abstract in first part of this project, the use of a new and biguanid-like catalyst supported on silica as a recyclable catalyst provides a new route for the synthesis of a variety of arylalkylidene rhodanine derivatives through knoevenagle reaction in at present of solvent at room temperature. rhodanine derivatives and especially arylalkylidene rhodanines have proven to be attractive compound...

in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...

in the past couple of decades sociocultural theory of sla and its implications in efl contexts have attracted attentions of research circles worldwide and aroused some controversies. firth and wagner (1997) have questioned the principles of the cognitive view which gives importance to mental constructs in favor of sociocultural view which highlights social and contextual constructs. but if soci...

there are many approaches for solving variety combinatorial optimization problems (np-compelete) that devided to exact solutions and approximate solutions. exact methods can only be used for very small size instances due to their expontional search space. for real-world problems, we have to employ approximate methods such as evolutionary algorithms (eas) that find a near-optimal solution in a r...

چکیده مجموعه حاضر با هدف معرفی و ارائه ی توصیفی برای اصطلاحات رایج در دانش معنی شناسی تهیه شده است. برای دستیابی به چنین هدفی سعی بر آن بود تا صرفاً به واژگان نقش مند در شاخه ی عمده ی معنی شناسی زبانی توجه شود. در حوزه معنی شناسی زبانی، به اصطلاحات در شاخه ای از این دانش، یعنی معنی شناسی نظری (theoretical semantics) و آنچه معنی شناسی کاربردی (applied semantics) نامیده ایم، اشاره شود. و هدف از ت...

just as motivation is important in sla research, demotivation constitutes an important factor, too. there are many studies done on demotivation and burnout of teachers. many of these studies have been conducted on one or two aspects of english instruction. consequently, there are few studies which have been done on more than two aspects of english teaching. the aim of this study is to find out ...

until now many studies have been done over recent decades throughout the world to show the right age to start english. in iran, research is still at an early stage in terms of evaluating teachers’ beliefs about teaching children english. the problem of at what age to start teaching english and how to teach english to elementary school children has not been solved neither in this country nor els...

one of the most important number sequences in mathematics is fibonacci sequence. fibonacci sequence except for mathematics is applied to other branches of science such as physics and arts. in fact, between anesthetics and this sequence there exists a wonderful relation. fibonacci sequence has an importance characteristic which is the golden number. in this thesis, the golden number is observed ...

abstract the present study was conducted to investigate the effect of using model essays on the development of writing proficiency of iranian pre-intermediate efl learners. to fulfill the purpose of the study, 55 pre- intermediate learners of parsa language institute were chosen by means of administering proficiency test. based on the results of the pretest, two matched groups, one as the expe...

fuzzy logic has been developed over the past three decades into a widely applied techinque in classification and control engineering. today fuzzy logic control is one of the most important applications of fuzzy set theory and specially fuzzy logic. there are two general approachs for using of fuzzy control, software and hardware. integrated circuits as a solution for hardware realization are us...