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1.
多并苯芳烃(polyacenes)是一类线性并芳香环碳氢化合物.多并苯化合物具有独特的线性π电子离域特性(linear delocalizedπ-system),是一类独特的有机半导体材料.多并苯材料由于其在有机电子学器件中的潜在应用而受到广泛的关注和研究,多并苯化合物能够实现高度有序的分子堆积,因此,能够被应用于大规模功能器件中.近20年来,高性能多并苯类材料的合成及应用已取得显著进展,尤其在有机场效应晶体管(OFETs)应用领域,多并苯类材料已发展成为OFETs的主要材料.文中综述了在OFETs中多并苯和杂环多并苯分子结构对材料电学性能的影响,最后展望了多并苯和杂环多并苯的应用前景.  相似文献   

2.
采用毛吸浸润法,研究了氧等离子及氩等离子处理对聚丙烯腈基碳纤维表面浸润特性的影响。发现了等离子处理可以使碳纤维表面对水的浸润性能大为改善,氧等离子处理效果更为明显。对在碳纤维表面预涂不饱和酸酐,经等离子处理可产生接枝的现象进行了验证,并发现接枝马来酸酐后浸润性能反而比原纤维有所下降。经等离子处理的纤维随其接触空气时间的延续,表面浸润性能不断退化,纤维对水的接触角呈曲折形式逐步增加。  相似文献   

3.
采用毛吸浸润性,研究了氧等离子及氩等离子处理对聚丙烯腈基碳纤维表面浸润特性的影响。发现了等离子处理可以使碳纤维表面对水的浸润性能大为改善,氧等离子处理效果更为明显。对在碳纤维表面预涂不饱和酸酐,经等离子处理可产生接枝的现象进行了验证,并发现接枝马来酸酐后浸润性能反而比原纤维有所下降。经等离子处理的纤维随其接触空气时间的延续,表面浸润性能不断退化,纤维对水的接触角呈曲折形式逐步增加。  相似文献   

4.
通过碳纤维表面的扫描电镜观察与复丝力学性能测定,发现等离子处理对纤维的模量几乎没有影响,而强度随着处理功率的增加和时间的延长稍有下降,在外观上仅表现为纤维表面纵向沟槽的加深。氩气等离子比氧化性空气等离子的损伤小。通过碳纤维表面的X射线光电子能谱分析,结合喇曼光谱的研究,还发现等离子处理的有效深度达到15mm左右。其作用是蚀刻去碳纤维表面脂肪链结构,产生石墨等晶体结构富集的高能表面。  相似文献   

5.
通过碳纤维表面的扫描电观察与复丝力学性能测定,发现等离子处理对纤维的模量几乎没有影响,而强度随着处理功率的增加和时间的延长稍有下降,在外观上仅表现为纤维表面纵向沟槽的加深。氩气等离子比氧化性空气等离子的损伤小。通过碳纤维表面的X射线光电子能谱分析,结合喇曼光谱的研究,还发现等离子处理的有效深度达到15nm左右。其作用是蚀刻去碳纤维表面脂肪链结构,产生石墨等晶体结构富集的高能表面。  相似文献   

6.
作者采用经典化学分析法、x射线光电子能谱分析法,研究了碳纤维经氧冷等离子体处理前后表面酸性基团的变化。化学分析结果表明,碳纤维表面酸性基团增加了3.4倍;x射线光电子能谱分析结果表明,碳纤维表面O/C原子比提高1倍,冷等离子体处理条件如处理时间、气体流量、压力及输出功率等对碳纤维表面酸性基团的变化有重大的影响。根据分析结果,还探讨了氧冷等离子体氧化碳纤维表面的反应机理及其表面化学结构的变化规律。作者认为,碳纤维表面处理所产生的酸性基团,是提高碳纤维增强树脂复合材料的层间剪切强度的一个重要因素。  相似文献   

7.
利用等离子处理方法,在碳纤维表面引入羟基,由氧化还原反应引发丙烯酸、丙烯酰胺等单体的聚合,可产生厚达300nm的接枝层.通过FT-IR、XPS、SEM以及力学性能的研究发现,碳纤维接枝后与等离子处理情况相反,强度及延伸率有明显增加,而模量却下降.  相似文献   

8.
利用二苯基苦基肼分析法发现,等离子处理后碳纤维表面上将产生2~6个/nm^2游离基。它们会在30h内转化成其它基团,再复转为酚羟基后慢慢消失。等离子处理的作用一方面可导致游离基或介稳基团的产生,另一方面又不断消除它们。提高处理功率或延长处理时间在一定程度上有利于基团的形成,但超过一定的限度后反会适得其反。利用等离子处理产生的游离基可使碳纤维在参与乙烯基单体聚合时,产生接枝聚合分子链。  相似文献   

9.
利用等离子处理方法,在碳纤维表面引入羟基,由氧化还原反应引发丙烯酸、丙烯酰胺等单体的聚合,可产生厚达300nm的接枝层。通过FT-IR、XPS、SEM以及力学性能的研究发现,碳纤维接枝后与等离子处理情况相反,强度及延伸率有明显增加,而模量却下降。  相似文献   

10.
利用二苯基苦基肼分析法发现,等离子处理后碳纤维表面上将产生2~6个/nm ̄2游离基.它们会在30h内转化成其它基团,再复转为酚羟基后慢慢消失.等离子处理的作用-方面可导致游离基或介稳基团的产生,另一方面又不断消除它们.提高处理功率或延长处理时间在一定程度上有利于基团的形成,但超过一定限度后反会适得其反.利用等离子处理产生的游离基可使碳纤维在参与乙烯基单体聚合时,产生接枝聚合分子链.  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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-  相似文献   

19.
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-  相似文献   

20.
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  相似文献   

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