in this research we have studied the effect of some transition-metals (cu, ag and au) substitutions on two-electron reduction potential of flavins by application of dft method. all geometries have been optimized at blyp level of theory and “6-31+g** + lanl2dz” mixed basis set. the frequency job at the same method and basis sets has been performed to obtain gibbs free energy of compounds. it h...

rested on sociocultural theory (sct), this study attempted to examine the effect of written corrective feedback (wcf) followed by producing written languaging on developing writing accuracy over new tasks. to this aim, two intact iranian efl classes at the low-intermediate level were randomly assigned to two experimental groups: direct (n = 25) and indirect (n = 25). both groups wrote on a numb...

most specialists in the field of foreign language teachingconsiderreading skill as an interactive process between the reader’s prior knowledge and the text.accordingly, the activation of prior knowledge for an effective comprehension is very important. it is generally agreed that the pre-reading phase is the stage where this type of interaction and activation may be enhanced throughcertain stra...

1.0 overview it seems that grammar plays a crucial role in the area of second and foreign language learning and widely has been acknowledged in grammar research. in other words, teaching grammar is an issue which has attracted much attention to itself, and a lot of teachers argue about the existence of grammar in language teaching and learning. this issue will remind us a famous sentence f...

abstract in a protocol analysis of second language writing from 20 adult english as a foreign language (efl) iranian students, this research observed how language-switching (l-s), i.e., first language use in l2 writing, was affected by l2 proficiency. switching interactively between first (l1) and second (l2) languages has been recognized as one of the salient characteristics of l2 writing....

abstract the cr(iii) and zn(ii) complexes with 2-((9,10-dihydro-1-hydroxy-9,10-dioxaanthracen-4-yloxy)carbonyl)benzoic acid as ligand have been prepared by reacting cr(no3) and zn(no3)2 and ligand in cloroform. the cr and zn complexes with 2-((9,10-dihydro-1-hydroxy-9,10-dioxaanthracen-4-yloxy)carbonyl) were also prepared in chloroform and aceton solutions. the uv-visible and ft-ir spectra of...

this is an original study on the effect of a polyisobutylene – polydimethylsiloxane (pibpdms) block copolymer modifier used as an interfacial active agent on the dynamics behaviour of single newtonian drops suspended in a polyisobutylene (pib) newtonian matrix. the results were divided in two sections. the first part included the experiments carried out on the non-modified and 2% block cop...

the purpose of this thesis was to investigate how differently metacognitive, cognitive, and social/affective strategies affect l2 learners’ reading comprehension. to this end, the study employed a quasi-experimental design with a placement test as a proficiency test to find the homogeneity of groups. three classes were randomly selected as the experimental groups (n =90), and each class was tau...