نتایج جستجو برای: radiofrequency field

تعداد نتایج: 803430  

Journal: :Medycyna pracy 2013
Krzysztof Gryz Patryk Zradziński Jolanta Karpowicz Wiesław Leszko

BACKGROUND The activities of rescue and uniformed services require the use of wireless communication devices, such as portable radiophones. Assessment of workers' exposure to electromagnetic fields emitted by radiophones is important in view of occupational safety and health (OSH), legislation requirements and reports on possible adverse health effects in users of devices emitting radiofrequenc...

Journal: :Chemical communications 2016
Nadia C Lara Asad A Haider Jason C Ho Lon J Wilson Andrew R Barron Steven A Curley Stuart J Corr

For potential applications in nano-mediated radiofrequency cancer hyperthermia, the nanomaterial under investigation must increase the heating of any aqueous solution in which it is suspended when exposed to radiofrequency electric fields. This should also be true for a broad range of solution conductivities, especially those that artificially mimic the ionic environment of biological systems. ...

Journal: :Journal of applied microbiology 2000
M Tyurin R Padda K X Huang S Wardwell D Caprette G N Bennett

Molecular biological improvement of industrial solventogenic clostridia could be enhanced by a higher efficiency of electrotransformation. In this research, we used a new approach to determine the frequency spontaneously generated by Clostridium acetobutylicum ATCC 824 cells during the application of a square high-voltage pulse. Once the frequency of 100 kHz was determined we transformed clostr...

Journal: :Journal of magnetic resonance imaging : JMRI 2000
C J Yeung E Atalar

The safety of the barewire loopless catheter antenna in transmit mode is addressed with respect to radiofrequency (RF) heating. Analytical expressions for electric field and specific absorption rate (SAR) distributions surrounding the antenna are postulated and experimentally verified. Limiting RF transmit power to 40-70 mW time-averaged power, depending on the specific antenna design, will ens...

2015
Krzysztof Gryz Patryk Zradziński Jolanta Karpowicz

The use of radiofrequency (98-2450 MHz range) personal exposimeters to measure the electric field (E-field) in far-field exposure conditions was modelled numerically using human body model Gustav and finite integration technique software. Calculations with 256 models of exposure scenarios show that the human body has a significant influence on the results of measurements using a single body-wor...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2004
Daniel Topgaard Rachel W Martin Dimitris Sakellariou Carlos A Meriles Alexander Pines

A way to use adiabatic radiofrequency pulses and modulated magnetic-field gradient pulses, together constituting a "shim pulse," for NMR spectroscopy and imaging is demonstrated. These pulses capitalize on phase shifts derived from probe gradient coils to compensate for nonlinear intrinsic main magnetic field homogeneity for spectroscopy, as well as for deviations from linear gradients for imag...

Journal: :Magnetic resonance in medicine 2015
Ingmar Graesslin Peter Vernickel Peter Börnert Kay Nehrke Giel Mens Paul Harvey Ulrich Katscher

PURPOSE The goal of this study is to increase patient safety in parallel transmission (pTx) MRI systems. A major concern in these systems is radiofrequency-induced tissue heating, which can be avoided by specific absorption rate (SAR) prediction and SAR monitoring before and during the scan. METHODS In this novel comprehensive safety concept, the SAR is predicted prior to the scan based on pr...

2015
Patryk Zradziński

Due to the various physical mechanisms of interaction between a worker's body and the electromagnetic field at various frequencies, the principles of numerical simulations have been discussed for three areas of worker exposure: to low frequency magnetic field, to low and intermediate frequency electric field and to radiofrequency electromagnetic field. This paper presents the identified difficu...

Journal: :Ek'sperimentuli da klinikuri medic'ina 2022

The modern development of civilization cannot be imagined without the constantly growing number many devices that emit electromagnetic waves. Mobile phones as sources field (EMF) belong to low radio frequency range. All this is great interest for studying influence frequencies an artificially created environmental factor on health humans and other living organisms. According experimental study,...

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