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...

there are many approaches for solving variety combinatorial optimization problems (np-compelete) that devided to exact solutions and approximate solutions. exact methods can only be used for very small size instances due to their expontional search space. for real-world problems, we have to employ approximate methods such as evolutionary algorithms (eas) that find a near-optimal solution in a r...

چکیده کنه تارتن دو لکه ای tetranychus urticae koch یکی از چندخوارترین آفات شناخته شده محصولات کشاورزی دنیا به حساب می آید. در این بررسی جمعیت تخم و مراحل فعال این کنه در شرایط آلودگی طبیعی و مصنوعی در برگ های 8 رقم لوبیا در سال 1392 در گلخانه و مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه ارومیه موردمطالعه قرار گرفت. آزمایش به صورت طرح کاملاً تصادفی برای شرایط مزرعه در10 تکرار و برای شرایط گلخانه ای...

the ability to speak two languages in the world is a remarkable achievement. there is a good reason to believe that bilingualism is the norm for the majority of people in the world because 70% of the earth’s population are supposed to be bilingual or multilingual. various investigations have shown that the native language impacts foreign word recognition, and this influence is adapted by the de...

there is less published research about how teachers in efl contexts respond to students who are relatively less mature and less competent l2 writers. while writing researchers have examined various issues concerning peer and teacher response in writing-oriented classes, little research has centered on the effect of collaborative tasks particularly dictogloss on writing skills. output collaborat...

abstract i the purpose of this study was to launch a thorough investigation concerning the possibility of differing orientations to the writing proficiency construct by native and non-native english speaking teacher raters. it mainly revolved around the international english language testing system (ielts) that is widely administered and employed as a measure of general proficiency in englis...

this study investigated the effects of manipulating the cognitive complexity of tasks along +/- few elements and the time limits on l2 learners writing performance. to conduct the study, 60 iranian efl learners with two levels of proficiency, low and high intermediate, were selected and assigned to three groups based on the time devoted to task completion. the participants performed both a simp...

all analytical methods are generally based on the measurement of a parameter or parameters which are somehow related to the concentration of the species.an ideal analytical method is one in which the concentration of a species can be measured to a high degree precision and accuracy and with a high sensitivity. unfortunately finding such a method is very difficult or sometimes even impossible.in...

this study investigated the impact of explicit instruction of morphemic analysis and synthesis on the vocabulary development of the students. the participants were 90 junior high school students divided into two experimental groups and one control group. morphological awareness techniques (analysis/synthesis) and conventional techniques were used to teach vocabulary in the experimental groups a...

after the soviet union dissolution, a chaotic period was begun in the russia. russia lost its glory and felt disgrace. the first group of elites came to power under yeltsin; they tried to re-define russia’s identity as a european country and build a foreign policy on this baseline. therefore russia tried to become closer with the west especially with the u.s. according to their view the sovie...