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[1] [2] 129 Xe is a stable, naturally occurring isotope of xenon with 26.44% isotope abundance. It is one of two Xe isotopes, along with 131 Xe, that has non-zero spin, which allows for magnetic resonance. 129 Xe is used for MRI because its large electron cloud permits hyperpolarization and a wide range of chemical shifts
In terms of detecting ventilation defects, 129 Xe has a lower signal-to-noise ratio but is more sensitive to defects due to its higher density and lower diffusivity. [30] Currently, using a larger volume of 129 Xe (up to 1 liter per scan) can compensate for its decreased signal-to-noise ratio compared to 3He (usually 0.1-0.3 liters per scan).
The first explicit recognition of non-atmospheric Xe in terrestrial samples came from the analysis of CO 2-well gas in New Mexico, displaying an excess of 129 I-derived or primitive source 129 Xe and high content in 131-136 Xe due to the decay of 238 U. [38] At present, the excess of 129 Xe and 131-136 Xe has been widely observed in mid-ocean ...
Naturally occurring xenon (54 Xe) consists of seven stable isotopes and two very long-lived isotopes. Double electron capture has been observed in 124 Xe (half-life 1.8 ± 0.5(stat) ± 0.1(sys) × 10 22 years) [2] and double beta decay in 136 Xe (half-life 2.165 ± 0.016(stat) ± 0.059(sys) × 10 21 years), [7] which are among the longest measured half-lives of all nuclides.
Using plastics and polymers in bio-MEMS is attractive because they can be easily fabricated, compatible with micromachining and rapid prototyping methods, as well as have low cost. [ 10 ] [ 11 ] Many polymers are also optically transparent and can be integrated into systems that use optical detection techniques such as fluorescence , UV/Vis ...
Because of its scarcity, xenon is much more expensive than the lighter noble gases—approximate prices for the purchase of small quantities in Europe in 1999 were 10 €/L (=~€1.7/g) for xenon, 1 €/L (=~€0.27/g) for krypton, and 0.20 €/L (=~€0.22/g) for neon, [67] while the much more plentiful argon, which makes up over 1% by volume ...
The ARSA system continuously collects xenon from the air in batch mode, processing approximately 48 m 3 in an 8-hour period. The average amount of xenon collected in this period is approximately 2 cc. The xenon gas is then transferred into a nuclear detection system consisting of a beta–gamma coincidence spectrometer.
A variant of the Armalite AR-15 and M16 rifle, using a Pneumatic Valve and Rod system. Used by the Special Operations Command. Night Fighting Weapons System Philippines: Assault rifle: 5.56×45mm: NFWS: unknown: Introduced in 2004, developed by the PMC based on M16A1 rifle after experiences in the MSSR. Used by MARSOG. [29] M4/M4A1 United States