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- Earths_field_NMR abstract "Nuclear magnetic resonance (NMR) in the geomagnetic field is conventionally referred to as Earth's field NMR (EFNMR). EFNMR is a special case of low field NMR.When a sample is placed in a constant magnetic field and stimulated (perturbed) by a time-varying (e.g., pulsed or alternating) magnetic field, NMR active nuclei resonate at characteristic frequencies. Examples of such NMR active nuclei are the isotopes carbon-13 and hydrogen-1 (hydrogen-1 often being referred as protons). The resonant frequency of each isotope is directly proportional to the strength of the applied magnetic field, and the magnetogyric or gyromagnetic ratio of that isotope. The signal strength is proportional both to the stimulating magnetic field and the number of nuclei of that isotope in the sample. Thus in the 21 tesla magnetic field that may be found in high resolution laboratory NMR spectrometers, protons resonate at 900 MHz. However, in the Earth's magnetic field the same nuclei resonate at audio frequencies of around 2 kHz and generate very weak signals.The location of a nucleus within a complex molecule affects the 'chemical environment' (i.e. the rotating magnetic fields generated by the other nuclei) experienced by the nucleus. Thus different hydrocarbon molecules containing NMR active nuclei in different positions within the molecules produce slightly different patterns of resonant frequencies.EFNMR signals can be affected by both magnetically noisy laboratory environments and natural variations in the Earth's field, which originally compromised its usefulness. However this disadvantage has been overcome by the introduction of electronic equipment which compensates changes in ambient magnetic fields.Whereas chemical shifts are important in NMR, they are insignificant in the Earth's field. The absence of chemical shifts causes features such as spin-spin multiplets (that are separated by high fields) to be superimposed in EFNMR. Instead, EFNMR spectra are dominated by spin-spin coupling (J-coupling) effects. Software optimised for analysing these spectra can provide useful information about the structure of the molecules in the sample.".
- Earths_field_NMR wikiPageExternalLink SS24.pdf.
- Earths_field_NMR wikiPageExternalLink www.magritek.com.
- Earths_field_NMR wikiPageExternalLink robinson_nmr_imaging_JMR2006.pdf.
- Earths_field_NMR wikiPageExternalLink index.shtml.
- Earths_field_NMR wikiPageID "11434033".
- Earths_field_NMR wikiPageLength "8500".
- Earths_field_NMR wikiPageOutDegree "48".
- Earths_field_NMR wikiPageRevisionID "689648908".
- Earths_field_NMR wikiPageWikiLink Amplifier.
- Earths_field_NMR wikiPageWikiLink Angular_momentum_coupling.
- Earths_field_NMR wikiPageWikiLink Animal.
- Earths_field_NMR wikiPageWikiLink Audio_frequency.
- Earths_field_NMR wikiPageWikiLink Carbohydrate.
- Earths_field_NMR wikiPageWikiLink Carbon-13.
- Earths_field_NMR wikiPageWikiLink Carbon-13_nuclear_magnetic_resonance.
- Earths_field_NMR wikiPageWikiLink Category:Geomagnetism.
- Earths_field_NMR wikiPageWikiLink Category:Nuclear_magnetic_resonance.
- Earths_field_NMR wikiPageWikiLink Chemical_shift.
- Earths_field_NMR wikiPageWikiLink Earths_magnetic_field.
- Earths_field_NMR wikiPageWikiLink Electromagnetic_spectrum.
- Earths_field_NMR wikiPageWikiLink Free_induction_decay.
- Earths_field_NMR wikiPageWikiLink Gyromagnetic_ratio.
- Earths_field_NMR wikiPageWikiLink Hydrocarbon.
- Earths_field_NMR wikiPageWikiLink Isotope.
- Earths_field_NMR wikiPageWikiLink Isotopes_of_hydrogen.
- Earths_field_NMR wikiPageWikiLink J-coupling.
- Earths_field_NMR wikiPageWikiLink Larmor_precession.
- Earths_field_NMR wikiPageWikiLink Low_field_nuclear_magnetic_resonance.
- Earths_field_NMR wikiPageWikiLink Magnetic_resonance_imaging.
- Earths_field_NMR wikiPageWikiLink Natural_gas.
- Earths_field_NMR wikiPageWikiLink Nuclear_magnetic_resonance.
- Earths_field_NMR wikiPageWikiLink Nuclear_magnetic_resonance_spectroscopy.
- Earths_field_NMR wikiPageWikiLink Petroleum.
- Earths_field_NMR wikiPageWikiLink Plant.
- Earths_field_NMR wikiPageWikiLink Proton.
- Earths_field_NMR wikiPageWikiLink Proton_magnetic_moment.
- Earths_field_NMR wikiPageWikiLink Proton_magnetometer.
- Earths_field_NMR wikiPageWikiLink Proton_nuclear_magnetic_resonance.
- Earths_field_NMR wikiPageWikiLink Radio_frequency.
- Earths_field_NMR wikiPageWikiLink Signal-to-noise_ratio.
- Earths_field_NMR wikiPageWikiLink Tesla_(unit).
- Earths_field_NMR wikiPageWikiLink Ultra_low_frequency.
- Earths_field_NMR wikiPageWikiLink Very_low_frequency.
- Earths_field_NMR wikiPageWikiLink Water.
- Earths_field_NMR wikiPageWikiLink Zero_field_NMR.
- Earths_field_NMR wikiPageWikiLinkText "Earth's field NMR".
- Earths_field_NMR wikiPageWikiLinkText "Earth's field nuclear magnetic resonance".
- Earths_field_NMR wikiPageWikiLinkText "Earth's magnetic field".
- Earths_field_NMR wikiPageUsesTemplate Template:About.
- Earths_field_NMR wikiPageUsesTemplate Template:Dead_link.
- Earths_field_NMR wikiPageUsesTemplate Template:Reflist.
- Earths_field_NMR subject Category:Geomagnetism.
- Earths_field_NMR subject Category:Nuclear_magnetic_resonance.
- Earths_field_NMR type Biophysic.
- Earths_field_NMR type Physic.
- Earths_field_NMR comment "Nuclear magnetic resonance (NMR) in the geomagnetic field is conventionally referred to as Earth's field NMR (EFNMR). EFNMR is a special case of low field NMR.When a sample is placed in a constant magnetic field and stimulated (perturbed) by a time-varying (e.g., pulsed or alternating) magnetic field, NMR active nuclei resonate at characteristic frequencies. Examples of such NMR active nuclei are the isotopes carbon-13 and hydrogen-1 (hydrogen-1 often being referred as protons).".
- Earths_field_NMR label "Earth's field NMR".
- Earths_field_NMR sameAs Q5326993.
- Earths_field_NMR sameAs m.02rcc9q.
- Earths_field_NMR sameAs Q5326993.
- Earths_field_NMR wasDerivedFrom Earths_field_NMR?oldid=689648908.
- Earths_field_NMR isPrimaryTopicOf Earths_field_NMR.