fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

abstract: in the paper of black and scholes (1973) a closed form solution for the price of a european option is derived . as extension to the black and scholes model with constant volatility, option pricing model with time varying volatility have been suggested within the frame work of generalized autoregressive conditional heteroskedasticity (garch) . these processes can explain a number of em...

a major concern in the last few years has been the fact that the cultural centers are keeping distance with what they have been established for and instead of reproducing the hegemony, they have turned into a place for resistance and reproduction of resistance against hegemony. because the cultural centers, as urban public spaces in the last two decades, have been the subject of ideological dis...

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...

in this thesis, we exploit a simple and suitable method for immobilization of copper(ii) complex of 4?-phenyl-terpyridine on activated multi-walled carbon nanotubes [amwcnts-o-cu(ii)-phtpy]. this nanostructure was characterized by various physico-chemical techniques. to ensure the efficiency and fidelity of copper species, the implementation of three-component strategies in click-chemistry all...

the purpose of this study was to investigate iranian efl learners’ beliefs about the role of rote learning (rl) in vocabulary learning strategies; besides, the study examined if english proficiency would influence learners’ vocabulary learning strategy use. this study addresses the need for a clear understanding of the role of rl in efl vocabulary learning by looking at iranian efl learners’ ow...

abstract this study aimed at investigating the effect of bilingual teaching of cognate words (persian-english) on iranian upper intermediate efl learners’ knowledge of lexical development. for this purpose,100 subjects participated in this study out of which 40 learners were selected for this study and they were assigned into two groups, control and experimental. cross-language cognates (wor...

the present study sought to investigate the impact of using mind-mapping technique instruction on female elementary efl learners reading comprehension; it also investigated their attitudes towards using mind-mapping technique as a tool to improve their reading comprehension. this study followed a quasi-experimental design with two intact groups as experimental, and control groups. the participa...

writing as a productive skill requires practice in the basic sub-skills of vocabulary and grammar. in fact, grammar has been viewed as the core of programs in writing classes to help the students put the elements of sentence together and combine sentences of specific lengths to come up with an error-free work of art. conceptualizing l2 writing in this way introduces writing as a product and enc...

چکیده تمام نما مقدمه: این تحقیق برای بررسی میزان خلاقیت و عناصر آن (انعطاف- سیالی- ابتکار و بسط) در کارشناسان فوق برنامه های تربیت بدنی دانشگاههای تهران صورت گرفته است. بطور کلی خلاقیت به معنای توانایی تولید اندیشه ها و ایده های جدید و ترکیب آنها با یکدیگر و بیشتر در جنبه های فکری نظری و به اصطلاح فعالیتهای ذهنی و طراحی قبل از عمل به کار می رود و دارای چهار عنصر به شرح زیر می باشد. 1- سیالی...