نتایج جستجو برای: radiocarbon dating

تعداد نتایج: 18604  

2011
Mario Bkassiny Yang Li Georges El-Howayek Sudharman K. Jayaweera Christos G. Christodoulou

In this paper, we review some of the recent patents on spectrum sensing techniques for cognitive radio (CR) applications. The presented patents are categorized under: 1) spectrum sensing algorithms and architectures, 2) spectrum sensing and data communication and 3) cooperative spectrum sensing. The presented patents include special sensing algorithms that are based on the multi-resolution spec...

2007
Davis A. Young

W ithin a decade of the discovery of radioactivity in 1896, the chemical elements uranium, radium, polonium, and thorium were recognized as radioactive; the basic theory, mechanisms, and mathematics of radioactive decay were established; decay rates of some radioactive chemical elements were determined; and the ages of two mineral specimens were calculated for the first time from their uranium ...

Journal: :Physical review letters 2011
I Galli S Bartalini S Borri P Cancio D Mazzotti P De Natale G Giusfredi

Radiocarbon ((14)C) concentrations at a 43 parts-per-quadrillion level are measured by using saturated-absorption cavity ringdown spectroscopy by exciting radiocarbon-dioxide ((14)C(16)O(2)) molecules at the 4.5 μm wavelength. The ultimate sensitivity limits of molecular trace gas sensing are pushed down to attobar pressures using a comb-assisted absorption spectroscopy setup. Such a result rep...

Journal: :Open Journal of Archaeometry 2014

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