含萘环液晶共聚芳酯的流变性能

使用Instron 3211型毛细管流变仪研究了含对羟基苯甲酸链节、2,7-萘二酚链节,对苯二甲酸链节、2,6-萘二甲酸链节和乙醇链节的共聚芳酯液晶熔体的流变性能。比较各向同性PET熔体发现,共聚芳酯液晶熔体具有较低的剪切粘度和结构粘度;而剪切速度、熔体温度及2,7-萘二酚链节含量对此两种粘度有重大的影响。共聚酯熔体的粘流活化能(E_η)_(γω)=72.32-193.12(kJ/mol)和(E_η)_(σω)=150.50-340.61(kJ/mol)。本文同时指出,液晶熔体的弹性很小,其挤出物胀大比在0.98—1.30之间。这些研究结果表明,液晶共聚芳酯熔体具有良好的可纺性。     

含萘环共聚芳酯的分子链结构及热稳定性

本文以对羟基苯甲酸、2,7-萘二酚、对苯二甲酸和少量的聚2,6-萘二甲酸乙二酯为单体制备了一系列具有不同配比的液晶共聚芳酯。用红外光谱法、直接裂解质谱法和裂解气相色谱法鉴定了共聚芳酯的分子链结构,指出共聚芳酯的分子链结构与所加5种单体链节结构基本一致。借助于热重分析仪研究了共聚芳酯的热稳定性及其与分子链结构之间的关系。结果表明:在空气介质中该共聚芳酯开始裂解的最低温度为320℃,裂解反应速度最快时的温度均高于490℃;并且发现,共聚芳酯的分子链结构对热稳定性有较明显的影响,链结构规整性好的共聚芳酯具有较高的热稳定性。实验结果指出,共聚芳酯在空气及氮气介质中的热裂解反应均分两步完成。正像文中的3号样品,空气中的第一步裂解反应在326℃开始发生,第二步裂解反应则发生在540℃左右。本文还探讨了共聚芳酯的热裂解机理。     

全芳香族聚酯的合成及其液晶性研究

为制备液晶聚芳酯,本文用DSC研究二元芳酰氯与二元酚的熔融缩聚反应。测得芳酰氯与邻氯对苯二酚反应的温区均在芳酰氯的熔点附近。并观察到当2.6-萘二甲酰基占大分子链中芳酰基总量的40%以下时,聚芳酯熔点较低;反之,熔点明显上升。于200℃、N_2保护下常量合成了一系列主链结构不同的全芳香型聚酯。讨论了单体结构和配比对聚芳酯液晶性的影响。对结构为的聚芳酯进行了分析和表征:Cl含量、IR、TG、DSC和热台偏光显微摄象的测试结果,表明该聚酯有如下特性: (1)T_g=155℃,T_m=180℃,T_n=310℃(向列型液晶态转变温度)。(2)在310—460℃范围内呈热致性向列型液晶态而不存在各向同性转变(T_i),其T_i>T_d。     

液晶含氯聚芳酯的热分析

本文采用热重法(TG)和差示扫描量热法(DSC)研究了不同结构含氯聚芳酯的热性能和液晶性.实验结果表明:含氯聚芳酯有良好的热稳定性和理想的液晶性,其中含柔性链段系列含氯聚芳酯熔融温度最低,液晶相变温度范围宽;萘二酚系列含氯聚芳酯熔融温度高,热稳定性好,但液晶相变温度范围窄.     

环己基双酚及其共聚芳酯的合成与性能研究

以环己酮和苯酚为原料合成高纯度的环己基双酚(BHPC),然后以BHPC、间苯二甲酰氯(IPC)和对苯二甲酰氯(TPC)为单体,采用相转移催化界面缩聚法合成共聚芳酯.用FT-IR、1H NMR、DSC、TGA及力学性能测试等对聚合物的结构和性能进行了表征.研究结果表明:在优化条件下,可制得玻璃化转变温度215.2℃、5%热失重温度480.4℃的环己基双酚型共聚芳酯.该聚芳酯具有良好的耐高温、高的透光率和紫外屏蔽性能.     

2,6-萘二甲酰氯的制备及其鉴测

全芳香族热致性液晶聚酯具有高强度高模量优越性能,近年来在国内外受到重视。2,6-取代的萘环结构引入全芳香族聚酯主链后可提高聚合物的液晶性和热稳定性,且能一定程度地降低聚合物的熔融温度,便于成型加工。2,6-萘二甲酰氯是合成这类聚芳酯的常用单体,     

含向列液晶交联剂的液晶弹性体液晶性能

把向列液晶交联剂 4 (ω 烯丙酰氧基己氧基 )苯甲酸 2 叔丁基 1,4 二酚酯和胆甾液晶单体 4 烯丙氧基苯甲酸胆甾醇酯接枝到含氢硅氧烷链上 ,交联剂的质量分数由 0至 12 %,得到系列液晶弹性体P1～P7·通过热分析、偏光显微分析等手段研究了向列液晶交联剂对弹性体液晶性能的影响·结果表明 ,P1～P7都有液晶性能 ,均为胆甾液晶织构 ,系列液晶弹性体的tg 随交联剂在链中浓度增加而降低 ,ti 变化不大 ,具有较宽的液晶区间 ,在 182℃以上·交联剂质量分数为 2 %时 ,即从P4 开始弹性增加 ,当交联剂的质量分数大于 8%时 ,液晶相存在至热分解温度 ,所有液晶弹性体的热稳...     

全芳香族共聚酯——聚合物的合成及表征

本文用熔融缩聚法合成了a,b两系列全芳香族共聚酯液晶。用元素分析、红外光谱及裂解气相色谱法研究了共聚芳酯高分子链段结构。实验结果表明,共聚芳酯的分子链段组成、配比与加入的初始单体配比一致。     

芳香-脂肪族共聚酰胺的液晶性能

采用低温溶液缩聚法，以对苯二胺、对苯二甲酰氯和己二酰氯为单体合成了一系列不同己二酰单元含量的芳－脂族共聚酞胺．并对其硫酸溶液的液晶性能进行了研究。结果表明，该类共聚酰胺在己二酰单元含量低于９０％（ｍｏｌ）情况下，其硫酸溶液仍保持溶致液 晶特性。经偏光显微镜、小角激光光散射和宽角Ｘ光衍射实验证明，这类芳－脂族共聚酰胺硫酸液晶溶液属向列型液晶，其临界浓度Ｃ＊随己二酰单元含量的增加而增加。     

舒兰褐煤快速热解过程温度对焦油化学组成的影响

本文研究了褐煤在６５０—７００℃范围内进行快速热分解所得焦油的化学组成的 变化。确证随过程温度提高快速焦油中的轻质组分，特别是苯、酚和萘的含量有规律 地增加。与同一种煤样进行的慢速热分解对比，其芳化度高．化学组成和分布比较简 单和集中，其中苯、酚和萘等贵重化合物含量显著提高。是一种优质的化工原料。     

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