among the low–dimensional allotropes of carbon, nanotubes and graphene have attracted very much attention from nano–science and nanotechnology specialists. they have been proposed as building blocks in nanometer device engineering. however, these structures are not defect–free. in this thesis, we focused on defective carbon nanotubes and graphene, and studied the effect of couple of very common...

this study sought to examine the effect of cooperative game on iranian students achievements in english alphabet learning. cooperative games are games, in which players or teams work together towards a common goal without defeating someone. the methodology used in this study was experimental. the population of the study was 60 female students from the grade one in secondary school in tabriz, ir...

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...

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...

some new water-soluble schiff base complexes of na2[m(5-so3-1,2-salophen)].nh2o; (5-so3-1,2-salophen = n,n’-bis(5-sulphosalicyliden)-1,2-phenylendiamine); na2[m(5-so3-2,3-salpyr)(h2o)n].2h2o; (5-so3-2,3-salpyr = n,n’-bis(5-sulphosalicyliden)-2,3-diaminopyridine); and na2[m(5-so3-3,4-salbenz)(h2o)n].nh2o; (5-so3-3,4-salbenz = n,n’-bis(5-sulphosalicyliden)-3,4-diaminobenzophenon); where m = cu, n...

deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are...

چکیده معضل چاقی به عنوان عارضه ای جدی برای زندگی بی تحرک و ماشینی، مورد توجه اغلب مراکز بهداشتی و درمانی دنیا قرار گرفته است. چاقی عامل زمینه ساز و در واقع عامل خطری برای بروز بیماری های قلبی - عروقی است که عموماً با کاهش طول عمر مورد انتظار و افزایش بیماری همراه است. هدف پژوهش حاضر تأثیر 12 هفته تمرینات ویبریشن کل بدن، تمرینات هوازی و تمرینات ترکیبی( هوازی و ویبریشن کل بدن) بر ترکیب بدنی زنان ...

based on the latest records of typhlops vermicularis merrem, 1820 from iran, this species is distributed in the northern and southern regions of the country. in this study, new records of typhlops vermicularis are presented and it is shown that distribution range of this species is extended towards the eastern and western iran, and according to the new distribution map, it can be assumed that t...

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 ...

the ability to speak two languages in the world is a remarkable achievement. there is a good reason to believe that bilingualism is the norm for the majority of people in the world because 70% of the earth’s population are supposed to be bilingual or multilingual. various investigations have shown that the native language impacts foreign word recognition, and this influence is adapted by the de...