abstract in first part of this project, the use of a new and biguanid-like catalyst supported on silica as a recyclable catalyst provides a new route for the synthesis of a variety of arylalkylidene rhodanine derivatives through knoevenagle reaction in at present of solvent at room temperature. rhodanine derivatives and especially arylalkylidene rhodanines have proven to be attractive compound...

within the components of communicative competence, a special emphasis is put on the “rules of politeness,” specifically the politeness strategies (brown and levinson, 1978) that speakers deploy when performing the request speech act. this is because the degree of imposition that making a request places upon one’s interlocutor(s) has been seen to be influenced by several factors among which, as ...

apart from other aspects, desert is a natural environment and is one of the appealing terrestrial elements. putting its symbolic and fictional senses aside, the term “desert” bears mystic sense more than material sense. in addition to the worlds materialistic experiences, desert has attracted the attention of writers because it creates a kind of inner experience, which returns the individual in...

the purpose of the present study was to investigate the effect of task-based instruction of vocabulary on the receptive and oral productive acquisition of english vocabulary and compare the results with those obtained from the traditional method. the method and procedure applied in this study was as follows: after the implementation of opt, a group of sixty female students were chosen. the stu...

abstract the present study deals with a comparison between reactive and pre-emptive focus-on-form in terms of application and efficiency. it was conducted in an intermediate english class in shahroud. 15 male learners participated in this research and their age ranged from 18 to 25. a course book, new interchange 3, and a complementary book were used. every session the learners gave lectures o...

in this work, a novel and fast method for direct analysis of volatile compounds (davc) of medicinal plants has been developed by holding a filament from different parts of a plant in the gc injection port. the extraction and analysis of volatile components of a small amount of plant were carried out in one-step without any sample preparation. after optimization of temperature, extraction time a...