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Mostrando ítems 211-220 de 223
Artículo
Overcoming ICP-QMS instrumental limitations for Tc-99 determination in environmental solid samples using radiochemistry
(PERGAMON-ELSEVIER SCIENCE LTD, 2006)
Besides its capabilities, quadrupole-based ICP-MS counting establishes several limitations on 99Tc analysis in environmental samples. Overcoming these limitations requires the use of radiochemical methods. We have developed ...
Artículo
A comparison between active and passive techniques for measurements of radon emanation factors
(PERGAMON-ELSEVIER SCIENCE LTD, 2009)
Some radon related parameters have been determined through two different techniques (passive and active) in soil and phosphogypsum samples. Emanation factors determined through these techniques show a good agreement for ...
Artículo
Multi-site H-bridge breathers in a DNA–shaped double strand
(IOP Publishing, 2004)
We investigate the formation process of nonlinear vibrational modes representing broad H-bridge multi–site breathers in a DNA–shaped double strand. Within a network model of the double helix we take individual motions ...
Artículo
Thermally induced delamination of amorphous hydrogenated carbon coatings monitored by positron beam analysis
(ScienceDirect, 2004-03)
In this work we have studied the adhesion of PVD amorphous hydrogenated carbon (a-C:H) thin coatings (<200 nm) on crystalline silicon by means of positron beam analysis (PBA). PBA allows the study of the a-C:H layer and ...
Artículo
Development and operational performance of a single calibration chamber for radon detectors
(Elsevier Science BV, 2007)
This work shows the design, setup and performance of a new single radon detector calibration chamber developed at the University of Huelva (Environmental Radioactivity Group). This system is based on a certified radon ...
Artículo
An assay on the effect of preliminary restoration tasks applied to a large TENORM wastes disposal in the south-west of Spain
(Elsevier Science BV, 2006)
A large industrial wastes disposal site, where two phosphate rock processing plants release their wastes, located close to Huelva town (SW of Spain) has been partially submitted to restoration as a preliminary step in a ...
Artículo
Method for the detection of Tc in seaweed samples coupling the use of Re as a chemical tracer and isotope dilution inductively coupled plasma mass spectrometry
(Elsevier Science BV, 2004)
The analysis of artificial radionuclide 99Tc in environmental samples requires of a chemical separation due to its low concentration, and therefore the use of a chemical yield tracer is peremptory. From the practical ...
Artículo
Radioactivity levels in aerosol particles surrounding a large TENORM waste repository after application of preliminary restoration work
(Elsevier Science BV, 2007)
In this paper, 238U-series radionuclides have been analysed in particulate matter samples collected at a phosphogypsum stack system located near the city of Huelva (SW Spain) during the course of 1 year. The results have ...
Artículo
Interfacial effects during the analysis of multilayer metal coatings by radio-frequency glow discharge optical emission spectroscopy. Part 1. Crater shape and sputtering rate effects
(The Royal Society of Chemistry, 2005)
In depth profile analysis by radio-frequency glow discharge optical emission spectroscopy (rf-GDOES) techniques, the depth resolution mainly depends on the roughening induced during the sputtering and the resulting crater ...
Artículo
Separation and measurement of Pa, Th and U isotopes in marine sediments by microwave-assisted digestion and MC ICP-MS
(AMER CHEMICAL SOC, 2009)
This manuscript describes a new protocol for determination of Pa/Th/U in marine sediments. Based on microwave-assisted digestion, it represents an important reduction of working time over conventional hot-plate digestion ...