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 ...

in recent years many researchers have been focused on interaction of small molecules with dna. dna is generally the primary intracellular of anticancer drugs, so the interaction between small molecules and dna can cause dna damage in cancer cells, blocking the division of cancer cells and resulting in cell death. the flavonoids are a large group of polyphenolic natural products that are widely ...

abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...

terms of address as an important linguistics items provide valuable information about the interlocutors, their relationship and their circumstances. this study was done to investigate the change route of persian address terms in the two recent centuries including three historical periods of qajar, pahlavi and after the islamic revolution. data were extracted from a corpus consisting 24 novels w...

the purpose of the present study was to investigate the relationship between fear of negative evaluation (fne) and communication strategies (css) among iranian efl learners. it was aimed to examine the differences in the use of communication strategies between speakers with high or low degree of fear of negative evaluation. the current study was a case study consisting of 10 english learners at...

nowadays,tourism industry considered as one of the main sources of income of a country.unfortunately and despite of owning plenty of cultural historical and natural attractions, iran has not reached to a proper position in this field. besides, the historical cities of a country are considered as the income resource and national wealth of it. qazvin with a rich cultural precedent, have suitable ...

saluk mount is selected for devonian biostratigraphy. this area located at southwest of bojnurd. in this study three sections are selected and two sections, chahar-borj and tabar sections with a thickness of 650 m, which consist mainly of calcareous sediments was studied in detailed but third section, qelli section, with a thickness of about 450m which consist mainly of sandstone and evaporates...

abstract this study aimed at investigating the possible relationship between self-assessment in writing and self-regulation of iranian efl learners. the main purpose of the study was not only to report and inform about this relationship, but also to investigate and find practical outcomes of the incorporation of self-assessment in writing, such as improving writing skill. the research was carr...

language learning courseware has been receiving growing attention by english educators since its advent. a variety of softwares have been designed by software designers and resorted to by language educators to supplement language textbooks. this experimental study investigated how the application of computerized version of language textbooks and the reception of the entire course through comput...