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G. Nguyen Vien

Publications and source records attributed to G. Nguyen Vien.

3 recordsLinked to original sources

Development of a RFID sensitive tag dedicated to the monitoring of the environmental corrosiveness for indoor applications

The environmental corrosiveness is governed for indoor applications by the presence of gaseous pollutants in air and levels of temperature and relative humidity. Its determination is a challenging task and requires the monitoring of thickness reduction of selected metals in the range of few tens of nanometers. The present work aims at developing an UHF RFID sensor dedicated to such measurements. The sensor is based on the coupling between the antenna of a commercial RFID tag and a thin layer of copper exposed to the environment. The ability of the proposed sensor to be sensitive to a variation of the metal thickness in the range of tens of nanometers is demonstrated experimentally through exposure tests in a climatic chamber. The results are supported by electromagnetic simulations performed in the case of a coupling between a dipolar antenna and a thin metallic layer.

cond-mat.mtrl-sci

Low energy (e,2e) ionization of Argon in the equal energy sharing geometry

Quantum Defect theory is a well established theoretical concept in modern spectroscopy. We show that this approach is useful in electron impact ionization problems where state of the art theoretical methods are presently restricted mostly to simple atomic targets. For the well documented Argon ionization case in equal energy sharing geometry the approach suggested leads to significant improvements compared to previous calculations.

quant-ph

Distorted Waves with Exact Non-Local Exchange: a Canonical Function Approach

It is shown how the Canonical Function approach can be used to obtain accurate solutions for the distorted wave problem taking account of direct static and polarisation potentials and exact non-local exchange. Calculations are made for electrons in the field of atomic hydrogen and the phaseshifts are compared with those obtained using a modified form of the DWPO code of McDowell and collaborators: for small wavenumbers our approach avoids numerical instabilities otherwise present. Comparison is also made with phaseshifts calculated using local equivalent-exchange potentials and it is found that these are inaccurate at small wavenumbers. Extension of our method to the case of atoms having other than s-type outer shells is dicussed.

quant-ph