We report results of direct measurements of the reduced Stokes parameters P 1 ,P 2 andP 3 for electron impact excitation of H(2p) at 54.4 eV over the scattering range 10-40 •. These three parameters have been measured simultaneously for the first time using a VUV double-rotation polarization analyser consisting of a MgF 2 retarder followed by a SiO 2 reflection linear polarizer. As expected, our measurements forP 1 andP 2 are in good agreement with theoretical calculations and previous experimental data. Our data forP 3 differ significantly from previous experimental measurements and theoretical calculations. Consequently, we find that the coherence parameter P + deviates significantly from unity at 30 •. If correct, this signifies that spin-exchange scattering may be more important than has previously been thought.
Hypomagnesaemic tetany and composition ofbody fluids. Use of vitreous for the postmortem diagnosis of hypomagnesaemia. Annales Universitatis Mariae Curie Sklodowska. Sectio DD, Medicina Veterinaria 51, 179-198 TODD, J. R. (1965) The influences of soil type on the effectiveness of single dressings of magnesia in raising pasture magnesium content and in controlling hypomagnesaemia.
First direct measurements are reported of the linear reduced Stokes parameters P 1 , P 2 for H(2p) excited by electron impact at the benchmark energy of 54.4 eV. The results differ significantly from previous values deduced from angular correlation measurements which are in serious conflict with all sophisticated theoretical approaches. Our results support the trend of theoretical predictions for P 2 and confirm that its value is negative at electron scattering angles above 100 ± , as predicted by theory. [S0031-9007(98)05388-5]
Abstract-A continuous wave near-infrared spectroscopy (NIRS) instrument for brain-computer interface (BCI) applications is presented. In the literature, experiments have been carried out on subjects with such motor degenerative diseases as amyotrophic lateral sclerosis, which have demonstrated the suitability of NIRS to access intentional functional activity, which could be used in a BCI as a communication aid. Specifically, a real-time, multiple channel NIRS tool is needed to realise access to even a few different mental states, for reasonable baud rates. The 12-channel instrument described here has a spatial resolution of 30mm, employing a flexible software demodulation scheme. Temporal resolution of ~100ms is maintained since typical topographic imaging is not needed, since we are only interested in exploiting the vascular response for BCI control. A simple experiment demonstrates the ability of the system to report on haemodynamics during single trial mental arithmetic tasks. Multiple trial averaging is not required.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.