Atomic electrostatic maps of point defects in MoS2

In this study, we use differential phase contrast images obtained by scanning transmission electron microscopy combined with computer simulations to map the atomic electrostatic fields of MoS2 monolayers and investigate the effect of sulphur monovacancies and divancancies on the atomic electric field and total charge distribution. A significant redistribution of the electric field in the regions containing defects is observed, with a progressive decrease in the strength of the projected electric field for each sulphur atom removed from its position. The electric field strength at the sulphur monovacancy sites is reduced by approximately 50% and nearly vanishes at the divacancy sites, where it drops to around 15% of the original value, demonstrating the tendency of these defects to attract positively charged ions or particles. In addition, the absence of the sulphur atoms leads to an inversion in the polarity of the total charge distribution in these regions.The authors would like to acknowledge that this project has received funding from the EU Framework Program for Research and Innovation H2020, Scheme COFUND-Cofunding of Regional, National and International Programs, under grant agreement no. 713640. This work was supported by FCT, through IDMEC, under LAETA, project no. UIDB/50022/2020. R.M.R. acknowledges the FCT grant UIDB/FIS/04650/2020-2023. D.A. acknowledges the Presidential Early Career Award for Scientists and Engineers (PECASE) through the Army Research Office (W911NF-16-1-0277) and a National Science Foundation grant (ECCS-1809017). R.M.R. acknowledges support by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020

Blood flow and blood pressure detection using RF antennas : first iteration design, fabrication, & measurements

Blood pressure is a critical measurement used to monitor general cardiovascular health and assess the risk of cardiovascular diseases. The traditional and common method of measuring blood pressure requires an inflatable cuff that is bulky, invasive, and not applicable for continuous measurements. The overall objective of this project is to devise a wearable, cuffless, and noninvasive RF antenna to monitor blood pressure continuously. This report discusses the comprehensive methodology developed for fabricating, assembling, and testing the first iteration of antennas and presents a proof of concept for a functional antenna that can detect liquid volume change. The primary antenna design chosen is a planar monopole antenna used to detect breast cancer designed by Bahramiabarghouei et al. The antenna is fabricated using a Silhouette cameo cutter to cut out the design from antenna material consisting of gold or copper on a Kapton polyimide or PET substrate and then assembled onto a Tegaderm film using a stencil technique. Next, various methods of connecting coaxial cables to the antenna are presented, and this work recommends using a pigtail coaxial cable connected to the antenna via a trident structure that is adhered on using conductive silver epoxy. An additional, optional layer of insulating epoxy can also be applied to provide mechanical reinforcement. Furthermore, experiments were performed using a Vector Network Analyzer to measure how the S11 parameter of the antenna responds to changes in the liquid volume. Large and small Ecoflex-based arterial models were constructed using PVC tubes imbued in a petri dish filled with Ecoflex to perform these liquid experiments. This study demonstrates that the chosen, first iteration antenna design can successfully detect volume change of various liquids through a visible S11 amplitude shift and frequency shift.Electrical and Computer Engineerin