a simple, sensitive and selective method for solvent extraction and spectrophotemetric determination of lanthanum (ii) europium (iii), and cerium (iii) is described , the rare earth metals are extracted into chloroform solution of n-phenylbenzohydroxamic acid (pbha) at ph 9-10 various parameters are studied to optimize the extraction conditions. the molar absorptivity is found to increase from ...

determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...

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...

the main purpose of this study was to investigate any relationship between high school efl teachers metaphorical understandings of their role in class and their self-efficacy beliefs. teachers metaphors were elicited through two different prompts: one picturing what they believed a language teacher should be like in class, and the other demonstrating what they are actually like in class; such...

چکیده هدف اصلی این پژوهش شناسایی الزامات نظام مدیریت کیفیت فراگیر در حوزه پژوهشی دانشگاه اصفهان بود. سوالهای پژوهش با توجه به مولفه های مدیریت کیفیت (تعهد مدیران، بهبود مستمر فرایندها ، مشتری محوری ، منابع انسانی ، مدیریت اطلاعات ، زیرساختهای کیفیت ، استفاده از نتایج ، انعطاف پذیری، مشارکت در فعالیتهای پژوهشی، ایجاد فرهنگ کیفیت و تناسب ساختارهای سازمانی) که بر اساس مطالعه استانداردهای بین المل...

power transformers are important equipments in power systems. thus there is a large number of researches devoted of power transformers. however, there is still a demand for future investigations, especially in the field of diagnosis of transformer failures. in order to fulfill the demand, the first part reports a study case in which four main types of failures on the active part are investigate...

foreign policy takes root from complicated matters. however, this issue may be more truth about armenia. although the new government of armenia is less than 20 years, people of this territory are the first ones who officially accepted christianity. in very past times, these people were a part of great emperors like iran, rome, and byzantium.armenia is regarded as a nation with a privileged hist...

the study aims to achieve research and testing of hypotheses survey techniques and questionnaires to collect information used. 61 questions in the questionnaire included 15 questions and 46 open questions according to research in the study population, girls and their mothers as the value of different children investment should be. mothers according to the research community benefits from havi...