نتایج جستجو برای: average of annual changes area
تعداد نتایج: 21258995 فیلتر نتایج به سال:
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 ...
converting rangelands to arable land such as dry farming is widely practiced in many places in iran. this activity could possibly contribute to the increase in downstream sedimentation. the effects of this activity on downstream watersheds are not well documented for many strategic areas in the country. one such area which is proposed for this study is the kardeh drainage basin, located in the ...
introduction: the increasing global consensus built on empirical evidence, expresses that the world, is facing a threat from climate change. as a result, this can affect the agricultural sector through its productivity changes and so influence food security in the world. this can be more intuitive for countries that are dependent on agriculture. agriculture is an important sector in iran that p...
abstract the influence of cation?? and anion?? interactions on the strength and nature of n…h hydrogen bond has been investigated by quantum chemical calculations in s-triazine…3hf complex. ab initio calculations were performed at mp2/6-311++g(d,p) level of theory. the natural bond orbital (nbo) analysis and the bader’s quantum theory of atoms in molecules (aim) were also used to elucidate t...
Analysis of the relationship between dust phenomenon and rural population changes in Sistan region Abstract Aims & Backgrounds: Dust storms are a phenomenon caused by weather conditions such as high wind speeds, dry air and bare and vulnerable soil to erosion. One of the most important areas affected by dust in other parts of Iran is the Sistan region in southeastern Iran. This study was condu...
plagiarism in esl/efl learning contexts has been established as a dynamic and multi-layered phenomenon and has become a topic engaging many researchers in a heated debate in recent years. comparisons of student-generated texts with their source texts have shown that students rely on source texts in their writings and copying is a major strategy used by both l1 and l2 writers. in our country a...
Abstract This study examines the effects of climate change on runoff in the Yellow River basin in Khuzestan province. In this study, the combination of 14 general circulation models under two emission scenarios A2 and B1 were used for simulating the climatic variables in the next period (2025-2054) compared to the baseline period (1971-2000). The weighting method of mean observed temperature...
Dust samples collected annually for 5 years from 55 sites in southern Nevada and California provide the first regional source of information on modem rates of dust deposition, grain size, and mineralogical and chemical composition relative to climate and to type and lithology of dust source. The average silt and clay flux (rate of deposition) in southern Nevada and southeastern California range...
background: the aim of this study was to measure137cs levels in soil and brick samples to set the baseline data and an indicator of fallout radioactivity for this part of the world. this study will help to probe, if there is any health threat posed by 137cs exposure to the residents of the area. materials and methods: twenty five samples of soil and 6 samples of bricks were collected from diffe...
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