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 is no doubt that human being needs to become integrated with industry and industry needs to be progressed, daily. on the other hand, serious events in industrial units specially in oil industries has been shown that such damages and events are industry related ones. the consequence of such events and damages which resulted in chemical and poisoned explosions and loss of life and property ...

tourism , today as one of the ways to make money, create jobs , and social and political interactions is considered. this paper aims to examine the strengths and weaknesses of tourism development in mahmoud abad ( mazandaran ). the research method in this study is " descriptive - analytical " and to collection of data used field methods such as questionnaires and documentation - library. the sa...

abstract: advertisements are the most accessible type of authentic materials, and this is one reason why they are used more and more in english teaching classes. for this cause, studies in the field of advertisements are very widespread nowadays. for pun is one aspect which makes advertisements more interesting, it is used more than before in advertisements. use of puns makes an advertisement m...

abstract the purpose of this study is twofold: on the one hand, it is intended to see what kind of noticing-the –gap activity (teacher generated vs. learner generated) is more efficient in teaching l2 grammar in classroom language learning. on the other hand, it is an attempt to determine which approach of the noticing-the-gap- activity is more effective in the long- term retention of grammar...

for several years, researchers in familiarity of efl teachers with post-method and its role in second and foreign language learners’ productions have pointed out that the opportunity to plan for a task generally develops language learners’ development (ellis, 2005). it is important to mention that the critical varies in language teaching was shown is the disappearances of the concept of method ...

the poor orientation of the restaurants toward the information technology has yet many unsolved issues in regards to the customers. one of these problems which lead the appeal list of later, and have a negative impact on the prestige of the restaurant is the case when the later does not respond on time to the customers’ needs, and which causes their dissatisfaction. this issue is really sensiti...

abstract nowadays, the science of decision making has been paid to more attention due to the complexity of the problems of suppliers selection. as known, one of the efficient tools in economic and human resources development is the extension of communication networks in developing countries. so, the proper selection of suppliers of tc equipments is of concern very much. in this study, a ...

magnetic resonance imaging (mri) is a notable medical imaging technique that makes of phenomenon of nuclear magnetic resonance. because of the resolution and the technology being harmless, mri has considered as the most desirable imaging technique in clinical applications. the visual quality of mri plays an important role in accuracy of medical delineations that can be seriously degraded by exi...

due to the limiting workspace of parallel manipulator and regarding to finding the trajectory planning of singularity free at workspace is difficult, so finding a best solution that can develop a technique to determine the singularity-free zones in the workspace of parallel manipulators is highly important. in this thesis a simple and new technique are presented to determine the maximal singula...