Radio Frequency Radiation
Radio Frequency Radiation - Related Videos
10:00
Calibration of Vector Network Analyzer for Measurements in Radio Frequency Propagation Channels
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Cited by 1 •
2020
This protocol describes best practices for calibrating a vector network analyzer prior to use as an accurate instrument, intended to measure components of a radio frequency propagation measurement test system.
06:53
Quantification of γH2AX Foci in Response to Ionising Radiation
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Cited by 23 •
2010
Quantification of DNA double-strand streaks using γH2AX formation as a molecular marker has become an invaluable tool in radiation biology. Here we demonstrate the use of an immunofluorescence assay for quantification of γH2AX foci after exposure of cells to radiation.
09:38
Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
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Cited by 4 •
2015
We describe the generation of far-infrared radiation using an optically pumped molecular laser along with the measurement of their frequencies with heterodyne techniques. The experimental system and techniques are demonstrated using difluoromethane (CH2F2) as the laser medium whose results include three new laser emissions and eight measured laser frequencies.
08:17
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
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Cited by 9 •
2015
Stereotactic ablative body radiation therapy (SBRT) involves the precise delivery of high-dose radiation to cancer tumor targets. A novel SBRT platform offers a first-of-its-kind gimbaled radiation accelerator mounted within a pivoting O-ring gantry capable of dynamic image-guided tumor tracking. Here, we describe dynamic tumor tracking for lung targets.
02:59
Biological Effects of Radiation
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2020
All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, α and β particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they produce ions...
FAQs
Alternating electric fields can drive molecular dipoles, causing their orientations to respond to the changing field. The resulting energy transfer depends on frequency, intensity, and the properties of the material exposed. These variables determine whether the dominant outcome is molecular response, dielectric heating, or another frequency-dependent interaction, making experimental conditions central to interpreting RF effects.
At specific resonant frequencies, radio frequency radiation can change nuclear spin states. This selective interaction is essential to nuclear magnetic resonance spectroscopy because the resulting signals depend on the molecular environment of the nuclei. Chemists can therefore use resonance responses to obtain information about molecular structure, composition, dynamics, and changes occurring during a reaction.
Dielectric heating results when alternating fields transfer energy through the response of molecular dipoles, raising the temperature of a material. NMR instead relies on radiofrequency pulses applied at resonant frequencies to change nuclear spin states and produce measurable signals. Thus, one outcome is controlled thermal energy transfer, while the other provides chemical information through spectroscopy.
Frequency, intensity, exposure, and material properties collectively influence the result. Frequency can determine whether a system responds through dipole motion or a resonant nuclear-spin transition, while intensity and exposure affect energy transfer. The material itself also matters because its molecular properties govern how strongly it responds, heats, or generates an informative signal.
In NMR spectroscopy, radio frequency pulses are applied to produce changes in nuclear spin states at relevant resonant frequencies. The system then generates signals that can be analyzed for molecular structure and composition, as well as molecular dynamics. Repeated measurements can also reveal reaction progress, extending the technique beyond a static structural snapshot.
RF methods are useful when heating must be controlled through interactions between alternating fields and the material. Their dependence on frequency, intensity, exposure, and material properties allows the energy-transfer conditions to be adjusted for a particular process. In chemistry, this supports controlled heating and materials processing rather than relying only on nonspecific thermal treatment.