in this thesis,spin dependend transport and electron transport through of ng/sg(graphene/ superconductor graphen) are studied in the junction of ng/fgt/sg. due to andreev reflection conductance increases in the presence of superconductor graphene.also, by applying a voltage gate on a superconductor, fermi level shifts and the conductance is independent of ferromagnatic substrate. also, the cond...

abstract because of the many geopolitical, geo economical and geo strategically potentials and communicational capabilities of eco region, members can expand the convergence and the integration in base of this organization that have important impact on members development and expanding peace in international and regional level. based on quality analyzing of library findings and experts interv...

with the increasing population and the need for more food, as well as with the development of science and technology, human approach to unnatural and often chemical inputs to increase agricultural production has been a great expansion and problems such as increased cancers, chronic diseases has created environmental pollution. implementation of organic organic is a solution to these problems . ...

in this investigation the effect of external field on the electron density of nanostructures of cds, cdse, cdte, gaas and polymeric structure of three, four, five and six units of cds as a kind of nanosolar cells has been studied theoretically. as modeling this system in nanodimension, molecular structures has used. specific properties of molecular structures permit us to consider different sym...

recent years have witnessed an increased attention to form focused instruction and consciousness raising activities (ellis, 2002; doughty & williams, 1998) on the one hand and extensive and meaningful exposure to the target language (klapper & rees, 2003; day & bamford, 1998) on the other. due to significance attributed to above mentioned issues by scholars, this study attempted to bridge them ...

the treatment of in completely formed pulpless teeth has presented considrable problems. these teeth have wide open apexes and the walls of the root canal diverge toward the apical tissues. mechanical preparation cannot be done in the normal manner beacause of the large initial size and the taper of apical part of the canal , a mechanical stop cannot be produced at the apex of the canal and , t...

heuristics are often used to provide solutions for flow shop scheduling problems.the performance of a heuristic is usually judged by comparing solutions and run times on test cases.this investigation proposes an analytical alternative ,called asymptotic convergence ,which tests the convergence of the heuristic to a lower bound as problem size grows. the test is a stronger variation of worst cas...