Polyimide/MWCNTs nanocomposites have been fabricated by solution mixing process. In the present study, we have investigated electrical conductivity and dielectric properties of PI/MWCNT nanocomposites in frequency range of 1 kHz to 100 kHz at different MWCNTs concentrations from 0 wt.% to 15 wt.%. It has been observed that the electrical conductivity and dielectric constants are enhanced significantly by several orders of magnitude up to 15 wt.% of MWCNTs content. The electrical conductivity increases as the frequency is increased, which can be attributed to high dislocation density near the interface. The rapid increase in the dielectric constant at a high MWCNTs content can be explained by the formation of a percolative path of the conducting network through the sample for a concentration corresponding to the percolation threshold. The high dielectric constant at a low frequency (1 kHz) is thought to originate from the space charge polarization mechanism. I-V characteristics of these devices indicate a significant increase in current with an increase in multi-walled carbon nanotube concentration in the composites. The SEM images show improved dispersion of MWCNTs in the PI matrix; this is due to the strong interfacial interactions.
It is not often easy to identify a certain group of words as a lexical bundle, since the same set of words can be, in different situations, recognized as idiom, a collocation, a lexical phrase or a lexical bundle. That is, there are many cases where the overlap among the four types is plausible. Thus, it is important to extract the most identifiable and distinguishable characteristics with which a certain group of words, under certain conditions, can be recognized as a lexical bundle, and this is the task of this paper.
We dealt with the nature of the points under the influence of periodic function chaotic functions associated functions chaotic and sufficient conditions to be a very chaotic functions Palace
Man has a great role in the development of society in all fields, and therefore the human thought played a great role in its continuous pursuit and insight into the social classes that differ in their privileges, which makes the members of society not reconcile because of that disparity that is not based on human principles, so one class exploits another, and this is what stopped me Rather, it prompted me to choose the topic (class and its impact on society) in order to show the impact of classes on each other negatively and positively, so I work to avoid the first with the recommendations I put forward and offer guidance, and strengthen the second, and after this topic of necessity in a place because of the imbalance and promise of appr
... Show MoreHedging is a linguistic phenomenon used to convey interpersonal messages in spoken interaction. It is a communicative strategy which enables speakers to soften the force of utterances or moderate the assertive force of utterances. It is resulted from different features such as uncertainty, doubt, tentativeness, ambiguity, neutrality, mitigation, and subjectivity. Hedging is used widely in TV debates to make utterances more acceptable to the interlocutors. Hedges are expressions used to communicate the speaker's weak commitment to information conveyed. The utterances in debates are often hedged because in an unhedged form might sound threatening to the addressees, and, therefore, be likely to be rejected.
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... Show MoreA new family of nematic liquid crystal dendrimers derived from 3,5-dihydroxybenzoic acid were synthesized. The synthesis of the dendrimers compounds shows the influence of the dendritic core on the mesomorphic properties. The liquid crystalline properties were studied by polarizing optical microscopy (POM) equipped with a hot stage, the structures of the synthesized compounds characterized using FTIR and 1HNMR spectroscopy.
the Reception and the Creative Reaction