PET—PTT共聚酯的热降解行为

采用热失重分析(TGA)和裂解气相质谱(Py-GC/MS)研究不同组成的PET(聚对苯二甲酸乙二醇酯)-PTT(聚对苯二甲酸丙二醇酯)共聚酯的热降解行为,并与PET和PTT均聚物作了比较.TGA结果表明,PET-PTT共聚酯的热稳定性介于均聚物PTT与PET之间,并随PET组分的增加而提高.利用Py-GC/MS得到PET-PTT共聚酯及均聚物的裂解产物的结构及分布,探讨PTT降解机理,并推测PET-PTT共聚酯的可能降解过程.发现PET-PTT共聚酯分解过程中产生了不同于PET和PTT裂解产物的组分,但不同组分的含量很小,这可能是由共聚酯中PTT(PET)序列长度较短所致.PET-PTT共聚酯在裂解过程中比PET和PTT均聚物产生了更多的挥发性产物.当PTT(PET)在共聚酯中的摩尔分数增大时由该链段降解产生的产物质量分数相应提高.     

PET/LCP反应性共混物序列结构与热性能的关系

利用2H－NMR方法对聚对苯二甲酸乙二酯（PET）和热致性液晶共聚酯60PHB／PET（LCP）体系在少量扩链剂双（2－恶唑啉）BOZ存在下形成的反应性共混物的序列长度进行表征，并研究序列长度对共混物热性能的影响，研究表明PET和PHB的序列长度均随共混时间的延长和温度的提高而降低，且在相同温度下，含扩链剂BOZ的共混体系的序列长度比不含BOZ的体系小，表明BOZ对酯交换起促进作用，共混物组分中PET的熔点Tm和熔体结晶工Tmc均随序列长度（LPET)的增大而降低，而冷结晶温度Tcc却升高。     

在线热裂解-气相色谱/质谱联用技术分析葫芦巴净油的热裂解产物

采用在线热裂解-气相色谱/质谱(Py-GC/MS)联用技术研究了氦气氛围中葫芦巴净油在300、400、500、600、700、800℃下的热裂解行为。结果表明:1在上述条件下共鉴定出86种裂解产物,主要是酯、酸、醇、烯烃类化合物;2裂解温度低于500℃时,检测到的成分基本相同;3裂解温度从600℃升至800℃,检测到危害性的苯系物种类增多、相对含量增大。此外,对葫芦巴净油裂解产物的致香机理和苯系物的形成机理进行了简单讨论。     

PBs/PET共混体系的制备与表征

以丁二酸、丁二醇为原料,通过直接缩聚反应合成了高分子量聚丁二酸丁二醇酯。并将聚丁二酸丁二醇酯 (PBS)同聚对苯二甲酸乙二醇酯 (PET)在不同温度下熔融共混。测定了不同组分共混物的熔点和水降解性。聚合物熔融峰随着共混时间的增加渐渐的下移。这说明PBS和PET热降解和酯交换反应随着共混温度的增加而同时发生。共混物的降解性与芳香组分的含量和链段长度都有关。     

PET/PEN共混物的热分解行为及其动力学

研究了惰性气氛下聚对苯二甲酸乙二酯(PET)/聚对萘二甲酸乙二酯(PEN)共混物的非等温热分解行为及其动力学.研究发现,不同PET/PEN共混物的热降解为一个主要的热分解过程,热分解反应为一级反应.随着共混物中PEN质量分数的增加,共混物的起始分解温度逐渐升高,共混物的热稳定性逐渐提高,而且共混物的热分解反应活化能也逐渐增加,这是由于PEN分子链中萘环的热分解温度比PET中苯环高,因此分子链的热稳定性比PET要高.共混物中萘环的化学组成含量越高,则热稳定性愈高.     

聚磷酸酯阻燃剂对PET结晶行为及形态结构的影响

采用共混法制备了不同磷含量的阻燃聚对苯二甲酸乙二醇酯(poly(ethylene terephthalate),PET)样品,差示扫描量热(differential scanning calorimetry,DSC)和Avrami方法研究了该阻燃体系的等温结晶动力学。原子力显微镜(atomic force microscope,AFM)、偏光显微镜(polarized optical microscopy,POM)和X射线衍射仪(Xray diffraction,XRD)分析了共混体系的晶体形貌、尺寸和结构。结果表明:阻燃剂的加入没有改变PET的成核机理,其初级结晶均为二维盘状和三维球晶生长;少量阻燃剂的加入可以在PET中起到异相成核作用,晶粒尺寸减小,结晶速率加快。     

聚酯类热致性液晶的合成与其反应性共混的热性能改性

以联苯二氯苄制备的对联苯二甲酰氯和1．6～已二醇为单体合成了热致型主链液晶高分子,并以此液晶高分子与对苯二甲酸乙二醇酯(PET)在少量扩链剂双2-恶唑啉(BOZ)存在下进行反应性共混．探讨了单体摩尔比、反应温度、催化剂等因素对液晶合成的影响．利用红外光谱对对联苯二甲酸和聚酯液晶进行了表征,用DSC对聚酯液晶进行了热分析．研究了对反应性共混条件对共混物热性能的影响．结果表明,BOZ对酯交换的促进作用使玻璃化温度(Tg)升高,延长共混时间和提高共混温度使冷结晶温度(Tcr)升高,溶体结晶温度(Tmc)和熔点(Tm)下降。     

TGA/SDTA、DSC和Py-GC-MS分析叶醇糖苷热降解性质

为了开发热稳定型香原料,采用热重分析／同步差热分析法（TGA／SDTA）、差示扫描量热法（DSC）和在线热裂解气相色谱质谱法（Py—GC—MS）对叶醇糖苷的热降解行为及产物进行了研究．TG—DTC曲线显示主要失重区间在230—370℃,峰值为339．8℃,总失重96．9％;DTA显示在290—360℃有一个吸热峰,峰值为339．8℃;DSC显示230～340℃为吸热区间,峰值为301．3℃;Py—GC—MS测定了在200,350,500,650℃各温度下叶醇糖苷裂解的主要产物．在200℃,裂解量很少,350℃时则产生大量的叶醇和少量副产物,随着温度的升高,500℃和650℃时产生的副产物增加,使叶醇糖苷释放叶醇的最佳温度是350℃;热裂解的特征产物是叶醇,说明主要的裂解反应是氧糖苷键的断裂．     

PET/PBT共混物和P(ET—BT)共聚物化学结构的各种分析方法研究

本文用红外光谱(IR)、核磁共振氢谱(~1H-NMR)、核磁共振碳谱(~(13)C-NMR)、差示扫描量热谱(DSC)、裂解色谱(PGC)和化学降解色谱(CDC)研究了PET/PBT共混物和P(ET-BT)共聚物的化学结构及其热转变,讨论了各种方法的适用性。结果表明,PGC和CDC法是组分分析最可靠的方法。~(13)C-NMR法是鉴别共混和共聚链结构的最有效手段。对于组分比的测定,CDC法最灵敏,PET和PBT的检测极限为0.5％,相对标准偏差<1％。     

PET／PEN扩链反应共混的研究——结晶与熔融行为

用差示扫描量热法（DSC）研究了PET／PEN扩链反应性共混物体系的热性能,对共混比例、温度和时间对热性能的影响进行了讨论,并进一步考察了序列结构变化和热性能的关系。结果表明,不同比例的PET／PEN都呈现出一个玻璃化温度,即PET、PEN在无定形态是相混溶的;冷结晶温度和熔融温度与共混比例、共混时间、温度等因素密切有关。PET／PEN50／50即使共混短时间,亦不结晶。其他比例共混物随共混时间的增加,冷结晶温度升高,熔点下降,与序列长度变化有关,当序列长度小于7时,冷结晶峰消失。当酯交换大于30％时熔融峰消失。     

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