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Potassium-argon and argon-argon dating
1997Potassium (Latin kalium from the Arabic gali meaning alkali) is an element with relative atomic mass of 39.0983 and atomic number 19. A silvery white and soft, very reactive alkali metal, it resembles Na. Its relative density is 0.86, its melting point is 63.5°C and its boiling point is 770°C.
H.-G. Attendorn, R. N. C. Bowen
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Wirkungsquerschnitt von Argon gegen Argon+
Zeitschrift f�r Physik, 1931Es wird eine Methode angegeben zur Messung des gegenseitigen Wirkungsquerschnitts von Gasionen und neutralen Gasmolekulen mit Besprechung apparativer und mestechnischer Einzelheiten. Die mit der Anordnung erhaltene Wirkungsquerschnittskurve fur Argongas gegenuber Argon+-Ionen verlauft bis etwa 520 Volt Geschwindigkeit nahezu horizontal und steigt bei ...
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Potassium-Argon/Argon-Argon Dating Methods
1997During the latter half of this century anthropological surveys in East Africa have made significant contributions to understanding how the human species has evolved. In the past two decades, particularly, discoveries of our fossil ancestors have been made in unprecedented numbers and diversity.
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Potassium-Argon and Argon-40/Argon-39 Dating
1994Potassium is an alkali metal of Group IA in which its companions are lithium, sodium, rubidium and caesium. It is highly reactive with a relative density of 0·86 and a melting point of 62·3° C, an atomic weight of 39·0983 and an atomic number of 19; it has 18 isotopes.
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2018
Argon–argon dating is a radioisotopic method based on the natural, spontaneous radioactive decay of an isotope of potassium, 40K, at a known rate to produce an isotope of argon, 40Ar. This method is one of the most versatile, precise and accurate of all radioisotopic dating tools applied to volcanic materials.
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Argon–argon dating is a radioisotopic method based on the natural, spontaneous radioactive decay of an isotope of potassium, 40K, at a known rate to produce an isotope of argon, 40Ar. This method is one of the most versatile, precise and accurate of all radioisotopic dating tools applied to volcanic materials.
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Physical Review Letters, 1996
The total cross section ${\ensuremath{\sigma}}_{T}$ for orthopositronium (o-Ps) scattering from argon gas has been measured directly for the first time using a variable energy o-Ps beam in the range 16--95 eV. The cross section is found to rise from a value of approximately $9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}20}$ to $15\ifmmode ...
, Zafar +3 more
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The total cross section ${\ensuremath{\sigma}}_{T}$ for orthopositronium (o-Ps) scattering from argon gas has been measured directly for the first time using a variable energy o-Ps beam in the range 16--95 eV. The cross section is found to rise from a value of approximately $9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}20}$ to $15\ifmmode ...
, Zafar +3 more
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American Journal of Ophthalmology, 1976
Argon laser photomydriasis was used to enlarge 20 miotic pupils in 18 open-angle glaucoma patients, with beneficial visual results in patients properly selected before treatment. During eight months of observation, significant complications such as persistent iritis and lens changes did not occur.
W A, James +3 more
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Argon laser photomydriasis was used to enlarge 20 miotic pupils in 18 open-angle glaucoma patients, with beneficial visual results in patients properly selected before treatment. During eight months of observation, significant complications such as persistent iritis and lens changes did not occur.
W A, James +3 more
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