نتایج جستجو برای: and improve such soils is very costly

تعداد نتایج: 17320819  

پایان نامه :دانشگاه بین المللی امام خمینی (ره) - قزوین - دانشکده علوم پایه 1392

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1390

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان 1389

run-out-table (rot) is located between last finishing stand and down coiler in a hot strip mill. as the hot steel strip passes from rot, water jets impact on it from top and bottom and strip temperature decreases approximately from 800-950 °c to 500-750°c. the temperature history that strip experience while passing through rot affects significantly the metallurgical and mechanical properties, s...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده زبانهای خارجی 1393

feminine voice and narratology in wuthering heights wuthering heights as a general "bronte" work has extraordinary dimensions to it which can make it focal to different ways of interpretation. among other differences the issue of narrative voice is essential in understanding the ultimate purpose of wuthering heights. emily bronte uses different narrators from various focal points speaking of m...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان - دانشکده ادبیات و علوم انسانی 1393

from its emergence till present time marxist principles has undergone great changes since their promulgation by marx. many theorists and thinkers set at rectifying marxist tenets and introducing those of their own while others advocated its main concepts and attempted at improving them. among marxist philosophers who had an intensive study of marxs ideology, is louis althusser whose reflections...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند 1388

a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...

Journal: :مرتع و آبخیزداری 0
غلامرضا زهتابیان استاد دانشکده منابع طبیعی، دانشگاه تهران حسن خسروی استادیار دانشکده منابع طبیعی، دانشگاه تهران علی آذره دانشجوی دکتری بیابان زدایی، دانشکده منابع طبیعی، دانشگاه تهران

need to increasing agricultural land in order to improve food resources in the past two centuries recentlead to widespread changes in land use and improper management of these lands. continue thisprocess can lead to land degradation and desertification, and improve such soils is very costly;therefore, prevention of land degradation is more desirable. this function requires to research on theuti...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده ادبیات و علوم انسانی 1392

the construct of self-efficacy has received increasing attention in research over the past two decades. many studies have been carried out 1.3 significance of the study this study has pedagogical implications since improving students’ self- efficacy and autonomy is important for promoting actual performance on classroom academic tasks. in academic settings, it has been shown that self-effi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان - دانشکده علوم انسانی 1393

colonialism is an important factor in cultural production and many of cultural constructs all over the world. english and english language teaching are at the center of the contemporary world. postcolonial literature, the genre achebe exercised, is a kind of historical text which has become central to different debates and criticisms. in this thesis, different elements related to the colonial...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه - پژوهشکده ادبیات 1393

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...

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