的染色性也随PU含量的增加,有较明显的改善。     

聚丙烯/乙烯-乙烯醇共聚物/聚丙烯接枝马来酸酐共混体系的流变性能

以聚丙烯接枝马来酸酐(PP-g-MAH)为相容剂,采用双螺杆共混法制备聚丙烯/乙烯-乙烯醇共聚物(PP/EVOH)共混物.利用毛细管流变仪研究PP/EVOH共混物的流变行为,研究了共混物配比、剪切速率和温度对流体的剪切应力、表观黏度、非牛顿指数和黏流活化能等方面的影响.结果表明,EVOH的加入降低了共混体系的剪切应力和表观黏度,温度在低剪切速率时对表观黏度的影响较大.     

PB-1/PP共混合金的结晶形态与动态流变性

采用熔融共混的方法制备了聚丁烯–1/聚丙烯(PB-1/PP)共混合金,利用偏光显微镜观察了共混合金的结晶形态,使用动态力学分析仪和旋转流变仪研究了共混合金的动态流变性.结果表明:PP的加入导致PB-1晶体尺寸略有减小,合金固体的储能模量以及损耗因子增大;随PP含量的增加,熔体的储能模量、损耗模量、复数黏度和剪切变稀敏感性逐渐下降;在熔融状态下,共混合金的两相具有一定的相容性.     

不同流场特性下的PS/HDPE共混物性能

介绍了动态拉伸形变支配的叶片式混合装置的结构及工作原理,在该混合装置及商品化的以剪切形变为主的Brabender转子密炼机上进行PS/HDPE熔融共混实验,分析了转子轴转速和混合时间对共混物力学性能、流变性能及微观形貌的影响.结果表明:与Brabender转子密炼机类似,叶片式混合装置制得的PS/HDPE共混物的拉伸强度随混合时间的延长和转子轴转速的升高先增加之后基本保持不变;与Brabender转子密炼机相比,叶片式混合装置的转子轴转速对共混物分散相粒径的影响较小,且转速相同时达到相同的分散相粒径叶片式混合装置需要的混合时间较短;随转子轴转速升高和混合时间延长,利用转子密炼机共混所得共混物表观黏度基本保持不变,而叶片混合装置共混得到的共混物表观黏度降低.叶片混合装置比Brabender转子密炼机的混合效率高,混合效果更好.     

不同增容剂对动态固化PP/EPDM/EP 共混物结构与性能的影响

将动态硫化技术应用于环氧树脂(EP)增强聚丙烯(PP)/三元乙丙橡胶(EPDM)体系中,研究了不同增容剂对动态固化共混物结构与性能的影响.实验结果表明,马来酸酐接枝PP(PP-g-MAH)增容的动态固化PP/EPDM/EP共混物是三相结构,即EPDM分散相、EP颗粒分散相和PP连续相.共混物具有较高的拉伸强度和弯曲模量,冲击强度变化不大.马来酸酐接枝EPDM(EPDM-g-MAH)增容的动态固化共混物是“核-壳”复合分散相和PP连续相结构,其中EP颗粒为核,外面包覆着EPDM-g-MAH和EPDM.这种“核-壳”结构变相地提高了EPDM橡胶的体积分数,使得共混物具有较高的冲击强度,同时保持一定的强度和模量.     

稀土Sm杂化材料/PP共混体系性能研究

PS/PP、Sm2O3-PS/PP共混体系性能研究表明,PS及Sm2O3-PS的加入影响了PP的结晶形态,使共混体系结晶速率增加.PS/PP和Sm2O3-PS/PP相同比例的共混体系,其熔融峰位置向低温偏移,体系熔点略低,其结晶峰位置向高温偏移,结晶温度有较明显的提高.     

聚丙烯／乙烯-辛烯共聚物共混体系的流变行为及相容性

使用旋转流变仪系统分析了聚丙烯／乙烯-辛烯共聚物共混物熔体黏弹性能对外部条件如剪切、温度和动态剪切频率的响应情况并分析PP／POE共混物的熔体相容性．随POE含量的增加（基体相由PP改为POE）,PP／POE共混物的流变行为出现分界．不同温度下的黏度曲线形状类似,非牛顿性指数n基本保持不变．PP／POE共混体系的零剪切黏度呈现负偏差,符合广义对数加和法则．在末端区（0．005～0．050Hz）,共混物的Ig G＇-lgω斜率明显与PP的有偏差且Han曲线在高频下出现了随温度变化的情形,表明PP／POE熔体不相容．在密炼机加工过程,即温度在190～250℃,PP质量分数在50％～95％之间时,共混体系处于相分离状态．     

赤泥改性沥青黏度及微观特性

在基质沥青中添加赤泥制备赤泥改性沥青,采用黏温关系分析法探讨不同剪切速率、赤泥掺量(质量分数)对赤泥改性沥青黏度的影响,并用扫描电子显微镜观测赤泥与沥青之间的微观状态变化。研究结果表明:赤泥改性沥青黏度方程与温度之间存在极高相关性,温度对赤泥改性沥青黏度的影响程度要高于剪切速率对其的影响。在相同条件下,赤泥改性沥青的黏度随赤泥掺量的增加而增大。随着赤泥掺量的增加,赤泥改性沥青相态分布由分散相逐渐转变成连续相态,在赤泥掺量为13%时的共混体系达到了理想的相态分布形式。     

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