The syntheses and structural characterizations of the first XeF coordination complexes of the [BrO] cation are described. The reactions of [BrO][PnF] (Pn = As, Sb) with XeF in anhydrous HF solvent yield the salts [OBr(FXeF)][AsF] ( = 1, 2) and [OBr(FXeF)][SbF], which were characterized by low-temperature (LT) Raman spectroscopy and single-crystal X-ray diffraction (SCXRD). The XeF ligands and [PnF] coordinate to the Lewis acidic [BrO] cation through primarily electrostatic Br---F σ-hole bonds that result from coordination of the F atoms into regions of high positive electrostatic potential on the Br(V) atom and have bond trajectories that avoid the stereoactive valence electron lone-pair of Br(V).
View Article and Find Full Text PDFThe use of global navigation satellite systems (GNSS) precise point positioning (PPP) to estimate zenith tropospheric delay (ZTD) profiles in kinematic vehicular mode in mountainous areas is investigated. Car-mounted multi-constellation GNSS receivers are employed. The Natural Resources Canada Canadian Spatial Reference System PPP (CSRS-PPP) online service that currently processes dual-frequency global positioning system (GPS) and Global'naya Navigatsionnaya Sputnikovaya Sistema (GLONASS) measurements and is now capable of GPS integer ambiguity resolution is used.
View Article and Find Full Text PDFA newly available portable unit with GNSS raw data recording capability is assessed to determine static and kinematic position accuracy in various environments. This unit is the GPSMap 66, introduced by Garmin in early September. It is all-weather and robust for field use, and comes with a helix antenna.
View Article and Find Full Text PDFIn the mining industry, personal measurements of elemental and total carbon are frequently used as surrogates of diesel particulate matter (DPM) exposure, and the respirable or submicron fractions are usually measured. However, vapor-phase organic carbon (OC) can be adsorbed in the filters, interfering with total carbon results. This study presents a comparative evaluation between the submicron fraction of DPM concentrations corrected for the adsorption of the vapor-phase OC (dynamic blank), and the respirable fraction of DPM corrected for a field blank.
View Article and Find Full Text PDFVarious measurement monitoring techniques are investigated to mitigate the effect of global navigation satellite systems (GNSS) code multipath through error correction, stochastic weighting of measurements and detection and exclusion (or de-weighting) of affected measurements. Following a comprehensive review of each approach, the paper focuses on detection/exclusion and detection/de-weighting techniques where several single and dual-frequency monitoring metrics are employed in a combination with time-averaging and the detection strategy. A new Geometry-Free (GF) detection metric is proposed given its capability to be combined with a preceding Code-Minus-Carrier (CMC)-based error correction to reduce the number of excluded or de-weighted measurements and thus preserve the measurement geometry.
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