نتایج جستجو برای: low frequency
تعداد نتایج: 1586424 فیلتر نتایج به سال:
the efficacious effects of pulsed electromagnetic field (pemf) under the certain field parameters like frequency and the field intensity have been reported for various tissue and molecules. since collagen is found abundantly in most tissue structures, this research was designed to further investigate the effects of extremely low frequency (elf) pemf on the synthesis of the epidermal collagen. t...
introduction: public and occupational exposure to extremely low frequency (elf) electric and magnetic fields induced by electrical equipment is a significant issue in the environment and at the workplace due to their potential health effects on public health. the purpose of this study was assessment of the electric and magnetic fields intensities and determination of mental and psychological ef...
the ever increasing rate of power consumption has led to an increase in public exposure to extremely low frequency magnetic fields (elf-mfs) and brought severe concerns about their health effects. considering previous studies and the facts about potential health effects of these fields, the present study aimed to evaluate the elf-mf flux densities from power distribution lines near hospitals in...
A simple model is developed to characterize the behavior of radio-frequency absorbers at low frequency. The absorber is represented by a flat, homogeneous, isotropic slab of lossy material, with effective constitutive parameters. These parameters are determined by a fit to measured data. Excellent fits are obtained in the two applications considered. The model is intended for use in the charact...
abstract the present study was conducted to examine the effect of proficiency on students interaction while carrying out the grammar-based task(s) in collaboration. in particular, the study examines whether the level of proficiency affects the learners’ focus of attention to grammatical and lexical features. the study takes a further step and examines whether there is any difference in the use...
knowledge about low flow statistics is essential for effective water resource planning and management in ungauged orpoorly gauged catchment areas, especially in arid and semi-arid regions such as iran. we employed a data set of 20 riverflow time-series from the iranian central plateau river basin, iran to evaluate the low-flow series using several frequencyanalysis methods and compared the resu...
this paper presents a new damping controller design based on fuzzy wavelet neural network (fwnn) to damp the multi-machine power system low frequency oscillations. the error between the desired system output and the output of control object is directly utilized to tune the network parameters. the orthogonal least square (ols) algorithm is used to purify the wavelets for each rule and determine ...
Background and Purpose: Although the evolution of industrial systems toward digital technologies decreased the exposure to high levels of noise, it has created some problems encountered with low level and provoking noise (low frequency noise). In the present work, the mental performance of students exposed to low frequency and reference noises at low and high levels (45 & 65 dB) were studied....
The main result of this paper is to reduce the calculation of higher-order terms in the asymptotic expansions of the electric and magnetic elds at low frequencies to the solutions of certain canonical problems. We also provide a new and simple variational proof of the convergence of the electric and magnetic elds solutions of the scattering problem for the Maxwell equations as the frequency goe...
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