efl/esl textbooks have been regarded as essential language teaching materials with which the learners spend about 70 up to 90 percent of their class time. the important role they play and their vast use make them not only influential in learning the language but also in shaping values and attitudes. put it another way, textbooks socialize learners using their contents (i.e. texts, illustrations...

any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...

peace and national security protection and ironic solving of international conflicts become the preliminary foundation of the united nations charter and had been considered as the main responsibilities of the security council, after world war ii and the establishment of united nations organization. therefore, the security council enables to analyze every kind of conflicts and challenges which ...

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...

this study investigated the potential role of age in inductive and deductive grammar learning among iranian foreign language learners. the experimental population consisted of our randomly selected samples including two groups of children (with age of exposure to english within 8-13), and two groups of adults (with age of exposure to english within 11-13). thus, the comparison was between ch...

the poor orientation of the restaurants toward the information technology has yet many unsolved issues in regards to the customers. one of these problems which lead the appeal list of later, and have a negative impact on the prestige of the restaurant is the case when the later does not respond on time to the customers’ needs, and which causes their dissatisfaction. this issue is really sensiti...

abstract: sayyed mohammad tabatabaee is accounted as one of the effective persons in iran contemporaneoushistory and his role in the events of iran constitution revolution is inevitable. sayyed mohammad tabatabaee from the time of naser al din shah qajar and arrival to iran, informed of the advantages and the basis of constitution, was in the thought of making the iran rule as a constituti...

abstract nowadaysphotovoltaic solar cells (pvs) areacknowledged the fastest growing energy technology in the word, however, they only account for only fraction of current global renewable energy capacity. it isrecognized that this incomplete market penetration has been largely a result of the technology’sexcessive cost. so researchers are trying to find innovative, economic way with theaim of ...

this study was an attempt to investigate and compare the effect of lexical inferencing and concept mapping on developing vocabulary retention of iranian language learners. sixty homogeneous students from different intact classes who were being taught as intermediate learners in sokhan english institute participated in this study. they were in different classes. a teacher made test as a pre-test...

asymmetric polyethersulfone (pes) microfiltration flat sheet membranes were composed by the phase inversion method (pim) and were used as supports. composite membranes were fabricated by coating silicone rubber as selective layer. effect of different concentrations of pes and pdms and different solvent such as nmp, dmf and dms effects as pes solvents and support thickness and different coagulat...