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...

power transformers are important equipments in power systems. thus there is a large number of researches devoted of power transformers. however, there is still a demand for future investigations, especially in the field of diagnosis of transformer failures. in order to fulfill the demand, the first part reports a study case in which four main types of failures on the active part are investigate...

abstract: in this thesis, we focus to class of convex optimization problem whose objective function is given as a linear function and a convex function of a linear transformation of the decision variables and whose feasible region is a polytope. we show that there exists an optimal solution to this class of problems on a face of the constraint polytope of feasible region. based on this, we dev...

abstract the present study was conducted in order to investigate the impact of an integrated model of form-focused and task-based instruction on iranian efl learners vocabulary learning and retention.it also aimed to detect efl learners attitude towards the implementation of form-focused task-based vocabulary instruction in the classroom. in order to address the purposes of this study, a sampl...

this study aimed to investigate the effects of listening strategy training on iranian efl learners listening comprehension and use of such strategies. this work, employing an experimental methodology, was conducted among 60 adult efl learners from a language institute in isfahan, iran, as participants. the participants, who were selected based on the results of a placement test, were assigned t...

this study was conducted to investigate the effect of favorite-text on iranian intermediate efl learners’ vocabulary development. sixty learners from nour-al-mahdi english institute participated in the present study. having been homogenized by oxford placement test (opt), they were randomly assigned into two groups of 30, control and experimental. then both groups sat for a pre-test which was a...

abstract: country’s fiber optic network, as one of the most important communication infrastructures, is of high importance; therefore, ensuring security of the network and its data is essential. no remarkable research has been done on assessing security of the country’s fiber optic network. besides, according to an official statistics released by ertebatat zirsakht company, unwanted disconnec...

the present research was conducted to explore the effect of employing two language teaching approaches, i.e. schema-based instruction (sbi) and translation-based instruction (tbi), on vocabulary knowledge, structure and reading comprehension ability of forty one female students learning english in grade one senior high school in rivash, kuhsorkh, iran. while sbi focuses on schemata, i.e. words ...

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...