分子筛复合催化剂催化合成乙酸正丁酯

以乙酸与正丁醇为原料,催化合成乙酸正丁酯,催化剂为分子筛复合材料,考察了催化剂用量、原料比以及反应时间和反应温度对乙酸正丁酯产率的影响.结果表明,分子筛复合催化剂的催化活性良好,当催化剂用量为正丁醇质量的9%,醇酸摩尔比为1.25:1,反应温度120℃,反应时间120 min时,乙酸正丁酯的酯化率达到90%以上.     

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.     

超声波辅助粉煤灰/淀粉吸水保水材料的制备及性能

利用超声波辅助合成粉煤灰/淀粉吸水保水复合材料,考察了粉煤灰、淀粉、交联剂、引发剂及中和度等因素对复合材料吸水倍率的影响,用X-射线衍射及红外光谱分析样品的微观结构.结果表明:粉煤灰、淀粉与丙烯酸交联聚合良好.当粉煤灰、淀粉、交联剂和引发剂用量分别为丙烯酸单体质量的10%、5%、0.11%和0.20%,中和度为80%,反应温度为80℃时,复合材料吸自来水倍率达571.6 g/g,吸NaCl水溶液倍率达74.5 g/g.     

用于煤矿防灭火的高吸水树脂的合成与吸水性能研究

以蒙脱土、丙烯酸为主要原料,采用溶液聚合法合成了超强吸水性复合树脂.讨论了蒙脱土加入量、引发剂加入量、交联剂的用量、丙烯酸的中和度对高吸水性复合树脂吸水倍率的影响,优化了该复合材料吸自来水性能的配方,即蒙脱土添加量为40％,单体的中和度为80％,交联剂用量为0.08％,引发剂用量为0.15％.在此配方下制备的复合材料吸自来水倍率达到156倍.傅里叶红外光谱图研究证实蒙脱土能够有效地与高聚物结合,不但提高了树脂的保水能力和耐热性,而且大大降低了树脂成本.     

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.     

柱撑酸化蒙脱土催化合成丙烯酸正丁酯的研究

将蒙脱土经不同方法进行改性处理,并以此为催化剂,催化丙烯酸与正丁醇反应生成丙烯酸正丁酯。考察了以微波处理的柱撑酸化蒙脱土为催化剂催化合成丙烯酸正丁酯的反应条件。结果表明,以微波处理的柱撑酸化蒙脱土催化效果最好,适宜的反应条件为:丙烯酸为0.1 mol,醇酸的摩尔比为1.2:1,阻聚剂为对苯二酚,其用量为0.3 g,约为丙烯酸质量的4%,催化剂的用量1.7g,约为丙烯酸质量的20%,反应的时间为7 h,在回流状态下,其酯化率为84.1%。催化剂可以重复使用。     

粉煤灰/聚（丙烯酸-丙烯酰胺）保水材料的制备与表征

以粉煤灰、丙烯酸、丙烯酰胺为原料,采用超声辅助水溶液聚合法制备保水材料.用SEM对其进行结构表征,考察制备条件对保水材料吸水性能的影响.结果表明:粉煤灰与有机相聚合良好,且在聚合物中有效分散.当粉煤灰添加量为丙烯酸单体质量的20%,引发剂用量为0.01%,交联剂用量为0.03%,丙烯酰胺用量为20%,中和度为0.7时,复合材料吸水率达203g/g.     

敞开体系水溶液法合成膨润土/聚丙稀酸钠超吸水性复合树脂

以丙烯酸,膨润土为原料,利用水溶液法合成了膨润土聚丙烯酸钠高吸水性复合材料,并对膨润土用量、引发剂用量、交联剂用量、丙烯酸中和度和温度对悬浮聚合反应及对产物吸水性能的影响进行了研究.所制备的吸水性复合材料吸水速率快,吸水率高达700g/g.     

聚丙烯酸类互穿聚合物网络高吸水性树脂的合成

以丙烯酸(AA)和丙烯酰胺(AM)为单体,以N,N′–亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,将改性聚乙烯醇引入聚合体系,采用水溶液聚合法制备聚丙烯酸型吸水性树脂.重点研究了n(AM)∶n(AA)、丙烯酸中和度、交联剂和引发剂用量以及聚乙烯醇含量对吸水树脂性能的影响,研究了吸水树脂粒径与吸水速率的关系.实验结果表明:实验范围内n(AM)∶n(AA)=1∶2、丙烯酸中和度为60%,、改性聚乙烯醇用量为AM质量的10%,、交联剂和引发剂分别占单体总质量的0.04%,和2.5%,时,树脂的吸水率和耐盐性都达到最佳效果.此外,产物粒径为120目时,前30,s内吸水速率最快;但是粒径为100目时,吸水树脂最先达到吸水饱和.     

聚丙烯酸型吸水树脂的合成及性能研究

以N’N-亚甲基双丙烯酰胺和丙三醇作交联剂,制得了丙烯酸类吸水树脂,讨论了不同时间下吸水树脂的吸水情况,结果发现了在吸水1 h时达到吸水平衡.吸水树脂的平衡吸水率随交联剂用量的增大呈现单调下降的趋势,N’N-亚甲基双丙烯酰胺用量相对单体用量的0.024%(质量比),丙三醇的用量相对单体用量的0.011%(质量比)时,交联聚合物的平衡吸水率均最大,分别为808.71和745.63.两类吸水树脂在去离子水中的平衡吸水率最高,在0.36%的盐酸溶液中最低.该吸水树脂的热稳定性较好,不论是N’N-亚甲基双丙烯酰胺、还是丙三醇做交联剂,在200℃以下的热失重均在2%左右.     

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