نتایج جستجو برای: magnetic fields

تعداد نتایج: 535087  

Journal: :journal of sciences, islamic republic of iran 2011
p. davoudifar

cosmic rays (cr) travel at speeds essentially indistinguishable from the speed of light. however whilst travelling through magnetic fields, both regular and turbulent, they are delayed behind the light since they are usually charged particles and their paths are not linear. those delays can be so long that they are an impediment to correctly identifying sources which may be variable in time. fu...

In this paper, the Hartree-Fock method has been formulated to investigate some of the ground state properties of quasi-one-dimensional interacting electron gas in the presence of the magnetic field. The bare coulomb interaction between electrons has been assumed. For this system, we have also computed some of its thermodynamic and magnetic properties such as the energy, pressure, incompressibil...

ژورنال: سلامت کار ایران 2009
رضائی, فرشید, رنجبریان, محمد,

Background and aimsIntensity of Magnetic and Electric fields around visual displayterminals and its association on health effects were studied.Methodsmagnetic and electric fields intensities around 237 VDTs at distances 30¡50¡ 60 cm and different operating conditions (active¸ screen saver¸ shut down) with use of HI-3603 device  according to Svensk standard method were monitored. Resultsmagnetic...

Journal: :تحقیقات نظام سلامت 0
سمیه بلقن آبادی دانشجوی کارشناسی ارشد گروه مهندسی بهداشت حرفه ای، دانشکده بهداشت، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران حسینعلی یوسفی مربی، عضو هیأت علمی گروه مهندسی بهداشت حرفه ای، دانشکده بهداشت، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران حبیب اله دهقان استادیار، عضو هیأت علمی، گروه مهندسی بهداشت حرفه ای، دانشکده بهداشت، دانشگاه علوم پزشکی اصفهان، ایران

background: with increased use of computers, exposure to electric and magnetic fields is increasing, the main objective of this study was to evaluate the electric and magnetic field strength in portable computers (laptops) and its relation with eyestrain users. methods: in this cross – sectional study, magnetic and electric fields in 125 laptop computers were measured from 30 cm and 50 cm dista...

ژورنال: سلامت کار ایران 2013
علی آبادی, محسن, علیایی, محمد, فرهادیان, مریم, نوروزی, مرتضی, کمالی نیا, مجتبی,

 Background and aim:  Magnetic resonance imaging as one of the best medical scanning technique is considered to be the most important sources of static magnetic fields. The staffs of MRI ´s units frequently exposed to these static magnetic fields. This study aims to determine the occupational exposure level to mentioned field and its related health effects in MRI´s units.    Methods:  The occup...

2000
E. Battaner E. Florido A. Guijarro

Magnetic fields are considered to be dominant when εB ≥ εK , being εB = B /8π the magnetic energy density and εK = 1/2ρθ 2 the rotation energy density, for a conventional moderate B= 1 μG. They are considered to be negligible when εB < εK for B ∼ 10μG. With no assumption and no theoretical calculation, we show that magnetic fields cannot be ignored in the outer parts of a galaxy like the Milky ...

In this study, waves instability in free electron laser with background plasma, under the influence of self-electric and self-magnetic fields, are analyzed. A dispersion relation in the Raman regime for free electron laser with a helical wiggler magnetic field and an axial magnetic field derived in which all possible wave modes can have unstable couplings with each other. This dispersion relati...

آزاده اختری زواره, , بهروز میرزا, , علیرضا حجتی, ,

 We investigate the generation of large scale magnetic fields in the universe from quantum fluctuations that are produced in the inflationary stage. By coupling these quantum fluctuations to the dilaton field and Ricci scalar, we show that the magnetic fields with the strength observed today can be produced. We consider two situations. First, the evolution of dilaton ends by starting the reheat...

ژورنال: سنجش و ایمنی پرتو 2018

In the extremely low frequency range (3 to 300 Hz), the intensities of electric and magnetic fields increase with increasing voltage and current. If the intensities of electric and magnetic fields are high compared with standard exposure limits, they can have harmful effects on human health. In the vicinity of power lines and high voltage power stations, the intensities of these fields are usua...

Journal: :journal of advanced medical sciences and applied technologies 0
ali dadras ibb, tehran university deyhim atarod ibb, tehran university ali afrasiabi ibb, tehran university atiye liaghi ibb, tehran university ali naghshineh ibb, tehran university gholam hossein riazi ibb, tehran university

recently, the hypothesis in which memory and information would be stored as magnetic forms in astrocytes is expanding and neuromagnetic interactions between neurons and neighboring astrocytes in neocortex have potential to be the basis of memory formation. it has been proposed that all sorts of information may be maintained in form of neuronal activity-associated magnetic fields (naamfs) and th...

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