among the low–dimensional allotropes of carbon, nanotubes and graphene have attracted very much attention from nano–science and nanotechnology specialists. they have been proposed as building blocks in nanometer device engineering. however, these structures are not defect–free. in this thesis, we focused on defective carbon nanotubes and graphene, and studied the effect of couple of very common...

abstract this quasi-experimental study was aimed at examining the impact of storyline complexity on the grammatical accuracy and complexity of advanced and intermediate efl learners. a total of 65 advanced and intermediate efl learners were selected from iran language institute (ili). an intact group including 35 intermediate participants and another intact group with 30 advanced participants ...

the methods which are used to analyze microstrip antennas, are divited into three categories: empirical methods, semi-empirical methods and full-wave analysis. empirical and semi-empirical methods are generally based on some fundamental simplifying assumptions about quality of surface current distribution and substrate thickness. thses simplificatioms cause low accuracy in field evaluation. ful...

any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...

1.0 overview it seems that grammar plays a crucial role in the area of second and foreign language learning and widely has been acknowledged in grammar research. in other words, teaching grammar is an issue which has attracted much attention to itself, and a lot of teachers argue about the existence of grammar in language teaching and learning. this issue will remind us a famous sentence f...

according to webster and wind (1972) and anderson et al (1987), “organizational buying is a complex process and involves many people from different functional areas, multiple goals and potentially conflicting decision criteria. moreover, the customers of today are also more knowledgeable and selective when making their purchasing decisions. since a key to organizational survival is the retentio...

abstract since heubners (1985) pioneering study, there have been many studies on (mis) use/ non-use of articles by l2 learners from article-less and article languages. the present study investigated how persian l2 learners of english produce and interpret english definite descriptions and demonstrative descriptions. it was assumed that definite and demonstrative descriptions share the same cen...

abstract although music possesses some kind of power and using it has been welcome by many students in language classrooms, it seems that they take a non-serious image of the lesson while listening to songs and they may think that it is a matter of fun. the main objective of the present study was to investigate whether learning a foreign language through musical texts (songs) can have an impac...

why some learners are willing to communicate in english, concurrently others are not, has been an intensive investigation in l2 education. willingness to communicate (wtc) proposed as initiating to communicate while given a choice has recently played a crucial role in l2 learning. it was hypothesized that wtc would be associated with language learning orientations (llos) as well as social suppo...