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...

‏‎applications such as high definition viedeo reproduction, portable computers, wireless, and multimedia demand, and ever-increasing need for ligh-frequency high-resolution and low-power analog-to-digital converters. flash, two-step flash, and pipeline convertors are fast but consume large amount of power and require large area. to overcome these problems, successive approximation converter blo...

today, persian poetry is of great importance to many scholars around the world. the interest and attention of various cultures toward such a fine literature has given quite a good motivation for a comparative study. the major concern of the study is to investigate how nature is depicted through the works of the great english poet, william wordsworth (1770-1850) and the outstanding contemporary ...

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...

in fact, this study focused on the following questions: 1. is there any difference between the effect of functional/notional approach and the structural approaches to language teaching on the proficiency test of efl learners? 2. can a rather innovative language test referred to as "functional test" ge devised so so to measure the proficiency test of efl learners, and thus be as much reliable an...

in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...

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...

abstract the present study is concerned with the syntactic deviation in hafezs poetry. poems are known to be accompanied with various linguistic deviations. these deviations may be phonological, morphological and/or syntactic. the relatively high frequency of the cases of the syntactic deviation in hafezs poems makes this rhetorical feature as a main characteristic of his poetry. this thesis, ...