We have developed an energy-filtering device coupled to a quadrupole mass spectrometer to deposit ionized molecules on surfaces with controlled energy in ultra high vacuum environment. Extensive numerical simulations as well as direct measurements show that the ion beam flying out of a quadrupole exhibits a high-energy tail decreasing slowly up to several hundred eV. This energy distribution renders impossible any direct soft-landing deposition of molecular ions. To remove this high-energy tail by energy filtering, a 127° electrostatic sector and a specific triplet lenses were designed and added after the last quadrupole of a triple quadrupole mass spectrometer. The results obtained with this energy-filtering device show clearly the elimination of the high-energy tail. The ion beam that impinges on the sample surface satisfies now the soft-landing criterion for molecular ions, opening new research opportunities in the numerous scientific domains involving charges adsorbed on insulating surfaces.
The challenges of constructing a noninvasive screening system for electrocardiodiagnostics, focused on visualization of electric potential maps on the surface of the epicardium, is addressed. A functional diagram of a module for recording multiple-lead electrocardiosignals is proposed, the essential component of which is a vest (in several standard sizes) worn by the subject and carrying pre-installed electrodes. Results obtained from experimental verification of the operation of the recording module are presented. The issues of computer processing of electrocardiosignals were addressed and led to the ability to obtain 2D maps of the electric potential on a spherical quasi-epicardium, these 2D maps changing synchronously with changes in the position of the time marker on electrocardiograms familiar to cardiologists.
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