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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).
Ion thrusters in operation typically consume 1–7 kW of power, have exhaust velocities around 20–50 km/s (I sp 2000–5000 s), and possess thrusts of 25–250 mN and a propulsive efficiency 65–80% [3] [4] though experimental versions have achieved 100 kW (130 hp), 5 N (1.1 lb f).
129 Xe was derived from the extinct nuclide of iodine, iodine-129 or 129 I (with a half-life of 15.7 Million years, or Myr), which can be used in iodine-xenon (I-Xe) dating. The production of 129 Xe stopped within about 100 Myr after the start of the Solar System because 129 I became extinct. [1]
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.
Ion engine: 1 1: Mercury Cesium: NASA: NASA Hughes: Space Electric Rocket Test, suborbital (31 min), the first demonstration of an ion engine in space - only the mercury engine by NASA was operated Program 661A Flight B: 29 Aug 1964: 29 Aug 1964: Ion engine: 1: Cesium: USAF: EOS: Suborbital, experimental test (19 min operation) Zond 2: 30 Nov ...
1.5 L (1,493 cc or 91.1 cu in) I3, with a single overhead camshaft, four valves-per-cylinder, and common-rail direct fuel injection. This engine was designed in 1998 with the related 4-cylinder variant R 420 SOHC. In 1999, VM granted Hyundai the license to manufacture both engines.
2 1/2-ton Utility Vehicle: M35 – Divided into several variants and series. More delivered in 2013. Kia KM25 Series Republic of Korea: 2 1/2-ton Utility Vehicle: KM250 – Several dozens received in multiple batches acquired by the Philippine Navy and the Armed Forces of the Philippines. M939 truck United States: Heavy Utility Vehicle: M923 –