this thesis basically deals with the well-known notion of the bear-invariant of groups, which is the generalization of the schur multiplier of groups. in chapter two, section 2.1, we present an explicit formula for the bear-invariant of a direct product of cyclic groups with respect to nc, c>1. also in section 2.2, we caculate the baer-invatiant of a nilpotent product of cyclic groups wuth resp...

in the first chapter we study the necessary background of structure of commutators of operators and show what the commutator of two operators on a separable hilbert space looks like. in the second chapter we study basic property of jb and jb-algebras, jc and jc-algebras. the purpose of this chapter is to describe derivations of reversible jc-algebras in term of derivations of b (h) which are we...

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...

abstract since heubners (1985) pioneering study, there have been many studies on (mis) use/ non-use of articles by l2 learners from article-less and article languages. the present study investigated how persian l2 learners of english produce and interpret english definite descriptions and demonstrative descriptions. it was assumed that definite and demonstrative descriptions share the same cen...

abstract al- muntazam by ibn al -jawzi is one of the greatest the book ancient book of texts on history of islam in the 6th century.it is very important one;because of including rare reports which are not found any where.in addition to historical reports,his outlook , in which embodies information on mythologies, milal wa nihal (sects and creeds), geography, and political, social and religiou...

august wilson is undoubtedly one of the rare black playwrights whose works have attracted streams of attention and worldwide audience. the present study aims at analyzing fences and piano lesson which are two of the most successful plays in his pittsburgh cycle from the perspective of michel foucault’s theories and ideas. studying these two plays from foucault’s perspective opens new windows in...

this study focuses on jane austens representation of her heroines in two of her novels: pride and prejudice, and mansfield park. i have concentrated only on a single idea: how jane austen takes her heroines through a course of psychogical reformation to which almost everything else in her novel is subsidiary. although i have discussed only pride and prejudice, we can trace austens carefully pla...

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...

testing plays a vital role in any language teaching program. it allows teachers and stakeholders, including program administrators, parents, admissions officers and prospective employers to be assured that the learners are progressing according to an accepted standard (douglas, 2010). the problems currently facing language testers have both practical and theoretical implications but the first i...

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 ...