مبدل های الکترونیک قدرت را می توان از منظر سخت افزاری و نرم افزاری مطالعه کرد. در بحث سخت افزاری مسئله مهم پیشرفت علوم الکترونیک نیمه هادی است که منجر به تولید سوییچ هایی با قابلیت سوییچینگ سریع تر و هدایت جریان بالاتر است. این سوییچ ها کنترل پذیری بهتری دارند و با استفاده از آن ها مبدل هایی با سطح توان بالاتر ساخته خواهد شد.در بحث نرم افزاری مبدل های الکترونیک قدرت مسئله مهم کنترل مبدل است. مد...

the major aim of this study was to investigate the relationship between iq, eq and test format in the light of test fairness considerations. this study took this relationship into account to see if people with different eq and iq performed differently on different test formats. to this end, 90 advanced learners of english form college of ferdowsi university of mashhad were chosen. they were ask...

the treatment of in completely formed pulpless teeth has presented considrable problems. these teeth have wide open apexes and the walls of the root canal diverge toward the apical tissues. mechanical preparation cannot be done in the normal manner beacause of the large initial size and the taper of apical part of the canal , a mechanical stop cannot be produced at the apex of the canal and , t...

the thesis has been arranged into five chapters and mainly concerned with the baer-invariant of groups which is the generalization of the schur-multiplier with respect to the variety of groups. chapter one is devoted to collect some notation and background information which are needed in the next chapters. its also contains some important statements which will be generalized in this thesis. cha...

اندازه گیری چربیهای پلاسما جز مهمی از طب پیشگیری را تشکیل می دهد. این اندازه گیری باید دقیق، ساده و ارزانقیمت باشد. اندازه گیری ‏‎ldl‎‏ پلاسما به عنوان تست تشخیصی طلائی جهت تخمین عوارض عروقی ‏‎ناشی از هایپرلیپیدمی شناخته می شود. اندازه گیری ‏‎ldl‎‏ از طریق فرمول فریدوالد صورت می گیرد که نیاز به اندازه گیری تریگلیسیرید ‏‎(tg)‎‏ پلاسما (پس از یک شب ناشتا بودن) و کلسترول پلاسما و ‏‎hdl‎‏ دارد. اما...

abstract this research is about a longitudinal case study of english morpheme acquisition by a persian speaking child l2 learner of english (2 .9-3).the goal of this research has been discovery of the child ‘s ability in acquiring of english morphemes in a persian context while only one person (the child’ s father)has been talking to her.this child has also been exposed to english languag...

a large number of single research studies on the effects of strategy-based instruction (sbi) in teaching english as a foreign or second language has been conducted so far. however, the lack of a comprehensive meta-analysis targeting the effectiveness of english language sbi is observed. moreover, the findings of experimental studies regarding the context of the english language, proficiency lev...

abstract: about 60% of total premium of insurance industry is pertained?to life policies in the world; while the life insurance total premium in iran is less than 6% of total premium in insurance industry in 2008 (sigma, no 3/2009). among the reasons that discourage the life insurance industry is the problem of adverse selection. adverse selection theory describes a situation where the inf...

this thesis deals essentially (but not from all aspects) with the extension of the notion of semigroup compactification and the construction of a general theory of semitopological nonaffine (affine) transformation semigroup compactifications. it determines those compactification which are universal with respect to some algebric or topological properties. as an application of the theory, it is i...