氧化多壁碳纳米管对PVA-CS-O-MWNTs/PAN渗透汽化膜性能的影响

在涂膜液聚乙烯醇(PVA)-壳聚糖(CS)混合物中加入无机相氧化多壁碳纳米管(O-MWNTs),使用浸渍法涂膜的方式制备PVA-CS-O-MWNTs/PAN中空纤维膜(PAN为聚丙烯腈),应用于渗透汽化分离甲醇(Me OH)/碳酸二甲酯(DMC)混合物.考察了O-MWNTs含量、热处理温度、料液温度对渗透汽化性能的影响.结果表明,加入氧化多壁碳纳米管可以提高PVA-CS/PAN膜的渗透通量、亲水性和机械性能.较佳的工艺条件为:O-MWNTs质量分数为0.1%,热处理温度为80℃,料液温度为40℃,Me OH的质量分数为70%.在此实验条件下,PVA-CS-O-MWNTs/PAN膜的渗透汽化性能达到最佳,渗透通量为210 g·m-2·h-1,甲醇选择性为7.82.     

渗透汽化法分离乙醇／水混合物

将壳聚糖（ＣＳ）和聚乙烯醇（ＰＶＡ）混合物涂到聚丙烯腈（ＰＡＮ）底膜上,通过交联制成壳聚糖复合膜。研究了膜对乙醇／水溶液的渗透汽化性能,讨论了料液浓度、温度对膜分离性能的影响。结果表明,ＣＳ－ＰＶＡ／ＰＡＮ膜具有优异的渗透选择性能。当料液乙醇含量为９５ｗｔ％,温度为６０℃和７０℃时,渗透通量分别为３１０ｇ／（ｍ２·ｈ）和４３３ｇ／（ｍ２·ｈ）;分离因子为１１６和１２７。渗透通量与温度呈Ａｒｒｈｅｎｉｕｓ关系     

壳聚糖-海藻酸钠/聚丙烯腈聚离子复合膜渗透汽化分离乙酸乙酯水溶液

制备了壳聚糖-海藻酸钠/聚丙烯腈(CS-SA/PAN)聚离子复合膜,将此膜用于渗透汽化分离乙酸乙酯水溶液.用红外光谱(FT-IR)表征CS、SA、CS/SA均质膜.研究CS-SA/PAN聚离子复合膜的溶胀性、料液浓度和SA质量分数、操作温度对乙酸乙酯水溶液脱水效果的影响.实验表明:CS/SA聚离子均质膜在乙酸乙酯水溶液中的溶胀度随溶液中水质量分数的增加而增大,随SA的质量分数增加而减小,40 ℃、SA质量分数为2.0%时,CS/SA聚离子均质膜在乙酸乙酯质量分数为97%的水溶液中溶胀度可达51%.随着SA质量分数的增加,CS-SA/PAN聚离子复合膜的渗透通量减小,分离因子增大,40 ℃、SA质量分数为2.0%时,分离乙酸乙酯质量分数为97%的水溶液,CS-SA/PAN聚离子复合膜渗透通量可达348 g/(m2·h),分离因子为7 245.随着料液中水含量的增加和料液温度的升高,膜渗透通量增大,分离系数减小,渗透通量与料液温度的关系能较好地吻合Arrhenius方程.     

PVA-PFSA/PAN渗透汽化膜强化乙酸乙酯酯化脱水及工艺过程模拟

以聚丙烯腈(PAN)中空纤维超滤膜为底膜,以酒石酸(Tac)为交联剂,制备了聚乙烯醇(PVA)与全氟磺酸(PFSA)共混复合膜,并用于乙酸乙酯-水、乙酸乙酯-乙醇-水溶液的脱水研究。考察了分离乙酸乙酯-水二元溶液时,料液温度和含水量对复合膜分离性能的影响;40℃下分离含水2%(质量分数,下同)的乙酸乙酯水溶液时,其总渗透通量81.1 g/(m2.h),分离因子为1 890;考察了复合膜用于分离乙酸乙酯-乙醇-水(质量比90∶2∶8)三元溶液时,料液温度的影响及脱水效果。结果表明:40℃时复合膜对三元溶液的总渗透通量可达251.0 g/(m2.h),此温度下,只需12 h就可将含8%初始水的三元溶液脱水至4.66%。PVA-PFSA/PAN渗透汽化膜对乙酸乙酯体系的脱水效果良好,可应用于强化乙酸乙酯酯化生产工艺。利用Aspen Plus 11.1软件对工艺流程进行了模拟,结果表明:在同等操作条件下,渗透汽化膜强化酯化工艺流程相对于普通的反应精馏,提高了乙酸乙酯的单程收率和原料的转化率,简化了乙酸乙酯生产流程。     

戊二醛交联PVA/PAN复合膜渗透汽化性能的实验研究

研究了戊二醛交联时间对PVA/PAN复合膜分离性能的影响,并用于乙醇水溶液的分离。结果表明,交联处理存在着最优时间。对应于最优交联时间的膜,当料液中乙醇质量分数(wE)为96.2%,料液温度(t)为70℃时,渗透通量(J_t)为337(g·m^-2·h^-1),分离因数(α_W/E)为389.7。进一步考察了料液质量分数为30%～98.3%,料液温度为50～78℃时,交联膜的分离性能。     

渗透汽化法复合膜分离乙醇/水的研究

以脱乙酰化度为77．5％的壳聚糖为原料，分别将CS膜，CSA／PAN膜，CS－PVA／PAN膜用于乙醇／水混合物的分离，研究了原料组成，温度，膜厚等的影响，结果表明，这些膜均具有良好的分离性能，其中CS－PVA／PAN膜具有最优的渗透选择性。     

改性聚乙烯醇复合膜的渗透蒸发性质

研究了经化学改性后的聚乙烯醇-聚丙烯晴复合膜的渗透蒸发性质,制成了活性层厚度小于3μm,强度好,在热水中稳定的复合膜。其主要性能同德国GFT公司生产的膜相当:当渗透温度为75℃,乙醇浓度为95%时,渗透液通量为170 g/(h·m~3),渗透液中水的含量大于99%,分离系数为1880。改变处理条件,膜的选择性略有下降,但渗透液通量可     

管式聚二甲基硅氧烷/陶瓷复合内膜的制备及其渗透汽化应用

采用浸渍-提拉法在多孔管式陶瓷支撑体内表面制备完整无缺陷的聚二甲基硅氧烷(PDMS)膜层。采用扫描电子显微镜(SEM)、渗透汽化(PV)性能测试等手段,研究支撑体孔径和涂膜时间对管式PDMS/陶瓷复合内膜的形貌和分离性能的影响。同时,考察丁醇-水体系中料液温度、料液中丁醇含量对管式PDMS/陶瓷复合内膜渗透汽化性能的影响,并对膜的渗透汽化长期稳定性进行了研究,将复合内膜的渗透汽化性能与复合外膜进行了比较。结果表明:复合膜均匀完整,有良好的过渡层。支撑体孔径较大的复合膜,其渗透通量更高。随涂膜时间的延长,膜厚依次增加,渗透通量下降,分离因子升高;随料液中丁醇含量增加,通量逐渐上升,分离因子先升高后下降;随操作温度的升高,通量和分离因子都有所增加。在料液温度为40℃、丁醇质量分数为1.5%的条件下连续运行180h,膜渗透总通量高达1 050 g/(m~2·h),选择性可达30。     

分子印迹中空纤维复合膜对异丙醇/水体系的渗透汽化

以聚砜(PSF)中空纤维超滤为基膜,二苯甲酰-L-酒石酸(L-DBTA)为模板分子,甲基丙烯酸甲酯(MMA)为功能单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,采用表面热聚合方法制备了L-DBTA印迹中空纤维复合膜。该复合膜对异丙醇/水体系具有很好的分离效果,对于w=0.20和0.50的异丙醇/水体系,经过一次浸膜制得的L-DBTA分子印迹复合膜的分离因子分别为2 400和5 690,通量分别为1 440 g/(m2.h)和551 g/(m2.h);对于w=0.95的异丙醇/水体系,浸膜液浓缩一倍,经过两次浸膜制得的L-DBTA分子印迹复合膜分离因子可达82 100,渗透通量可达739 g/(m2.h);对于异丙醇/水体系,通过实验,获得了L-DBTA分子印迹复合膜与一般渗透汽化膜相反的分离规律:料液温度升高,L-DBTA分子印迹复合膜的渗透通量下降;随着料液浓度的升高,分离因子出现最大值时的温度逐渐升高。     

聚合物溶液黏度对PDMS/PVDF复合膜微结构及渗透汽化性能的影响

采用不同黏度的聚二甲基硅氧烷(PDMS)溶液制备平板聚二甲基硅氧烷/聚偏二氟乙烯(PDMS/PVDF)复合膜,并比较膜对乙醇/水混合物的渗透汽化性能的影响。通过扫描电子显微镜(SEM)、接触角分析仪等表征手段研究聚合物溶液黏度对膜微结构的影响。结果表明:聚合物溶液黏度为90 mPa·s时制备的复合膜分离性能最佳,当进料温度为313 K时,膜对5%乙醇水溶液的通量可达761 g/(m2·h),分离因子为9.1。     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

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     

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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