Radiofrequency electromagnetic radiation

Electrical sources static electricity, electrical current, lightning, stray currents (radiofrequency electromagnetic radiation, overhead high voltage transmission lines, galvanic and cathodic protection stray currents)... 

SC-52 Conceptual Basis of Calculations of Dose Distributions SC-53 Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Radiation... 

Fillers which generate heat upon exposure to certain electromagnetic fields can be used in heat cure epoxies where the parts to be bonded cannot be heated to the appropriate cure temperature, either due to size or heat sensitivity. Barium titanate and/or hydrated aluminosilicate show hysteresis loss (heat generation) when exposed to radiofrequency electromagnetic radiation. 

Nuclear magnetic resonance (NMR) spectroscopy is based on the absorption of radiofrequency electromagnetic radiation (of the order of 100 MHz) by atomic nuclei [mainl> protons proton magnetic resonance (PMR), but also C, N, F, Na, Mg, etc.] in substances placed ir... 

In brief, a magnetic atomic nucleus in a magnetic field may be either lined up with or opposed to the external field, and the transition from one state to the other corresponds to an amount of energy which can be provided by electromagnetic radiation in the radiofrequency range. 

The basis of NMR spectroscopy lies in the absorption of electromagnetic radiation at radiofrequencies by atomic nuclei.426 427 432-437 All nuclei with odd mass numbers (e.g., H, 13C, 15N, 170,19F, and 31P), as well as those with an even mass number but an odd atomic number, have magnetic properties. Absorption of a quantum of energy E = hv occurs only when the nuclei are in the strong magnetic field of the NMR spectrometer and when the frequency v of the applied electromagnetic radiation is appropriate for "resonance"... 

The electromagnetic spectrum - units. The wavelengths of electromagnetic radiation of interest vary from metres for the radiofrequency range to about 10 10 m for X-rays. A wave has associated with it both wavelength, X, and frequency, v, which are related by the equation ... 

Radiofrequency Electromagnetic Fields—Properties, Quantities and Units, Biophysical Interaction, and Measurements (1981) Radiation Protection in Pediatric Radiology (1981)... 

NMR collects information concerning interactions between the nuclei of certain atoms present in the sample when they are submitted to a static magnetic field which has a very high and constant intensity and exposed to a second oscillating magnetic field. The second magnetic field, around 10 000 times weaker than the first is produced by a source of electromagnetic radiation in the radiofrequency domain. 

The radiofrequency cavity system (RF in Figure 2.4), which acts on the circulating electrons and restores the energy they lose through the emission of electromagnetic radiation. 

On our planet, we live at the bottom of an ocean if air. The two "windows" of air for electromagnetic radiations are in the visible and radiofrequency regions. The former window has been used by living organisms since immemorial times, but the latter window has only recently allowed mankind to obtain information on our universe. The discovery by radioastronomic means of quasars, pulsars and (most relevant for the present discussion) polyacetylenic nitriles and dinitriles indicates that carbon-containing cages and chains are ubiquitous in the cosmos. 

A rather small fraction of the cosmic radiation consists of electromagnetic radiation and electrons. The former vary in energy from a small percentage of y-rays to a considerable intensity of X-rays, to visible light and to radiation in the radiofrequency region. The types... 

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