PVC共混膜制备及其在造纸黑液处理中的应用(英文)

以聚氯乙烯(PVC)为膜材料,二甲基乙酰胺(DMAc)为溶剂,聚丙烯腈(PAN)为高分子添加物,研制出PVC/PAN共混膜,讨论了PVC、PAN的共混比例对共混膜性能的影响。同时,考察了PVC/PAN共混膜在处理造纸废水中的应用。实验结果表明:PVC/PAN共混膜的水通量和截留率可达到537.6(L/m2.h)和85.4%,并随PAN共混比例的增加,膜的水通量增加,截留率减小。通过电镜观察,共混膜具有不对称结构。当PAN含量为4%时,共混膜处理造纸黑液的效率较高,出水稳定,黑液的COD、色度去除率分别可达83.2%和90.8%,黑液的浊度和SS等指标也大幅降低。     

PVC共混膜制备及其在造纸黑液处理中的应用

以聚氯乙烯（PVC）为膜材料，二甲基乙酰胺（DMAc）为溶剂，聚丙烯腈（PAN）为高分子添加物，研制出PVC／PAN共混膜，讨论了PVC、PAN的共混比例对共混膜性能的影响。同时，考察了PVC／PAN共混膜在处理造纸废水中的应用。实验结果表明：PVC／PAN共混膜的水通量和截留率可达到537．6（L／m^2·h）和85．4％，并随PAN共混比例的增加，膜的水通量增加，截留率减小。通过电镜观察，共混膜具有不对称结构。当PAN含量为4％时，共混膜处理造纸黑液的效率较高，出水稳定，黑液的COD、色度去除率分别可达83．2％和90．8％，黑液的浊度和ss等指标也大幅降低。     

不同阻燃剂与PAN共混阻燃的效果比较

采用不同阻燃剂与PAN聚合物共混,制备出多种具有一定阻燃效果的共混物,其中十溴联苯醚与三氧化二锑混合物与PAN聚合物共混的阻燃效果最好.进一步实验发现,水洗后十溴联苯醚在聚合物中的浓度降低,引起阻燃效果下降,无法作为PAN的理想共混阻燃材料.硫氰酸根插层水滑石与PAN共混的红外光谱和X射线衍射分析表明:在共混过程中,有部分聚丙烯腈大分子插入到了水滑石片层之间,水滑石层间距有一定程度的增大;并且由PAN/SCN-LDH共混制得的聚丙烯腈样品其晶态有序性有所降低,说明两者之间形成纳米插层共混,共混方式较理想,但阻燃效果仍有待提高.     

高相对分子质量PAN纺丝溶液的流变性能研究

研究了高相对分子质量PAN纺丝溶液的制备工艺,讨论了影响纺丝溶液的流动曲线、非牛顿指数、结构粘度指数、孔口膨化比等的主要因素,为确定合理的PAN基碳纤维原丝生产工艺提供了科学依据.     

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.     

静电纺PVDF/PAN共混纳米纤维膜对含油污水的过滤性能

制备不同共混比的静电纺聚偏氟乙烯/聚丙烯腈(PVDF/PAN)纳米纤维膜.应用扫描电子显微镜分析膜的表面形态,并测试共混纤维膜的亲水性、孔径及对自制乳化油污水的过滤效率.试验结果表明:随着PAN共混比例的增加,共混膜的纤维直径减小;共混膜的水接触角随PAN共混比例的增加呈明显下降趋势,下降幅度为30°,亲水性改善效果明显;共混膜的平均孔径为0.784~2.070μm;测得共混膜的纯水通量为4 019~5 340L/(m~2·h),约是PVDF商品超滤膜的30倍;共混膜对乳化油的截留率最高达到95.31%,稍小于PVDF商品超滤膜的97%.     

乙烯-辛烯共聚物/淀粉共混物的非等温热解动力学

利用动态热重分析(TG)技术对乙烯-辛烯共聚物(POE)/糊化蜡质玉米淀粉(GWCS)共混物在惰性气体条件下的热性能和非等温热解动力学进行了分析,探讨了其热解机理.结果表明,随着淀粉含量的增加,POE/GWCS共混物的热失重曲线向低温方向移动,材料的外延起始温度降低,即材料的热稳定性降低,说明淀粉的加入降低了聚合物的耐热性能.随着升温速率的增加,POE/GWCS共混物最大热分解速率对应的温度向高温方向移动,最大热分解速率增大.采用Kissinger和Flynn-Wall-Ozawa两种方法进行热解动力学分析,发现随着淀粉含量增加,共混物体系的热分解E/logA值降低,表明淀粉含量对共混物的热稳定性有显著影响.     

聚苯胺与聚乙烯醇共混相容性研究

本文以乳液聚合法合成聚苯胺,分别用N-甲基吡咯烷酮为溶剂溶解本征态聚苯胺(PAN)、水溶解聚乙烯醇(PVA),再通过共混浇铸制备PAN-PVA共混膜.用差热分析法和扫描电镜对共混膜进行共混相容性研究,实验结果表明它们共混后具有很好的相容性.并初步探讨了PAN-PVA共混膜的静电屏蔽效应.     

HEC/CMC复配溶液协同效应的流变学研究

为了研究不同类型纤维素醚之间的协同效应,采用黏度和动态力学测试方法,以羟乙基纤维素(HEC)与羧甲基纤维素(CMC)复配体系为研究对象,通过对两种纤维素醚按不同质量比例复配水溶液的表观黏度、流变性及动态力学参数的变化,分析离子/非离子型纤维素醚间相互作用的机理.实验结果表明,HEC/CMC复配体系可以形成协同增黏效应并且降低触变性,提高溶液微观结构稳定性.协同作用在m(HEC)∶m(CMC)接近1∶1时趋于明显;当m(HEC)∶m(CMC)为2∶1时,可部分形成共用电子域效应;当m(HEC)∶m(CMC)为1∶2时,组分间协同作用较弱,溶液结构稳定性相对较差.     

羟乙基纤维素/NaOH溶液体系动态黏度特性

碱溶性羟乙基纤维素(HEC)具有独特的碱溶性和成纤性能,采用气固相反应制备碱溶性HEC.研究了碱溶性HEC纺丝原液在不同温度、不同质量分数和不同角频率下的动态黏度特性,表明HEC/NaOH溶液为切力变稀的非牛顿流体.溶液动态黏度随HEC质量分数的增加呈非线性增大.由于HEC的半刚性分子链,溶液黏度对角频率,尤其对温度的变化不敏感.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

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