Wikipedia-diskussion:AA-TaskForce/Ædelgasser/Xenon

message: Er helt ude og.... her. Og jo mere jeg roder mig ud i oversættelsen af dette afsnit, jo mere forviret bliver jeg.
Hvad jeg har fået oversat (tror jeg):
=== Medicinsk billeddannelse ===
Gamma udledningen fra radioisotopen 133Xe kan for eksempel bruges til at scanne (og derved danne billeder) af hjerte, lunger og hjernen ved hjælp af Single Photon Emission Computed Tomography metoden. 133Xe er også blevet brugt til at måle blodgennemstrømning.
Kernen af de to stabile isotoper af xenon, 129Xe og 131Xe, har et indre ikke-nul impulsmoment (nuklearspin). Når det blandes med et alkalie og nitrogen og derefter udsat for en laserstråle bestående af cirkulært polariseret lys som er indstillet til en spektrallinje inden for alkalie atomerne område,
Engelsk:
===Medical imaging===
Gamma emission from the radioisotope 133Xe of xenon can be used to image the heart, lungs, and brain, for example, by means of single photon emission computed tomography.  133Xe has also been used to measure blood flow.
Nuclei of two of the stable isotopes of xenon, 129Xe and 131Xe, have non-zero intrinsic angular momenta (nuclear spins). When mixed with alkali vapor and nitrogen and exposed to a laser beam of circularly polarized light that is tuned to an absorption line of the alkali atoms, their nuclear spins can be aligned by a spin exchange process in which the alkali valence electrons are spin-polarized by the light and then transfer their polarization to the xenon nuclei via magnetic hyperfine coupling.  Typically, pure rubidium metal, heated above 100 °C, is used to produce the alkali vapor. The resulting spin polarization of xenon nuclei can surpass 50% of its maximum possible value, greatly exceeding the equilibrium value dictated by the Boltzmann distribution (typically 0.001% of the maximum value at room temperature, even in the strongest magnets). Such non-equilibrium alignment of spins is a temporary condition, and is called hyperpolarization.
Because a 129Xe nucleus has a spin of 1/2, and therefore a zero electric quadrupole moment, the 129Xe nucleus does not experience any quadrupolar interactions during collisions with other atoms, and thus its hyperpolarization can be maintained for long periods of time even after the laser beam has been turned off and the alkali vapor removed by condensation on a room-temperature surface. The time it takes for a collection of spins to return to their equilibrium (Boltzmann) polarization is called the T1 relaxation time. For 129Xe it can range from several seconds for xenon atoms dissolved in blood to several hours in the gas phase and several days in deeply frozen solid xenon. In contrast, 131Xe has a nuclear spin value of 3/2 and a nonzero quadrupole moment, and has T1 relaxation times in the millisecond and second ranges. Hyperpolarization renders 129Xe much more detectable via magnetic resonance imaging and has been used for studies of the lungs and other tissues.  It can be used, for example, to trace the flow of gases within the lungs.
--Seekers 27. jul 2009, 01:39 (CEST)
thread_title:  Hjælp til oversættelse... 

message: Gamma udledningen fra radioisotopen 133Xe kan for eksempel bruges til at scanne (og derved danne billeder) af hjerte, lunger og hjernen ved hjælp af Single Photon Emission Computed Tomography metoden. 133Xe er også blevet brugt til at måle blodgennemstrømning.
Kernen af de to stabile isotoper af xenon, 129Xe og 131Xe, har et indre ikke-nul impulsmoment (nuklearspin). Når det blandes med et alkalie og nitrogen og derefter udsat for en laserstråle bestående af cirkulært polariseret lys som er indstillet til en spektrallinje inden for alkalie atomerne område,
Engelsk:
thread_title:  Medicinsk billeddannelse 

message: Gamma emission from the radioisotope 133Xe of xenon can be used to image the heart, lungs, and brain, for example, by means of single photon emission computed tomography.  133Xe has also been used to measure blood flow.
Nuclei of two of the stable isotopes of xenon, 129Xe and 131Xe, have non-zero intrinsic angular momenta (nuclear spins). When mixed with alkali vapor and nitrogen and exposed to a laser beam of circularly polarized light that is tuned to an absorption line of the alkali atoms, their nuclear spins can be aligned by a spin exchange process in which the alkali valence electrons are spin-polarized by the light and then transfer their polarization to the xenon nuclei via magnetic hyperfine coupling.  Typically, pure rubidium metal, heated above 100 °C, is used to produce the alkali vapor. The resulting spin polarization of xenon nuclei can surpass 50% of its maximum possible value, greatly exceeding the equilibrium value dictated by the Boltzmann distribution (typically 0.001% of the maximum value at room temperature, even in the strongest magnets). Such non-equilibrium alignment of spins is a temporary condition, and is called hyperpolarization.
Because a 129Xe nucleus has a spin of 1/2, and therefore a zero electric quadrupole moment, the 129Xe nucleus does not experience any quadrupolar interactions during collisions with other atoms, and thus its hyperpolarization can be maintained for long periods of time even after the laser beam has been turned off and the alkali vapor removed by condensation on a room-temperature surface. The time it takes for a collection of spins to return to their equilibrium (Boltzmann) polarization is called the T1 relaxation time. For 129Xe it can range from several seconds for xenon atoms dissolved in blood to several hours in the gas phase and several days in deeply frozen solid xenon. In contrast, 131Xe has a nuclear spin value of 3/2 and a nonzero quadrupole moment, and has T1 relaxation times in the millisecond and second ranges. Hyperpolarization renders 129Xe much more detectable via magnetic resonance imaging and has been used for studies of the lungs and other tissues.  It can be used, for example, to trace the flow of gases within the lungs.
--Seekers 27. jul 2009, 01:39 (CEST)
thread_title: Medical imaging

message: Memo til mig selv: Xenonforgiftning er et fænomen, hvor den inaktive luftart xenon dannes ved radioaktive henfald i kernereaktorer. Efter et stykke tid med et voksende mængde af xenon kan der være problemer med at starte reaktoren igen. Dette kendes som xenonforgiftning.
Man kan sikre en jævn udbrænding ved at kontrollere brændselsstængerne.
(KILDER!? Tjek Nuclear_poison på en.wiki) --Seekers 23. dec 2009, 07:21 (CET)
thread_title:  Memo: Evt tilføj afsnit om forgiftning