聚丙烯酸钠/壳聚糖/淀粉智能凝胶材料合成研究

采用溶液聚合的方法,将淀粉和壳聚糖与丙烯酸接枝制备了高溶胀性接枝共聚物.研究了淀粉和壳聚糖配比、引发剂用量、交联剂用量、丙烯酸中和度、反应温度及反应时间等因素对接枝产物溶胀度的影响规律.结果表明,当淀粉和壳聚糖配比为8:1,引发剂用量为0.5%、交联剂用量为0.02%、丙烯酸中和度为80%、反应温度为50℃、反应时间为2 h时,该凝胶材料在蒸馏水中溶胀度接近800.     

聚丙烯酸钠高吸水树脂合成及尿素控释性研究

利用新型交联剂制备了聚丙烯酸钠高吸水性树脂,研究考察了交联剂种类及用量、引发剂用量、丙烯酸中和度以及反应时间等因素对高吸水性树脂溶胀率及溶解率的影响,得到了制备高溶胀率、低溶解率产物的最佳反应条件:交联剂用量0.08%(占丙烯酸单体的质量分数,下同),引发剂用量0.10%,丙烯酸的中和度60%,反应时间10 h.同时利用高吸水性树脂凝胶作为尿素控制释放基质,考察了高吸水树脂交联度、中和度等因素对尿素控制释放速率的影响.     

乙醇脱水对聚丙烯酸水凝胶pH敏感性的影响

以丙烯酸和无水乙醇为原料,N,N’-亚甲基双丙烯酰胺为交联剂,过硫酸钾和亚硫酸氢钠为引发剂制备了聚丙烯酸水凝胶,并研究了不同pH值的缓冲溶液对水凝胶溶胀度的影响。结果表明,水凝胶在酸性条件下的溶胀度比在碱性条件下大,pH值为4时的溶胀度最大,可达40倍。乙醇脱水干燥水凝胶的溶胀度和溶胀速率都得到了明显提高,且具有良好的温度敏感性和稳定性。     

PEG致孔快速响应pH/温度双重敏感性PNIPAM/SA水凝胶的制备与性能

以聚乙二醇(PEG)为致孔剂,以海藻酸钠(SA)和N-异丙基丙烯酰胺(NIPAM)为原料,制备出具有温度和pH双重敏感性的快速响应水凝胶.研究温度、pH值对凝胶溶胀度,以及PEG用量和分子量对凝胶溶胀速率的影响.结果表明,海藻酸钠的加入能够赋于PNIPAM pH敏感性能,所制备水凝胶的溶胀度随着pH值的改变而改变.在酸性条件下,凝胶溶胀度随SA用量的增加而减小;在碱性条件下,凝胶溶胀度随SA用量的增加而增大.在酸性和碱性条件下,水凝胶溶胀度都随着PEG用量的增多和PEG分子量的增大而增大,且与传统水凝胶相比,溶胀速率有较大程度的提高.     

坡缕石/聚乙二醇/丙烯酸水凝胶的合成及性能测试

在水溶液中,以N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,坡缕石(PGS)、聚乙二醇(PEG)和丙烯酸(AA)为原料,用辉光放电电解等离子体(GDEP)引发聚合技术一步制备坡缕石/聚乙二醇/丙烯酸(PGS/PEG/AA)水凝胶.对合成过程中GDEP的影响因素,如放电电压、放电时间进行了优化.探讨了水凝胶的溶胀动力学行为,研究了不同pH溶液、盐浓度对水凝胶胀率的影响以及反复吸液功能,初步测试了PGS/PEG/AA水凝胶对阳离子染料的吸附行为.结果表明,该水凝胶具有pH敏感性、盐敏感性和可逆溶胀-消溶胀行为,其对阳离子染料有较高的吸附量.     

高温油藏暂堵剂的制备与性能研究

针对现有油田暂堵剂耐盐性差、在高温地层条件下凝胶时间较短的问题,设计研发了以丙烯酰胺(AM)、丙烯酸(AA)、功能单体2-丙烯酰胺-2-甲基丙磺酸(AMPS)为主要原料,N,N-亚甲基双丙烯酰胺(BIS)为交联剂,高温引发剂过氧化二异丙苯为引发体系,利用溶液聚合法合成了一种耐温耐盐性化学胶塞暂堵剂.研究了引发剂加量、交联剂加量、固含量以及增韧剂加量对聚合物凝胶的成胶时间、溶胀度及压缩强度的影响.结果表明:该体系的凝胶时间大于2,h,在矿化度为2.2×105,mg/L的模拟地层水中溶胀度可以达到9,g/g,压缩量为80%,条件下强度大于0.4,MPa,在330,℃下没有明显的热分解,适用于高温高盐油藏的堵漏工作.     

非离子型UV固化聚氨酯水凝胶的合成与性能研究

以聚乙二醇2000(PEG2000)、异佛尔酮二异氰酸酯(IPDI)、1,4-丁二醇(BDO)、丙三醇(GLY)、丙烯酸-2-羟乙酯(HEA)为主要原料,采用丙酮预聚体法合成了一系列透明的、非离子型UV固化聚氨酯水凝胶.研究了BDO/GLY的配比对水凝胶溶胀性能、拉伸性能的影响;探讨了温度、离子强度对水凝胶溶胀性能的影响;并以硫酸庆大霉素作为模拟药物,对其在模拟体液PBS缓冲溶液中的释放进行了初步探讨.当nBDO/nGLY为1时,水凝胶干膜拉伸强度达到1.46 MPa,伸长率为87%,20℃去离子水中溶胀比达到370%,且表现出显著的温度敏感性和较好的离子强度稳定性,并具有载药和释放药物的能力.     

聚(丙烯酸-丙烯酰胺)/膨润土/淀粉吸水性复合材料的制备及其性能

采用N,N-亚甲基双丙烯酰胺为交联剂,以过硫酸钾为引发剂,利用水溶液聚合法制备了聚(丙烯酸-丙烯酰胺)/膨润土/淀粉吸水性复合材料,研究了膨润土用量、引发剂、交联剂、中和度、单体质量比等因素对材料吸水性能的影响,探讨了材料的保水性和吸水速率.结果表明:当膨润土含量为丙烯酸单体的13%,引发剂含量为0.8%,交联剂含量为0.04%,中和度为85%,m(AA)/m(AM)为1时,该复合材料吸水倍数为390,其保水性能良好.     

丙烯酸十六酯与丙烯酸羟乙酯共聚物凝胶的合成及其性能

合成了丙烯酸十六酯(HDA)与丙烯酸羟乙酯(HEA)的共聚物凝胶,研究了共聚组成对共聚物凝胶性能的影响.结果表明:经二甲亚砜(DMSO)平衡溶胀后的凝胶,在HDA∶HEA(摩尔比)为1∶1时,具有较高的规整性和较高的溶胀倍率.溶剂的极性对聚合物凝胶的规整性有较大的影响.DSC及X射线衍射表明共聚物凝胶具有液晶性能.     

P(CMSNa-NaAlg-AA)高吸水树脂制备及其性能研究

以一定比例的羧甲基淀粉钠(CMSNa)、海藻酸钠(Na Alg)为接枝基体,丙烯酸(AA)为单体,过硫酸铵(NPS)为引发剂,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法合成高吸水树脂。探讨了不同反应条件对吸水性能的影响,并研究了吸水树脂吸附重金属(Cd2+)的动力学及热力学特性。结果表明,当m(CMSNa):m(Na Alg)=2.5,引发剂用量为单体用量0.3%,交联剂用量为单体用量0.025%,丙烯酸中和度为70%,反应温度为65℃时,吸去离子水及0.9%Na Cl溶液倍率分别为2 308.48 g/g、126.8 g/g。吸水树脂对于镉离子的吸附研究表明,高吸水树脂对于镉离子的吸附在p H值为7时吸附容量最大,为343.44 mg/g,且吸附符合准二级动力学模型及Langmuir吸附等温模型。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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