Cellular Based Small Unmanned Aircraft Systems (sUAS) MIMO Communications

The use of remotely piloted unmanned aircraft systems/vehicles (UAS/UAV or drones) increases dramatically in recent years. This paper discusses the use of multiple-input and multiple-output (MIMO) technologies in cellular (i.e., LTE) based small UAS (sUAS) communications. More specifically, we will first provide background information about this work, followed by a review of state-of-the-art. Then, we will discuss the benefits of MIMO technologies and propose practical MIMO configurations (e.g., the type, size and number of antennas) that are suitable for NASA's sUAS research and operations. Finally, the design tradeoff among multiplexing, diversity, and interference/jamming cancellation will also be discussed

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Water-Soluble pillararene-functionalized graphene oxide for in vitro raman and fluorescence dual-mode imaging

This study provides a successful preparation of biocompatible hybrid materials (1-GO and 2-GO) by the integration of graphene oxide (GO) with water-soluble pillararenes (bolaamphiphile 1 and tadpolelike amphiphile 2) for dual-mode Raman and fluorescence bioimaging in vitro. The investigations show that pillararenes 1 and 2 were loaded onto the surface of GO through strong hydrogen-bonding interactions. Aqueous suspensions of 1-GO and 2-GO are stable and can be kept for a long time. After confirming their good biocompatibility by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the 1-GO and 2-GO hybrids were endocytosed by HeLa cells for in vitro Raman imaging. It was found that 1-GO presents better Raman imaging than 2-GO. When a fluorescent guest molecule, bipyridinium derivative 3, was added into the suspensions of the hybrids, the suspensions of 1-GO and 2-GO were as stable as the original. The suspensions of the inclusion complexes (1-GO[DOT OPERATOR]3 and 2-GO[DOT OPERATOR]3) formed from 1-GO and 2-GO with 3 can also be endocytosed by HeLa cells to enable in vitro fluorescence imaging to be performed. It was found that 1-GO[DOT OPERATOR]3 performs better than 2-GO[DOT OPERATOR]3. The current research has determined the capacities of pillararene-modified GO for combined bioimaging, which paves the way for using these biocompatible materials towards dual-mode diagnostics