نتایج جستجو برای: frequency
تعداد نتایج: 484143 فیلتر نتایج به سال:
the present research was conducted to accomplish two purposes. firstly, it aimed to explore and describe schematic structure or what halliday and hassan (1989, p.64) have called “generic structure potential” (gsp) of american english, iranian persian and iranian english newspaper editorials within systemic functional linguistics. secondly, a quantitative cross-comparison was made to investigate...
in this work we deal with the coefficients of a (e it ) 2 , where a is in a class of polynomialshaving unimodular coefficients. we first present a technique that calculates lower bounds for particularautocorrelations and then in a more general case we present an upper bound for their maximal order.
background: weaning plays a major role in determining the nutritional status of a child. poor weaning practices during infancy and early childhood, resulting in malnutrition, contribute to impairment of cognitive and social development, poor school performance and reduced productivity in later life. the objective of this study is to know weaning practices of mothers of difficult terrain. method...
introduction: it has been reported that cardiovascular effects are among the possible health effects of being exposed to extremely low frequency electromagnetic fields (elf emss). material and methods: this study has been conducted to evaluate the long term effects of exposure to magnetic and electric fields on electrocardiogram signal changes. nine power transmission posts having different vol...
background: for a long time, intestinal parasite infections are among the major problems of public health in iran. our aim was epidemiological studies on the frequency of intestinal parasites in patients referred to three hospitals in tehran during 2007-2008. methods : during 2007-2008, by simple random selection, 1000 stool samples were collected from milad, hazrat-e-rasoul and shahid fahmid...
the drawing of frequency-path (f-p) models of optical beams is an approach for nonlinearity analysis in nano-metrology systems and sensors based on the laser interferometers. in this paper, the frequency-path models of four nano-metrology laser interferometry systems are designed, analyzed and simulated, including conventional and modified two- and three-longitudinal-mode laser interferometers....
objectives : anterior maxilla, known as the esthetic zone, plays an important role in facial and smile esthetics. this study assessed the frequency of implant treatments in the esthetic zone of patients presenting to dental implant department of tehran university during 2002-2012. materials and methods: this descriptive study was conducted on dental records of patients receiving implant treatme...
a bstract background: nutrition pattern is one of the important factors predicting menstrual distress, which varies among different cultures and countries. the purpose of this study is to determine the relationship between food frequency and menstrual distress in high school girls from mashhad. materials and methods: this cross‑sectional study was conducted in 2012 using a two‑stage sampling ...
objective despite numerous reports on the effects of meal frequency on biochemical parameters such as plasma lipid profile, glucose and insulin, there is almost no study to investigate the influence of meal frequency on immune system. in the present article, for the first time, the effect of meal frequency on complement components c3 and c4, as key components of the complement system, has been ...
spectral decomposition is a powerful tool for analysis of seismic data. fourier transform determines the frequency contents of a signal. but for analysis of non-stationary signals, 1-d transform to frequency domain is not sufficient. in early years, transforming of seismic traces into time and frequency domain was done via windowed fourier transform, called a short time fourier transform (stft)...
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