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光引发合成聚丙烯酰胺的研究 总被引:12,自引:2,他引:12
采用光引发聚合技术进行聚丙烯酰胺(PAM)的合成。选取合适的光引发剂并进行了改性,同时研究了光引发合成PAM的影响因素。在紫外光照射下,采用改性的商品光引发剂,用量为丙烯酰胺(AM)的0.01%-0.05%,聚合单体浓度ω(AM)为15%-25%,聚合时间50—90min,可获得特性粘数η=800-l400mL/g,AM残留量<0.05%的高纯聚丙烯酰胺。 相似文献
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文章采用均聚共水解的方法,以丙烯酰胺为单体、Na2CO3为水解剂,β-二酮为配位剂,复合引发体剂体系下,制备了高分子量速溶型聚丙烯酰胺,研究了单体、引发剂、配位剂、pH值以及引发温度对反应速率和产物分子量的影响。结果表明,当单体、引发剂、配位剂的质量分数分别为25%、0.005%、0.05%,pH值为10.5,引发温度为15℃时,得到水解度为25%左右,重均分子量为1 900×104以上的高分子量速溶型阴离子部分水解聚丙烯酰胺。 相似文献
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丙烯酰胺在异丙醇——水中调节沉淀聚合物的研究 总被引:2,自引:0,他引:2
本文描述了一种调节沉淀聚合法制备不同分子量聚丙烯酰胺的方法,并研究了聚合烯酰胺的分子量与调节剂含量之间的一些规律,以及温度,引发剂浓度和单体浓度对分子量的影响。 相似文献
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合成低分子量聚丙烯酸钠的新方法 总被引:7,自引:0,他引:7
采用水溶液静态聚合法,用平板式反应器合成低分子量聚丙烯酸钠,通过选择合适的分子量调节剂、引发剂用量和聚合温度,可以有效防止爆聚现象发生,且反应周期短,生产成本低。研究了分子量调节剂用量、引发剂用量、单体浓度和反应时间等因素对聚合物粘均分子量的影响,结果表明:当mn-C12SH/mM=0.04,mI/mM=0.04,wM=0.30,温度60°C,反应3 h时,可合成分子量5 000左右的低分子量聚丙烯酸钠,分子量分布较窄,且单体转化率在99%以上。 相似文献
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PDMDAAC-AM共聚物的反相乳液聚合研究 总被引:10,自引:0,他引:10
研究了用二甲基二烯丙基氯化铵(DimethylDiallylAmmoniumChloride,DMDAAC)和丙烯酰胺(Acylamide,AM)为原料。以煤油为分散剂,在反相乳液环境中合成PDMDAAC-AM(Poly DMDAAC—AM)的方法.从反相乳液聚合的机理出发。研究了油水体积比、引发剂的用量、单体配比、引发温度和反应温度等因素对共聚产物的特性黏度和转化率的影响,确定了最佳反应条件.在DMDAAC/AM=2:8,油水比为3:7,采用过硫酸钾为引发剂,其用量为体系总质量的0.05%的条件下,采用逐步聚合的方法得到了固含量为45%,特性黏度为800.5cm^3/g,溶解迅速且絮凝效果好的产品. 相似文献
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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. 相似文献
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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. 相似文献
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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。 相似文献
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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. 相似文献
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In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time. 相似文献
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Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
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- 相似文献
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Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
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- 相似文献
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Bernard Kirtman 《华南师范大学学报(自然科学版)》2014,(6)
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 相似文献
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Michael Springborg 《华南师范大学学报(自然科学版)》2014,(6):136
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the 相似文献
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Zhu Chaoyuan 《华南师范大学学报(自然科学版)》2014,46(6):140-140
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of 相似文献